A Comparative Study of the Pulmonary Mycoses of Canada and the United States: Epidemiologic Aspects

ACOMPARATIVE study of the pulmonary mycoses of Canada and the United States shows a basic similarity in the types of diseases that occur in these two countries.Coccidioidomycosis is the only systemic mycotic disease that is present in one country (the United States) and not in the other.All the other mycoses are shared; however, there are significant national differences in their prevalence and incidence.This paper describes, from an epidemiologic point of view, the pulmonary mycoses that pre- vail in these two northern countries.The diseases are discussed under two categories: endogenous and exogenous infections. Endogenous Pulmonary MycosesIn the category of endogenous pulmonary my- coses are the mycoses caused by organisms that are not known to be free-living in nature but are normal components of the body's microflora.The two diseases caused by such organisms are acti- nomycosis and candidiasis.Actinomycosis.Human actinomycosis is caused exclusively by Actinomyces israelii.Un- til recently this organism had been confused with Actinomnyces bovis, the etiological agent of