Dan,
 
Following is an article about the hazards of  being in caves that are
actively used by bats.  I retrieved two other "hits" from the Centers for
Disease Control web site <http://www.cdc.gov>.  Try
<http://www.cdc.gov/nchstp/tb/pubs/mmwr/mm4438.pdf> for a longer article on
workers affected by Histoplasmosis from a cave in Kentucky.  IF that does
not wrok, use the CDC search enginer and search under "bat guano."
 
Marc Kodack
[log in to unmask]
 
 
 
 
International Notes Cave-Associated Histoplasmosis -- Costa Rica
 
An outbreak of histoplasmosis occurred among a group of university students
who entered a cave in Santa Rosa National Park, Guanacaste Province, Costa
Rica,
on January 4, 1988. The cave was inhabited by about 500 bats, including
three species of fruit bats (Glossophaga soricina, Carollia perspicillata,
and Carollia
subrufra) and one species of vampire bats (Desmodus rotundus). The cave
consisted of two entrances to a single chamber 20 x 75 x 5 feet in size.
Bat guano
covered the floor of the cave, and the ground was noted to be exceptionally
dry for the season.
 
Seventeen students (mean age, 24 years; range, 20-40 years) entered the
cave to observe the bats and photograph a small boa constrictor feeding on
them. The
students were in the cave an average of 26 minutes (range, 3-90 minutes).
Fifteen (88%) of the 17 students became acutely ill within 9-24 days (mean,
14.4 days);*
12 remained ill 14 days after onset of symptoms. One student, who did not
enter the cave, did not become ill. Signs and symptoms among the 15 ill
persons included
fever (93%), headache (87%), cough (80%), dyspnea (80%), chest pain (73%);
and myalgia (53%). Two patients were hospitalized, but all recovered without
antifungal treatment.
 
Chest x-rays were obtained for 12 of the 15 patients; 10 had bilateral
diffuse fluffy nodular parenchymal infiltrates. Late acute-phase and early
convalescent-phase
serum specimens (3 and 5 weeks after exposure to the cave) and urine
specimens (5 weeks after exposure) were obtained from all 15 patients.
Twelve of the 15
patients had evidence of histoplasmosis by complement fixation test,
immunodiffusion test, or urinary antigen detection test (1,2). Reported by:
JE Johnson, RN,
BSN, JD Kabler, MD, Univ Health Svc, Univ of Wisconsin- Madison; MF
Gourley, MD, DJ D'Alessio, MD, Univ of Wisconsin-Madison Medical School; RW
Dodge, MS, R Golubjatnikov, PhD, Wisconsin State Laboratory of Hygiene; JP
Davis, MD, State Epidemiologist, Wisconsin Dept of Health and Social Svcs. LJ
Wheat, MD, Indiana Univ School of Medicine, Indianapolis. DH Janzen, PhD,
Univ of Pennsylvania, Philadelphia. Pan American Health Organization. Div
of Field
Svcs, Epidemiology Program Office; Immunology Br, Div of Mycotic Diseases,
Center for Infectious Diseases; Respiratory Diseases Br, Div of Bacterial
Diseases,
Center for Infectious Diseases, CDC. Editorial Note: Histoplasmosis is
caused by inhalation of spores of Histoplasma capsulatum from its natural
soil habitat.
Growth of H. capsulatum requires moderate temperatures, high humidity, and
a source of nitrates, often from decomposing feces of bats or birds. H.
capsulatum has
been isolated from both bat caves and bird roosts, and human infection has
been associated with exposure to both sources (3).
 
This outbreak is typical of bat-cave-associated histoplasmosis (4). The
high attack rate (88%) could be explained by the relatively young age of
the persons entering
the cave or by exposure to a large inoculum of H. capsulatum spores. The
extraordinarily dry ground in the cave also may have increased the
dispersion of spores in
the cave. H. capsulatum has been more readily isolated from caves under dry
conditions than after flooding (5).
 
Cave-acquired histoplasmosis differs in several respects from
histoplasmosis associated with bird roosts. Bats, unlike avian species, may
become infected with H.
capsulatum (6). Therefore, formaldehyde spraying, a useful control measure
for avian-associated sources of histoplasmosis (7), may be ineffective in
reducing the
risk of infection in a bat cave because bats can recontaminate the cave.
Furthermore, skin test surveys have shown that persons living near
contaminated caves have
a lower prevalence of reactivity to histoplasmin than spelunkers living in
the same area (3). This finding suggests that H. capsulatum infection
occurs only in persons
who enter contaminated caves. In contrast, airborne dispersal of organisms
from bird roosts can cause outbreaks involving at least several square
kilometers (8).
 
Much of Santa Rosa National Park consists of mature deciduous dry forest in
the relatively dry climate of northwest Costa Rica. During the rainy season
(June-November), a seasonal river usually floods the cave that was
associated with this outbreak and washes out the bat guano. However,
flooding had not
occurred because of extraordinarily low rainfall during this year's rainy
season. Measured rainfall since 1978 has averaged 160 cm per year, but only
50-70 cm were
recorded during 1987. The cave is accessible from a hiking trail and is
commonly included on tours of the park led by local field biologists. No
illness was reported
among groups from the same university who entered the cave in January 1983
and January 1986. Officials of Santa Rosa National Park and field
biologists in the
area have been notified of the outbreak, and warning signs have been posted
outside the cave. References
 
   1.Kaufman L, Reiss E. Serodiagnosis of fungal diseases. In: Lennette EH,
Balows A, Hausler WJ Jr, Shadomy HJ, eds. Manual of clinical microbiology.
4th ed.
     Washington, DC: American Society for Microbiology, 1985:924-44.
 
   2.Wheat LJ, Kohler RB, Tewari RP. Diagnosis of disseminated
histoplasmosis by detection of Histoplasma capsulatum antigen in serum and
urine specimens. N
     Engl J Med 1986; 314:83-8.
 
   3.Larsh HW. The epidemiology of histoplasmosis. In: Al-Doory Y, ed. The
epidemiology of human mycotic diseases. Springfield, Illinois: Charles C
Thomas,
     1975:52-73.
 
   4.Sacks JJ, Ajello L, Crockett LK. An outbreak and review of
cave-associated histoplasmosis capsulati. J Med Vet Mycol 1986;24:313-25.
 
   5.DiSalvo AF, Bigler WJ, Ajello L, Johnson JE, Palmer J. Bat and soil
studies for sources of histoplasmosis in Florida. Public Health Rep
1970;85:1063-9.
 
   6.Emmons CW, Klite PD, Baer GM, Hill WB Jr. Isolation of Histoplasma
capsulatum from bats in the United States. Am J Epidemiol 1966;84:103-9.
 
   7.Centers for Disease Control. Histoplasmosis control: decontamination
of bird roosts, chicken houses, and other point sources. Atlanta: US
Department of
     Health, Education, and Welfare, Public Health Service, 1979; HEW
publication no. (CDC)80-8380.
 
   8.DiSalvo AF, Johnson WM. Histoplasmosis in South Carolina: support for
the microfocus concept. Am J Epidemiol 1979;109:480-92. *A tour member who
     experienced any two of the following symptoms within 30 days after
returning to the United States was considered to have histoplasmosis:
fever, headache,
     cough, dyspnea, or chest pain.