MANY FACES OF PULMONARY ASPERGILLOSIS

Aspergillus is a ubiquitous fungus. It is commonly isolated as an uppe r respiratory tract saprophyte and is the most frequent contaminant in laboratory specimens, Because species of aspergillus are omnipresent, one must be cautious in ascribing a causal role to the fungus obtaine d from patients, Aspergillus has low pathogenicity for humans and anim als and rarely invades the immunologically competent host, Although th e fungus can affect any organ system, the respiratory tract is involve d in >90% of afflicted patients. Pulmonary aspergillosis, depending wh ether the host is atopic or immunosuppressed, may be classified under four categories: allergic or hypersensitivity syndromes, saprophytic c olonization, invasive (infective) dissemination, and chemical or toxic pneumonitis. These entities differ clinically, radiologically, immuno logically, and in their response to various therapeutic agents. An inc reased awareness, an aggressive approach to securing the diagnosis, an d instituting early and appropriate therapy are needed to reduce the h igh morbidity and mortality caused by many of the aspergillus-related syndromes.