The disease causes a variety of respiratory and intestinal symptoms. Some animals recover from the infection without any therapy and others require treatment with anti-fungal medication that is usually successful. Histoplasma prefers areas that are moist and humid and grows best in soils that contain nitrogen rich organic matter such as bird or bat droppings. Most infections occur in the region of the Ohio, Missouri, and Mississippi rivers. Cats and dogs can both be infected.
Infections are more common in outside cats and dogs, particularly in hunting dogs.
Animals of any age can get histoplasmosis, however, most infections occur in animals under four years of age. Pets get infected by inhaling the spore-like particles of the fungus that inhabit the soil. A few cases of infections in strictly indoor animals have been reported and it is suspected that potting soil or dirt brought in from outside may be the source of infection in these animals. The symptoms are varied and depend somewhat on the severity of the infection. Histoplasmosis infections start in the lung.