In the United States, an estimated 60% to 90% of people who live in areas surrounding the Ohio and Mississippi River valleys (where Histoplasma is common in the environment) have been exposed to the fungus at some point during their lifetime.1 One study calculated the incidence of histoplasmosis in adults aged 65 years and older in the U.S. to be 3.4 cases per 100,000 population.2 Rates were highest in the Midwest, with an estimated 6.1 cases per 100,000 population.2
This map shows the incidence of histoplasmosis, by county (number of cases/100,000 population) for 12 states for which surveillance data were available, 2011–2014.3 Rates cannot be directly compared across states because different histoplasmosis case definitions were used.3
Worldwide, histoplasmosis is most common among people who have HIV/AIDS or a weakened immune system for another reason. It’s especially a problem in areas of the world where antiretroviral therapy (ART) is not widely available, because ART helps keep HIV-infected people from reaching the stage where they are most vulnerable to histoplasmosis and other opportunistic infections.4 In Latin America, for example, histoplasmosis is one of the most common opportunistic infections among people living with HIV, and approximately 30% of HIV/AIDS patients diagnosed with histoplasmosis die from it.5
Histoplasmosis is reportable in certain states. Check with your local, state, or territorial public health department for more information about disease reporting requirements and procedures in your area.
Although most cases of histoplasmosis are not associated with outbreaks, histoplasmosis outbreaks linked to a common source do occasionally occur.6 Common-source histoplasmosis outbreaks often involve activities that disrupt soil, especially soil that contains bird or bat droppings. Examples of these types of activities include: construction,7 renovation,8 exploring caves,9 tilling soil,10 and cleaning up bird roosting sites.11 If you live in an area where Histoplasma is common in the environment, contact your local or state health department for the most up-to-date information about outbreaks.
One study of patients who were hospitalized for histoplasmosis in the U.S. estimated the crude mortality rate to be approximately 5% for children and 8% for adults.12 Another study found a six-month mortality rate of 4% among patients with symptomatic histoplasmosis.13 The overall mortality rate for histoplasmosis is likely lower than these estimates because these studies did not include patients who had less severe forms of the infection.
- Manos NE, Ferebee SH, Kerschbaum WF. Geographic variation in the prevalence of histoplasmin sensitivity. Dis chest. 1956 Jun;29(6):649-68.
- Baddley JW, Winthrop KL, Patkar NM, Delzell E, Beukelman T, Xie F, et al. Geographic distribution of endemic fungal infections among older persons, United States. Emerg Infect Dis. 2011 Sep;17(9):1664-9.
- Armstrong PA, Jackson BR, Haselow D, Fields V, Ireland M, Austin C, et al. Multistate Epidemiology of Histoplasmosis, United States, 2011-2014. Emerg Infect Dis. 2018 Mar;24(3):425-31.
- Haddad NE, Powderly WG. The changing face of mycoses in patients with HIV/AIDS. The AIDS reader 2001;11:365-8, 75-8.
- Colombo AL, Tobon A, Restrepo A, Queiroz-Telles F, Nucci M. Epidemiology of endemic systemic fungal infections in Latin America. Med Mycol. 2011 Nov;49(8):785-98
- Benedict K, Mody RK. Epidemiology of Histoplasmosis Outbreaks, United States, 1938-2013. Emerg Infect Dis. 2016 Mar;22(3).
- Wheat LJ, Slama TG, Eitzen HE, Kohler RB, French MLV, Biesecker JL. A Large Urban Outbreak of Histoplasmosis – Clinical-Features. Ann Intern Med. 1981;94(3):331-7.
- CDC. Outbreak of histoplasmosis among travelers returning from El Salvador–Pennsylvania and Virginia, 2008. MMWR. 2008 Dec 19;57(50):1349-53.
- Lyon GM, Bravo AV, Espino A, Lindsley MD, Gutierrez RE, Rodriguez I, et al. Histoplasmosis associated with exploring a bat-inhabited cave in Costa Rica, 1998-1999. Am J Trop Med Hyg. 2004 Apr;70(4):438-42.
- Brodsky AL, Gregg MB, Loewenstein MS, Kaufman L, Mallison GF. Outbreak of histoplasmosis associated with the 1970 Earth Day activities. Am J Med. 1973 Mar;54(3):333-42.
- Chamany S, Mirza SA, Fleming JW, Howell JF, Lenhart SW, Mortimer VD, et al. A large histoplasmosis outbreak among high school students in Indiana, 2001. The Pediatric infectious disease journal. 2004 Oct;23(10):909-14.
- Chu JH, Feudtner C, Heydon K, Walsh TJ, Zaoutis TE. Hospitalizations for endemic mycoses: a population-based national study. Clin Infect Dis. 2006 Mar 15;42(6):822-5.
- Ledtke C, Tomford JW, Jain A, Isada CM, van Duin D. Clinical presentation and management of histoplasmosis in older adults. J Am Geriatr Soc. 2012 Feb;60(2):265-70.