[New knowledge about viral hepatitis]

Epidemics caused by a faecaloral transmitted hepatitis virus other than the hepatitis A virus are reported from developing countries. This type of hepatitis is called hepatitis E and is caused by a calicivirus termed hepatitis E virus. Many characteristics of this disease are similar to those of hepatitis A. The groups usually infected are older children and young adults in developing countries with poor sanitary facilities. Faecal contamination of the drinking water is assumed to be the main path of transmission. Large epidemics with thousands of icteric cases have been described. Neither hepatitis A nor hepatitis E develops into chronicity. In pregnant women there is an unexplained high case fatality rate of nearly 20%. The available diagnostic tools are based upon demonstration of nucleic acids in the virus genome extracted from faecal and blood specimens and upon immunological tests founded on synthetic peptides or antigens developed by means of gene technology. Hepatitis E is an important kind of epidemic hepatitis in the countries of the third world. Up to now the source of the virus remains unknown, but it has been possible to inoculate and cause replication of the virus in primates and even pigs. The possibility that this kind of hepatitis is a zoonosis has to be further documented.