Definition:

Pulmonary aspergillus infections can be classified based on clinical syndromes into saprophytic infections, allergic disease and invasive disease. Invasive pulmonary aspergillosis, occurring in immunocompromised patients, reflects the most serious disease with a high case-fatality rate. Of the 185 recognized species of Aspergillus, 20 are known to cause infections in humans. Aspergillus fumigatus accounts for about 65 percent of all invasive infections in humans and is the mostly encountered species in pulmonary infections. Aspergillus flavus, Aspergillus niger, Aspergillus terreus and Aspergillus nidulans are less frequently causes of invasive and pulmonary infections.