June 12, 2025, 12:19 pm | Read time: 5 minutes
A mysterious virus is causing fear in Germany: One man has died, and another is fighting for his life—both infected with the same deadly pathogen. Particularly alarming: Cat owners are now at the center of warnings. Here’s why and how you can protect yourself and your pets.
In the Upper Bavarian district of Pfaffenhofen, two men have contracted the dangerous Bornavirus–one has died, and the other is in intensive care. Authorities are investigating the cases, while cat owners, in particular, are being urged to exercise caution. PETBOOK examines current research on Bornavirus and summarizes what is known so far.
Two Infections in Bavaria—One Already Fatal
In the district of Pfaffenhofen an der Ilm, two middle-aged men have contracted the highly dangerous Bornavirus–one of them has died, and the second is fighting for his life in intensive care. According to information from “BR24,” both patients are in their mid-fifties. How they became infected is currently unclear. The dramatic cases are reminiscent of a similar incident two years ago, in which two children died from a Bornavirus infection.
The Bornavirus, specifically Borna Disease Virus 1 (BoDV-1), causes acute inflammation of the brain (encephalitis) in humans. This is fatal in most cases, with a mortality rate of over 90 percent. Our colleagues at FITBOOK provide comprehensive information on this disease.
The symptoms initially start with unremarkable fever and headaches but quickly progress to neurological failures, leading to coma. There is no vaccine, and treatment options are currently scarce.
How Is the Bornavirus Transmitted?
The main carrier of the virus is considered to be the field shrew. The animal sheds the virus through urine, feces, and saliva. Infection occurs indirectly through contaminated soil, dust, or food—direct contact with the animal is not necessary, it is said. Some media now warn that cat owners are particularly at risk, as outdoor cats are considered a risk because they may come into contact with infected shrews.
However, a first study on transmission routes in Germany found no statistical correlation here. The Robert Koch Institute (RKI), the Bavarian State Office for Health and Food Safety, and the Bernhard Nocht Institute for Tropical Medicine examined how the shrew disease is transmitted in the journal “Emerging Microbes & Infections.”
They investigated 20 PCR-confirmed deaths from BoDV-1 encephalitis that occurred between 1996 and 2021—90 percent of them since 2015. In personal interviews with relatives, experts recorded the deceased’s medical history, living conditions, professional life, animal contacts, leisure activities, and dietary habits. The analyses included the size of the place of residence, type of house, proximity to nature, animal contacts, and more. Additionally, soil samples from the gardens of four cases were examined. If you want to be safe in your home garden, our colleagues at myHOMEBOOK have some tips for you.
Cat Ownership as a Risk for Bornavirus?
The most significant risk factor for infection was the place of residence—specifically, an isolated or settlement-edge location with direct proximity to nature. People living in such areas had a 10.8 times higher risk of contracting BoDV-1 encephalitis.
Other variables, such as keeping cats, outdoor activities, or contact with animals, were not significantly associated with the disease. Although 65 percent of the cases showed evidence of shrews in the vicinity, there were no specific transmission events like bites or skin contact. Soil samples were negative.
However, it is further stated that cats are so-called dead-end hosts and can transmit the virus but do not become seriously ill themselves. In the study, nine of the twenty households where the deceased lived reported keeping cats. In four other households, relatives reported regular close contact of the deceased with neighboring or stray cats, even though no cats were kept.
What Cat Owners Should Know
Thus, a total of 13 out of 20 cases had verifiable contact with cats, either through their own pets or through animals from the neighborhood. In six households, it was observed that cats brought shrews onto the property. However, the animals were not examined or tested for the virus themselves but were described as sightings by laypeople.
Therefore, it is not even certain whether the captured animals were actually shrews.
Furthermore, the study did not differentiate between indoor cats and outdoor cats. In the rural areas studied, outdoor access is considered common. This makes the survey results unreliable, as it is not verifiable whether the cats were actually outdoor cats and whether the respondents’ observations were indeed shrews.
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Whether cats contribute to infection, are merely indicators of proximity to infected shrews, or even have protective effects cannot be determined based on the data. The exact role of cat ownership in transmission remains unclear.
However, the study shows that cat ownership itself is not an independent risk factor for contracting BoDV-1 encephalitis. Although there were indications of contact between cats and “shrews” in several cases, specific transmission events were lacking. The role of the cat in the infection process remains open and requires further research.
Owners concerned about themselves and their cats can, however, take precautions by ensuring their pets only have access to a secured garden. This can reduce the risk of contact with an infected shrew. Additionally, many native shrew species are considered “endangered” due to climate change, according to the Red List. They are, therefore, strictly protected—and should not end up in a cat’s paw or stomach.