A recent outbreak of histoplasmosis has been linked to a group of 12 US family members who visited a bat-colonized cave in Costa Rica, according to a new report. The disease, primarily affecting the lungs, is caused by inhaling Histoplasma spores from disturbed soil containing bat guano or bird droppings.
The outbreak occurred during a 7-day vacation in December 2024 and January 2025, when 12 of 13 family members toured Venado Caves. Six were aged 42 to 49 years, while six were between 8 and 16 years old. All reported seeing bats and coming into contact with bat droppings during the tour.
Symptoms included headache, malaise, fever, night sweats, muscle pain, respiratory problems, and gastrointestinal issues. Four family members tested positive for Histoplasma capsulatum species complex, while three received antibiotics and one was hospitalized due to abnormal chest radiographic findings.
Despite receiving treatment, all 12 affected family members recovered or were getting better by day 28 post-exposure. However, the study highlights that histoplasmosis can be misdiagnosed, and antibiotics may not be effective. Clinicians should consider fungal illness in the differential diagnosis of patients with recent caving or other activities associated with risk for histoplasmosis.
The outbreak is a reminder of the risks associated with visiting caves containing bat colonies, where Histoplasma spores are present. The CDC has alerted health departments and recommended adding information about histoplasmosis risks into tour waiver forms to prevent future outbreaks.
Source: https://www.cidrap.umn.edu/misc-emerging-topics/family-likely-infected-histoplasmosis-bat-colonized-cave