Materiały źródłowe

• #1 About Histoplasmosis | Histoplasmosis | CDC

  https://www.cdc.gov/histoplasmosis/about/index.html

  Histoplasmosis is a lung infection caused by breathing in fungal spores from Histoplasma, a fungus that lives in soil. It also spreads in bird and bat droppings that mix in soil. […] Histoplasmosis does not spread between people or between people and pets (cats and dogs).

• #2 Histoplasmosis: Cause, Types & Complications

  https://www.healthline.com/health/histoplasmosis

  Histoplasmosis is a type of lung infection. It is caused by inhaling Histoplasma capsulatum fungal spores. These spores are found in soil and in the droppings of bats and birds. […] Fungal spores can be released into the air when contaminated soil or droppings are disturbed. Breathing the spores may lead to an infection. […] The spores that cause this condition are commonly found in places where birds and bats have roosted, such as caves, chicken coops, parks, and older barns. […] The fungus doesn’t spread from one person to another and it’s not contagious.

• #3 Histoplasmosis

  https://dph.illinois.gov/topics-services/diseases-and-conditions/diseases-a-z-list/diseases/histoplasmosis.html

  Histoplasmosis is an infection caused by a fungus, Histoplasma capsulatum. The principal habitat for this fungus is soil enriched by the buildup of bird or bat droppings, and in fresh bat droppings. […] In some areas where the fungus is common, 80 percent or more of the population has been exposed to the fungus by breathing in airborne spores. […] Elevated risk of exposure to the histoplasmosis fungus include: workers who perform demolition or renovation work in buildings where bat or bird droppings have accumulated, gardeners who use bird or bat droppings as fertilizer, excavation workers who uproot trees that have been used for bird or bat roosting, persons cleaning fireplaces below chimneys in which bats or birds have roosted. […] The fungus is found throughout the world and grows in soil that has been enriched with bat or bird droppings or in bat droppings themselves. […] The disease is not spread from person to person. It is not acquired from animals that have the disease. […] You should always take steps to limit exposure to the histoplasmosis fungus, even if you have had histoplasmosis in the past.

• #4 Histoplasmosis – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK448185/

  Histoplasma capsulatum is a dimorphic fungus present worldwide in pockets of endemicity particularly associated with river valleys. The endemic regions in the United States are Ohio and Mississippi river valleys as well as southeastern states. It is a soil-based fungus, and when it is disturbed, the conidia become airborne and can be inhaled. Often the infections are asymptomatic, but a granulomatous inflammation results in pulmonary disease akin to pulmonary tuberculosis. In immunocompromised patients, histoplasmosis can become disseminated and lead to considerable morbidity and mortality. […] […] In 1905, a pathologist, Samuel Darling, named H. capsulatum; so it also is known as Darling disease. Twenty years later Histoplasma yeast was isolated, and its dimorphic nature determined. At body temperature, H. capsulatum was yeast, but at ambient temperatures (25 C) it exists as a mold. H. capsulatum likes moist soil, particularly with decaying guano. Bats carry the fungus in their gastrointestinal tract, and birds carry H. capsulatum on their feathers. Birds are not affected by H. capsulatum due to their high body temperatures (40 C). Outbreaks have occurred where there was intense construction activity in endemic regions. […]

• #5 Histoplasmosis

  https://www.michigan.gov/mdhhs/safety-injury-prev/environmental-health/topics/mitracking/histoplasmosis

  Histoplasmosis is a fungal disease. The organism Histoplasma causes histoplasmosis. The fungal disease happens when a person breathes in fungal spores from infected soil or other decomposing matter that is disturbed (digging in dirt, raking leaves, etc.). Infected soil often contains bird or bat droppings. Histoplasma is found in some central and eastern states including Michigan. […] Histoplasma is a dimorphic fungus, which means it exists in two different forms, mold and yeast, based on temperature. It grows as a mold at outside air temperatures. The mold develops spores called conidia. Disturbing contaminated soil can lead to breathing in fungal spores. The spores then transform into a yeast at higher temperatures found inside the human body. The yeast can stay in the lungs or spread through the bloodstream to other parts of the body.

• #6 Histoplasmosis – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK448185/

  Histoplasma capsulatum is a dimorphic fungus present worldwide in pockets of endemicity particularly associated with river valleys. The endemic regions in the United States are Ohio and Mississippi river valleys as well as southeastern states. It is a soil-based fungus, and when it is disturbed, the conidia become airborne and can be inhaled. Often the infections are asymptomatic, but a granulomatous inflammation results in pulmonary disease akin to pulmonary tuberculosis. In immunocompromised patients, histoplasmosis can become disseminated and lead to considerable morbidity and mortality. […] […] In 1905, a pathologist, Samuel Darling, named H. capsulatum; so it also is known as Darling disease. Twenty years later Histoplasma yeast was isolated, and its dimorphic nature determined. At body temperature, H. capsulatum was yeast, but at ambient temperatures (25 C) it exists as a mold. H. capsulatum likes moist soil, particularly with decaying guano. Bats carry the fungus in their gastrointestinal tract, and birds carry H. capsulatum on their feathers. Birds are not affected by H. capsulatum due to their high body temperatures (40 C). Outbreaks have occurred where there was intense construction activity in endemic regions. […]

• #7 Histoplasmosis – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK448185/

  H. capsulatum is a member of the family ascomycetes and exists as two mating types. While in nature the mating types + and – exist in 1:1 ratio, most patient isolates are mating type -. This reasons for increased representation of (-) mating types in clinical specimens is unknown. Microscopic evaluation of the mycelial phase reveals two types of conidia. Macroconidia are 8 micrometers to 15 micrometers in diameter while microconidia are 2 micrometers to 5 micrometers. Microconidia are believed to be the infective particles and are small enough to be lodged in the alveoli when inhaled. […] […] H. capsulatum has five to seven chromosomes. Recently, molecular techniques have identified eight clades of H. capsulatum, which are distributed in different parts of the world. There are two North American clades, two South American clades, one Australian, one Indonesian, one African, and one Eurasian clade. The genetic differences have clinical implications as North American clades do not cause primary skin disease while South American clades do. The African clade includes all of H. capsulatum variety duboisii. […]

• #8 Histoplasmosis – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK448185/

  H. capsulatum is a member of the family ascomycetes and exists as two mating types. While in nature the mating types + and – exist in 1:1 ratio, most patient isolates are mating type -. This reasons for increased representation of (-) mating types in clinical specimens is unknown. Microscopic evaluation of the mycelial phase reveals two types of conidia. Macroconidia are 8 micrometers to 15 micrometers in diameter while microconidia are 2 micrometers to 5 micrometers. Microconidia are believed to be the infective particles and are small enough to be lodged in the alveoli when inhaled. […] […] H. capsulatum has five to seven chromosomes. Recently, molecular techniques have identified eight clades of H. capsulatum, which are distributed in different parts of the world. There are two North American clades, two South American clades, one Australian, one Indonesian, one African, and one Eurasian clade. The genetic differences have clinical implications as North American clades do not cause primary skin disease while South American clades do. The African clade includes all of H. capsulatum variety duboisii. […]

• #9 What is Histoplasmosis?
  — Wildlife Control Services LLC

  https://wildlifecontrolservicesct.com/histoplasmosis

  Histoplasmosis is an infectious disease of the lungs caused by a fungus called Histoplasma capsulatum. The infection sometimes can spread to other parts of the body. […] This Histoplasma organism thrives in moderate temperatures and moist environments. Droppings from chickens, pigeons, starlings, blackbirds, and bats support its growth. […] Bats can be infected because they have a lower body temperature than birds and can excrete the organism in their droppings. […] To multiply, Histoplasma capsulatum produces small spores called conidia. The conidia of Histoplasma capsulatum are only two millionths of a meter (microns, m) in diameter. When these conidia are inhaled, they are small enough that they enter the lungs and start an infection. […] However, histoplasmosis can be severe and produce an illness similar to tuberculosis.

• #10 Histoplasmosis: MedlinePlus

  https://medlineplus.gov/histoplasmosis.html

  Histoplasmosis is an infection caused by a fungus called Histoplasma. This fungus is common in the central and eastern United States, especially around the Ohio and Mississippi River valleys. It can also be found in parts of Central and South America, Africa, Asia, and Australia. It lives in the environment, especially in soil that contains large amounts of bat or bird droppings (poop). […] You get histoplasmosis by breathing in Histoplasma fungal spores from the air. It usually happens after you have been doing an activity that disturbs the soil, such as farming, construction, and landscaping. Histoplasmosis is not contagious. This means that you cannot get the infection from another person or an animal. […] Severe histoplasmosis can develop into a long-term lung infection. It can also spread from the lungs to other parts of the body, such as the central nervous system (the brain and spinal cord). This is known as disseminated histoplasmosis.

• #11 Histoplasmosis Information | Mount Sinai – New York

  https://www.mountsinai.org/health-library/diseases-conditions/histoplasmosis

  Histoplasmosis is an infection that occurs from breathing in the spores of the fungus Histoplasma capsulatum. […] Histoplasmosis occurs throughout the world. In the United States, it is most common in the southeastern, mid-Atlantic, and central states, especially in the Mississippi and Ohio River valleys. […] Histoplasma fungus grows as a mold in the soil. You may get sick when you breathe in spores produced by the fungus. Soil that contains bird or bat droppings may have larger amounts of this fungus. The threat is greatest after an old building is torn down, or in caves. […] This infection can occur in people with a healthy immune system. Having a weakened immune system increases the risk of getting or reactivating this disease. Very young or very old people, or those with HIV/AIDS, cancer, or an organ transplant have more severe symptoms. […] People with long-term (chronic) lung disease (such as emphysema and bronchiectasis) are also at higher risk for a more severe infection.

• #12 Histoplasmosis: Symptoms, Causes, and Treatment

  https://www.verywellhealth.com/histoplasmosis-7111772

  Histoplasmosis is a fungal infection, usually of the lungs. It is caused by breathing in fungal spores from bird or bat feces in the soil. […] Histoplasmosis is caused by an infection of the fungus Histoplasma capsulatum. […] Bats and birds spread Histoplasma capsulatum in their droppings. Outbreaks can occur when people are exposed to large amounts of disturbed bird or bat droppings and they breathe in fungal spores from the air. […] Activities that can lead to histoplasmosis include digging in soil or chopping wood around bird or bat droppings, cleaning chicken coops, exploring caves, and cleaning, remodeling, or tearing down old buildings. […] Histoplasma can be found in soil in the central and eastern United States. Its common in areas around the Ohio and Mississippi River valleys. The fungus also lives in Central America, South America, Africa, Asia, and Australia.

• #13 Histoplasmosis – Symptoms & causes – Mayo Clinic

  https://www.mayoclinic.org/diseases-conditions/histoplasmosis/symptoms-causes/syc-20373495

  Histoplasmosis is an infection caused by breathing in spores of a fungus often found in bird and bat droppings. […] Histoplasmosis is caused by the reproductive cells (spores) of the fungus Histoplasma capsulatum. They float into the air when dirt or other material is disturbed. […] The fungus thrives in damp soil that’s rich in organic material, especially the droppings from birds and bats. It’s particularly common in chicken and pigeon coops, old barns, caves, and parks.

• #14 Histoplasmosis: Causes, Symptoms, Diagnosis & Treatment

  https://my.clevelandclinic.org/health/diseases/24811-histoplasmosis

  Histoplasmosis is an infection caused by the fungus Histoplasma capsulatum. […] The fungus that causes histoplasmosis is more likely to be found in soil where theres bird or bat poop. […] The fungus Histoplasma capsulatum causes histoplasmosis. You get it from breathing in the mold from the soil. It grows best in soil that has bat or bird poop in it. […] Most people breathe in H. capsulatum without getting sick. But some people, especially those who are exposed to a lot of fungi or who have certain health conditions, can get noticeable symptoms.

• #15 Histoplasmosis – acute (primary) pulmonary: MedlinePlus Medical EncyclopediaLock

  https://medlineplus.gov/ency/article/000098.htm

  Acute pulmonary histoplasmosis is a respiratory infection that is caused by inhaling the spores of the fungus Histoplasma capsulatum. […] Histoplasma capsulatum is the name of the fungus that causes histoplasmosis. It is found in the central and eastern United States, eastern Canada, Mexico, Central America, South America, Africa, and Southeast Asia. It is commonly found in the soil in river valleys. It gets into the soil mostly from bird and bat droppings. […] You can get sick when you breathe in spores that the fungus produces. Every year, thousands of people with a normal immune system worldwide are infected, but most do not become seriously sick. Most have no symptoms or have only a mild flu-like illness and recover without any treatment. […] Risk factors include traveling to or living in the central or eastern United States near the Ohio and Mississippi river valleys and being exposed to the droppings of birds and bats. This threat is greatest after an old building is torn down and spores get into the air, or when exploring caves.

• #16 Histoplasmosis

  https://dph.illinois.gov/topics-services/diseases-and-conditions/diseases-a-z-list/diseases/histoplasmosis.html

  Histoplasmosis is an infection caused by a fungus, Histoplasma capsulatum. The principal habitat for this fungus is soil enriched by the buildup of bird or bat droppings, and in fresh bat droppings. […] In some areas where the fungus is common, 80 percent or more of the population has been exposed to the fungus by breathing in airborne spores. […] Elevated risk of exposure to the histoplasmosis fungus include: workers who perform demolition or renovation work in buildings where bat or bird droppings have accumulated, gardeners who use bird or bat droppings as fertilizer, excavation workers who uproot trees that have been used for bird or bat roosting, persons cleaning fireplaces below chimneys in which bats or birds have roosted. […] The fungus is found throughout the world and grows in soil that has been enriched with bat or bird droppings or in bat droppings themselves. […] The disease is not spread from person to person. It is not acquired from animals that have the disease. […] You should always take steps to limit exposure to the histoplasmosis fungus, even if you have had histoplasmosis in the past.

• #17 Pulmonary Histoplasmosis: A Clinical Update

  https://www.mdpi.com/2309-608X/9/2/236

  Histoplasma capsulatum, the etiological agent for histoplasmosis, is a dimorphic fungus that grows as a mold in the environment and as a yeast in human tissues. […] Human histoplasmosis is caused by two distinct organisms: Histoplasma capsulatum var. capsulatum and Histoplasma capsulatum var. duboisii. […] In North America, the highest endemicity areas include the valleys of the Mississippi and Ohio Rivers in the central and eastern United States. […] In these areas, the incidence is estimated to be 6.1 cases per 100,000, and 80–90% of the population will be exposed to histoplasmosis during their lifetime. […] In recent decades, environmental disruptions, climate change, increased travel and connectivity, and increased immunosuppressive conditions have led to changes in the epidemiology of histoplasmosis.

• #18 How People Get Histoplasmosis | Histoplasmosis | CDC

  https://www.cdc.gov/histoplasmosis/causes/index.html

  Histoplasmosis is a lung infection caused by breathing in spores from the fungus, Histoplasma. […] People can get histoplasmosis by breathing in spores from the fungus, Histoplasma. The fungus is typically found in soil and bird or bat droppings in certain areas of the United States and the world. […] After the spores enter the lungs, the person’s body temperature allows the spores to transform into yeast. […] Outbreaks of histoplasmosis are not common. Of the few that have been reported, most occurred after events that disturb soil contaminated with bird or bat droppings. […] Investigating histoplasmosis outbreaks helps public health officials understand where the fungus lives.

• #19

  https://www.ccohs.ca/oshanswers/diseases/histopla.html

  Histoplasmosis is an infectious disease caused by a fungus called Histoplasma capsulatum. […] The Histoplasma organism thrives in moderate temperatures, rich soil, and moist environments. […] To multiply, Histoplasma capsulatum produces small spores called conidia. […] When a person breathes in the conidia (spores) of Histoplasma capsulatum, the lungs’ defence mechanisms attempt to neutralize them. […] The symptoms of the infection appear within 5 to 18 days after exposure, most commonly in 10 days. […] Confirmation of a histoplasmosis diagnosis often requires laboratory examinations which identify Histoplasma capsulatum in sputum or lung biopsy. […] Most patients who develop histoplasmosis do not require treatment. […] Persons whose occupations involve contact with the soil, in particular soil enriched with bird and bat droppings, are at high risk of acquiring infection.

• #20 Histoplasmosis: Causes, risk factors, and treatment

  https://www.medicalnewstoday.com/articles/318078

  Histoplasmosis is a fungal infection that can cause no symptoms or may cause symptoms similar to those of pneumonia. But what causes it and how is it treated? […] The Histoplasma capsulatum fungus is responsible for the histoplasmosis infection. […] People experience histoplasmosis when they breathe in fungal spores. […] Exposure to bird and bat droppings brings a particular risk for breathing in the histoplasmosis spores. […] Some of the activities and areas that are linked with histoplasmosis infection include: caving, such as spelunking; cutting and transporting wood from decaying wood piles or dead trees; engaging in demolishing, remodeling, or working in old buildings; working in chicken coops, especially when dealing with bird droppings. […] There are additional groups, as well, who tend to be more vulnerable to the effects of histoplasmosis and experience a more severe infection. They include people with: cancer, HIV, long-term corticosteroid use, prednisone, a history of lung diseases, such as emphysema, a history of organ transplant, the very old or very young.

• #21 Histoplasmosis

  https://dph.illinois.gov/topics-services/diseases-and-conditions/diseases-a-z-list/diseases/histoplasmosis.html

  Histoplasmosis is an infection caused by a fungus, Histoplasma capsulatum. The principal habitat for this fungus is soil enriched by the buildup of bird or bat droppings, and in fresh bat droppings. […] In some areas where the fungus is common, 80 percent or more of the population has been exposed to the fungus by breathing in airborne spores. […] Elevated risk of exposure to the histoplasmosis fungus include: workers who perform demolition or renovation work in buildings where bat or bird droppings have accumulated, gardeners who use bird or bat droppings as fertilizer, excavation workers who uproot trees that have been used for bird or bat roosting, persons cleaning fireplaces below chimneys in which bats or birds have roosted. […] The fungus is found throughout the world and grows in soil that has been enriched with bat or bird droppings or in bat droppings themselves. […] The disease is not spread from person to person. It is not acquired from animals that have the disease. […] You should always take steps to limit exposure to the histoplasmosis fungus, even if you have had histoplasmosis in the past.

• #22 Histoplasmosis – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK448185/

  Once microconidia are lodged in the alveoli, these particles undergo a transformation in response to body temperature resulting in unicellular yeast forms typically 2 micrometers to 5 micrometers in diameter. Genes essential for transition and growth of yeast cells have been identified and are Ryp1, Ryp2, and Ryp. Conidia within the alveoli bind to the CD11-CD18 family of integrins and are engulfed by neutrophils and macrophages. It is, therefore, possible that the phase transformation from conidia to yeast is intracellular. The duration of the phase transition ranges from hours to days. The yeast phase is responsible for the infectivity of the fungus. This yeast reproduces by narrow-based and sometimes multipolar budding.

• #23 Histoplasmosis of the nervous system | MedLink Neurology

  https://www.medlink.com/articles/histoplasmosis-of-the-nervous-system

  Histoplasma capsulatum is a dimorphic fungus with 2 variants, Histoplasma capsulatum variety capsulatum, which is encountered chiefly in America and the tropics, and histoplasma capsulatum variety duboisii, which occurs in Africa. H. capsulatum typically results in pulmonary infections, whereas H. duboisii affects the skin and skeleton. […] The organism grows as a mold in the soil, and consists of hyphen-bearing large tuberculate macroconidia (8 to 14 um in diameter) and smaller microconidia (2 to 5 um). The latter is the infectious form of the fungus. Conidia inhaled into the lungs germinate into yeast-like forms and incite an immune reaction. The extent of disease depends on the number of conidia inhaled and the hosts cellular immune response. In patients with adequate immunity, T-lymphocytes activate against the H. capsulatum antigen and stimulate macrophages to kill the engulfed yeast. T cells are pivotal in clearance of the infection. A direct correlation exists between the CD4+ T cell count and the capacity of macrophages to bind yeast cells. As a result, patients with HIV or AIDS are more susceptible to disseminated disease. Involvement of the central nervous system arises following dissemination from a pulmonary source.

• #24 Pulmonary Histoplasmosis: A Clinical Update

  https://www.mdpi.com/2309-608X/9/2/236

  The heat shock protein 60 (Hsp60) of H. capsulatum is the major surface adhesin to macrophages and binds to complement receptor 3 (CR3). […] Once inside the macrophage, Histoplasma evades reactive oxygen and nitrogen species and is also able to regulate the phagosome acidification and the phagolysosomal fusion. […] The diagnosis of histoplasmosis can be ascertained by the direct observation or isolation of the pathogen (culture, histopathology, and cytopathology) or by the detection of antigens, antibodies, or nucleic acids. […] Isolation of H. capsulatum from clinical specimens remains the gold standard for the diagnosis of histoplasmosis, though histopathologic or direct microscopic identification are also considered definitive diagnoses. […] Histopathology can show characteristic features including granulomas (both caseating or non-caseating), and staining with Grocott-Gomori’s methenamine silver or Wright’s periodic acid-Schiff allows for the visualization of ovoid, narrow-based budding yeasts.

• #25 Sources of Histoplasmosis | Types of Diseases | Histoplasmosis | Fungal Disease | CDC

  http://med.iiab.me/modules/en-cdc/www.cdc.gov/fungal/diseases/histoplasmosis/causes.html

  Histoplasma, the fungus that causes histoplasmosis, lives throughout the world, but its most common in North America and Central America. […] Histoplasma grows best in soil that contains bird or bat droppings. Bats can get histoplasmosis and spread the fungus in their droppings. […] When people breathe in the spores, they are at risk for developing histoplasmosis. After the spores enter the lungs, the persons body temperature allows the spores to transform into yeast. The yeast can then travel to lymph nodes and can spread to other parts of the body through the bloodstream.

• #26 Histoplasmosis: Treatment, Contagious, Symptoms & Test

  https://www.emedicinehealth.com/histoplasmosis/article_em.htm

  Histoplasmosis is an infection caused by a dimorphic fungus, Histoplasma capsulatum. […] Risk factors for histoplasmosis include immunocompromised people and association with airborne particles containing the fungi (caves containing bats, bird feces, construction sites). […] Histoplasmosis is caused by a dimorphic (two forms) fungus named Histoplasma capsulatum. The dimorphic fungus has a branching (mycelial) phase consisting of branches and spores that can be inhaled while they are airborne and may reach the lung alveoli. […] The larger the number of mycelia and spores the person is exposed to, the more likely the person will develop symptomatic disease. […] Severe histoplasmosis occurs when the yeast forms are spread by the blood and lymphatic systems to other organs. […] Immunosuppressed patients (for example, cancer or AIDS patients) are at the highest risk for severe histoplasmosis.

• #27 Pulmonary Histoplasmosis: A Clinical Update

  https://www.mdpi.com/2309-608X/9/2/236

  The heat shock protein 60 (Hsp60) of H. capsulatum is the major surface adhesin to macrophages and binds to complement receptor 3 (CR3). […] Once inside the macrophage, Histoplasma evades reactive oxygen and nitrogen species and is also able to regulate the phagosome acidification and the phagolysosomal fusion. […] The diagnosis of histoplasmosis can be ascertained by the direct observation or isolation of the pathogen (culture, histopathology, and cytopathology) or by the detection of antigens, antibodies, or nucleic acids. […] Isolation of H. capsulatum from clinical specimens remains the gold standard for the diagnosis of histoplasmosis, though histopathologic or direct microscopic identification are also considered definitive diagnoses. […] Histopathology can show characteristic features including granulomas (both caseating or non-caseating), and staining with Grocott-Gomori’s methenamine silver or Wright’s periodic acid-Schiff allows for the visualization of ovoid, narrow-based budding yeasts.

• #28 Histoplasmosis: Practice Essentials, Pathophysiology, Etiology

  https://emedicine.medscape.com/article/299054-overview

  Histoplasma capsulatum is a dimorphic fungus that remains in a mycelial form at ambient temperatures and grows as yeast at body temperature in mammals. Infection causes histoplasmosis. Although the fungus that causes histoplasmosis can be found in temperate climates throughout the world, it is endemic to the Ohio, Missouri, and Mississippi River valleys in the United States. […] The risk of infection is mostly related to environmental exposure and underlying immune status. Living in endemic areas with contaminated soil increases the risk of exposure. Inoculum size plays a role. Individuals who are immunocompetent and exposed to a low inoculum of histoplasmosis usually are asymptomatic. Inhalation of a large inoculum can cause diffuse pulmonary symptoms that may have a protracted course. […] Immune status and comorbid factors affect causation. Reactivation, reinfection, or complications of infection usually occur in individuals who are immunocompromised or immunosuppressed. Cases of histoplasmosis have been reported in patients receiving infliximab. A high index of suspicion should be present in patients on tumor necrosis factor-alpha inhibitors. […] Chronic pulmonary histoplasmosis is more prevalent in patients with underlying emphysema. The risk factors include AIDS, primary immunodeficiencies, drug-induced immunosuppressive states, and the extremes of age.

• #29 Histoplasmosis: Causes, risk factors, and treatment

  https://www.medicalnewstoday.com/articles/318078

  Histoplasmosis is a fungal infection that can cause no symptoms or may cause symptoms similar to those of pneumonia. But what causes it and how is it treated? […] The Histoplasma capsulatum fungus is responsible for the histoplasmosis infection. […] People experience histoplasmosis when they breathe in fungal spores. […] Exposure to bird and bat droppings brings a particular risk for breathing in the histoplasmosis spores. […] Some of the activities and areas that are linked with histoplasmosis infection include: caving, such as spelunking; cutting and transporting wood from decaying wood piles or dead trees; engaging in demolishing, remodeling, or working in old buildings; working in chicken coops, especially when dealing with bird droppings. […] There are additional groups, as well, who tend to be more vulnerable to the effects of histoplasmosis and experience a more severe infection. They include people with: cancer, HIV, long-term corticosteroid use, prednisone, a history of lung diseases, such as emphysema, a history of organ transplant, the very old or very young.

• #30 Histoplasmosis: Practice Essentials, Pathophysiology, Etiology

  https://emedicine.medscape.com/article/299054-overview

  Histoplasma capsulatum is a dimorphic fungus that remains in a mycelial form at ambient temperatures and grows as yeast at body temperature in mammals. Infection causes histoplasmosis. Although the fungus that causes histoplasmosis can be found in temperate climates throughout the world, it is endemic to the Ohio, Missouri, and Mississippi River valleys in the United States. […] The risk of infection is mostly related to environmental exposure and underlying immune status. Living in endemic areas with contaminated soil increases the risk of exposure. Inoculum size plays a role. Individuals who are immunocompetent and exposed to a low inoculum of histoplasmosis usually are asymptomatic. Inhalation of a large inoculum can cause diffuse pulmonary symptoms that may have a protracted course. […] Immune status and comorbid factors affect causation. Reactivation, reinfection, or complications of infection usually occur in individuals who are immunocompromised or immunosuppressed. Cases of histoplasmosis have been reported in patients receiving infliximab. A high index of suspicion should be present in patients on tumor necrosis factor-alpha inhibitors. […] Chronic pulmonary histoplasmosis is more prevalent in patients with underlying emphysema. The risk factors include AIDS, primary immunodeficiencies, drug-induced immunosuppressive states, and the extremes of age.

• #31 Histoplasmosis Information | Mount Sinai – New York

  https://www.mountsinai.org/health-library/diseases-conditions/histoplasmosis

  Histoplasmosis is an infection that occurs from breathing in the spores of the fungus Histoplasma capsulatum. […] Histoplasmosis occurs throughout the world. In the United States, it is most common in the southeastern, mid-Atlantic, and central states, especially in the Mississippi and Ohio River valleys. […] Histoplasma fungus grows as a mold in the soil. You may get sick when you breathe in spores produced by the fungus. Soil that contains bird or bat droppings may have larger amounts of this fungus. The threat is greatest after an old building is torn down, or in caves. […] This infection can occur in people with a healthy immune system. Having a weakened immune system increases the risk of getting or reactivating this disease. Very young or very old people, or those with HIV/AIDS, cancer, or an organ transplant have more severe symptoms. […] People with long-term (chronic) lung disease (such as emphysema and bronchiectasis) are also at higher risk for a more severe infection.

• #32 Histoplasmosis – Infectious Diseases – Merck Manual Professional Edition

  https://www.merckmanuals.com/professional/infectious-diseases/fungi/histoplasmosis

  Histoplasmosis is a pulmonary and hematogenous disease caused by Histoplasma capsulatum; it is often chronic and usually follows an asymptomatic primary infection. […] Infection follows inhalation of conidia (spores produced by the mycelial form of the fungus) in soil or dust contaminated with bird or bat droppings. […] Risk factors for severe histoplasmosis include heavy, prolonged exposure, age 55 years, infancy, and compromised T-cell-mediated immunity (eg, in those who have HIV/AIDS or an organ transplant or who are taking immunosuppressants such as corticosteroids or tumor necrosis factor inhibitors). […] Initial infection occurs in the lungs and usually remains there but may spread hematogenously to other organs if it is not controlled by normal cell-mediated host defenses. […] Progressive disseminated histoplasmosis is one of the defining opportunistic infections for AIDS.

• #33 What Is Histoplasmosis? How Is It Treated? | AAFP

  https://www.aafp.org/pubs/afp/issues/2002/1215/p2255.html

  Forty million people in the United States have been infected with histoplasmosis. About a half million new cases occur each year. Most infected people have few or no symptoms. […] Severe infections may develop in children under age 2 and in adults older than 55. People who have human immunodeficiency virus (HIV) infection or cancer, and those who are taking some medicines are more likely to get it. A chronic infection can occur in patients with lung diseases like emphysema. […] The best way to not get this infection is to stay away from places where you could breathe in contaminated dust. Spraying the area with water can reduce the dust that gets stirred up by cleaning chicken coops or digging in the dirt. If you work in contaminated areas, you can wear protective clothing and face masks.

• #34 Histoplasmosis: MedlinePlus

  https://medlineplus.gov/histoplasmosis.html

  Histoplasmosis is an infection caused by a fungus called Histoplasma. This fungus is common in the central and eastern United States, especially around the Ohio and Mississippi River valleys. It can also be found in parts of Central and South America, Africa, Asia, and Australia. It lives in the environment, especially in soil that contains large amounts of bat or bird droppings (poop). […] You get histoplasmosis by breathing in Histoplasma fungal spores from the air. It usually happens after you have been doing an activity that disturbs the soil, such as farming, construction, and landscaping. Histoplasmosis is not contagious. This means that you cannot get the infection from another person or an animal. […] Severe histoplasmosis can develop into a long-term lung infection. It can also spread from the lungs to other parts of the body, such as the central nervous system (the brain and spinal cord). This is known as disseminated histoplasmosis.

• #35 Histoplasmosis – Infectious Diseases – Merck Manual Professional Edition

  https://www.merckmanuals.com/professional/infectious-diseases/fungi/histoplasmosis

  Histoplasmosis is a pulmonary and hematogenous disease caused by Histoplasma capsulatum; it is often chronic and usually follows an asymptomatic primary infection. […] Infection follows inhalation of conidia (spores produced by the mycelial form of the fungus) in soil or dust contaminated with bird or bat droppings. […] Risk factors for severe histoplasmosis include heavy, prolonged exposure, age 55 years, infancy, and compromised T-cell-mediated immunity (eg, in those who have HIV/AIDS or an organ transplant or who are taking immunosuppressants such as corticosteroids or tumor necrosis factor inhibitors). […] Initial infection occurs in the lungs and usually remains there but may spread hematogenously to other organs if it is not controlled by normal cell-mediated host defenses. […] Progressive disseminated histoplasmosis is one of the defining opportunistic infections for AIDS.

• #36 Histoplasmosis – Wikipedia

  https://en.wikipedia.org/wiki/Histoplasmosis

  Histoplasmosis is a fungal infection caused by Histoplasma capsulatum. […] H. capsulatum is found in soil, often associated with decaying bat guano or bird droppings. Disruption of soil from excavation or construction releases infectious spores that can be inhaled by humans. […] Histoplasmosis is not contagious but is contracted by inhalation of the spores from disturbed soil or guano. […] The inoculum is represented principally by microconidia. These are inhaled and reach the alveoli. […] In immunocompromised individuals, the organisms disseminate to different organs such as bone, spleen, liver, adrenal glands, and mucocutaneous membranes, resulting in progressive disseminated histoplasmosis. […] Histoplasma capsulatum is commonly found across the United States. The fungus can grow in any materials corrupted with bird and bat droppings, but particularly manifests in soils. […] Workers in a variety of fields can be exposed to the fungus as spores can be released into the air through any activities which disturb soil.

• #37 Histoplasmosis – Infections – Merck Manual Consumer Version

  https://www.merckmanuals.com/home/infections/fungal-infections/histoplasmosis

  Histoplasmosis is an infection caused by the fungus Histoplasma capsulatum. It occurs mainly in the lungs but can sometimes spread throughout the body. […] Histoplasmosis is acquired by inhaling spores of the fungus. […] Histoplasma grows best in soil and dust that are contaminated with bird or bat droppings. […] The risk of infection is greatest when activity generates airborne spores (for example, tree or building removal at construction sites in areas where birds or bats live) or when exploring caves. […] Severe illness can result when large numbers of spores are inhaled. […] If the immune system is weakened or is immature, the infection may spread (disseminate) from the lungs through the bloodstream to other parts of the body, such as the brain, spinal cord, liver, spleen, lymph nodes, adrenal glands, digestive system, or bone marrow.

• #38 Disseminated histoplasmosis – Life Worldwide

  https://en.fungaleducation.org/disseminated-histoplasmosis/

  Histoplasma capsulatum is an endemic fungus that causes various disease manifestations, including two invasive forms: progressive disseminated histoplasmosis and acute pulmonary histoplasmosis. […] The global number of disseminated histoplasmosis cases in AIDS worldwide has been estimated to be 100,000 annually. […] PDH is also an AIDS-defining infection. […] The gold standard is a Histoplasma antigen test in urine, which is positive in 90% of cases. […] The treatment of choice is 3 mg/kg intravenous liposomal amphotericin B (AmBisome) for 2 weeks, followed by itraconazole 200-400 mg daily, assuming no drug interaction with rifampicin. […] Primary infection in immunocompromised patients, especially those with advanced HIV infection and taking corticosteroids can be severe and fatal. […] Histoplasma antigen and PCR may also be positive in the acute phase and are important investigations in immunocompromised patients.

• #39

  https://www.xiahepublishing.com/2310-8819/JCTH-2020-00080

  Histoplasma capsulatum is the most common cause of endemic mycosis in developing countries. […] Histoplasmosis is a systemic fungal disease that is caused by the dimorphic fungus Histoplasma capsulatum, which usually infects an individual by way of the respiratory tract. […] Hepatic histoplasmosis can occur both in children and adults, in immunocompetent and immunocompromised patients, and in endemic and nonendemic areas. […] Hepatic involvement is frequent in disseminated histoplasmosis. The liver is reportedly involved in about 90% of patients with disseminated histoplasmosis. […] However, liver histoplasmosis as a primary sign of histoplasmosis without lung involvement is uncommon. […] The full spectrum of hepatic manifestations of this disease is unknown but spans the range in the literature from mildly abnormal liver enzymes to severe icteric cholestasis with fever and pain. […] H.capsulatum is an uncommon cause of granulomatous liver disease. […] The typical clinical presentations are fever and jaundice in the setting of immunosuppression. […] There are limited case reports of disseminated histoplasmosis presenting as primary hepatic histoplasmosis.

• #40 Presumed Ocular Histoplasmosis Syndrome

  https://www.asrs.org/patients/retinal-diseases/18/presumed-ocular-histoplasmosis-syndrome

  Histoplasmosis is a disease caused by Histoplasma capsulatum (H. capsulatum), a soil fungus prevalent in certain parts of the American continent, in particular the Ohio and Mississippi River valleys. […] Consequently, it is thought that H. capsulatum enters the eye from the bloodstream, invading the choroidal vessels and ultimately causing scarring. However, it has never been directly proven that H. capsulatum causes POHS, hence the name presumed ocular histoplasmosis syndrome. […] One theory is that when childhood infection with H. capsulatum occurs, the fungus spreads through the bloodstream to the eye and choroid, where scars form and remain long after the systemic infection subsides.

• #41 Presumed Ocular Histoplasmosis (POHS): Symptoms & Treatment

  https://my.clevelandclinic.org/health/diseases/5635-histoplasmosis

  Histoplasmosis is caused by a fungus that can make you sick if you inhale it. […] Histoplasmosis occurs when the fungus Histoplasma capsulatum infects the lungs. […] POHS is an eye condition thats a complication of histoplasmosis. […] What causes ocular histoplasmosis? […] When Histoplasma capsulatum is in the soil, plowing a field or digging a hole stirs up the fungus. […] Researchers arent sure how it travels from the lungs to the back of the eyes. […] Your care will likely not include antifungal medications. Even though a fungus causes ocular histoplasmosis, its not the same as having a fungal infection. […] POHS occurs when the fungus Histoplasma capsulatum affects the eyes.

• #42 Ocular Histoplasmosis — Retina Imaging Centre Ltd.

  https://www.edmontonretinacentre.ca/new-page-4

  Presumed Ocular Histoplasmosis Syndrome (POHS) causes atrophy around the optic nerve and multiple scars scattered throughout the retina. […] Histoplasmosis is a disease caused by Histoplasma capsulatum (H. capsulatum), a soil fungus prevalent in certain parts of the American continent, in particular the Ohio and Mississippi River valleys, and in Canada in the Niagara peninsula. […] Consequently, it is thought that H. capsulatum enters the eye from the bloodstream, invading the choroidal vessels and ultimately causing scarring. However, it has never been directly proven that H. capsulatum causes POHS, hence the name presumed ocular histoplasmosis syndrome. […] One theory is that when childhood infection with H. capsulatum occurs, the fungus spreads through the bloodstream to the eye and choroid, where scars form and remain long after the systemic infection subsides. […] The histoplasmosis infection usually causes only mild flu-like symptoms so most people never realize they have histoplasmosis scars in their retina. The scars can later lead to neovascularization in the macula resulting in visual loss.

• #43 Histoplasmosis of the nervous system | MedLink Neurology

  https://www.medlink.com/articles/histoplasmosis-of-the-nervous-system

  Histoplasma capsulatum is a dimorphic fungus with 2 variants, Histoplasma capsulatum variety capsulatum, which is encountered chiefly in America and the tropics, and histoplasma capsulatum variety duboisii, which occurs in Africa. H. capsulatum typically results in pulmonary infections, whereas H. duboisii affects the skin and skeleton. […] The organism grows as a mold in the soil, and consists of hyphen-bearing large tuberculate macroconidia (8 to 14 um in diameter) and smaller microconidia (2 to 5 um). The latter is the infectious form of the fungus. Conidia inhaled into the lungs germinate into yeast-like forms and incite an immune reaction. The extent of disease depends on the number of conidia inhaled and the hosts cellular immune response. In patients with adequate immunity, T-lymphocytes activate against the H. capsulatum antigen and stimulate macrophages to kill the engulfed yeast. T cells are pivotal in clearance of the infection. A direct correlation exists between the CD4+ T cell count and the capacity of macrophages to bind yeast cells. As a result, patients with HIV or AIDS are more susceptible to disseminated disease. Involvement of the central nervous system arises following dissemination from a pulmonary source.

• #44 Pulmonary Histoplasmosis: A Clinical Update

  https://www.mdpi.com/2309-608X/9/2/236

  The heat shock protein 60 (Hsp60) of H. capsulatum is the major surface adhesin to macrophages and binds to complement receptor 3 (CR3). […] Once inside the macrophage, Histoplasma evades reactive oxygen and nitrogen species and is also able to regulate the phagosome acidification and the phagolysosomal fusion. […] The diagnosis of histoplasmosis can be ascertained by the direct observation or isolation of the pathogen (culture, histopathology, and cytopathology) or by the detection of antigens, antibodies, or nucleic acids. […] Isolation of H. capsulatum from clinical specimens remains the gold standard for the diagnosis of histoplasmosis, though histopathologic or direct microscopic identification are also considered definitive diagnoses. […] Histopathology can show characteristic features including granulomas (both caseating or non-caseating), and staining with Grocott-Gomori’s methenamine silver or Wright’s periodic acid-Schiff allows for the visualization of ovoid, narrow-based budding yeasts.

• #45 Chapter 4–histoplasmosis – PubMed

  https://pubmed.ncbi.nlm.nih.gov/20011851/

  Histoplasmosis is systemic mycosis caused by a small fungus, Histoplasma capsulatum var. capsulatum, whose natural habitat is soil contaminated by bat or bird excrement. […] Human infection occurs when airborne spores of H. capsulatum are inhaled. […] Histoplasmosis is diagnosed by means of the identification or culture growth of the fungus in sputum or fiberoptic bronchoscopy specimens. […] Histopathological examination reveals the fungus itself within or surrounding macrophages, as well as granulomatous lesions with or without caseous necrosis. […] Acute histoplasmosis with prolonged symptoms requires treatment, as do the disseminated or chronic pulmonary forms of the disease.

• #46 Histoplasmosis of the nervous system | MedLink Neurology

  https://www.medlink.com/articles/histoplasmosis-of-the-nervous-system

  Histoplasma capsulatum is a dimorphic fungus with 2 variants, Histoplasma capsulatum variety capsulatum, which is encountered chiefly in America and the tropics, and histoplasma capsulatum variety duboisii, which occurs in Africa. H. capsulatum typically results in pulmonary infections, whereas H. duboisii affects the skin and skeleton. […] The organism grows as a mold in the soil, and consists of hyphen-bearing large tuberculate macroconidia (8 to 14 um in diameter) and smaller microconidia (2 to 5 um). The latter is the infectious form of the fungus. Conidia inhaled into the lungs germinate into yeast-like forms and incite an immune reaction. The extent of disease depends on the number of conidia inhaled and the hosts cellular immune response. In patients with adequate immunity, T-lymphocytes activate against the H. capsulatum antigen and stimulate macrophages to kill the engulfed yeast. T cells are pivotal in clearance of the infection. A direct correlation exists between the CD4+ T cell count and the capacity of macrophages to bind yeast cells. As a result, patients with HIV or AIDS are more susceptible to disseminated disease. Involvement of the central nervous system arises following dissemination from a pulmonary source.

• #47 Pulmonary Histoplasmosis: A Clinical Update

  https://www.mdpi.com/2309-608X/9/2/236

  Histoplasma capsulatum, the etiological agent for histoplasmosis, is a dimorphic fungus that grows as a mold in the environment and as a yeast in human tissues. […] Human histoplasmosis is caused by two distinct organisms: Histoplasma capsulatum var. capsulatum and Histoplasma capsulatum var. duboisii. […] In North America, the highest endemicity areas include the valleys of the Mississippi and Ohio Rivers in the central and eastern United States. […] In these areas, the incidence is estimated to be 6.1 cases per 100,000, and 80–90% of the population will be exposed to histoplasmosis during their lifetime. […] In recent decades, environmental disruptions, climate change, increased travel and connectivity, and increased immunosuppressive conditions have led to changes in the epidemiology of histoplasmosis.

• #48 Histoplasmosis (Cave Disease): Causes, Symptoms, Treatment, Diagnosis

  https://www.medicinenet.com/histoplasmosis_facts/article.htm

  Histoplasmosis is a disease caused by an infection with a fungus known as Histoplasma capsulatum, which is common in the environment, most frequently in association with bird or bat droppings. […] The causative organism is a fungus, Histoplasma capsulatum. The fungus is associated with bird or bat droppings in the environment, especially in caves. […] Estimates indicate that around 250,000 people are infected each year in the U.S. […] Histoplasma capsulatum exists throughout the world, but it is most commonly located in North and Central America. […] The soil may also become contaminated with the fungus, so those who work with soil, such as landscapers and farmers, are at greater risk. […] Histoplasmosis is not contagious or spread from person to person.

• #49 Histoplasmosis: MedlinePlus

  https://medlineplus.gov/histoplasmosis.html

  Histoplasmosis is an infection caused by a fungus called Histoplasma. This fungus is common in the central and eastern United States, especially around the Ohio and Mississippi River valleys. It can also be found in parts of Central and South America, Africa, Asia, and Australia. It lives in the environment, especially in soil that contains large amounts of bat or bird droppings (poop). […] You get histoplasmosis by breathing in Histoplasma fungal spores from the air. It usually happens after you have been doing an activity that disturbs the soil, such as farming, construction, and landscaping. Histoplasmosis is not contagious. This means that you cannot get the infection from another person or an animal. […] Severe histoplasmosis can develop into a long-term lung infection. It can also spread from the lungs to other parts of the body, such as the central nervous system (the brain and spinal cord). This is known as disseminated histoplasmosis.

• #50 Sources of Histoplasmosis | Types of Diseases | Histoplasmosis | Fungal Disease | CDC

  http://med.iiab.me/modules/en-cdc/www.cdc.gov/fungal/diseases/histoplasmosis/causes.html

  Histoplasma, the fungus that causes histoplasmosis, lives throughout the world, but its most common in North America and Central America. […] Histoplasma grows best in soil that contains bird or bat droppings. Bats can get histoplasmosis and spread the fungus in their droppings. […] When people breathe in the spores, they are at risk for developing histoplasmosis. After the spores enter the lungs, the persons body temperature allows the spores to transform into yeast. The yeast can then travel to lymph nodes and can spread to other parts of the body through the bloodstream.

• #51 Histoplasmosis – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK448185/

  Histoplasma capsulatum is a dimorphic fungus present worldwide in pockets of endemicity particularly associated with river valleys. The endemic regions in the United States are Ohio and Mississippi river valleys as well as southeastern states. It is a soil-based fungus, and when it is disturbed, the conidia become airborne and can be inhaled. Often the infections are asymptomatic, but a granulomatous inflammation results in pulmonary disease akin to pulmonary tuberculosis. In immunocompromised patients, histoplasmosis can become disseminated and lead to considerable morbidity and mortality. […] […] In 1905, a pathologist, Samuel Darling, named H. capsulatum; so it also is known as Darling disease. Twenty years later Histoplasma yeast was isolated, and its dimorphic nature determined. At body temperature, H. capsulatum was yeast, but at ambient temperatures (25 C) it exists as a mold. H. capsulatum likes moist soil, particularly with decaying guano. Bats carry the fungus in their gastrointestinal tract, and birds carry H. capsulatum on their feathers. Birds are not affected by H. capsulatum due to their high body temperatures (40 C). Outbreaks have occurred where there was intense construction activity in endemic regions. […]

• #52 Pulmonary Histoplasmosis: A Clinical Update

  https://www.mdpi.com/2309-608X/9/2/236

  Histoplasma capsulatum, the etiological agent for histoplasmosis, is a dimorphic fungus that grows as a mold in the environment and as a yeast in human tissues. […] Human histoplasmosis is caused by two distinct organisms: Histoplasma capsulatum var. capsulatum and Histoplasma capsulatum var. duboisii. […] In North America, the highest endemicity areas include the valleys of the Mississippi and Ohio Rivers in the central and eastern United States. […] In these areas, the incidence is estimated to be 6.1 cases per 100,000, and 80–90% of the population will be exposed to histoplasmosis during their lifetime. […] In recent decades, environmental disruptions, climate change, increased travel and connectivity, and increased immunosuppressive conditions have led to changes in the epidemiology of histoplasmosis.

• #53 Pulmonary Histoplasmosis: A Clinical Update

  https://www.mdpi.com/2309-608X/9/2/236

  Histoplasmosis is also endemic to Central and South America, where the prevalence of infection may be higher than 30%. […] The advent of the HIV pandemic has highlighted the epidemiology of Histoplasmosis, as patients living with HIV are at an increased risk of having symptomatic disease. […] The incidence of symptomatic histoplasmosis in Central and South America is unknown, as many cases are misdiagnosed as tuberculosis. […] In China, 75% of the reported cases occurred within the Yangtze River basin. […] The mycelial phase in the environment has two types of conidia: macroconidia measuring 8–14 μm in diameter with distinct tuberculate projections on the surface (ship’s wheel) and microconidia measuring 2–5 μm in diameter (infectious form). […] Infection occurs following the inhalation of microconidia, which can reach the lower respiratory tract.

• #54 Histoplasmosis | Eye Disorders | Ophthalmology | Area of Care | SUNY Downstate

  https://www.downstate.edu/patient-care/find-treatment/areas-of-care/ophthalmology/eye-disorders/histoplasmosis.html

  Histoplasmosis is a disease caused when airborne spores of the fungus Histoplasma capsulatum are inhaled into the lungs, the primary infection site. […] Scientists believe that Histoplasma capsulatum (histo) spores spread from the lungs to the eye, lodging in the choroid, a layer of blood vessels that provides blood and nutrients to the retina. […] OHS develops when fragile, abnormal blood vessels grow underneath the retina. […] Although only a tiny fraction of the people infected with the histo fungus ever develops OHS, any person who has had histoplasmosis should be alert for any changes in vision similar to those described above. […] In the United States, the highest incidence of histoplasmosis occurs in a region often referred to as the „Histo Belt,” where up to 90 percent of the adult population has been infected by histoplasmosis. […] Histo spots have been associated with the growth of the abnormal blood vessels underneath the retina. […] The only proven treatment for OHS is a form of laser surgery called photocoagulation. […] OHS cannot be cured. Once contracted, OHS remains a threat to a person’s sight for their lifetime.

• #55 Pulmonary Histoplasmosis: A Clinical Update

  https://www.mdpi.com/2309-608X/9/2/236

  Histoplasma capsulatum, the etiological agent for histoplasmosis, is a dimorphic fungus that grows as a mold in the environment and as a yeast in human tissues. […] Human histoplasmosis is caused by two distinct organisms: Histoplasma capsulatum var. capsulatum and Histoplasma capsulatum var. duboisii. […] In North America, the highest endemicity areas include the valleys of the Mississippi and Ohio Rivers in the central and eastern United States. […] In these areas, the incidence is estimated to be 6.1 cases per 100,000, and 80–90% of the population will be exposed to histoplasmosis during their lifetime. […] In recent decades, environmental disruptions, climate change, increased travel and connectivity, and increased immunosuppressive conditions have led to changes in the epidemiology of histoplasmosis.

• #56 What Is Histoplasmosis? How Is It Treated? | AAFP

  https://www.aafp.org/pubs/afp/issues/2002/1215/p2255.html

  Forty million people in the United States have been infected with histoplasmosis. About a half million new cases occur each year. Most infected people have few or no symptoms. […] Severe infections may develop in children under age 2 and in adults older than 55. People who have human immunodeficiency virus (HIV) infection or cancer, and those who are taking some medicines are more likely to get it. A chronic infection can occur in patients with lung diseases like emphysema. […] The best way to not get this infection is to stay away from places where you could breathe in contaminated dust. Spraying the area with water can reduce the dust that gets stirred up by cleaning chicken coops or digging in the dirt. If you work in contaminated areas, you can wear protective clothing and face masks.

• #57 Disseminated histoplasmosis – Life Worldwide

  https://en.fungaleducation.org/disseminated-histoplasmosis/

  Histoplasma capsulatum is an endemic fungus that causes various disease manifestations, including two invasive forms: progressive disseminated histoplasmosis and acute pulmonary histoplasmosis. […] The global number of disseminated histoplasmosis cases in AIDS worldwide has been estimated to be 100,000 annually. […] PDH is also an AIDS-defining infection. […] The gold standard is a Histoplasma antigen test in urine, which is positive in 90% of cases. […] The treatment of choice is 3 mg/kg intravenous liposomal amphotericin B (AmBisome) for 2 weeks, followed by itraconazole 200-400 mg daily, assuming no drug interaction with rifampicin. […] Primary infection in immunocompromised patients, especially those with advanced HIV infection and taking corticosteroids can be severe and fatal. […] Histoplasma antigen and PCR may also be positive in the acute phase and are important investigations in immunocompromised patients.

• #58 Pulmonary Histoplasmosis: A Clinical Update

  https://www.mdpi.com/2309-608X/9/2/236

  Histoplasmosis is also endemic to Central and South America, where the prevalence of infection may be higher than 30%. […] The advent of the HIV pandemic has highlighted the epidemiology of Histoplasmosis, as patients living with HIV are at an increased risk of having symptomatic disease. […] The incidence of symptomatic histoplasmosis in Central and South America is unknown, as many cases are misdiagnosed as tuberculosis. […] In China, 75% of the reported cases occurred within the Yangtze River basin. […] The mycelial phase in the environment has two types of conidia: macroconidia measuring 8–14 μm in diameter with distinct tuberculate projections on the surface (ship’s wheel) and microconidia measuring 2–5 μm in diameter (infectious form). […] Infection occurs following the inhalation of microconidia, which can reach the lower respiratory tract.

• #59 Pulmonary Histoplasmosis: A Clinical Update

  https://www.mdpi.com/2309-608X/9/2/236

  Histoplasma capsulatum, the etiological agent for histoplasmosis, is a dimorphic fungus that grows as a mold in the environment and as a yeast in human tissues. […] Human histoplasmosis is caused by two distinct organisms: Histoplasma capsulatum var. capsulatum and Histoplasma capsulatum var. duboisii. […] In North America, the highest endemicity areas include the valleys of the Mississippi and Ohio Rivers in the central and eastern United States. […] In these areas, the incidence is estimated to be 6.1 cases per 100,000, and 80–90% of the population will be exposed to histoplasmosis during their lifetime. […] In recent decades, environmental disruptions, climate change, increased travel and connectivity, and increased immunosuppressive conditions have led to changes in the epidemiology of histoplasmosis.

• #60 Histoplasmosis: Practice Essentials, Pathophysiology, Etiology

  https://emedicine.medscape.com/article/299054-overview

  Histoplasma capsulatum is a dimorphic fungus that remains in a mycelial form at ambient temperatures and grows as yeast at body temperature in mammals. Infection causes histoplasmosis. Although the fungus that causes histoplasmosis can be found in temperate climates throughout the world, it is endemic to the Ohio, Missouri, and Mississippi River valleys in the United States. […] The risk of infection is mostly related to environmental exposure and underlying immune status. Living in endemic areas with contaminated soil increases the risk of exposure. Inoculum size plays a role. Individuals who are immunocompetent and exposed to a low inoculum of histoplasmosis usually are asymptomatic. Inhalation of a large inoculum can cause diffuse pulmonary symptoms that may have a protracted course. […] Immune status and comorbid factors affect causation. Reactivation, reinfection, or complications of infection usually occur in individuals who are immunocompromised or immunosuppressed. Cases of histoplasmosis have been reported in patients receiving infliximab. A high index of suspicion should be present in patients on tumor necrosis factor-alpha inhibitors. […] Chronic pulmonary histoplasmosis is more prevalent in patients with underlying emphysema. The risk factors include AIDS, primary immunodeficiencies, drug-induced immunosuppressive states, and the extremes of age.

• #61 Pulmonary Histoplasmosis: A Clinical Update

  https://www.mdpi.com/2309-608X/9/2/236

  Histoplasma capsulatum, the etiological agent for histoplasmosis, is a dimorphic fungus that grows as a mold in the environment and as a yeast in human tissues. […] Human histoplasmosis is caused by two distinct organisms: Histoplasma capsulatum var. capsulatum and Histoplasma capsulatum var. duboisii. […] In North America, the highest endemicity areas include the valleys of the Mississippi and Ohio Rivers in the central and eastern United States. […] In these areas, the incidence is estimated to be 6.1 cases per 100,000, and 80–90% of the population will be exposed to histoplasmosis during their lifetime. […] In recent decades, environmental disruptions, climate change, increased travel and connectivity, and increased immunosuppressive conditions have led to changes in the epidemiology of histoplasmosis.

• #62 Histoplasmosis – Infectious Diseases – Merck Manual Professional Edition

  https://www.merckmanuals.com/professional/infectious-diseases/fungi/histoplasmosis

  Histoplasmosis is a pulmonary and hematogenous disease caused by Histoplasma capsulatum; it is often chronic and usually follows an asymptomatic primary infection. […] Infection follows inhalation of conidia (spores produced by the mycelial form of the fungus) in soil or dust contaminated with bird or bat droppings. […] Risk factors for severe histoplasmosis include heavy, prolonged exposure, age 55 years, infancy, and compromised T-cell-mediated immunity (eg, in those who have HIV/AIDS or an organ transplant or who are taking immunosuppressants such as corticosteroids or tumor necrosis factor inhibitors). […] Initial infection occurs in the lungs and usually remains there but may spread hematogenously to other organs if it is not controlled by normal cell-mediated host defenses. […] Progressive disseminated histoplasmosis is one of the defining opportunistic infections for AIDS.

• #63 Pulmonary Histoplasmosis: A Clinical Update

  https://www.mdpi.com/2309-608X/9/2/236

  Histoplasmosis is also endemic to Central and South America, where the prevalence of infection may be higher than 30%. […] The advent of the HIV pandemic has highlighted the epidemiology of Histoplasmosis, as patients living with HIV are at an increased risk of having symptomatic disease. […] The incidence of symptomatic histoplasmosis in Central and South America is unknown, as many cases are misdiagnosed as tuberculosis. […] In China, 75% of the reported cases occurred within the Yangtze River basin. […] The mycelial phase in the environment has two types of conidia: macroconidia measuring 8–14 μm in diameter with distinct tuberculate projections on the surface (ship’s wheel) and microconidia measuring 2–5 μm in diameter (infectious form). […] Infection occurs following the inhalation of microconidia, which can reach the lower respiratory tract.

• #64 How People Get Histoplasmosis | Histoplasmosis | CDC

  https://www.cdc.gov/histoplasmosis/causes/index.html

  Histoplasmosis is a lung infection caused by breathing in spores from the fungus, Histoplasma. […] People can get histoplasmosis by breathing in spores from the fungus, Histoplasma. The fungus is typically found in soil and bird or bat droppings in certain areas of the United States and the world. […] After the spores enter the lungs, the person’s body temperature allows the spores to transform into yeast. […] Outbreaks of histoplasmosis are not common. Of the few that have been reported, most occurred after events that disturb soil contaminated with bird or bat droppings. […] Investigating histoplasmosis outbreaks helps public health officials understand where the fungus lives.

• #65 Histoplasmosis: Treatment, Contagious, Symptoms & Test

  https://www.emedicinehealth.com/histoplasmosis/article_em.htm

  High concentrations of the fungus occur in caves where bats or birds reside, and the fungi are in the soil. […] Most outbreaks occur when construction or renovation projects disturb and aerosolize dust containing the fungi so people who participate in or live near such projects are at higher risk for histoplasmosis.

• #66 Histoplasmosis – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK448185/

  Histoplasma capsulatum is a dimorphic fungus present worldwide in pockets of endemicity particularly associated with river valleys. The endemic regions in the United States are Ohio and Mississippi river valleys as well as southeastern states. It is a soil-based fungus, and when it is disturbed, the conidia become airborne and can be inhaled. Often the infections are asymptomatic, but a granulomatous inflammation results in pulmonary disease akin to pulmonary tuberculosis. In immunocompromised patients, histoplasmosis can become disseminated and lead to considerable morbidity and mortality. […] […] In 1905, a pathologist, Samuel Darling, named H. capsulatum; so it also is known as Darling disease. Twenty years later Histoplasma yeast was isolated, and its dimorphic nature determined. At body temperature, H. capsulatum was yeast, but at ambient temperatures (25 C) it exists as a mold. H. capsulatum likes moist soil, particularly with decaying guano. Bats carry the fungus in their gastrointestinal tract, and birds carry H. capsulatum on their feathers. Birds are not affected by H. capsulatum due to their high body temperatures (40 C). Outbreaks have occurred where there was intense construction activity in endemic regions. […]

• #67

  https://www.ccohs.ca/oshanswers/diseases/histopla.html

  Histoplasmosis is an infectious disease caused by a fungus called Histoplasma capsulatum. […] The Histoplasma organism thrives in moderate temperatures, rich soil, and moist environments. […] To multiply, Histoplasma capsulatum produces small spores called conidia. […] When a person breathes in the conidia (spores) of Histoplasma capsulatum, the lungs’ defence mechanisms attempt to neutralize them. […] The symptoms of the infection appear within 5 to 18 days after exposure, most commonly in 10 days. […] Confirmation of a histoplasmosis diagnosis often requires laboratory examinations which identify Histoplasma capsulatum in sputum or lung biopsy. […] Most patients who develop histoplasmosis do not require treatment. […] Persons whose occupations involve contact with the soil, in particular soil enriched with bird and bat droppings, are at high risk of acquiring infection.

• #68 Histoplasmosis

  https://dph.illinois.gov/topics-services/diseases-and-conditions/diseases-a-z-list/diseases/histoplasmosis.html

  Histoplasmosis is an infection caused by a fungus, Histoplasma capsulatum. The principal habitat for this fungus is soil enriched by the buildup of bird or bat droppings, and in fresh bat droppings. […] In some areas where the fungus is common, 80 percent or more of the population has been exposed to the fungus by breathing in airborne spores. […] Elevated risk of exposure to the histoplasmosis fungus include: workers who perform demolition or renovation work in buildings where bat or bird droppings have accumulated, gardeners who use bird or bat droppings as fertilizer, excavation workers who uproot trees that have been used for bird or bat roosting, persons cleaning fireplaces below chimneys in which bats or birds have roosted. […] The fungus is found throughout the world and grows in soil that has been enriched with bat or bird droppings or in bat droppings themselves. […] The disease is not spread from person to person. It is not acquired from animals that have the disease. […] You should always take steps to limit exposure to the histoplasmosis fungus, even if you have had histoplasmosis in the past.

• #69 Histoplasmosis – Wikipedia

  https://en.wikipedia.org/wiki/Histoplasmosis

  Histoplasmosis is a fungal infection caused by Histoplasma capsulatum. […] H. capsulatum is found in soil, often associated with decaying bat guano or bird droppings. Disruption of soil from excavation or construction releases infectious spores that can be inhaled by humans. […] Histoplasmosis is not contagious but is contracted by inhalation of the spores from disturbed soil or guano. […] The inoculum is represented principally by microconidia. These are inhaled and reach the alveoli. […] In immunocompromised individuals, the organisms disseminate to different organs such as bone, spleen, liver, adrenal glands, and mucocutaneous membranes, resulting in progressive disseminated histoplasmosis. […] Histoplasma capsulatum is commonly found across the United States. The fungus can grow in any materials corrupted with bird and bat droppings, but particularly manifests in soils. […] Workers in a variety of fields can be exposed to the fungus as spores can be released into the air through any activities which disturb soil.

• #70 Histoplasma Capsulatum

  https://www.tamuk.edu/finance/risk/animal-safety/histoplasma-capsulatum.html

  Histoplasmosis is an infectious disease of the lungs caused by a fungus, Histoplasma capsulatum. The infection can sometimes spread to other parts of the body. […] Histoplasma capsulatum may also be found in the soil, particularly soil which has been enriched with bird or bat droppings. […] People get histoplasmosis by breathing air which contains small spore forms of the organism. […] Persons whose occupations involve contact with the soil, in particular with soil enriched with bird and bat droppings, are at high risk of acquiring infection. […] Most histoplasmosis infections are easily overlooked because they either produce mild symptoms or none at all. […] However, histoplasmosis can be severe and produce an illness similar to tuberculosis. […] Histoplasmosis causes a spectrum of illness, and the symptoms vary depending on the type of infection, the underlying health of the patient, and the extent of exposure.

• #71 Histoplasmosis

  https://dph.illinois.gov/topics-services/diseases-and-conditions/diseases-a-z-list/diseases/histoplasmosis.html

  Histoplasmosis is an infection caused by a fungus, Histoplasma capsulatum. The principal habitat for this fungus is soil enriched by the buildup of bird or bat droppings, and in fresh bat droppings. […] In some areas where the fungus is common, 80 percent or more of the population has been exposed to the fungus by breathing in airborne spores. […] Elevated risk of exposure to the histoplasmosis fungus include: workers who perform demolition or renovation work in buildings where bat or bird droppings have accumulated, gardeners who use bird or bat droppings as fertilizer, excavation workers who uproot trees that have been used for bird or bat roosting, persons cleaning fireplaces below chimneys in which bats or birds have roosted. […] The fungus is found throughout the world and grows in soil that has been enriched with bat or bird droppings or in bat droppings themselves. […] The disease is not spread from person to person. It is not acquired from animals that have the disease. […] You should always take steps to limit exposure to the histoplasmosis fungus, even if you have had histoplasmosis in the past.

• #72 Histoplasmosis – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK448185/

  Once microconidia are lodged in the alveoli, these particles undergo a transformation in response to body temperature resulting in unicellular yeast forms typically 2 micrometers to 5 micrometers in diameter. Genes essential for transition and growth of yeast cells have been identified and are Ryp1, Ryp2, and Ryp. Conidia within the alveoli bind to the CD11-CD18 family of integrins and are engulfed by neutrophils and macrophages. It is, therefore, possible that the phase transformation from conidia to yeast is intracellular. The duration of the phase transition ranges from hours to days. The yeast phase is responsible for the infectivity of the fungus. This yeast reproduces by narrow-based and sometimes multipolar budding.

• #73 Pulmonary Histoplasmosis: A Clinical Update

  https://www.mdpi.com/2309-608X/9/2/236

  The heat shock protein 60 (Hsp60) of H. capsulatum is the major surface adhesin to macrophages and binds to complement receptor 3 (CR3). […] Once inside the macrophage, Histoplasma evades reactive oxygen and nitrogen species and is also able to regulate the phagosome acidification and the phagolysosomal fusion. […] The diagnosis of histoplasmosis can be ascertained by the direct observation or isolation of the pathogen (culture, histopathology, and cytopathology) or by the detection of antigens, antibodies, or nucleic acids. […] Isolation of H. capsulatum from clinical specimens remains the gold standard for the diagnosis of histoplasmosis, though histopathologic or direct microscopic identification are also considered definitive diagnoses. […] Histopathology can show characteristic features including granulomas (both caseating or non-caseating), and staining with Grocott-Gomori’s methenamine silver or Wright’s periodic acid-Schiff allows for the visualization of ovoid, narrow-based budding yeasts.

• #74 Histoplasmosis – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK448185/

  H. capsulatum is a member of the family ascomycetes and exists as two mating types. While in nature the mating types + and – exist in 1:1 ratio, most patient isolates are mating type -. This reasons for increased representation of (-) mating types in clinical specimens is unknown. Microscopic evaluation of the mycelial phase reveals two types of conidia. Macroconidia are 8 micrometers to 15 micrometers in diameter while microconidia are 2 micrometers to 5 micrometers. Microconidia are believed to be the infective particles and are small enough to be lodged in the alveoli when inhaled. […] […] H. capsulatum has five to seven chromosomes. Recently, molecular techniques have identified eight clades of H. capsulatum, which are distributed in different parts of the world. There are two North American clades, two South American clades, one Australian, one Indonesian, one African, and one Eurasian clade. The genetic differences have clinical implications as North American clades do not cause primary skin disease while South American clades do. The African clade includes all of H. capsulatum variety duboisii. […]

• #75 Histoplasmosis – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK448185/

  Once microconidia are lodged in the alveoli, these particles undergo a transformation in response to body temperature resulting in unicellular yeast forms typically 2 micrometers to 5 micrometers in diameter. Genes essential for transition and growth of yeast cells have been identified and are Ryp1, Ryp2, and Ryp. Conidia within the alveoli bind to the CD11-CD18 family of integrins and are engulfed by neutrophils and macrophages. It is, therefore, possible that the phase transformation from conidia to yeast is intracellular. The duration of the phase transition ranges from hours to days. The yeast phase is responsible for the infectivity of the fungus. This yeast reproduces by narrow-based and sometimes multipolar budding.

• #76 How People Get Histoplasmosis | Histoplasmosis | CDC

  https://www.cdc.gov/histoplasmosis/causes/index.html

  Histoplasmosis is a lung infection caused by breathing in spores from the fungus, Histoplasma. […] People can get histoplasmosis by breathing in spores from the fungus, Histoplasma. The fungus is typically found in soil and bird or bat droppings in certain areas of the United States and the world. […] After the spores enter the lungs, the person’s body temperature allows the spores to transform into yeast. […] Outbreaks of histoplasmosis are not common. Of the few that have been reported, most occurred after events that disturb soil contaminated with bird or bat droppings. […] Investigating histoplasmosis outbreaks helps public health officials understand where the fungus lives.

• #77 Histoplasmosis

  https://www.michigan.gov/mdhhs/safety-injury-prev/environmental-health/topics/mitracking/histoplasmosis

  Histoplasmosis is a fungal disease. The organism Histoplasma causes histoplasmosis. The fungal disease happens when a person breathes in fungal spores from infected soil or other decomposing matter that is disturbed (digging in dirt, raking leaves, etc.). Infected soil often contains bird or bat droppings. Histoplasma is found in some central and eastern states including Michigan. […] Histoplasma is a dimorphic fungus, which means it exists in two different forms, mold and yeast, based on temperature. It grows as a mold at outside air temperatures. The mold develops spores called conidia. Disturbing contaminated soil can lead to breathing in fungal spores. The spores then transform into a yeast at higher temperatures found inside the human body. The yeast can stay in the lungs or spread through the bloodstream to other parts of the body.

• #78 Histoplasmosis – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK448185/

  Once microconidia are lodged in the alveoli, these particles undergo a transformation in response to body temperature resulting in unicellular yeast forms typically 2 micrometers to 5 micrometers in diameter. Genes essential for transition and growth of yeast cells have been identified and are Ryp1, Ryp2, and Ryp. Conidia within the alveoli bind to the CD11-CD18 family of integrins and are engulfed by neutrophils and macrophages. It is, therefore, possible that the phase transformation from conidia to yeast is intracellular. The duration of the phase transition ranges from hours to days. The yeast phase is responsible for the infectivity of the fungus. This yeast reproduces by narrow-based and sometimes multipolar budding.

• #79 Histoplasmosis – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK448185/

  Once microconidia are lodged in the alveoli, these particles undergo a transformation in response to body temperature resulting in unicellular yeast forms typically 2 micrometers to 5 micrometers in diameter. Genes essential for transition and growth of yeast cells have been identified and are Ryp1, Ryp2, and Ryp. Conidia within the alveoli bind to the CD11-CD18 family of integrins and are engulfed by neutrophils and macrophages. It is, therefore, possible that the phase transformation from conidia to yeast is intracellular. The duration of the phase transition ranges from hours to days. The yeast phase is responsible for the infectivity of the fungus. This yeast reproduces by narrow-based and sometimes multipolar budding.

• #80 Pulmonary Histoplasmosis: A Clinical Update

  https://www.mdpi.com/2309-608X/9/2/236

  The heat shock protein 60 (Hsp60) of H. capsulatum is the major surface adhesin to macrophages and binds to complement receptor 3 (CR3). […] Once inside the macrophage, Histoplasma evades reactive oxygen and nitrogen species and is also able to regulate the phagosome acidification and the phagolysosomal fusion. […] The diagnosis of histoplasmosis can be ascertained by the direct observation or isolation of the pathogen (culture, histopathology, and cytopathology) or by the detection of antigens, antibodies, or nucleic acids. […] Isolation of H. capsulatum from clinical specimens remains the gold standard for the diagnosis of histoplasmosis, though histopathologic or direct microscopic identification are also considered definitive diagnoses. […] Histopathology can show characteristic features including granulomas (both caseating or non-caseating), and staining with Grocott-Gomori’s methenamine silver or Wright’s periodic acid-Schiff allows for the visualization of ovoid, narrow-based budding yeasts.

• #81 Histoplasmosis of the nervous system | MedLink Neurology

  https://www.medlink.com/articles/histoplasmosis-of-the-nervous-system

  Histoplasma capsulatum is a dimorphic fungus with 2 variants, Histoplasma capsulatum variety capsulatum, which is encountered chiefly in America and the tropics, and histoplasma capsulatum variety duboisii, which occurs in Africa. H. capsulatum typically results in pulmonary infections, whereas H. duboisii affects the skin and skeleton. […] The organism grows as a mold in the soil, and consists of hyphen-bearing large tuberculate macroconidia (8 to 14 um in diameter) and smaller microconidia (2 to 5 um). The latter is the infectious form of the fungus. Conidia inhaled into the lungs germinate into yeast-like forms and incite an immune reaction. The extent of disease depends on the number of conidia inhaled and the hosts cellular immune response. In patients with adequate immunity, T-lymphocytes activate against the H. capsulatum antigen and stimulate macrophages to kill the engulfed yeast. T cells are pivotal in clearance of the infection. A direct correlation exists between the CD4+ T cell count and the capacity of macrophages to bind yeast cells. As a result, patients with HIV or AIDS are more susceptible to disseminated disease. Involvement of the central nervous system arises following dissemination from a pulmonary source.

• #82 Pulmonary Histoplasmosis: A Clinical Update

  https://www.mdpi.com/2309-608X/9/2/236

  The heat shock protein 60 (Hsp60) of H. capsulatum is the major surface adhesin to macrophages and binds to complement receptor 3 (CR3). […] Once inside the macrophage, Histoplasma evades reactive oxygen and nitrogen species and is also able to regulate the phagosome acidification and the phagolysosomal fusion. […] The diagnosis of histoplasmosis can be ascertained by the direct observation or isolation of the pathogen (culture, histopathology, and cytopathology) or by the detection of antigens, antibodies, or nucleic acids. […] Isolation of H. capsulatum from clinical specimens remains the gold standard for the diagnosis of histoplasmosis, though histopathologic or direct microscopic identification are also considered definitive diagnoses. […] Histopathology can show characteristic features including granulomas (both caseating or non-caseating), and staining with Grocott-Gomori’s methenamine silver or Wright’s periodic acid-Schiff allows for the visualization of ovoid, narrow-based budding yeasts.

• #83 Histoplasmosis of the nervous system | MedLink Neurology

  https://www.medlink.com/articles/histoplasmosis-of-the-nervous-system

  Histoplasma capsulatum is a dimorphic fungus with 2 variants, Histoplasma capsulatum variety capsulatum, which is encountered chiefly in America and the tropics, and histoplasma capsulatum variety duboisii, which occurs in Africa. H. capsulatum typically results in pulmonary infections, whereas H. duboisii affects the skin and skeleton. […] The organism grows as a mold in the soil, and consists of hyphen-bearing large tuberculate macroconidia (8 to 14 um in diameter) and smaller microconidia (2 to 5 um). The latter is the infectious form of the fungus. Conidia inhaled into the lungs germinate into yeast-like forms and incite an immune reaction. The extent of disease depends on the number of conidia inhaled and the hosts cellular immune response. In patients with adequate immunity, T-lymphocytes activate against the H. capsulatum antigen and stimulate macrophages to kill the engulfed yeast. T cells are pivotal in clearance of the infection. A direct correlation exists between the CD4+ T cell count and the capacity of macrophages to bind yeast cells. As a result, patients with HIV or AIDS are more susceptible to disseminated disease. Involvement of the central nervous system arises following dissemination from a pulmonary source.

• #84 Histoplasmosis: Practice Essentials, Pathophysiology, Etiology

  https://emedicine.medscape.com/article/299054-overview

  Histoplasma capsulatum is a dimorphic fungus that remains in a mycelial form at ambient temperatures and grows as yeast at body temperature in mammals. Infection causes histoplasmosis. Although the fungus that causes histoplasmosis can be found in temperate climates throughout the world, it is endemic to the Ohio, Missouri, and Mississippi River valleys in the United States. […] The risk of infection is mostly related to environmental exposure and underlying immune status. Living in endemic areas with contaminated soil increases the risk of exposure. Inoculum size plays a role. Individuals who are immunocompetent and exposed to a low inoculum of histoplasmosis usually are asymptomatic. Inhalation of a large inoculum can cause diffuse pulmonary symptoms that may have a protracted course. […] Immune status and comorbid factors affect causation. Reactivation, reinfection, or complications of infection usually occur in individuals who are immunocompromised or immunosuppressed. Cases of histoplasmosis have been reported in patients receiving infliximab. A high index of suspicion should be present in patients on tumor necrosis factor-alpha inhibitors. […] Chronic pulmonary histoplasmosis is more prevalent in patients with underlying emphysema. The risk factors include AIDS, primary immunodeficiencies, drug-induced immunosuppressive states, and the extremes of age.

• #85 Histoplasmosis – Infectious Diseases – Merck Manual Professional Edition

  https://www.merckmanuals.com/professional/infectious-diseases/fungi/histoplasmosis

  Histoplasmosis is a pulmonary and hematogenous disease caused by Histoplasma capsulatum; it is often chronic and usually follows an asymptomatic primary infection. […] Infection follows inhalation of conidia (spores produced by the mycelial form of the fungus) in soil or dust contaminated with bird or bat droppings. […] Risk factors for severe histoplasmosis include heavy, prolonged exposure, age 55 years, infancy, and compromised T-cell-mediated immunity (eg, in those who have HIV/AIDS or an organ transplant or who are taking immunosuppressants such as corticosteroids or tumor necrosis factor inhibitors). […] Initial infection occurs in the lungs and usually remains there but may spread hematogenously to other organs if it is not controlled by normal cell-mediated host defenses. […] Progressive disseminated histoplasmosis is one of the defining opportunistic infections for AIDS.

• #86 Histoplasmosis – Infectious Diseases – Merck Manual Professional Edition

  https://www.merckmanuals.com/professional/infectious-diseases/fungi/histoplasmosis

  Histoplasmosis is a pulmonary and hematogenous disease caused by Histoplasma capsulatum; it is often chronic and usually follows an asymptomatic primary infection. […] Infection follows inhalation of conidia (spores produced by the mycelial form of the fungus) in soil or dust contaminated with bird or bat droppings. […] Risk factors for severe histoplasmosis include heavy, prolonged exposure, age 55 years, infancy, and compromised T-cell-mediated immunity (eg, in those who have HIV/AIDS or an organ transplant or who are taking immunosuppressants such as corticosteroids or tumor necrosis factor inhibitors). […] Initial infection occurs in the lungs and usually remains there but may spread hematogenously to other organs if it is not controlled by normal cell-mediated host defenses. […] Progressive disseminated histoplasmosis is one of the defining opportunistic infections for AIDS.

• #87 Histoplasmosis – Infectious Diseases – Merck Manual Professional Edition

  https://www.merckmanuals.com/professional/infectious-diseases/fungi/histoplasmosis

  The acute primary form of histoplasmosis is almost always self-limited; however, very rarely, death occurs after massive infection. […] Chronic cavitary histoplasmosis can cause death due to severe respiratory insufficiency. […] Untreated progressive disseminated histoplasmosis has a mortality rate of 90%. […] Histoplasmosis is a common fungal infection acquired by inhaling spores. […] It may cause an acute primary pulmonary infection, a chronic cavitary pulmonary infection, or progressive disseminated infection.

• #88 Histoplasmosis – Wikipedia

  https://en.wikipedia.org/wiki/Histoplasmosis

  Histoplasmosis is a fungal infection caused by Histoplasma capsulatum. […] H. capsulatum is found in soil, often associated with decaying bat guano or bird droppings. Disruption of soil from excavation or construction releases infectious spores that can be inhaled by humans. […] Histoplasmosis is not contagious but is contracted by inhalation of the spores from disturbed soil or guano. […] The inoculum is represented principally by microconidia. These are inhaled and reach the alveoli. […] In immunocompromised individuals, the organisms disseminate to different organs such as bone, spleen, liver, adrenal glands, and mucocutaneous membranes, resulting in progressive disseminated histoplasmosis. […] Histoplasma capsulatum is commonly found across the United States. The fungus can grow in any materials corrupted with bird and bat droppings, but particularly manifests in soils. […] Workers in a variety of fields can be exposed to the fungus as spores can be released into the air through any activities which disturb soil.

• #89 Histoplasmosis – Infections – Merck Manual Consumer Version

  https://www.merckmanuals.com/home/infections/fungal-infections/histoplasmosis

  Histoplasmosis is an infection caused by the fungus Histoplasma capsulatum. It occurs mainly in the lungs but can sometimes spread throughout the body. […] Histoplasmosis is acquired by inhaling spores of the fungus. […] Histoplasma grows best in soil and dust that are contaminated with bird or bat droppings. […] The risk of infection is greatest when activity generates airborne spores (for example, tree or building removal at construction sites in areas where birds or bats live) or when exploring caves. […] Severe illness can result when large numbers of spores are inhaled. […] If the immune system is weakened or is immature, the infection may spread (disseminate) from the lungs through the bloodstream to other parts of the body, such as the brain, spinal cord, liver, spleen, lymph nodes, adrenal glands, digestive system, or bone marrow.

• #90

  https://www.xiahepublishing.com/2310-8819/JCTH-2020-00080

  Histoplasma capsulatum is the most common cause of endemic mycosis in developing countries. […] Histoplasmosis is a systemic fungal disease that is caused by the dimorphic fungus Histoplasma capsulatum, which usually infects an individual by way of the respiratory tract. […] Hepatic histoplasmosis can occur both in children and adults, in immunocompetent and immunocompromised patients, and in endemic and nonendemic areas. […] Hepatic involvement is frequent in disseminated histoplasmosis. The liver is reportedly involved in about 90% of patients with disseminated histoplasmosis. […] However, liver histoplasmosis as a primary sign of histoplasmosis without lung involvement is uncommon. […] The full spectrum of hepatic manifestations of this disease is unknown but spans the range in the literature from mildly abnormal liver enzymes to severe icteric cholestasis with fever and pain. […] H.capsulatum is an uncommon cause of granulomatous liver disease. […] The typical clinical presentations are fever and jaundice in the setting of immunosuppression. […] There are limited case reports of disseminated histoplasmosis presenting as primary hepatic histoplasmosis.

• #91 Histoplasmosis of the nervous system | MedLink Neurology

  https://www.medlink.com/articles/histoplasmosis-of-the-nervous-system

  Histoplasmosis is an infection caused by the fungus Histoplasma capsulatum. Infection is endemic to certain areas of the United States, including the Mississippi and Ohio River Valleys, as well as parts of Central America, South America, Africa, and Southeast Asia. Organisms are spread by disturbance of ground soil contaminated by bat and avian excrement. Inhalation of spores causes infection, which primarily involves the lungs. Extrapulmonary infection can occur, though this is much less common. Immunocompromised individuals are at an increased risk for disseminated infection. In rare but serious cases, histoplasmosis affects the nervous system. Central nervous system involvement is clinically recognized in 10% to 20% of progressive, disseminated cases. CNS infection can also be isolated. Meningitis is the most common clinical manifestation of CNS histoplasmosis.

• #92

  https://www.xiahepublishing.com/2310-8819/JCTH-2020-00080

  Histoplasma capsulatum is the most common cause of endemic mycosis in developing countries. […] Histoplasmosis is a systemic fungal disease that is caused by the dimorphic fungus Histoplasma capsulatum, which usually infects an individual by way of the respiratory tract. […] Hepatic histoplasmosis can occur both in children and adults, in immunocompetent and immunocompromised patients, and in endemic and nonendemic areas. […] Hepatic involvement is frequent in disseminated histoplasmosis. The liver is reportedly involved in about 90% of patients with disseminated histoplasmosis. […] However, liver histoplasmosis as a primary sign of histoplasmosis without lung involvement is uncommon. […] The full spectrum of hepatic manifestations of this disease is unknown but spans the range in the literature from mildly abnormal liver enzymes to severe icteric cholestasis with fever and pain. […] H.capsulatum is an uncommon cause of granulomatous liver disease. […] The typical clinical presentations are fever and jaundice in the setting of immunosuppression. […] There are limited case reports of disseminated histoplasmosis presenting as primary hepatic histoplasmosis.

• #93 Histoplasmosis of the nervous system | MedLink Neurology

  https://www.medlink.com/articles/histoplasmosis-of-the-nervous-system

  Histoplasmosis is an infection caused by the fungus Histoplasma capsulatum. Infection is endemic to certain areas of the United States, including the Mississippi and Ohio River Valleys, as well as parts of Central America, South America, Africa, and Southeast Asia. Organisms are spread by disturbance of ground soil contaminated by bat and avian excrement. Inhalation of spores causes infection, which primarily involves the lungs. Extrapulmonary infection can occur, though this is much less common. Immunocompromised individuals are at an increased risk for disseminated infection. In rare but serious cases, histoplasmosis affects the nervous system. Central nervous system involvement is clinically recognized in 10% to 20% of progressive, disseminated cases. CNS infection can also be isolated. Meningitis is the most common clinical manifestation of CNS histoplasmosis.

• #94 Presumed Ocular Histoplasmosis Syndrome

  https://www.asrs.org/patients/retinal-diseases/18/presumed-ocular-histoplasmosis-syndrome

  Histoplasmosis is a disease caused by Histoplasma capsulatum (H. capsulatum), a soil fungus prevalent in certain parts of the American continent, in particular the Ohio and Mississippi River valleys. […] Consequently, it is thought that H. capsulatum enters the eye from the bloodstream, invading the choroidal vessels and ultimately causing scarring. However, it has never been directly proven that H. capsulatum causes POHS, hence the name presumed ocular histoplasmosis syndrome. […] One theory is that when childhood infection with H. capsulatum occurs, the fungus spreads through the bloodstream to the eye and choroid, where scars form and remain long after the systemic infection subsides.

• #95 What Is African Histoplasmosis?

  https://www.icliniq.com/articles/infectious-diseases/african-histoplasmosis

  African histoplasmosis is a fungal infection caused by Histoplasma capsulatum var. duboisii. It is common in Africa and affects skin, bone, and lymph nodes. […] The exact mechanism of the disease manifestation is not fully understood. The fungus can reach the lungs through direct inhalation. The fungus is said to spread to other organs through the bloodstream from the lungs. […] According to reports, bat intestines carry the fungus, and soil mixed with bat excreta is thought to be a natural reservoir of the fungus. […] African histoplasmosis is caused by a fungus that makes you sick if inhaled. […] This fungus is found in the environment, especially in the soil containing bat and bird droppings. […] This disease spreads through inhalation. Outbreak occurs when there is exposure to bird or bat droppings, contaminated soil, etc. It spreads when a person inhales it. […] African histoplasmosis is a type of fungal infection. The fungus Histoplasma causes it.

• #96

  https://www.xiahepublishing.com/2310-8819/JCTH-2020-00080

  Histoplasma capsulatum is the most common cause of endemic mycosis in developing countries. […] Histoplasmosis is a systemic fungal disease that is caused by the dimorphic fungus Histoplasma capsulatum, which usually infects an individual by way of the respiratory tract. […] Hepatic histoplasmosis can occur both in children and adults, in immunocompetent and immunocompromised patients, and in endemic and nonendemic areas. […] Hepatic involvement is frequent in disseminated histoplasmosis. The liver is reportedly involved in about 90% of patients with disseminated histoplasmosis. […] However, liver histoplasmosis as a primary sign of histoplasmosis without lung involvement is uncommon. […] The full spectrum of hepatic manifestations of this disease is unknown but spans the range in the literature from mildly abnormal liver enzymes to severe icteric cholestasis with fever and pain. […] H.capsulatum is an uncommon cause of granulomatous liver disease. […] The typical clinical presentations are fever and jaundice in the setting of immunosuppression. […] There are limited case reports of disseminated histoplasmosis presenting as primary hepatic histoplasmosis.

• #97 Mediastinal granuloma and fibrosing mediastinitis – UpToDate

  https://www.uptodate.com/contents/mediastinal-granuloma-and-fibrosing-mediastinitis

  Mediastinal granuloma and fibrosing mediastinitis are rare causes of mediastinal masses. Mediastinal granuloma is characterized by a granulomatous mass-like lesion in the hilum or mediastinum. Fibrosing mediastinitis (also known as sclerosing mediastinitis or mediastinal fibrosis) is characterized by an excessive fibrotic reaction in the mediastinum. Both entities are uncommon complications of prior histoplasmosis infection. […] It is widely thought that fibrosing mediastinitis and mediastinal granuloma are two divergent host responses that occur in mediastinal lymph nodes from a previous infection (or insult). Most cases are thought to be due to previous infection with Histoplasma capsulatum, which is by far the most common cause in the United States. […] Among the etiologies, the dimorphic fungus, Histoplasma capsulatum, is by far the most common etiology for both disorders in the United States. This is supported by the higher concentration of reported cases in endemic areas (eg, southeastern, mid-Atlantic, and central United States along the Ohio and Mississippi river valleys) and the lower number of reported cases in other regions of the world where infection with Histoplasma is rare. […] Mediastinal granuloma due to tuberculosis is well described and may be more commonly seen in patients who live or have previously lived in endemic areas (eg, West Africa, India).

• #98 Pulmonary Histoplasmosis: A Clinical Update

  https://www.mdpi.com/2309-608X/9/2/236

  The heat shock protein 60 (Hsp60) of H. capsulatum is the major surface adhesin to macrophages and binds to complement receptor 3 (CR3). […] Once inside the macrophage, Histoplasma evades reactive oxygen and nitrogen species and is also able to regulate the phagosome acidification and the phagolysosomal fusion. […] The diagnosis of histoplasmosis can be ascertained by the direct observation or isolation of the pathogen (culture, histopathology, and cytopathology) or by the detection of antigens, antibodies, or nucleic acids. […] Isolation of H. capsulatum from clinical specimens remains the gold standard for the diagnosis of histoplasmosis, though histopathologic or direct microscopic identification are also considered definitive diagnoses. […] Histopathology can show characteristic features including granulomas (both caseating or non-caseating), and staining with Grocott-Gomori’s methenamine silver or Wright’s periodic acid-Schiff allows for the visualization of ovoid, narrow-based budding yeasts.

• #99 Pulmonary Histoplasmosis: A Clinical Update

  https://www.mdpi.com/2309-608X/9/2/236

  The heat shock protein 60 (Hsp60) of H. capsulatum is the major surface adhesin to macrophages and binds to complement receptor 3 (CR3). […] Once inside the macrophage, Histoplasma evades reactive oxygen and nitrogen species and is also able to regulate the phagosome acidification and the phagolysosomal fusion. […] The diagnosis of histoplasmosis can be ascertained by the direct observation or isolation of the pathogen (culture, histopathology, and cytopathology) or by the detection of antigens, antibodies, or nucleic acids. […] Isolation of H. capsulatum from clinical specimens remains the gold standard for the diagnosis of histoplasmosis, though histopathologic or direct microscopic identification are also considered definitive diagnoses. […] Histopathology can show characteristic features including granulomas (both caseating or non-caseating), and staining with Grocott-Gomori’s methenamine silver or Wright’s periodic acid-Schiff allows for the visualization of ovoid, narrow-based budding yeasts.

• #100 Histoplasmosis of the nervous system | MedLink Neurology

  https://www.medlink.com/articles/histoplasmosis-of-the-nervous-system

  Histoplasma capsulatum is a dimorphic fungus with 2 variants, Histoplasma capsulatum variety capsulatum, which is encountered chiefly in America and the tropics, and histoplasma capsulatum variety duboisii, which occurs in Africa. H. capsulatum typically results in pulmonary infections, whereas H. duboisii affects the skin and skeleton. […] The organism grows as a mold in the soil, and consists of hyphen-bearing large tuberculate macroconidia (8 to 14 um in diameter) and smaller microconidia (2 to 5 um). The latter is the infectious form of the fungus. Conidia inhaled into the lungs germinate into yeast-like forms and incite an immune reaction. The extent of disease depends on the number of conidia inhaled and the hosts cellular immune response. In patients with adequate immunity, T-lymphocytes activate against the H. capsulatum antigen and stimulate macrophages to kill the engulfed yeast. T cells are pivotal in clearance of the infection. A direct correlation exists between the CD4+ T cell count and the capacity of macrophages to bind yeast cells. As a result, patients with HIV or AIDS are more susceptible to disseminated disease. Involvement of the central nervous system arises following dissemination from a pulmonary source.

• #101 Pulmonary Histoplasmosis: A Clinical Update

  https://www.mdpi.com/2309-608X/9/2/236

  The heat shock protein 60 (Hsp60) of H. capsulatum is the major surface adhesin to macrophages and binds to complement receptor 3 (CR3). […] Once inside the macrophage, Histoplasma evades reactive oxygen and nitrogen species and is also able to regulate the phagosome acidification and the phagolysosomal fusion. […] The diagnosis of histoplasmosis can be ascertained by the direct observation or isolation of the pathogen (culture, histopathology, and cytopathology) or by the detection of antigens, antibodies, or nucleic acids. […] Isolation of H. capsulatum from clinical specimens remains the gold standard for the diagnosis of histoplasmosis, though histopathologic or direct microscopic identification are also considered definitive diagnoses. […] Histopathology can show characteristic features including granulomas (both caseating or non-caseating), and staining with Grocott-Gomori’s methenamine silver or Wright’s periodic acid-Schiff allows for the visualization of ovoid, narrow-based budding yeasts.

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