The outbreak in Chad was of hepatitis E.All the various types of hepatitis cause liver disease but differ in modes of transmission, severity of the illness, geographical distribution and prevention methods. Hepatitis E is a global health problem with about 20 million cases occurring annually, three million symptomatic cases and 60,000 deaths.Hepatitis E can cause acute hepatitis without symptoms, or mildly symptomatic, or sometimes severely symptomatic illness.