[Protothecosis in cattle. Report of a case (author's transl)]

A brief review of the classification of the genus Prototheca is followed by a report on a case of protothecosis in cattle. A pure culture of Prototheca was isolated from the milk of the affected quarter. Despite the fact that the alga showed some sensitivity of nystatin in vitro, the mastitis failed to disappear on treatment with this agent. In the discussion, the incidence of Prototheca infection in man and animals and the appearance of infections with this facultatively pathogenic alga are reviewed.