Researchers from Frankfurt are sequencing the genome of the omnivores, which originate from Asia and have spread widely in Europe.
Like raccoons, raccoons have also spread widely in Europe, although they are not native here – some came from North America, others from Asia via Russia, where they were settled as fur animals from 1928 onwards. Around 1960 the first raccoon dogs appeared in the Federal Republic of Germany, where they are now considered an “invasive species”.
The fox-related omnivores may look cute, similar to raccoons, but according to scientists, as food competitors and predators, they can endanger the populations of native animals – such as birds that breed on the ground. And they can transmit diseases such as rabies, distemper and fox tapeworm to pets and, with close contact, to people.
A research team from the Loewe Center for Translational Biodiversity Genomics at Senckenberg Biodiversity and Climate Research Center in Frankfurt has now found evidence in the raccoon dog’s genome that the animals are also a reservoir for Sars-CoV-2 and can therefore potentially pass the pathogen on. To do this, the scientists sequenced the raccoon dog’s entire genome. Their study was published in the journal “Frontiers in Genetics”.
The team around Sven Klimpel, Professor of Parasitology and Infection Biology at Goethe University Frankfurt, obtained the genetic material from blood and tissue samples from the animals. In total, the raccoon dog’s genome comprises 2.39 billion base pairs, which in their sequence form the genetic information of the DNA. Using laboratory tests and high-performance computers at the Loewe Center, the researchers found which gene for which protein can be found in this huge amount of data.
“In the raccoon dog’s genome, we found the genes for two membrane proteins that can dock on Sars-CoV-2,” reports molecular ecologist Marks Pfenninger: “They form the genetic basis for raccoon dogs to become infected with the coronavirus and to transmit it. “One of these raccoon dog membrane proteins therefore binds to the spike protein of the coronavirus with greater affinity than is the case with related species such as foxes or wolves or bats and Asian pangolins.
So far, science has assumed that the first animal host of Sars-CoV-2 was the bat. It is not entirely certain whether there was an intermediate host and which animal it could have been; Since the beginning of the pandemic, the pangolin has been a candidate in particular. “From which animal host the coronavirus was ultimately transmitted to humans is still unclear,” says Sven Klimpel: “However, our study shows that the raccoon dog can act as a suitable reservoir host for the coronavirus.”
In the project “Zoonotic and Wildlife Ecological Effects of Invasive Carnivores”, Klimpel and his team are investigating, among other things, how individual genes are related to the transmission of certain diseases – not only for raccoon dogs, but also for other immigrant species.