CIENCIASMEDICASNEWS: Histoplasmosis - Chapter 3 - 2014 Yellow Book | Travelers' Health

martes, 3 de junio de 2014

Histoplasmosis - Chapter 3 - 2014 Yellow Book | Travelers' Health | CDC

Histoplasmosis

Tom M. Chiller

Histoplasma capsulatum, a dimorphic fungus that grows as a mold in soil and as a yeast in animal and human hosts.

Through inhalation of spores (conidia) from soil that may be contaminated with bat guano or bird droppings; not transmitted directly from person to person.

Distributed worldwide, except in Antarctica, but most often associated with river valleys. Activities such as spelunking, mining, construction, excavation, demolition, roofing, chimney cleaning, farming, gardening, and installing heating and air-conditioning systems are associated with histoplasmosis. Activities that expose people to areas where bats live and birds roost also increase risk. Outbreaks have been reported associated with travel to many countries in Central and South America, most often associated with visiting caves.

Incubation period is typically 3–17 days for acute disease. Ninety percent of infections are asymptomatic or result in a mild influenzalike illness. Some infections may cause acute pulmonary histoplasmosis, manifested by high fever, headache, nonproductive cough, chills, weakness, pleuritic chest pain, and fatigue. Most people spontaneously recover 2–3 weeks after onset of symptoms, although fatigue may persist longer. Dissemination, especially to the gastrointestinal tract and central nervous system, can occur in people who are immunocompromised.

Culture of H. capsulatum from bone marrow, blood, sputum, and tissue specimens is the definitive method. Demonstration of the typical intracellular yeast forms by microscopic examination strongly supports the diagnosis of histoplasmosis when clinical, epidemiologic, and other laboratory studies are compatible. EIA on urine, serum, plasma, bronchoalveolar lavage, or cerebrospinal fluid is a rapid diagnostic test commercially available in the United States.

Treatment is not usually indicated for healthy, immunocompetent people with acute, localized pulmonary infection. People with more extensive disease or persistent symptoms beyond 1 month are generally treated with an azole drug, such as itraconazole, for mild to moderate illness or amphotericin B for severe infection.

People at increased risk for severe disease should avoid high-risk areas, such as bat-inhabited caves.

CDC website: www.cdc.gov/fungal/histoplasmosis

CDC. Outbreak of histoplasmosis among travelers returning from El Salvador—Pennsylvania and Virginia, 2008. MMWR Morb Mortal Wkly Rep. 2008 Dec 19;57(50):1349–53.
Kauffman CA. Histoplasmosis. Clin Chest Med. 2009 Jun;30(2):217–25.
Kauffman CA. Histoplasmosis: a clinical and laboratory update. Clin Microbiol Rev. 2007 Jan;20(1):115–32.
Morgan J, Cano MV, Feikin DR, et al. A large outbreak of histoplasmosis among American travelers associated with a hotel in Acapulco, Mexico, spring 2001. Am J Trop Med Hyg. 2003;69:663–9.
Weinberg M, Weeks J, Lance-Parker S, Traeger M, Wiersma S, Phan QN, et al. Severe histoplasmosis in travelers to Nicaragua. Emerg Infect Dis. 2003 Oct;9(10):1322–5.
Wheat LJ. Histoplasmosis: a review for clinicians from non-endemic areas. Mycoses. 2006 Jul;49(4):274–82.