Effects of various induced local environmental conditions and histopathological studies in experimental Dermatophilus congolensis infection on the bovine skin.

Although localised to the site of inoculation, experimental cutaneous streptothricosis was readily produced on scarified and/or defatted bovine skin infected with nutrient broth cultures of Dermatophilus congolensis. There was no difference in the extent and duration of lesions produced by either method. D congolensis failed to infect intact normal skin. Simulated rainfall and insect bite did not effect spread and production of generalized streptothricosis. On the other hand, localised experimental lesions regressed more rapidly when subjected to simulated rainfall. The histopathological changes were characterised by invasion of hair follicles by the germinating hyphae and mycelia of D gongolensis, accumulation of neutrophilic exudate beneath the infected epidermis, migration of some neutrophils through the epidermis resulting in intra-epidermal microabscess formation and regeneration of new epidermis from follicular sheath epithelium.