Identification of the agent: Dermatophilus congolensis normally affects the epidermis, causing the formation of scabs. It may be demonstrated in smears made from scabs emulsified or softened in water or in impression smears from the base of freshly removed adherent scabs. The organism is Gram positive, but its morphology is more readily appreciated in smears stained with Giemsa. In stained smears, the organism is seen as branching filaments containing multiple rows of cocci. This characteristic appearance is diagnostic. In wet or secondarily infected scabs, only free cocci may be present, so that staining by immunofluorescence is necessary. Dermatophilus congolensis is demonstrated in histopathological sections by Giemsa staining or by immunofluorescence. Dermatophilus cheloniae may be found in crocodiles, chelonids and cobras.