Borna disease virus is found in bi-coloured shrews in Germany and Austria. The illness can cause encephalitis, a brain infection in humans. Doctors say at least 14 patients in Germany have died from encephalitis caused by Borna disease virus 1. However, it is feared the total could be much higher, given the shrews that carry the bug are found in Austria, Switzerland and Liechtenstein. The virus makes the brain swell up and experts are now calling for more research into the spread of the virus to work out if may be behind even more unexplained human deaths.
The illness of the virus brought on symptoms such as fever, headaches and confusion and progress to unsteady walking, memory loss, seizures, deep coma and ultimately death.
Encephalitis makes the brain swell up and can cause vomiting, limb weakness and loss of consciousness.
Other symptoms include viruses such as herpes, measles, mumps and rubella.
Although the effects of Borna disease on humans are not well documented, it can cause similar other symptoms like anxiety, mania, psychosis and depression, according to scientists.
What has the expert said?
Professor Barbara Schmidt said: “Our findings indicate Borna disease virus infection has to be considered a severe and potentially lethal human disease transmitted from a wildlife reservoir.
“It appears to have occurred unnoticed in humans for at least decades. The virus may have caused other unexplained cases of encephalitis in regions where the virus is endemic in the host shrew populations.
“It is still relatively rare in absolute numbers, but it might be behind a larger proportion of unexplained severe to fatal encephalitis cases.
“Only more tests on patients with severe or even deadly encephalitis will find this out.”
What is encephalitis?
Encephalitis is an uncommon but serious condition in which the brain becomes inflamed.
It can be life-threatening and requires urgent treatment in hospital. Anyone can be affected, but the very young and very old are more at risk.
Encephalitis sometimes starts off with flu-like symptoms, such as high temperatures and headache.
More serious symptoms develop over hours, days or weeks, including confusion, seizures or changes in personality and behaviour.
In at least seven of the 14 deaths, the patients had close contact with pet cats.
The scientists suggest cats may bring infected shrews into the home after hunting them.
Most patients also lived in rural areas, agricultural work or outdoor activities appeared to be more common amongst them.
The same virus is also found in sheep and horses, but all cases of the disease can be tracked back to shrews, which is the virus’ natural host.