Hepatitis viruses can cause inflammation of the liver. Of the five most significant virus types, A, B, C, D and E, the latter mentioned hepatitis E viruses (HEV) alone cause an estimated 20 million human infections worldwide each year. However, it has only been known for a few years that humans can also be infected with a variant of the hepatitis E virus that is usually prevalent in rats.
Following reports of individual cases, mainly from Hong Kong and Spain, the first infection with ratHEV has now also been described in a patient from Germany.
“How the virus is transmitted is still largely unclear,” says Professor Reimar Johne, head of the Unit Viruses in Food at the BfR. “However, the results of the investigation suggest that ratHEV has to be considered a new zoonotic pathogen in Germany and Central Europe.”
Researchers will present the current state of knowledge on ratHEV and new findings on the spread and transmission of the pathogen at the 6th BfR Symposium on “Foodborne Viruses”. In addition to HEV, other viruses, especially those that are also transmitted through consumption of food, will be on the agenda of the event. These include well-known foodborne viruses such as the highly contagious noroviruses and hepatitis A viruses.
Wild rats
Whether ratHEV can be transmitted via food is still a relatively new research question. The pathogen was first detected in wild Norway rats in 2010 by a working group led by Prof. Johne. While experts initially assumed that this virus only affects rats, it is now clear that it can also be present in other animals. Since 2018, it is known that humans can also become infected in individual cases and develop acute or chronic liver inflammation (hepatitis) as a result. At least in Berlin, the virus appears to circulate permanently in wild rats, as Prof. Johne, the main organiser of the symposium, will explain based on his own research findings.
Johne is part of the research team that also identified the first ratHEV infection in a human in Germany. Current research is investigating whether the pathogen is transmitted directly from rats or through contact with their excretions, or whether, like other hepatitis E viruses, it is transmitted indirectly via the intermediate host pig and food made from pork. As an essential prerequisite for investigating the pathogen and its transmission routes, researchers at the BfR have tested in which cell culture systems different hepatitis E viruses can be propagated and studied. The results will be presented in another lecture at the symposium.
Adenoviruses, viral pathogens about whose transmission via food relatively little is known, are also on the conference agenda. Similar to noroviruses, they are transmitted via the faecal-oral route, but their significance for foodborne infections is unclear, partly because there has been a lack of appropriate methods for detection of the pathogen in food. A new detection method developed at the BfR and now validated in collaboration with several other laboratories will be presented at the symposium.
Viral transmission
However, the potential risks posed by the transmission of other viruses will also be discussed, for example the relatively little-investigated gastrointestinal adenoviruses, and influenza viruses, which are currently causing a resurgence of bird flu.
Experts will provide information on the latest findings on these pathogens in three thematic blocks: “Basic Knowledge”, “Detection Methods” and “Hygiene, Inactivation and Evaluation of Results”. The symposium will take place on 27 November in Berlin at the BfR site in Marienfelde and is aimed at interested parties from scientific institutions, food safety laboratories and regional authorities in German-speaking countries. Journalists are cordially invited to attend.
The full programme and registration information can be found here:
https://www.bfr-akademie.de/english/events/viren2025.html
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