Hepatitis E virus, which has not yet been definitively classified (formerly classified as a member of the Caliciviridae).
Hepatitis E is a waterborne disease usually acquired from contaminated drinking-water. Direct faecal–oral transmission from person to person is also possible. There is no insect vector. Various domestic animals, including pigs, may be reservoirs of hepatitis E.
Nature of the disease
The clinical features and course of the disease are generally similar to those of hepatitis A (Chapter 6). As with hepatitis A, there is no chronic phase. Young adults are most commonly affected. In pregnant women, there is an important difference between hepatitis E and hepatitis A: during the third trimester of pregnancy, hepatitis E takes a much more severe form, with a case–fatality rate reaching 20%.
Worldwide. Most cases, both sporadic and epidemic, occur in countries with poor standards of hygiene and sanitation.
Risk for travellers
Travellers to developing countries may be at risk when exposed to poor conditions of sanitation and drinking-water control.
Travellers should follow the general conditions for avoiding potentially contaminated food and drinking-water (Chapter 3).