Description

Histoplasmosis is a disease caused by the fungus Histoplasma capsulatum. The fungus usually grows in soil enriched with accumulations of bat or bird droppings. The disease is acquired via inhalation of spores (conidia) from soil contaminated with bat or bird droppings.

ccurrence

In the United States, H. capsulatum var. capsulatum is found along the Ohio and Mississippi River valleys, mostly in the central and southeastern states. Its occurrence has been described on every continent except Antarctica. Autochthonous human cases have been reported throughout Central and South America, the Caribbean, eastern Asia (Iran, Pakistan, India, China, Thailand, Indonesia, Vietnam, Malaya, Philippines, Burma, and Japan), parts of Europe (northern Italy, Bulgaria, Spain, Hungary, Austria, France, Portugal, Romania, Turkey, the countries of the former Soviet Union, Great Britain, Ireland, and Norway), parts of Africa, and Australia. In May 2001, an outbreak of histoplasmosis occurred among college students vacationing in Acapulco.

Risk for Travelers

Persons who visit endemic areas and are exposed to accumulations of bat guano or bird droppings are at increased risk for infection. Exposures can occur during activities such as spelunking, mining, construction, excavation, demolition, roofing, chimney cleaning, farming, gardening, and installing heating and air-conditioning systems. While in caves or mines, spending time close to the ground or kicking up dirt infested with bat guano containing H. capsulatum can increase the risk of infection. With sufficient exposure, persons can be reinfected with H. capsulatum.

Clinical Presentation

Ninety percent of infections are asymptomatic or result in a mild influenza-like illness. Some infections, however, cause acute pulmonary histoplasmosis, manifested by high-grade fever, headache, nonproductive cough, chills, weakness, and pleuritic chest pain. Symptoms occur 3-17 days after exposure, and most persons recover spontaneously 2-3 weeks after symptom onset. Dissemination, especially to the gastrointestinal tract and central nervous system, can occur in persons with severe immunocompromising conditions (e.g, HIV infection). Reinfection and reactivation can occur. Histoplasmosis is not transmitted directly from person to person.

Prevention

Persons at increased risk for infection, especially for severe disease, should be advised to avoid high-risk areas, such as bat-inhabited caves. If exposure cannot be avoided, persons should be advised to decrease dust generation in infested areas by watering the areas before engaging in dust-generating activities and to wear masks and special protective equipment. Further details about the protective equipment can be obtained from http://www.cdc.gov/niosh/97-146.html. No effective vaccine for histoplasmosis is currently available.

Treatment

For persons with acute, localized pulmonary histoplasmosis, specific antifungal treatment is not usually necessary because the disease is self-limited. Persons with severe or persistent symptoms can be treated with itraconazole or Amphotericin B. All persons with severe disease, including diffuse pulmonary and disseminated histoplasmosis, should be treated with either itraconazole (available orally and intravenously) or Amphotericin B (available in intravenous form). Pregnant women for whom treatment is indicated should be given Amphotericin B. Consultation with an infectious diseases specialist is advised.

Health Information for International Travel 2003-2004

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