Histoplasmosis
Background and Symptoms
Histoplasmosis
is a fungal infection caused by Histoplasma capsulatum, a
soil saprophyte that produces infective spores. Human infection
results about 10 days (3-17) after the inhalation of airborne
spores, which are dislodged from soils enriched with animal
feces. Approximately 80% of those infected with histoplasmosis
 experience
either a subclinical or acute benign form that is characteristic
of a flu-like syndrome
(headache, myalgia, malaise, and cough) and resolves without
specific treatment.1 Progressive or chronic
disseminated and chronic pulmonary (cavitary) forms of
histoplasmosis have a poor prognosis and are difficult to
diagnose and treat. Avian habitats associated with domestic
poultry, pigeons, roosting flocks of wild birds and zoological
parks are considered to be especially suitable for proliferation
of H. capsulatum.1 Approximately 90% of all
cases reported in the US come from the Ohio and Mississippi
River valleys and some portions of Virginia and Maryland.2
Histoplasmosis in Florida
In Florida, histoplasmosis became
a reportable disease in 1957. From that time through 1998, 150
confirmed human cases of histoplasmosis were reported. However,
it was determined that less than one-third of Florida
histoplasmosis cases were acquired in the state and all of those
were derived from exposure to caves inhabited by bats.3
The first documented case of histoplasmosis in the state
associated with caves and bats occurred in 1955.4
Since then, reported cases have been sporadic and rare, with a
few cases reported in spelunkers in 1966 (1), 1972(3) and
1982(3).5 An unusual outbreak that involved 23 high
school students attending a cave party, in 1973, has also been
documented.6 Epidemiological studies have
demonstrated that H. capsulatum can be recovered from the
soil and bats (Myotis austroriparius and Pipistrellus
subflavus) associated with the caves frequented by these
cases.3,6,7 In 1999, Histoplasmosis was removed
from the list of reportable diseases within the state of
Florida.
For more
information
on histoplasmosis, visit the
Centers for Disease Control and Prevention (CDC)
References
1. Friedman, L and Domer, JK.
Systemic mycoses:histoplasmosis. In Diagnostic Procedures
for Bacterial, Mycotic and Parasitic Infections. Balows, A and
Hausler, WJ, (eds) Am. Pub. Hlth. Assn. 6th edition, 1981; pp.
959-64.
2. Larsh, HW. The epidemiology
of histoplasmosis. In: The Epidemiology of Human Mycotic
Diseases. Y. Al-Dorry ed. Charles C. Thomas Publishers,
Springfield, Ill.
3. Hoff, GL, and Bigler, WJ. The
role of bats in the propagation and spread of histoplasmosis:a
review. J. Wildl. Dis. 1981; 17(2):191-96.
4. Tegeris, AS and Smith, DT.
Acute disseminated pulmonary histoplasmosis treated with
cortisone and MRO-112. Ann. Int. Ned. 1958; 48:1414-20.
5. Johnson, JE, Radimer, JE,
Disalvo, AF, et al. Histoplasmosis in Florida: 1. Report of a
case and epidemiologic findings. Am. Rev of Resp. Dis; 1970,
101:299-305.
6. Lottenberg, R, Waldman, RH,
Ajello L, et al. Pulmonary histoplasmosis associated with
exploration of a bat cave. Am. J. Epidemiol.
1979,110:156-61.
7. Disalvo, AF, Bigler, WJ,
Ajello L. et al. Bat and soil studies for sources of
histoplasmosis in
Florida. Pub. Hlth.
Rep., 1970; 85:1063-69.
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