Bovine malignant catarrhal fever

Bovine malignant catarrhal fever (BMCF) is a disease caused by alcelaphine herpesvirus 1 (AlHV-1) of the family Herpesviridae. The disease is fatal in cattle and other ruminants such as deer, antelope, and buffalo.

Epidemiology
The term bovine malignant catarrhal fever has been applied to three different patterns of disease: The incubation period of BMCF is not known, but may be as high as 200 days.
 * In Africa, wildebeests carry AlHV-1 but are not affected by the disease. It is passed from mother to offspring and shed in the nasal secretions of wildebeest calves.  Cattle are infected by contact with the secretions, but do not spread the disease to other cattle.  Hartebeests and topi also may carry the disease.
 * In the rest of the world, cattle and deer contract BMCF by close contact with sheep during lambing. Ovine herpesvirus 2 (OHV-2) is thought to cause BMCF in these situations, but the virus has not yet been isolated.  Susceptibility to OHV-2 varies by species, with domestic cattle and zebus somewhat resistant, water buffalo and most deer somewhat susceptible, and bison, Bali cattle, and Pere David's deer very susceptible.  Antibody from sheep is cross reactive with AlHV-1.
 * Feedlot cattle in North America not exposed to sheep have also been diagnosed with a form of BMCF, but the viral agent has not been identified.

Symptoms
Symptoms of BMCF include fever, depression, discharge from the eyes and nose, erosions on the muzzle, swelling of the lymph nodes, opacity of the corneas leading to blindness, and diarrhea. Erosions of the mouth and skin may occur. Some animals have neurologic signs such as ataxia, nystagmus, and head pressing. Death usually occurs within ten days. The mortality rate in symptomatic animals is 90 to 100 percent.

BMCF is diagnosed by history and symptoms. Treatment is supportive only.