Research

Squirrel virus kills three breeders

It started with a failure of our diagnostics department to find the cause of a fatal brain infection of a man from Saxony-Anhalt. Inquiries revealed that the man was a breeder of South American coloured squirrels and that two of his breeder colleagues had also died from unclassified brain infections one and one and a half years ago, respectively.

Variegated squirrel (Sciurus variegatoides atrirufus), carrier of a new Borna virus causing fatal encephalitis in humans (Photography: Hans Hillewaert, CC BY-SA 3.0).
Variegated squirrel (Sciurus variegatoides atrirufus), carrier of a new Borna virus causing fatal encephalitis in humans (Photography: Hans Hillewaert, CC BY-SA 3.0).

All re-examinations for known pathogens again were negative, also in the squirrels. Finally, colleagues from the Friedrich Loeffler Institute sequenced all RNA genetic material from the brain of a squirrel and were successful. In addition to the squirrel’s mammalian genes, sequences were found that clearly originated from a virus. Virus-specific tests, designed based on these sequences, revealed the presence of the new virus in several squirrels and, notably, in the brains and cerebrospinal fluids of the deceased breeders. The new virus, a Borna virus, clearly differs from all Borna viruses identified so far, most of which cause encephalitis in horses. The new virus had presumably been transmitted to the breeders by bites or scratches of the squirrels.

 


Hoffmann B. et al. N Engl J Med 2015; 373:154-62

Dennis Tappe, Daniel Cadar, Jonas Schmidt-Chanasit and 
external co-operation partners (see publication)