Of approximately forty zoonotic diseases of agricultural importance, six (Mycobacterium avium infection, erysipeloid, listerosis, conjunctival Newcastle infection, psittacosis, and dermatophytosis) are of concern to poultry workers. Non-zootic infectious diseases of concern include candidiasis, staphylococcosis, salmonellosis, aspergillosis, cryptococcosis, and histoplasmosis. Of thses diseases, histoplasmosis may be the one most likely to cause serious illness in a poultry worker. Histoplasmosis is an infectious disease caused by inhaling the spores of a fungus called Histoplasma capsulatum. This disease primarily affects a person's lungs, and its symptoms vary greatly. The vast majority of infected people are asymptomatic (no apparent ill effects), or they experience symptoms so mild they do not seek medical attention and may not even realize that their illness was histoplasmosis. If symptoms do occur, they will usually start within 3 to 17 days after exposure, with an average of 10 days. Histoplasmosis can appear as a mild flu-like respiratory illness with a combination of symptoms including malaise (a general ill feeling), fever, chest pain, dry or nonproductive cough, headache, loss of appetite, shortness of breath, joit and muscle pain, chills, and hoarseness. Histoplasmosis is not contagious; it cannot be transmitted from an infected person or animal to someone else.