Reservoir animal: Researchers have discovered a new type of corona virus in Swedish bank voles. Like SARS-CoV-2, the pathogens belong to the betacoronaviruses, but within this group they are more closely associated with one of the common cold coronaviruses. The new Grimsö virus is probably also circulating in Central European bank voles, as the scientists explain. Whether it can be transmitted to humans and whether there is a risk of zoonosis is still unknown.
It is still controversial whether the SARS-CoV-2 coronavirus was transmitted to humans from pangolins or bats. What is clear, however, is that small mammals such as rodents and bats are widespread reservoirs for these viruses. They can often even carry several corona viruses at the same time – and thus offer the pathogens the potential to recombination. So far, South Asia in particular has been considered Hotspot animal corona viruses, but also in Europa Several such viruses have already been detected in bats and rodents.
Virus search in wild mice
A research team led by Anishia Wasberg from Uppsala University has now found a new variant of the coronavirus in bank voles (Myodes glareolus) – one of the most common rodents in Europe. It was already known from previous studies that these mice can carry various corona viruses and other viral pathogens. So far, there has been evidence in France, Poland and Germany, among others.
For their study, Wasberg and her team captured around 260 bank voles near the town of Grimsö in central Sweden and took tissue samples from them. They analyzed these for viral RNA and compared the gene sequences obtained with those of known strains of coronavirus.
New variant of the beta corona virus
The result: The researchers detected RNA from corona viruses in 3.4 percent of the bank voles examined. The comparative analyzes showed that the genetic material was from pathogens from the group of betacoronaviruses – the group that also includes MERS, SARS and SARS-CoV-2 in addition to some rodent viruses. Within this group, however, the new Grimsö coronavirus more closely resembles the embecovirus subgroup, which also includes two of the common cold human coronaviruses.
However, the newly discovered bank vole pathogens differ significantly from these already known pathogens and also from the rodent coronaviruses: “The Grimsö sequences showed less than 60 percent agreement in the RNA and less than 50 percent at the amino acid level,” report Wasberg and her colleagues. “This suggests that the Grimsö virus forms its own group within the embecoviruses.”
Zoonotic potential still unknown
According to the researchers, bank voles in central Sweden carry a novel, previously unidentified coronavirus. Because this virus was repeatedly detectable in the Swedish mice over a period of two years, they assume that this coronavirus is relatively widespread in the population of these rodents. However, it is still unknown whether the Grimsö virus is also found in bank voles outside of Sweden.
It is also unclear what risk the Grimsö virus poses to humans or other animal species. “We do not yet know what potential public health risks this virus poses,” explains the team. “But we cannot rule out that the Grimsö virus has zoonotic potential for livestock or humans.” In order to find out, the coronavirus would first have to be cultured and then analyzed for its receptor binding.
“Nonetheless, there are good reasons to keep a close eye on coronaviruses in wild rodents,” says Wasberg’s colleague Åke Lundkvist. (Viruses, 2022; doi: 10.3390/v14061205)
Quelle: The Swedish Research Council