an acute, infectious viral disease of sheep and goats, characterized by fever and hemorrhagic gastroenteritis. Nairobi disease occurs in Kenya, in Uganda, in some regions of the Republic of South Africa, and elsewhere. It is caused by a virus transmitted by ticks from infected animal to infected animal. In the wild, the blue gnu and members of the genus Rattus may be the reservoir of the disease.
The first symptom of Nairobi disease is a rise in temperature to 41–41.6°C; this continues for two to three days and then decreases to normal. The animals become listless; the pulse grows fast and thready and breathing accelerates and becomes labored; there is a purulent nasal mucous discharge, sometimes mixed with blood; and severe diarrhea, often bloody, occurs. Abortions are frequent among pregnant animals. Intense and prolonged immunity is developed in animals that survive the disease. No treatment has been developed. Control of tick infestation is the prophylactic measure.