Histoplasmosis is a fungal infection that primarily affects the lungs. The condition is caused by Histoplasma organisms, which are often found in soil contaminated with bird or bat droppings. On January 17, 2025, a Georgia infectious disease physician notified CDC of suspected histoplasmosis cases among 12 members of an extended family from households in Georgia, Texas, and Washington. The ill family members included six adults aged 42-49 years and six children aged 8-16 years. They had recently returned from Costa Rica, where they toured a cave linked to a previous histoplasmosis outbreak (1).