Chronic histoplasmosis cases can  resemble tuberculosis; disseminated histoplasmosis affects multiple organ systems and is fatal unless treated.While histoplasmosis is the most common cause of mediastinitis, this remains a relatively rare disease. Severe infections can cause hepatosplenomegaly, lymphadenopathy, and adrenal enlargement. Lesions often left calcification nodules as they are healed.Presumed ocular histoplasmosis syndrome  causes chorioretinitis, where  the choroid and retina of the eyes are scarred, resulting in a loss of vision not unlike macular degeneration. Despite its name, the relationship to Histoplasma is controversial. Distinct from POHS, acute ocular histoplasmosis may rarely occur in immunodeficiency. Complications
In absence of proper treatment and especially in immunocompromised individuals, complications can arise. These include recurrent pneumonia, respiratory failure, fibrosing mediastinitis, superior vena cava syndrome, pulmonary vessel obstruction, and progressive fibrosis of lymph nodes. Fibrosing mediastinitis is a serious complication and can be fatal. Smokers with structural lung disease have higher probability of developing chronic cavitary histoplasmosis.After healing of lesions, hard, calcified lymph nodes can erode the walls of the airway, causing hemoptysis. Mechanisms
H. capsulatum grows in soil and material contaminated with bird or bat droppings (guano). The fungus has been found in poultry-house litter, caves, areas harboring bats, and bird roosts (particularly those of starlings). The fungus is thermally dimorphic; in the environment, it grows as a brownish mycelium, and at body temperature (37°C in humans), it morphs into a yeast. Histoplasmosis is not contagious but is contracted by inhalation of the spores from disturbed soil or guano. The inoculum is represented principally by microconidia.
Positive Histoplasmin skin tests occur in as many as 90% of the people living in areas where H. capsulatum is common, such as the eastern and central United States.In Canada, the St. Lawrence River Valley is the site of the most frequent infections, with 20–30% of the population testing positive. A review of reported cases in 2018 showed disease presence throughout Southeast Asia, In India, the Gangetic West Bengal is the site of most frequent infections, with 9.4% of the population testing positive. H. c. capsulatum was isolated from the local soil proving endemicity of Histoplasmosis in West Bengal. History
Histoplasma was discovered in 1905 by Samuel T. Darling, but only in the 1930s was it discovered to be a widespread infection. Before then, many cases of histoplasmosis were mistakenly attributed to tuberculosis, and patients were mistakenly admitted to tuberculosis sanatoria. Some patients contracted tuberculosis in these sanatoriums. Society and culture
Johnny Cash included a reference to the disease, even correctly noting its source in bird droppings, in the song "Beans for Breakfast". Bob Dylan was hospitalized due to Histoplasmosis in 1997, causing the cancellation of concerts in the United Kingdom and Switzerland. In episode 21 of season three of the television series House M.D., a patient was diagnosed with Histoplasmosis. In episode five of season one of the television series Dexter, Vince Masuka gets worried about getting Histoplasmosis from the dust in the air and the hair of the rats.