Histoplasmosis is also called the cave disease. The reason is simply that it is rather rare and all cases known were related to cave visits. In certain parts of the world, especially south Africa and south America, bats and birds are infected by a fungus, which is harmless for them. This fungus produces spores which are then in their droppings. When the cave is dry, the droppings become dust and the spores fly in the air, when people walk through this dust. Then the cavers may become infected by breathing them in.
The disease is a fungal infection of the lungs. The symptoms are similar to a flu, but they may differ in a wide range between not noticeable and breathing problems similar to tuberculosis. In very rare cases, untreated histoplasmosis can be fatal. However, treatment is simple, normal antifungal medication works very well. The problem is simply that the disease is extremely rare and most doctors will not diagnose it correctly.
Cavers have to be careful and avoid dry bat caves in the tropics. It also helps to wear respirators, which simply filter the spores from the air. If an infection happened, a notice to the doctor about the cave visit and the possibility of histoplasmosis is also a good idea.