Importance

Dourine is a serious, often chronic, venereal disease of horses and other equids. This protozoal infection can result in neurological signs and emaciation, and the mortality rates are high. No vaccine is available, and treatment with drugs may result in inapparent carriers. Etiology Dourine is caused by the protozoan parasite Trypanosoma equiperdum. This organism belongs to the subgenus Trypanozoon and Salivarian section of the genus Trypanosoma. Strains of T. equiperdum vary in their pathogenicity. Whether T. equiperdum can be considered a distinct species is controversial. It is very closely related to Trypanosoma brucei subsp. brucei, T. brucei subsp. gambiense and T. brucei subsp. rhodesiense, which cause African trypanosomiasis in a variety of species, and to T evansi, which causes surra. Based on genetic evidence, some authors argue that some strains of T. equiperdum were misidentified strains of T. evansi, and the others should be placed in T. brucei subsp. brucei or in a new subspecies Trypanosoma brucei subsp. equiperdum