An in vivo method of assay for Dermatophilus congolensis

An in vivo method of assay for Dermatophitus congolensis in rats is described. The optimal conditions for preparing skin before infection and subsequently harvesting the zoospores from infected skin were investigated. These experiments showed that clipping the skin had no effect on infection with this bacterium and that when the infected skin was soaked in water, increased amounts of dissolved CO2 had no effect on the release of zoospores, which was maximal within 2.5 h of immersion. Vaccination studies demonstrated that this assay gave results comparable to previously published data, where these data were quantitative. Infection with D. congolensis was not related to the production of exudate on the skin surface. This is the first report that D. congolensis can infect skin without producing an exudate. Hypotheses linking skin damage and susceptibility to infection with this bacterium are discussed in the light of this observation.