The Effect of Mouse Passage on Cultural Characteristics and Virulence for Mice of Organisms Causing Blastomycosis
Roger Denio Baker
From the Department of Pathology, Duke University School of Medicine, Durham, North Carolina
1. Repeated mouse transfer did not enhance the virulence formice of two strains of Blastomyces dermatitidis which had causedhuman blastomycosis. Virulence was judged by the duration ofsurvival of the animals following intraperitoneal inoculationand the extent of the lesions produced.
2. The yeast formof the two strains was obtained from the mycelialform as readilyby growing the organism directly on blood agarat 37°C.as by first passing it through a mouse. The culturaland microscopicappearances of each organism on blood agar at37°C. werenot altered by repeated mouse transfer.
3. The experimentalresults suggest that the virulence of thisfungus, at leastfor mice, is an attribute which is not readilychanged.