Four deaths: Bornavirus infections in humans are isolated
In Germany, four people died as a result of a viral disease that, according to experts, has so far only been observed in animals. Those affected had an inflammation of the brain caused by the classic Bornavirus. According to current knowledge, infections are isolated cases.
Very rare individual cases
In Germany, infections with the classical Bornavirus virus (Borna disease virus 1, BoDV-1) were detected for the first time in individual people. The infection, which can trigger inflammation of the brain, occurred in a total of five people, three of whom were recipients of donor organs from the same donor, reports the Gesellschaft für Virologie (GfV) in a message published by the Informationsdienst Wissenschaft (idw). Four of the patients have died. According to the GfV, all scientific knowledge available to date indicates that human diseases are very rare individual cases. The scientific society has written a detailed statement on the current cases.
Severe inflammation of the brain
The Robert Koch Institute (RKI) reported on the cases in the “Epidemiological Bulletin” (10/2018).
It states that studies by the Friedrich-Loeffler-Institut (FLI) in cooperation with the university clinics in Regensburg, Munich and Leipzig, among others, for the first time the classic Bornavirus (Borna disease virus 1, BoDV-1; species Mammalian 1 Bornavirus) as a probable trigger of severe inflammation of the brain (encephalitis) in humans.
"The diseases occurred in three recipients of donor organs from the same postmortem organ donor and two of the transplanted patients died later," write the experts.
In addition, a BoDV-1 infection was detected in two other independent deaths with symptoms of acute encephalitis.
Virus differs from the pathogen that was identified in 2015
At the end of 2016, researchers from the FLI, the Federal Research Institute for Animal Health, were brought in by the university hospitals where the patients were treated because the cause of the brain inflammation could not be found using standard diagnostics.
In 2015, the FLI was involved in the elucidation of three unclear brain inflammations. At that time, they found a new Bornavirus (Bornavirus der Hörnchen, VSBV-1) from deceased Bunthörnchen breeders in Saxony-Anhalt, which was transmitted by the animals.
This time, thanks to special analysis methods, the researchers discovered the classic BoDV-1, known from horses and sheep, which, according to the RKI, differs from the virus detected in 2015.
Possibly transmission by shrews
In some of the current BoDV-1 infections, organ recipients had become infected through the transplantation of the organs of the infected donor.
"It is still unclear how the donor and the other two affected have been infected with the virus," explains Professor Dr. med. Hartmut Hengel, President of the GfV.
Transmission through shrews, the pathogen's natural reservoir, currently appears to be the most likely source of infection and is the subject of further investigation.
No transmission of the virus from sick horses or sheep to humans or other mammals has been proven.
Scientists were also unable to determine whether the infected people had excreted the virus. So there is currently no evidence that human-to-human transmission is taking place.
According to current knowledge, the occurrence of BoDV-1 in the shrew populations is regionally limited to parts of eastern and southern Germany, Austria, Switzerland and Liechtenstein.
An infection with BoDV-1 can currently only be diagnosed reliably in acutely ill people.
Controversy over the dangerousness of the virus
There has been scientific controversy in the past about the virus and its dangerousness. Research at the RKI on possible Bornavirus infections in humans, which began in the early 1990s, was discontinued in 2005.
At the time, it was said that despite years of efforts, no reliable evidence of a risk to humans had been found.
Alleged Bornavirus evidence in human samples was later traced back to contamination in the laboratory.
The topic had also received a lot of attention because some of the scientists described the Bornavirus as a factor in the development of diseases such as depression and schizophrenia.
However, according to the GfV, "there is still no scientifically substantiated evidence for the thesis that a large part of the population is infected with the virus and is associated with the occurrence of various neurological and psychiatric disorders".
The GfV experts see a great need for further research into the virus in order to clarify open questions regarding the spread, transmission routes, early diagnosis and therapy of the virus.
As part of the interdisciplinary project "Zoonotic Bornavirus Consortium" funded by the Federal Ministry of Education and Research, corresponding research projects have already begun and are now being further intensified. (ad)