Situation in Austria
In Austria, 47 human cases of hepatitis E were reported in 2022.
At the Institute of Veterinary Investigations Mödling of AGES, we have conducted investigations on the occurrence of hepatitis E genotype 3 antigen and antibodies in domestic and wild pigs in recent years. An investigation of 1,152 slaughter pigs from 72 conventional farms in Austria showed that hepatitis E virus genome could be detected in liver or faeces of 64 pigs (6 %) from 30 farms. Of 75 wild pigs tested, hepatitis E virus was detected by PCR in 17 (23 %).
The hepatitis E virus (HEV) is one of the five known human hepatitis viruses. Infections with the hepatitis E virus are a health problem especially in developing countries. For a long time, it was assumed that hepatitis E infections in humans were mainly due to travel in Asia and Africa. In recent years, an increasing number of cases of hepatitis E infection have also been detected in Western European countries, mostly due to genotypes different from those in Africa and Asia.
Hepatitis E virus (HEV) is a small, non-enveloped, single and positive stranded RNA virus with a genome length of about 7.2 kb, a diameter of about 30 - 32 nm and belongs to the family of Hepeviridae. The virus reacts very labile at high salt concentrations, fast freezing and thawing processes as well as at heat. A total of 4 human genotypes of the hepatitis E virus can be distinguished. Genotype III and IV have also been found in pigs. The presence of HEV genotype 3 (HEV-3) RNA in faeces, serum and organ samples as well as the high frequency of anti-HEV antibodies in pigs have already been described in many developed Asian, North American and also in European countries. This suggests a wide distribution of HEV-3 within domestic and wild pig populations.
Host animals, risk to humans
The extent to which infection of pigs causes infection of humans in the presence of inadequate hygienic precautions has not yet been scientifically investigated in detail. The detection in faeces and organs of pigs allows the conclusion that the zoonotic potential of hepatitis E in Austrian domestic pigs may well be relevant for public health in order to assess a possible risk for occupational risk groups such as hunters, butchers or even veterinarians or consumers. Furthermore, the virus has been detected in chickens, rabbits, rats, mongooses and deer. There are also indications that the hepatitis E virus can occur in cattle and sheep.
In a scientific opinion published on 11 July 2017, the European Food Safety Authority (EFSA) identifies raw or undercooked pork as the main cause of hepatitis E infections in humans: Over 21,000 infections were reported in EU Member States between 2007 and 2017. Cases of hepatitis E disease mainly affect immunocompromised individuals, especially transplant patients. Hepatocytes (liver cells) are considered the main target cells of hepatitis E viruses, the virus particles themselves are then excreted through bile and stool and can also be detected in wastewater. The viruses enter the environment with pig manure. In pigs, perinatal transmission from mother sow to piglet is possible.
Most people infected with hepatitis E show no or only mild symptoms such as fatigue, exhaustion, fever, nausea, vomiting, icterus, upper abdominal pain. Fulminant courses are rare (less than 1%), but these are associated with a high mortality rate. When cured, there is usually no permanent damage and the disease does not usually become chronic (except in the case of immunosuppression). So far, no clinical changes have been detected in pigs. The highest excretion rate has been found in piglets aged 1-3 months, which means that although the pig does not contract the disease itself, it plays an important role as a carrier.
There is no specific therapy for HEV infections. Hygiene must be observed when cutting and preparing pork. Thorough hand washing is considered the most important preventive measure in food preparation. Since the virus is sensitive to heat, safe preparation in which meat is well heated is the best protection.
Last updated: 10.10.2023