As more and more animal species susceptible to SARS-CoV-2 infection were identified under natural or experimental conditions, the risk of zoonosis was suspected by the National Academy of Medicine of pandemic origin. then confirmed when the Netherlands detected contamination of humans with farmed mink.
Subsequently, several cases of animal contamination with different variants of SARS-CoV-2 of human origin have been reported, affecting a wide range of species among pets, domestic animals (mustelidae) or wildlife. . Zoos (big cats, great apes, hippos, otters) have been contaminated by their keepers. In India, a wild leopard in the wild became infected with the Delta variant.
Although cases of contamination of dogs and cats by humans are sporadic, the establishment of a virus reservoir in nomadic cats is still possible due to their contact with the liminal fauna of wild origin, which is still little studied, and susceptibility of felines to various variants. of SARS-CoV-2. Among new pets, a natural infection has been reported in two rabbits with SARS-CoV-2 in France .
In Hong Kong, in January 2022, golden hamsters, imported from the Czech Republic via the Netherlands, would have been the cause of an epidemic focus from the Delta variant, which started at a pet store before reaching 58 people. Since the episode of farmed mink, it is the first time that contamination of hamsters of human origin has been followed by infection back to humans, then by epidemic spread by human-to-human transmission. The hamster’s high susceptibility to SARS-CoV-2 describes this pet as a potential reservoir. In addition, the study conducted around this outbreak reveals that international trade in pets poses a risk of remote transmission of SARS-CoV-2. .
In North America, the white-tailed deer (Odocoileus virginiatus) could constitute an animal reservoir of SARS-CoV-2. The hypothesis was reinforced in 2022: this overpopulated species is approaching urban or suburban areas, which has probably favored its pollution of humans. The seroprevalence of anti-SARS-CoV-2 antibodies has been estimated at between 13.5 and 70% in these wild deer, with a peak of 82.5% during the hunting season in the United States. . It rises to 94.4% in captive animals, probably because of their promiscuity. In Pennsylvania, where the population of white-tailed deer is the densest (30 deer per square kilometer), the Alpha variant circulated simultaneously with the Delta variant in the fall-winter of 2021, when the Delta variant dominated the human population. The dynamics of intraspecific transmission have been investigated experimentally after intranasal inoculation of fawns by monitoring contact animals. . Finally, a new highly divergent lineage of SARS-CoV-2, detected in Canada in white-tailed deer, has been isolated from a human case in the same region, suggesting possible transmission from deer to humans. .
In Europe, the hypothesis of a reservoir in deer has not been confirmed, but other animal species are very sensitive to SARS-CoV-2. This is the case with wild or wild mouse sufferers who have been found to be HIV positive: otters and mink in Spain marten and badger in Brittany . In France, the epidemic spread of Covid-19 due to the Marseille-4 variant (B.1.160) in 2020 appears to have originated from a mink farm in Eure-et-Loir . Several species classified as harmful in France due to their distribution are also highly susceptible to SARS-CoV-2: the American mink, raccoon dog and the red fox.
In the Joint Declaration of 7 March 2022, the OIE, WHO and FAO emphasize the risk of SARS-CoV-2’s animal reservoir and its potential role in the emergence of new variants by mutation or recombination . In addition, it should not be forgotten that the animal reservoir of coronavirus at the origin of the Covid-19 pandemic was probably a bat, and that coronaviruses very close to SARS-CoV-2 in this species have recently been identified. specially monitored .
It is therefore National Academy of Medicine recommends :
- to maintain continuous monitoring of infections detected in domestic animals as well as in wild and indigenous animals susceptible to SARS-CoV-2;
- to perform systematic sequencing for each case found positive by RT-PCR;
- to warn infected people, symptomatic or not, that they should also apply isolation measures to animals living in their environment;
- to inform hunters, forest workers and anyone carrying out an activity in contact with wild and liminal fauna (specialized care centers, zoos, etc.), as well as visitors to zoos, about the zoonotic risks that have arisen.
- Press release from the National Academy of Medicine and the French Veterinary Academy “Do animals infected with SARS-CoV-2 pose a risk to humans?», July 23, 2020.
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