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.