ESTABLISHMENT OF DEMODEX-CANIS ON CANINE SKIN ENGRAFTED ONTO SCID-BEIGE MICE

A small animal model of canine demodicosis is described. Normal canine skin was engrafted onto scid (severe combined immunodeficient)-beige mice, which lack functional B and T lymphocytes and have reduced natur al killer cell activity. The xenografts were later infected with Demod ex canis collected from a dog with demodicosis. At 30-112 days followi ng infection, mites were seen histologically in the canine hair follic les of the engrafted skin. Demodex canis adults, nymphs, larvae, and e ggs were present in samples macerated in sodium hydroxide. Mite infest ations could not be demonstrated in the mouse skin, nor were mites pas sed from the infected graft to uninfected skin grafts on in-contact mi ce. This model may be utilized to assess the efficacy of miticidal tre atments, to evaluate the importance of specific components of the immu ne response, and to study the biology of D. canis.