Deadly Bornavirus infections first occurred in humans in Germany

Four deaths: bornavirus infections in humans are isolated cases

In Germany, four people 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, which was triggered by the classic bornavirus. The infections are according to current knowledge but isolated cases.

Very rare isolated cases

In Germany, infections with the classical Borna virus (Borna disease virus 1, BoDV-1) were first detected in individual humans. The infection, which can cause inflammation of the brain, occurred in a total of five persons, three of which were donors of donor organs of the same donor, reports the Society for Virology (GfV) in a release published by the Information Service Science (idw). Four of the patients have died. According to the GfV, all scientific evidence available to date indicates that human diseases are very rare individual cases. The scientific society has written a detailed opinion on the current cases.

For the first time, infections with classical Borna virus were detected in individuals in Germany. The infection, which can cause inflammation of the brain, occurred in a total of five persons. Four of the patients have died. (Image: science photo / fotolia.com)

Heavy inflammation of the brain

The Robert Koch Institute (RKI) has already reported on the cases in the "Epidemiological Bulletin" (10/2018).

There it is said that investigations of the Friedrich Loeffler Institute (FLI) in collaboration with the university hospitals in Regensburg, Munich and Leipzig for the first time the classical Bornavirus (Borna disease virus 1, BoDV-1, species Mammalian 1 bornavirus) as a probable trigger of severe brain inflammation (encephalitis) 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.

In addition, BoDV-1 infection was detected in two other independent deaths with symptoms of acute encephalitis.

Virus is different from pathogen detected in 2015

At the end of 2016, researchers from the FLI, the federal research institute for animal health, called on the university hospitals where the patients had been treated, because the cause of the brain inflammation was not found with 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.

Possibly transmission by Feldspitzmäuse

In some of the current BoDV-1 infections, organ recipients had been infected by transplanting the organs of the infected donor.

"So far, it's still unclear how the donor and the two other people affected became infected with the virus," explains Professor Dr. med. med. Hartmut Hengel, President of the GfV.

Transmission by fieldtail mice, the natural reservoir of the pathogen, currently appears to be the most likely source of infection and is the subject of further investigation.

Transmission of the virus from diseased horses or sheep to humans or other mammals has not been demonstrated.

Even an excretion of the virus by the infected persons could not find scientists. Thus, there is currently no indication that human-to-human transmission is taking place.

The occurrence of BoDV-1 in the Feldspitzmaus populations is according to current knowledge regionally limited to parts of eastern and southern Germany, Austria, Switzerland and Liechtenstein.

An infection with BoDV-1 can currently be diagnosed only in acutely ill persons.

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, according to the GfV, "there is still no scientific evidence to support the sometimes-published theory that a large proportion of the population is infected with the virus and that there are a number of neurological and psychiatric disorders".

The experts of the GfV see a high demand for further investigation of the virus, in order to clarify open questions regarding distribution, transmission paths, early diagnosis and therapy of the virus.

As part of the interdisciplinary project "Zoonotic Bornavirus Consortium" funded by the German Federal Ministry of Education and Research, corresponding research projects have already begun and will now be further intensified. (Ad)