Histoplasmosis
Histoplasmosis is a fungal infection caused by Histoplasma capsulatum, a mould that lives in soil enriched by bird and bat droppings. Most infections are mild and self-limiting, but in people with weakened immune systems the fungus can spread beyond the lungs and become life-threatening.
Key points
- Exploring caves or areas with heavy bird droppings is a recognised way to inhale the spores that cause infection.
- Long-term immune suppression, whether from HIV, a transplant, or ongoing corticosteroid therapy, raises the risk of severe disease substantially.
- Severe or spreading disease usually starts with antifungal medicine given directly into a vein before switching to tablets.
Who encounters it
Histoplasma is found in the environment in certain regions, particularly in areas with caves, old buildings, or dense bird roosts. Travellers exploring cave systems are at recognised risk, as are people living with HIV, transplant recipients, or anyone on long-term immunosuppressive therapy.
How antifungals address the infection
Mild to moderate histoplasmosis is typically treated with an oral antifungal for several months. Itraconazole is the standard agent for non-severe disease and maintenance therapy, working by disrupting the fungal cell membrane. Severe or disseminated cases usually require initial intravenous treatment in hospital before stepping down to oral therapy.
If you develop persistent fever, unexplained weight loss, or breathing difficulties after visiting a cave or high-risk environment, seek medical assessment promptly.