Hepatitis refers to an inflammatory condition of the liver. It is commonly caused by a viral infection from one of five unrelated hepatotropic viruses: hepatitis A (HAV), hepatitis B (HBV), hepatitis C (HCV), hepatitis D (HDV) and hepatitis E (HEV). HAV is an acute, short-term disease, which is commonly transmitted by consuming food or water contaminated by feces from an infected person. HBV and HCV are transmitted through direct contact with infectious body fluids such as blood, or semen, and typically lead to an ongoing, chronic form of liver disease. HDV is a rare form of hepatitis that only occurs in conjunction with HBV infection as the virus cannot multiply without the presence of HBV. HEV is a waterborne disease mainly found in areas with poor sanitation and typically results from ingesting fecal matter that contaminates the water supply. The disease is usually acute but can be particularly dangerous in pregnant women.
Viral hepatitis is primarily diagnosed through blood tests for levels of viral antigens, anti-viral antibodies, or viral DNA/RNA. Overall, hepatitis causes more than a million deaths a year, most of which occur indirectly from liver scarring or liver cancer.