Rat Hepatitis Virus Found in Humans – Germany

In 2018, the first human case of rat hepatitis was discovered in Hong Kong. The man was infected with the rat variant of the hepatitis E virus (Rocahepevirus ratti or ratHEV). Until this point, experts had assumed that this strain of the virus could not be transmitted to humans. Almost two months later, another case was reported, also in Hong Kong. Since then there have been repeated reports of individual cases. For example in Spain, France and North America.

Now researchers led by Victor Max Corman from the Charité Berlin report: Rat hepatitis has also reached Germany. The virus (see box) was detected in a man from the Berlin area.

Berliner’s hepatitis symptoms were initially misinterpreted

The man’s infection was discovered as part of a study. For this purpose, Corman’s team analyzed samples from more than 1,000 people between 2022 and 2024. The affected man had signs of hepatitis at the time of detection, especially elevated liver values, according to the “Journal of Hepatology”. These had previously been interpreted as “chemotherapy-related toxicity”.

Only a PCR test revealed the true trigger, according to the team. Around six weeks later the values ​​were back to normal. When tested again for rat hepatitis viruses a year later, the result was negative. At the time of diagnosis, the patient was “in his 50s” and immunocompromised. He did not receive HEV-specific therapy. The man recovered on his own.

It is unclear where and how the man became infected

According to the researchers, the virus strain of the rat variant that he identified is closely related to those that were detected in wild rats in Berlin. According to the BfR, it is unclear whether the patient had contact with rats or their excretions or whether the virus was ingested through food. “This is the subject of current research.” Normal hepatitis E viruses are primarily transmitted through the consumption of insufficiently heated meat products from pigs and wild animals.

What danger does rat hepatitis pose?

That is still unclear. “However, the study results suggest that rat HEV must be considered as a new zoonotic pathogen in Germany and Central Europe,” says Johne. Zoonoses are infectious diseases that can be transmitted from animals to humans and vice versa from humans to animals. Like bird flu and Covid-19, among other things.

Symptoms: This is how rat hepatitis manifests itself

All hepatitis viruses (see box) can cause inflammation of the liver. Many infections with classic hepatitis E are mild and without symptoms, explains the Robert Koch Institute. They often resemble the flu. The German’s infection manifested itself primarily in the liver values. The second case in Hong Kong involved abdominal pain, loss of appetite, weight loss and headaches. People with a healthy immune system generally do not need any special therapy.