Viral hepatitis is divided into the following main categories: Hepatitis A. Hepatitis A is transmitted through the gastrointestinal tract and is commonly contracted through unclean drinking water, unboiled food and fecal contaminated food. The incubation period for hepatitis A averages about 28 days. Hepatitis A does not become chronic, and the 2012 China Health Statistics Yearbook shows that the incidence of hepatitis A was 2.35 per 100,000 people in 2011. Hepatitis B Hepatitis B is mainly transmitted through contact with the patient’s blood and other body fluids. After a person is infected with the hepatitis B virus, a person whose virus has not been cleared for 6 months is called chronically infected with HBV. Patient symptoms commonly include fever, depression, abdominal pain, jaundice, spider nevus, bloating and diarrhea, etc. Often, they will also be asymptomatic and go undetected. Hepatitis C The main routes of transmission of hepatitis C are blood and body fluids. Symptoms of acute hepatitis C include depression, loss of appetite, nausea, etc. Chronic hepatitis C is usually asymptomatic. To date, there is no effective vaccine or preventive treatment for hepatitis C. The only preventive measure is to prevent blood contact. Hepatitis C in China is predominantly genotype 1b, a relatively intractable form of hepatitis C, followed by type 2a. The annual incidence of cirrhosis after 20 years of HCV infection in patients is 10%-15%, while the annual incidence of liver cancer in patients with cirrhosis is 1%-7%. It is estimated that hepatitis C-related deaths will continue to rise over the next 10-15 years, increasing twofold by 2015 and threefold by 2025. Hepatitis E Hepatitis E is transmitted by fecal-oral transmission through contact. Improved hygiene and boiling of water can prevent transmission of hepatitis E. Clinical symptoms are the same as those of hepatitis A, but are more severe than hepatitis A and are especially dangerous for pregnant women. Hepatitis E can be prevented by the hepatitis E vaccine.