Hepatitis E (HEV) is an inflammatory disease of the liver and is caused by the hepatitis E virus. First recognized as a distinct human disease in 1980, HEV antibodies have been detected in primates, such as pigs, cows, sheep, goats and rodents. The disease is transmitted by the fecal-oral route. Hepatitis E is a waterborne disease. Consumption of fecal contaminated drinking water has resulted in epidemics of HEV. The ingestion of raw shellfish has been the source of sporadic cases in epidemic areas. HEV does not appear to be transmitted from person to person.
The highest incidence of HEV is in areas of the world where substandard sanitary conditions exist. Sporadic cases have been reported elsewhere and evidence suggest a global distribution of strains of hepatitis E of low pathosgenesis (development of disease).
In general, HEV is a self-limiting viral infection, not a chronic infection and is followed by recovery. Occasionally, a fulminant (sudden and severe) form develops, more frequently during pregnancy and regularly induces a mortality rate of 20% among pregnant women in the third trimester.
The incubation period following exposure to HEV ranges from 3 to 4 weeks. HEV infection is most common in young adults, ages 15 to 40 years old. Typical symptoms include jaundice (yellow discoloration of the skin and sclera of the eye), dark urine, and plae stools. Patients experience anorexia (loss of appetite). Other signs are hepatomegaly (an enlarged, tender liver), abdominal pain and tenderness, nausea and vomiting, and fever. Although the occurrence of HEV is frequent in children, it mostly asymptomatic or causes a very mild illness that goes undiagnosed.
Diagnosis of HEV is made by blood tests that detect elevated antibody levels of specific antibodies to HEV. Unfortunately, such tests are not available worldwide. Currently, no commercially available vaccine exists for the prevention of hepatitis E. Good personal hygiene, high quality standards for public water supplies and proper disposal of sanitary wastes have resulted in a low prevalence of HEV in many well developed countries.