Nairobi sheep disease (NSD), is a serious tick-borne viral disease of sheep and goats. The RNA virus belongs to the family Bunyaviridae, in the genus Nairovirus. Nairobi sheep disease is characterized by fatal hemorrhagic gastroenteritis, starting with high fever, depression, respiration problems, myocarditis and tubular nephritis, often pulmonary edema, and very high mortality rate up to 30– 90%. The principal vector for NSDV in Africa is the brown ear tick (Rhipicephalus appendiculatus), in which the virus can survive up to 800 days. Transovarial and transstadial transmission occurs via this vector. Affected animals may die within a few days, and pregnant ewes abort. Subclinical infections also occur, and recovered animals are immune. Nairobi sheep disease virus is shed in urine and feces; however, the disease is not transmitted directly between animals. Indirect fluorescent antibody tests are recommended for detecting antibodies in the infected and recovered animals. Immunodiffusion, hemagglutination, ELISA, and complement fixation tests may also be used. RT-PCR for virus detection is applied. There is no commercial vaccine for NSD. However, in endemic countries, experimental vaccines have been developed for use in naïve animals entering enzootic areas, or to protect animals when tick vectors expand their geographical range.