A new report Described how 12 members of an extended American family who visited a Costarian cave colonized by bat linked to a previous epidemic of histoplasmosis rising with confirmed or likely cases of fungal disease.
Histoplasmosis, which mainly affects the lungs, is caused by inhalation Histoplasm Disturbed floor spores containing bat guano or bird excrement. Most people have no symptoms, but the disease can put infants and people with an immune system weakened in danger of serious illness that can be chronic or deadly if untreated.
For the study, published last week Weekly ratio of morbidity and mortalityA team led by researchers from the US Centers for Disease Control and Prevention (CDC) examined the alleged histoplasmosis cluster affecting family members, who lived in Georgia, Texas and the State of Washington, in December 2024 and January 2025.
Travel contact details have raised suspicion
As part of a 7-day vacation, on December 24, 12 of the 13 members of the travel group family visited Venado Caves, a popular tourism destination in the province of Alajuela, in the northern part of the Costa Rica North Center near the southern border of Nicaragua. Six family members were aged 42 to 49 and six were aged 8 to 16.
All said they had seen bats and get in touch with bat excrement while crawling in restricted areas during the 2-hour visit and became slightly or moderately patient after returning to the United States 8 to 19 days after the visit. Five adults and a child asked for treatment in an urgent care center or primary care after having experienced symptoms but have not mentioned any trip. The family member who did not tour the cave did not fall ill.
Signs and symptoms included headache, discomfort, fever, night sweats, muscle pain and respiratory and gastrointestinal problems. No other activity previously reported, during or after the trip was linked to risk factors for exposure to Histoplasm species. Four family members were tested for fungal antigens, with two of them positive for Capsulatum histoplasm Species complex.
Three patients received antibiotics, two received corticosteroids and one received a cough suppressant. An adult was referred to an emergency service and hospitalized due to abnormal thoracic radiographic results that have raised concerns about lung cancer. This patient has received antifungal drugs.
But the day after admission, the healthcare providers who asked if the patient had recently traveled learned the visit of the caves and began to suspect histoplasmosis. On January 17, an infectious georgia doctor informed the CDC of cases.
The cave was associated with histoplasmosis epidemic In 1998 and 1999, which missed 51 people.
All patients improved in one month
On January 21, 2025, the CDC launched a multi-state survey on the 12 cases with the Georgia Department of Public Health, the Texas Department of State Health Services and the Washington State Department of Health.
“Antigen tests for the four patients occurred within one month of the appearance of symptoms, the optimal time,” noted the researchers. “However, because the sensitivity to the detection of the antigen for histoplasmosis is lower in patients with light disease who are immunocompetent, the results of the negative tests could have been false negatives.”
A patient with a positive test result has also twice received the results of the positive supplement fixing antibody tests. In addition to the patient with suspicious radiographic results for lung cancer, another patient also had abnormal radiographic results characterized by pulmonary nodules and opacities compatible with histoplasmosis.
However, as sensitivity to the detection of antigen for histoplasmosis is lower in patients with light disease who are immunocompetent, the results of negative tests could be false negatives.
The members of the IAL family were classified as having confirmed (1 patient), probable (8) or a suspected histoplasmosis (3) based on the definition of the Council of Council epidemiologists and epidemiologists. On day 28 After the exhibition, all affected family members had recovered or improved, which, according to the study authors, complies with light or moderate histoplasmosis.
Antibiotics, unhounded corticosteroids
The CDC has alerted health services through a notification of exchange of epidemic information to identify cases of additional histoplasmosis and works with the United States Embassy in Costa Rica and the Costa Rica Ministry of Health to add information on the risks of histoplasmosis in the forms of waiver of Venado Caves Tour.
Currently, the website For the Venado Caves Tour, which presents photos of bats, says that the cave houses a colony of bats and that guests will receive a mask of an unpertified type but does not mention histoplasmosis.
On March 18, the American embassy published a health alert To inform the public of the risk of contracting the histoplasmosis of the strike. Exposed to H Capslatum In Venado, the caves could be in progress.
Antibiotic drugs (ie antibacterial) are ineffective and corticosteroids can worsen fungal infections.
Histoplasmosis diagnoses are often delayed and treatment guidelines recommend antifungal drugs for severe histoplasmosis. “Antibiotic drugs (ie antibacterial) are ineffective and corticosteroids can worsen fungal infections; the prescription of these drugs to certain affected family members suggest that fungal infections were not initially considered as the cause of the disease,” wrote researchers.
“Clinicians should consider fungal diseases in the differential diagnosis of patients with constitutional signs or symptoms after possible possibility or other activities associated with the risk of histoplasmosis and should report suspicious cases of histoplasmosis to local health services, if any,” they concluded.
