HISTOPLASMOSIS

What is histoplasmosis? older persons, in particular those with underlying illnesses such as diabetes and chronic lung disease, Histoplasmosis is an infectious disease caused by are at increased risk for developing symptomatic inhaling spores of a fungus called Histoplasma histoplasmosis. capsulatum. Histoplasmosis is not contagious; it cannot be transmitted from an infected person or People with weakened immune systems are at great- animal to someone else. est risk for developing severe and disseminated histoplasmosis. Included in this high-risk group are What are the symptoms of histoplasmosis? persons with AIDS or cancer and persons receiving cancer chemotherapy; high-dose, long-term steroid Histoplasmosis primarily affects a person’s lungs, therapy; or other immuno-suppressive drugs. and its symptoms vary greatly. The vast majority of infected people are asymptomatic (have no appar- Before 2000, a person could learn from a histo- ent ill effects) or they experience symptoms so plasmin skin test whether he or she had been pre- mild they do not seek medical attention. If symp- viously infected by H. capsulatum. However, the toms do occur, they will usually start within 3 to 17 manufacturing of histoplasmin was discontinued in days after exposure, with an average of 10 days. 2000, and the skin testing reagents were still Histoplasmosis can appear as a mild, flu-like respi- unavailable in 2004. A previous infection can pro- ratory illness and has a combination of symptoms, vide partial immunity to reinfection. Since a posi- including malaise (a general ill feeling), fever, tive skin test does not mean that a person is com- chest pain, dry or nonproductive cough, headache, pletely immune to reinfection, appropriate expo- loss of appetite, shortness of breath, joint and mus- sure precautions should be taken regardless of a cle pains, chills, and hoarseness. A chest X-ray of worker’s past skin-test status whenever distur- a person with acute pulmonary histoplamosis will bances of materials that might be contaminated commonly show a patchy pneumonitis, which with H. capsulatum occur. eventually calcifies. Chronic lung disease due to histoplasmosis resembles tuberculosis and can What is the treatment for histoplasmosis? worsen over months or years. The most severe and rare form of this disease is disseminated histoplas- Mild cases of histoplasmosis are usually resolved mosis, which involves spreading of the fungus to without treatment. For severe cases, special anti- other organs outside the lungs. fungal medications are needed to arrest the disease. Disseminated histoplasmosis is fatal if untreated, Who can get histoplasmosis? but death can also occur in some patients even when medical treatment is received. Anyone working at a job or present near activities where material contaminated with H. capsulatum Where are H. capsulatum spores found? becomes airborne can develop histoplasmosis if enough spores are inhaled. After an exposure, how H. capsulatum grows in soils throughout the world. ill a person becomes varies greatly and most likely In the United States, the fungus is endemic (more depends on the number of spores inhaled and a per- prevalent) and the proportion of people infected by son’s age and susceptibility to the disease. The H. capsulatum is higher in central and eastern number of inhaled spores needed to cause disease states, especially along the Ohio and Mississippi is unknown. Children younger than 2 years of age, River valleys. The fungus seems to grow best in persons with compromised immune systems, and soils having a high nitrogen content, especially those enriched with bat droppings or bird manure. How can exposure to H. capsulatum Disturbances of contaminated material cause small be controlled and histoplasmosis H. capsulatum spores to become airborne or prevented? aerosolized. Once airborne, spores can easily be car- ried by wind currents over long distances. The best way to prevent exposures to H. capsulatum spores is to avoid situations where material that How can someone know if soil or might be contaminated can become aerosolized and droppings are contaminated with subsequently inhaled. This is especially important H. capsulatum spores? for persons with weakened immune systems. To learn whether soil or droppings are contaminated Dust suppression methods, such as carefully wetting with H. capsulatum spores, samples must be collected with a water spray, may be useful for reducing the and cultured. Presently, the method used to isolate amount of material aerosolized during an activity. H. capsulatum is expensive and requires several For some activities, such as removing an accumula- weeks to complete. If not enough samples are tion of bat droppings or bird manure from an collected, small but highly contaminated areas can enclosed place such as an attic, wearing a be overlooked. Until a less expensive and more NIOSH-approved respirator and other items of per- rapid method is available, testing samples for sonal protective equipment may be needed to further H. capsulatum will continue to be impractical for reduce the risk of H. capsulatum exposure. However, most situations. Consequently, when thorough test- only persons trained in the proper selection and use ing is not done, the safest approach is to assume soil of personal protective equipment should undertake in endemic regions and any accumulations of bat work where this equipment is needed droppings or bird manure are contaminated with H. capsulatum and take appropriate exposure Disinfectants have occasionally been used to treat precautions. soil and accumulated bat manure when removal was impractical or as a precaution before a removal What jobs and activities have risks process was started. There is no product or chemical for exposure to H. capsulatum spores? that is registered by the EPA that has the specific Below is a partial list of occupations and hobbies claim of being effective against H. capsulatum. A with risks for exposure to H. capsulatum spores. manufacturer of a product claiming to disinfect soil Appropriate exposure precautions should be taken contaminated with H. capsulatum will have to meet by these people and others whenever contaminated the EPA’s regulatory requirements and complete the soil, bat droppings, or bird manure is disturbed. registration process.

➧ Bridge inspector or painter Where can I get more information ➧ Chimney cleaner about histoplasmosis? ➧ Construction worker This histoplasmosis fact sheet was prepared by the ➧ Demolition worker National Institute for Occupational Safety and Health (NIOSH) and the National Center for Infectious ➧ Farmer Diseases (NCID), both of the Centers for Disease ➧ Gardener Control and Prevention. For answers to other ques- ➧ Heating and air-conditioning system installer or tions about histoplasmosis or histoplasmin skin-test- service person ing, please contact your physician, your local health department, or NCID in Atlanta, Georgia. NCID’s ➧ Microbiology laboratory worker Internet address is http://www.cdc.gov/ncidod/. For ➧ Pest control worker other questions about worker health and safety pre- ➧ Restorer of historic or abandoned buildings cautions during disturbances of soil, bat droppings, or bird manure that might be contaminated with ➧ Roofer H. capsulatum spores, call NIOSH in Cincinnati, ➧ Spelunker (cave explorer) Ohio, at (800) 356-4674. 2004