Bornavirus: This rare disease is very serious; it has caused one death in Germany. What are the symptoms?

German media reported the death of a man who had been infected with the virus.

A disease as rare as it is deadly. Only a few cases are detected each year in Europe, particularly in Germany. In May and June 2025, the German media outlet Frankfurter Rundschau reported the death of a man who had been infected. Another person was affected and was reportedly placed in intensive care.

Borna disease, caused by the virus of the same name, is a very rare disease in humans but fatal in most cases. While the first human case was reported in 2015 in Germany, the disease has been known in animals, particularly horses, for much longer. It is also transmitted to humans via animals, particularly the common shrew, which excrete the virus in their urine, feces, or saliva. While it is not common to come into contact with a shrew, cats can hunt rodents and indirectly infect their owners.

People in contact with animals are therefore particularly at risk of contracting the virus. To avoid infection, it is recommended to avoid all contact with rodents and their droppings, and to protect yourself when cleaning or gardening in areas that could be contaminated. According to current knowledge of the disease, it cannot be transmitted between humans. However, a few cases of transmission to humans during organ transplants have been described.

Borna disease causes acute encephalitis, an inflammation of the brain. It is characterized by various symptoms: malaise, headaches, fever, neurological disorders affecting walking or speaking, and even coma and death. There is currently no specific treatment or prevention. In France, while human cases have been suspected, none have been officially described.