[Water and viral hepatitis]

The main agents responsible for acute viral hepatitis throughout the world are the hepatitis A virus (HAV) and the hepatitis E virus (HEV). Both are transmitted by fecal-oral route and can provoke large epidemics, HAV in developed countries and HEV in developing countries. Water is a major vehicle of spread. However, two different epidemiological patterns have to be distinguished: level of HAV excretion is short but high. Because of its resistance to physical and chemical agents, HAV remains infectious for a long time under environmental conditions. Progress in hygiene have nearly stopped the circulation of HAV in industrialized countries, making populations more susceptible to the infection and increasing the epidemic risk. Conventional measures sometimes fail to prevent HAV infections. Vaccine is currently the best way for hepatitis A prophylaxis; HEV is excreted briefly and at low concentrations. Viral particles are fragile in vitro and their viability in environment is not yet understood. Epidemics mainly occur in countries with poor sanitary conditions, resulting from heavy water pollutions. High case-fatality rates are observed, especially among pregnant women. The control of enterically transmitted viral hepatitis remains a major public health challenge. Virological surveillance of waste water could improve strategies based on hygiene, sanitation and supply of drinking water.