Tick virus diseases of sheep and goats.

Tick-borne viruses affecting sheep and goats can be be locally important diseases. Viruses of the tick-borne encephalitis complex occur across Europe to North-East Asia and are the cause of significant losses in small ruminant production. Thogoto virus which can be transmitted by Ixodid ticks has been associated with abortion storms in sheep, it may contribute to the large proportion of abortions which are due to unknown causes. Nairobi sheep disease is the most pathogenic virus disease known for sheep and goats in East Africa. Ganjam virus in India may ultimately be shown to be a significant cause of disease in small ruminants. Some unidentified Orbiviruses have been found both in ticks and sick sheep, and are thought to be a cause of some losses in African sheep and goats. Small ruminant populations in both Africa and Asia are vertebrate host for Congo-Crimean haemorrhagic fever, an important human pathogen, and for many Arboviruses some of which are of zoonotic importance.