A dream family vacation to Costa Rica took an alarming turn when 12 out of 13 relatives exhibited symptoms of a fungal lung infection following an excursion through bat-inhabited caves. This incident highlights the real-world risks of airborne fungi, a concept familiar to fans of shows like The Last of Us, where the fictional cordyceps fungus becomes transmissible through inhalation. While the TV series is speculative, the danger of airborne fungal infections is a stark reality, as one U.S. family recently discovered after exploring a bat cave.
The Costa Rican Cave Expedition and Subsequent Illness
During their December vacation, 12 members of a 13-person family group embarked on a tour of the Venado Caves, an ancient cave system and popular tourist spot known for its bat population. The two-hour tour involved navigating areas with significant bat guano. Upon returning to the United States, all 12 who participated in the cave tour developed varying degrees of illness. Symptoms reported included fever, headaches, muscle pain, night sweats, respiratory difficulties, and gastrointestinal problems. The only family member who did not enter the cave remained symptom-free.
Understanding Histoplasmosis: The Fungal Culprit
According to a paper published in the Morbidity and Mortality Weekly Report, health officials identified confirmed or probable cases of histoplasmosis among the affected family members. Histoplasmosis is a pulmonary infection resulting from inhaling spores of the fungus Histoplasma capsulatum. This fungus commonly resides in soil enriched with bird or bat droppings and can become airborne when the soil is disturbed. While symptoms are often mild or absent in healthy individuals, the infection can pose a more significant threat to infants and those with compromised immune systems.
Five of the ill family members sought medical attention. Four were tested for fungal infections, with two testing positive for Histoplasma. Chest X-rays revealed abnormalities in two patients, one of which initially raised concerns about possible lung cancer. After learning about the family’s spelunking activity in Costa Rica, healthcare providers alerted the CDC, prompting an investigation. It was noted that the Venado Caves had been linked to a previous histoplasmosis outbreak in 1998 and 1999.
Diagnostic Challenges and Recovery Outlook
The CDC-led research team highlighted the complexities of diagnosing histoplasmosis. “Antigen testing for all four patients occurred within 1 month of symptom onset, the optimal time frame,” they wrote. “However, because antigen detection sensitivity for histoplasmosis is lower in patients with mild disease who are immunocompetent, the negative test results might have been false negatives.” This suggests that even family members who tested negative could have had the infection, as histoplasmosis is more challenging to detect in otherwise healthy individuals.
Ultimately, one family member was confirmed to have histoplasmosis, eight were classified as probable cases, and three were suspected cases. Fortunately, none developed severe complications, and all were recovering within 28 days of exposure. While antifungal medication is prescribed for severe histoplasmosis, many cases in healthy individuals resolve on their own without specific treatment. [internal_links]
Raising Awareness and Preventing Future Infections
Given the diagnostic difficulties, researchers emphasize the need for clinicians to “consider fungal illness in the differential diagnosis of patients with constitutional or pulmonary signs or symptoms after recent caving or other activities associated with risk for histoplasmosis.” In response to this incident, the CDC is collaborating with the U.S. Embassy in Costa Rica and the Costa Rica Ministry of Health to advocate for including histoplasmosis risk information in the Venado Caves tour waiver forms.
The popularity of narratives like The Last of Us perhaps stems from their ability to tap into primal fears. As Andrzej Sapkowski, author of The Witcher, observed, “there’s a grain of truth in every fairy tale.” This sentiment rings true, even when considering the less fantastical, yet still significant, threat posed by real-world fungal pathogens. Travelers and adventurers should remain aware of such environmental health risks.
