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New bornavirus strain in EU detected, following encephalitis cases in variegated squirrel breeders in Germany

27 Feb 2015
New bornavirus strain in EU detected, following encephalitis cases in variegated squirrel breeders in Germany
​Three cases of fatal encephalitis in breeders of variegated squirrels in Germany are possibly linked to a newly identified type of bornavirus – a zoonotic pathogen which can affect various animal species and possibly cause psychiatric disorders in humans. All infected persons bred variegated squirrels, a type of tree squirrel common to Central America that can be kept as an exotic pet.  A bornavirus strain different from all currently known bornaviruses so far was found in the patients and in a squirrel belonging to one of the patients. 
The cases are still under investigation and there is no proof yet of a direct relationship between the presence of the bornavirus and the encephalitis, hence, a zoonotic infection with bornavirus has not been confirmed. 
However, there could be a higher risk of exposure to infection for variegated squirrel breeders, their family members and the owners of variegated squirrel pets.  At present, such risk cannot be assessed because of the low number of cases reported, the lack of information about the new virus, its transmission and connection to the infection in variegated squirrels.
It is advised that direct contact with living or dead variegated squirrels should be avoided, as a precautionary measure, concludes ECDC risk assessment. 
Read the risk assessment: New bornavirus strain detected in the EU
Borna disease virus (BDV) is a zoonotic pathogen - it can infect many animal species, e.g. sheep, horses, birds, cats, squirrels, etc., which can possibly cause its transmission to humans. Few documented possible human infections with bornaviruses describe symptoms such as diverse psychiatric disorders in people infected with the virus. However, the existing evidence is insufficient to prove the potential bornavirus infection in humans and its connection with the said psychiatric disorders, mainly because of the complexity of the laboratory procedures related to diagnosing the bornavirus. Recently a new strain of bornaviruses has been detected in variegated squirrel and later in brain samples of three squirrel breeders with fatal encephalitis.
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