Already several deaths confirmed Bornavirus also for humans a health risk

Rare viral disease: Three people died of Bornavirus

Borna virus is a pathogen that has so far only been observed in animals. But now there is evidence that the brain inflammation in which three people died, were triggered by the dangerous virus. However, experts assume very few isolated cases.

First confirmed Bornavirus detection in humans

In Germany, three patients have died as a result of a viral disease that according to experts has so far only been observed in animals. Those affected had encephalitis, most likely caused by the classic bornavirus. The Robert Koch Institute (RKI) in Berlin and the head of the Institute for Viral Diagnostics at the Friedrich Loeffler Institute (FLI) in Greifswald, Martin Beer, assume that it is the first confirmed Bornavirus evidence in humans at all.

In horses, Bornavirus infections have been known for more than 100 years - with brain inflammation as a possible consequence. Now apparently three people have died as a result of an infection with the dangerous virus. (Image: Tanja Esser / fotolia.com)

Heavy inflammation of the brain

The RKI recently reported cases in the "Epidemiological Bulletin" (10/2018).

It states that investigations by the FLI in cooperation with, among others, the university hospitals in Regensburg, Munich and Leipzig are the first to detect the classical Borna virus (Borna disease virus 1, BoDV-1, species Mammalian 1 bornavirus) as a probable cause of severe inflammation of the brain (encephalitis ) identified in humans.

"Diseases occurred in three recipients of donor organs from the same postmortem organ donor and two of the transplanted patients died in the process," the experts write.

"The new findings confirm the first confirmed BoDV-1 diseases in humans."

However, the participating institutions and the RKI currently agree that "the BoDV-1 diseases of the organ recipients described above are a very rare isolated case."

But: "Regardless of what happens during the transplantation, there is evidence of a fatal infection with the classic bornavirus with the symptoms of massive encephalitis in another patient. A similar case is currently under investigation. "

Virus is different from pathogen detected in 2015

At the end of 2016, the researchers were called in by the FLI, the federal research institute for animal health, from the university clinics where the patients had been treated, because the cause of the brain inflammation was not found in standard diagnostics.

As early as 2015, the FLI was involved in the elucidation of three unclear brain inflammations. At that time, they found a new bornavirus (bornavirus of the croissants, VSBV-1) among deceased Bunthorn breeders in Saxony-Anhalt, which was transmitted by the animals.

This time, the researchers discovered, thanks to special analysis methods, the classic BoDV-1 known from horses and sheep, which, according to RKI, differs from the virus detected in 2015.

"After brain inflammation was not searched because there was no evidence that it could play a role," said Martin Beer FLI in a message from the news agency dpa.

"Based on the current, new findings, in unclear human encephalitis diseases should also be examined for BoDV-1," writes the RKI.

Detect Bornavirus infections at an early stage

As dpa Hartmut Hengel, president of the Society for Virology and Virology at the University of Freiburg, said, the goal now is to develop new detection methods so that Bornavirus infections can be detected at an early or chronic stage.

In the case of the organ donor must have been such an infection, so that the person appeared healthy and organs could be transplanted.

However, Hengel does not believe that further arrangements to secure organ donation are currently possible - nor, given the apparent rarity of the virus, according to the information available, also not necessary.

"We do not yet have any suitable tools to test organ donors preventively," according to the professor.

In addition, it is not clear whether possibly pre-existing conditions in the now documented cases play a role.

Diseased animals usually die from the consequences of infection

In horses, Bornavirus infections have been known for more than 100 years - with brain inflammation as a possible consequence.

Diseased animals show movement disorders and behavioral problems. Often they die from the consequences.

Although according to experts, it has not been definitively clarified how the animals are infected, it is known, however, that the pathogen in Germany can multiply in field-headed mice and be excreted by them. The path to humans is then unclear.

According to the RKI, the virus named after Borna near Leipzig is generally rare.

Controversy over the danger of the virus

In the past, there was a scientific controversy about the virus and its dangerousness. The beginning of the 1990s started research at the RKI on possible bornavirus infections in humans was discontinued in 2005.

At that time it was said that despite many years of efforts, no reliable indication of a danger to humans was found.

Suspected bornavirus detection in human specimens was later attributed to contamination in the laboratory.

The topic was also receiving much attention because some of the scientists described bornavirus as a factor in the development of diseases such as depression and schizophrenia.

However, Martin Beer from the FLI emphasized: "One must separate the current individual cases clearly from the discussions of the past 20 years and the investigations at that time. We now see a very clear symptom, we have deaths and in the samples of the deceased patients can be detected very large amounts of virus genome. "

Researchers from several German institutions now want to investigate open questions about bornaviruses in a federally funded consortium ("ZooBoCo") - for example on infection routes and risk areas. (Ad)