An update on the hepatitis E virus.

There have been recent key advances in the understanding of hepatitis E virus infection. Since the early 1980s, when the virus was first discovered, hepatitis E has been described as a disease that is endemic only in the African and Asian subcontinents, a disease that is transmitted via the fecal-oral route, and a disease that causes an acute illness that typically resolves, with the exception of the third trimester of pregnancy, when infection can be deadly. We now know that genotype 3 is likely a porcine zoonotic disease that is quite prevalent in certain industrialized nations. Hepatitis E carries high morbidity and mortality in patients with underlying liver disease and can become a chronic infection that causes fibrosis in immunocompromised hosts. Lastly, two vaccines have been developed and studied in clinical trials, with excellent results.