CDC Yellow Book 2024

Travel-Associated Infections & Diseases

Author(s): Jeremy Gold, Diego Caceres, Brendan Jackson, Kaitlin Benedict

INFECTIOUS AGENT: Histoplasma capsulatum




Adventure tourists
Humanitarian aid workers
Immigrants and refugees
Long-term travelers and expatriates
Study-abroad students
Travelers visiting friends and relatives


Avoid exposure to soil contaminated with bird droppings or bat guano
Chemoprophylaxis might be appropriate in rare circumstances for immunocompromised people


A clinical laboratory certified in moderate complexity testing; or contact CDC’s Mycotic Diseases Branch Reference Laboratory Team (404-639-2569)

Infectious Agent

Histoplasmosis is caused by Histoplasma capsulatum, a thermal-dimorphic fungus that grows as a mold in the environment and as a yeast in animal and human hosts.


Histoplasmosis is transmitted through inhalation of spores (conidia) from the environment, often soil contaminated with bat guano or bird droppings, but is not transmitted from person to person.


Knowledge of global histoplasmosis epidemiology is incomplete, and cases in travelers are likely underreported to public health authorities. Travelers, including adventure tourists, humanitarian aid workers, long-term travelers and expatriates, study-abroad students, and people visiting friends and relatives could be at increased risk for histoplasmosis if they engage in activities involving soil disruption (e.g., caving, construction, demolition, excavation, farming, gardening), particularly in areas where bats and birds roost. Histoplasmosis also occurs in immigrants from endemic regions who become immunocompromised.

Clinical Presentation

Incubation period is typically 3–17 days for acute disease. About 90% of infections are asymptomatic or result in a mild influenza-like illness. Acute pulmonary histoplasmosis often involves body aches, chest pain, chills, cough, fatigue, fever, and headache. Most people spontaneously recover several weeks after symptom onset, but fatigue might persist longer. High-dose exposure can lead to severe disease. Dissemination, especially to the central nervous system and gastrointestinal tract, can occur in immunocompromised people. Histoplasmosis might be misdiagnosed as other illnesses, particularly as tuberculosis in people who travel from regions where both pathogens are endemic.


Several methods to diagnose histoplasmosis are available. Although culture and histopathologic identification remain the gold standards, a combination of antigen and antibody testing could be more useful in diagnosing travel-associated histoplasmosis. Rapid Histoplasma antigen testing by enzyme immunoassays, reagents for immunodiffusion, and complement fixation are commercially available as in vitro diagnostic kits. In immunocompetent patients, antigen testing is most useful when performed within 2 weeks of a high-dose exposure. Antibody testing of specimens collected during the acute and convalescent phases of illness can improve diagnostic yield; obtaining serial antigen and antibody titers can aid in monitoring response to treatment.

The Centers for Disease Control and Prevention (CDC)’s Mycotic Diseases Branch reference laboratory supports histoplasmosis diagnosis and outbreak investigations. Laboratory support includes immunodiagnostics by antibody and antigen testing, and molecular testing. To obtain diagnostic support from CDC, contact the Mycotic Diseases Branch reference laboratory team (404-639-2569).


Treatment is not usually indicated for immunocompetent people with acute, localized pulmonary infection. People with more extensive disease or persistent symptoms lasting >1 month generally can be treated with an azole drug (e.g., itraconazole) for mild to moderate illness, or amphotericin B for severe infection. Patients with acute respiratory distress might benefit from steroids as well as antifungal treatment.


People at increased risk for severe disease should avoid high-risk areas (e.g., bat-inhabited caves, hollow trees). No vaccine for histoplasmosis is available. Chemoprophylaxis with itraconazole is recommended for certain people living with HIV, and might be appropriate in specific circumstances for other immunosuppressed people.

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

The following authors contributed to the previous version of this chapter: Brendan R. Jackson, Tom M. Chiller

Adenis AA, Valdes A, Cropet C, McCotter OZ, Derado G, Couppie P, et al. (2018). Burden of HIV-associated histoplasmosis compared with tuberculosis in Latin America: a modelling study. Lancet Infect Dis. 2018;18(10):1150–9.

Armstrong PA, Beard JD, Bonilla L, Arboleda N, Lindsley MD, Chae S-R, et al. Outbreak of severe histoplasmosis among tunnel workers—Dominican Republic, 2015. Clin Infect Dis. 2018;66(10):1550–7.

Azar MM, Hage CA. Laboratory diagnostics for histoplasmosis. J Clin Microbiol. 2017;55(6):1612–20. Bahr NC, Antinori S, Wheat LJ, Sarosi GA. Histoplasmosis infections worldwide: thinking outside of the Ohio River valley. Curr Trop Med Rep. 2015;2(2):70–80.

Centers for Disease Control and Prevention. Outbreak of histoplasmosis among travelers returning from El Salvador—Pennsylvania and Virginia, 2008. MMWR Morb Mortal Wkly Rep. 2018;57(50):1349–53.

Cottle LE, Gkrania‐Klotsas E, Williams HJ, Brindle HE, Carmichael AJ, et al. A multinational outbreak of histoplasmosis following a biology field trip in the Ugandan rainforest. J Travel Med. 2013;20(2):83–7.

Kauffman CA. Histoplasmosis: a clinical and laboratory update. Clin Microbiol Rev. 2007;20(1):115–32.

Staffolani S, Buonfrate D, Angheben A, Gobbi F, Giorli G, Guerriero M, et al. Acute histoplasmosis in immunocompetent travelers: a systematic review of literature. BMC Infect Dis. 2018;18(1):673.

Wheat LJ, Freifeld AG, Kleiman MB, Baddley JW, McKinsey DS, Loyd JE, et al. Clinical practice guidelines for the management of patients with histoplasmosis: 2007 update by the Infectious Diseases Society of America. Clin Infect Dis. 2007;45(7):807–25.