Jembrana disease is an acute viral disease of cattle.[1] While it produces relatively mild symptoms in taurine cattle, the Jembrana virus is particularly severe in Bali cattle where it has a fatality rate of approximately 17 percent.[2] Its first documented outbreak occurred in 1964 in the Jembrana district of Bali, Indonesia.[1] Within two years of its appearance the disease had killed an estimated 26,000 of the approximately 300,000 cattle on Bali Island.[1] The Jembrana disease virus belongs to the genus Lentivirus, which include immunodeficiency viruses such as HIV.[1] Instead of the chronic disease produced by most lentiviruses, Jembrana disease produces acute effects.[2] After an incubation period of 5–12 days the disease produces symptoms including loss of appetite, fever, lethargy, enlargement of the lymph nodes, and diarrhea.