An emerging threat may be upon us following the mysterious deaths of three squirrel breeders in Germany who possibly died from a novel virus caught from the squirrels they were raising.
“This cluster of acute fatal encephalitis in three squirrel breeders possibly related to an infection with a newly identified bornavirus is an unusual event,” the European Centre for Disease Prevention and Control explained.
“The role of new bornavirus in the aetiology of these cases, the identification of natural hosts, reservoirs, and transmission route require additional investigations.” reads a statement released by the ECDC
According to the study published in the New England Journal of Medicine the men bred variegated squirrels, a species native to Central and southern North America, a known bonavirus species that is capable of infecting a wide range of warm-blooded animals, from birds to primates.
All three men were hospitalized in intensive care units and treated for initial symptoms of a fever, chills, and overall weakness, as well as delayed symptoms of confusion and loss of motor function, before eventually falling into a coma and dying.
While still alive, their cerebrospinal fluid showed pleocytosis, and MRI tests showed growing lesions in the cerebral cortical areas and basal ganglia or meninges.
Initial analysis of the affected brain areas showed tissue swelling and necrosis, glial activation, and lymphocyte infiltration, but no viral inclusions or microorganisms, they reported.
However, upon further investigation doctors began testing for a larger range of pathogens using one of the squirrels owned by the last patient to die. That screening also came back clean so they took the sample analysis a step further by using metagenomic sequencing.
The genomic analysis found a previously unknown bornavirus that they dubbed VSBV-1.
“VSBV-1 is likely to be a previously unknown zoonotic pathogen transmitted by the variegated squirrel,” they stated.
According to the EDCD, bornaviruses are a group of viruses that generally affect rhesus monkeys, horses, sheep, cattle, goats, rabbits, deer, llamas, alpacas, cats, rats, mice, shrews, gerbils, dogs, and ostriches.
Antibodies from this particular bornavirus were found in the blood and spinal fluid of one of the breeders, as well as a contact squirrel and in brain tissue from all three men, the researchers reported, and it is the “likely causative agent” in their deaths.
The report “remains uncertain” about the route of transmission from squirrels to patients, though family members of the deceased squirrel breeders reported that two of the patients had been bitten or scratched.
“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 ECDC stated. “Further investigations are ongoing to characterize these cases. Testing cases of human encephalitis for this newly identified bornavirus, especially in areas where the presence of bornavirus is documented in animals, can contribute to a better understanding of the risk of bornavirus infection in humans.”
The study concluded that all evidence currently gathered isn’t enough to prove that the novel virus caused the death of the three squirrel breeders, but it argues that the evidence is highly suggestive of a novel zoonotic illness.