Squirrel Virus Linked to Deaths

Bornavirus from squirrels transmitted to three German men

A cousin of the cute, acorn-eaters scampering around your backyard may be at the root of a mysterious virus responsible for the deaths of three men.

A new study from Germany found that the deaths of three squirrel breeders in Germany between 2011 and 2013 were caused by a virus that these men likely contracted from the animals.

The new form of bornavirus — usually found in sheep, horses, birds and rodents — is not known to be transmissible from one human to another, but does have the potential to spread from animals to humans.

"This cluster of acute fatal encephalitis in three squirrel breeders possibly related to an infection with a newly identified bornavirus is an unusual event," read a European Centre for Disease Prevention and Control statement on the virus. "Nevertheless, pending the completion of the cluster investigation, feeding or direct contact with living or dead variegated squirrels should be avoided as a precautionary measure."

The three men died within two to four months of developing symptoms of encephalitis — fever, chills, weakness, confusion and difficulty walking. This condition is characterized by swelling of the brain and is usually caused by a virus.

These men were friends and had exchanged squirrels with each other. Two of the three had been bitten or scratched by variegated squirrels.

This study was led by Martin Beer, DVM, a veterinarian from the Institute of Diagnostic Virology at the Friedrich-Loeffler-Institut in Germany.

Dr. Beer and team confirmed that these deaths were caused by a new form of the bornavirus, and traced the virus to variegated squirrels (an exotic breed native to southern Mexico and Central America).

No other infected humans or animals have been found.

This study was published in the July issue of the New England Journal of Medicine.

The Federal Ministry of Food and Agriculture, the Bundeswehr Medical Service and the European Union ERA-NET project funded this research.

No conflicts of interest were available at the time of publication.