Experimental infection of domesticated animals and the fowl with Dermatophilus congolensis

Rabbits, camels, calves, sheep, goats and donkeys were successfully infected by skin scarification with Dermatophilus congolensis. This is the first time that the camel has been shown to be susceptible to experimental infection. In contrast to the natural disease the lesions did not spread and regressed after 20 to 52 days. The histological changes were scab formation and degeneration, necrosis and micro-abscess formation in the superficial epidermal layer and the hair follicle sheaths. The fowl was refractory to infection by this route. Cutaneous lesions and foreign body granulomas were induced by embedding infected thorns in the skin of calves and rabbits. A tuberculin-type reaction was induced when the organism and Freund's adjuvant were inoculated intradermally. Calves and rabbits injected s.c. and rabbits i.p. failed to develop cutaneous lesions. The i.v. route also failed to produce skin lesions except at the site of injection in rabbits. Various gross internal lesions were observed in calves and rabbits inoculated i.v. and rabbits i.p. An anaphylactic-like reaction occurred in calves repeatedly inoculated i.v. Resistance to reinfection by scarification occurred. The histological changes in internal organs indicated severe inflammatory responses.