Hosts: Horse, ass.
Location: Same as B. besnoiti.
Geographic Distribution: Africa (Sudan, South Africa), Europe (southern France, Pyrenees), North America (Mexico, United States).
Prevalence: Relatively uncommon. Bennett (1927, 1933) recorded this species from 3 horses in the Sudan, all of which originated in the Nuba Mountains of Southern Kordofan. Schulz and Thorburn (1941) found it in South Africa. Jones (19 57) found it in the skin and other tissues of small burros which had been imported into the United States from Mexico. Gorlin et al. (1959) found it in the lip of a burro of unspecified origin in the United States.
Morphology: Same as B. besnoiti. According to Bennett (1933), the trophozoites measure 10 by 4 u.
Life Cycle: Presumably same as B. besnoiti.
Pathogenesis: According to Bennett (1933), the horse-owning tribes in Southern Kordofan know this disease quite well, can differentiate it from mange and ringworm and have given it a separate Arabic name. It was said that one tribe which not many years before had owned 600 to 800 horses, now had less than 50 due to besnoitiosis. On the other hand, the organism produces no grossly recognizable disease in burros, according to Jones (1957).
The disease as described by Bennett (1933) in horses is a chronic one, running a course of many months. Affected animals are weak and dejected, altho their appetite is good. The skin is scurfy and thickened, and contains many scabs and whitish scars. The hair may be destroyed by the lesions. The conjunctiva is a peculiar brick red color, with a few petechiae. The temperature is slightly elevated.
The muscles in advanced cases are pale brown and friable, but contain no parasites. The Besnoitia cysts are abundant in the skin and may also be found in the mucous membrane covering the larynx, nostrils, soft palate, etc.
Diagnosis: Same as for B. besnoiti.
Treatment: None known.
Remarks: It is possible that the same species of Besnoitia affects both cattle and horses, and that B. bennetti is a synonym of B. besnoiti. Until this is shown to be the case by cross-transmission studies, however, it is considered best to retain separate names for the forms in cattle and equids.