John Myers
One of the most important reasons for the increase in hepatitis E in Germany is raw or insufficiently heated pork products. It has long been known that eating them poses health risks. However, the hepatitis risk has been underestimated so far, also because such an infection is usually harmless in healthy people. For people with a weakened immune system, however, hepatitis E infection can be life-threatening.
Cases of hepatitis E in Germany have risen sharply
The number of hepatitis E cases reported in Germany has risen sharply in recent years: 238 cases were reported in 2011, and in 2019 there were 3,727, almost 16 times as many; in August 2020 the number for the current year was already 2,280 cases reported to the Robert Koch Institute. Scientists are convinced that around 17 percent of Germans have already been infected with the pathogen.
Even in medicine, hepatitis E viruses (HEV) were unknown in Europe for a long time. In the meantime, however, doctors have become more aware of a possible infection. Experts suspect that the increasing numbers are also due to the fact that doctors are increasingly testing for HEV in the presence of the corresponding symptoms.
Infection via meat, salami, and ground pork
Scientists estimate that 300,000 people in Germany become infected with HEV every year, mostly via pork products such as undercooked meat or raw sausages that have not been matured for a short time, such as salami or cabanossi. HEV can also be transmitted via Mett.
The Federal Institute for Risk Assessment (BfR) also warns against insufficiently heated wild boar meat. While it is estimated that 40 to 50 percent of the domestic pigs in German herds are infected with HEV, the experts also found antibodies against HEV in up to 68 percent of the wild boar shot in Germany, and occasionally in roe deer and red deer.
Since the animals themselves do not become ill, but only transmit the virus to humans, their infection usually remains undetected.
People who come into frequent contact with raw pork or wild boar meat, such as hunters, butchers, and cooks, are particularly at risk. You can reduce your risk of infection by wearing gloves.
The danger of a weakened immune system
When HEV enter the human body with pork, they travel through the stomach to the intestines, enter the bloodstream, and finally end up in the liver. In most healthy people, the viruses are destroyed by the body’s own defenses.
In immunocompromised people, however, the pathogen can multiply and spread throughout the body, reaching the kidneys and the brain. In some people, HEV infection therefore also leads to neurological disorders. Hepatitis E viruses can also cause acute liver inflammation – with fever, upper abdominal pain, and jaundice. In people with a weakened immune system, there is a risk of transition to chronic hepatitis E in 30 to 50 percent of cases – with potentially life-threatening consequences.
How high is the risk?
In Germany, pigs are the main carriers of HEV. People become infected through meat products, but above all through sausage products: In a recent study from 2020, more than ten percent of the 121 samples examined were contaminated with HEV. Pork livers, liver sausages, and mettwurst were examined. However, the study did not examine whether the viruses were still active. For example, if liver sausages are heated during production in accordance with the applicable regulations, the virus is inactive. It can then still be detected, but no longer trigger an infection.
Salamis and Mettwurst sausages, for example, are more problematic: Raw sausages that have been matured for a short time are preserved by seasoning, salting, and drying, but are not heated. This is how the virus can survive. In one large study, every fifth sausage sample contained traces of the virus. Viruses can get into the sausage because pork is not tested for hepatitis E before processing. The technology required for this is complex and expensive. This is how meat and meat products containing HEV get into the market and can infect anyone who processes or consumes them.
Researchers are looking for a solution to keeping pigs
A solution to the problem can be found in pig farming, say scientists at the Federal Institute for Risk Assessment. The question: How can the virus be kept out of animal populations or fought there. A Europe-wide study is currently being coordinated by German researchers. Management and hygiene measures are examined. There could also be a vaccination for pigs.
A human vaccine already exists in China. However, the European Medicines Agency has yet to evaluate it for the EU. Specific drugs to treat HEV infection do not yet exist.
