Viral hepatitis E: A disease of humans and animals

The hepatitis E virus is ubiquitous in all parts of the world where pig production exists. The infection occurs in several animal species and its course is mostly asymptomatic. Viral strains isolated from pigs and humans are genetically similar, which indicates a potential zoonotic nature of the disease, and the possibility that pigs, and perhaps also other species of animals diseased with viral hepatitis E are a source of infection to humans. The pig hepatitis E virus, which is similar to the hepatitis E virus in humans, was isolated and described for the first time in the USA in 1997. The infection of pigs with hepatitis E virus occurs through faeco-oral transmission, by ingestion of feed and water contaminated with the virus, or through direct contact between infected and healthy animals. The pathogenesis of this infection in pigs differs from its pathogenesis in humans and it has not been sufficiently examined in all its aspects. Even though viral hepatitis E in pigs has been described as a subclinical disease, some authors describe changes in the concentration of certain biochemical parameters in blood serum of the infected pigs. Histologically, a mild to moderate lymphotic-plasma cellular infiltration is observed in livers of infected pigs, as well as focal areas of hepatocyte necrosis. Viral hepatitis E is an endemic disease of humans in Asia, Africa, and Latin America. In developed countries, hepatitis E sporadically occurs in humans, but it is becoming of increasing importance in particular in Japan, North America, and Europe, because the populations of these areas travel extensively to the endemic regions or as a result of the consumption of thermally untreated meat of wild boar and products made from thermally untreated meat. Pork products can be contaminated with hepatitis E virus. Further proof that indicates the zoonotic potential of this virus and places this diseases among the group of professional diseases of farmers and veterinarians is the finding of antibodies to hepatitis E virus in farmers and veterinarians who work on pig farms without showing any clinical signs of the disease. Having in mind the fact that viral hepatitis E has been proven in pig farms in Serbia and neighboruign countries, there should be strict respect of biosecutiry measures from the episootiological and epidemiological aspects, and the principle of good production and hygiene practice should be adhered to on pig farms. This disease should in future also be included in the legal regulations of our country in order to ensure the production of products of animal origin that are safe from the aspect of hygiene. [Projekat Ministarstva nauke Republike Srbije, br. III 46009 i br. TR 31062