Definition of Histoplasmosis
Histoplasmosis is a blood-borne fungal infection that can affect domestic dogs and also people. Histoplasma capsulatum is the fungus that causes histoplasmosis. These organisms live in moist, nitrogen-rich soil contaminated by the feces of bats, chickens, starlings and other birds. The fungi produce tiny airborne spores that resist heat and are inhaled by dogs and other animals. The spores are taken up by the dog’s immune system through a process called “phagocytosis.” The fungi mature and reproduce inside the host’s immune system cells and are carried throughout the dog’s body in the blood. They eventually lodge in the respiratory tract, gastrointestinal tract, lymph nodes, bone marrow, lungs, liver and spleen. Many infected dogs don’t get sick, but others develop mild to severe respiratory and/or gastrointestinal disease, with breathing difficulties, fever, weight loss, vomiting, muscle wasting, coughing and intractable diarrhea. Fortunately, histoplasmosis is treatable.