a potential reservoir for new variants of SARS-CoV-2?

United States – More and more testimonies report American deer infected with SARS-CoV-2 and sick with Covid-19. The phenomenon has also been observed in zoo animals and pets. Some experts fear not only that animals become a source of transmission of the virus to humans but also that they represent a reservoir for the development of new variants.

Concerned deer and felines

Last July, the US Department of Agriculture revealed that antibodies to SARS-CoV-2 had been detected in white-tailed deer in Illinois, Pennsylvania, Michigan and New York State. A month later, the department reported the presence of the virus in deer in Ohio. A few weeks ago, researchers at Penn State University published a study showing that an increasing number of deer had tested positive in Iowa, most likely reflecting human-to-deer transmission (the phenomenon being mainly observed in animal parks) then between deer.

In parallel, three snow leopards housed at the Lincoln Children’s Zoo in Nebraska recently succumbed to complications related to Covid-19. Two tigers at the zoo also contracted the virus in October, but they have recovered. A comparable phenomenon occurred in Smithsonian National Zoo from Washington DC in September, with six African lions, a Sumatran tiger and two Siberian tigers testing positive for SARS-CoV-2. Zoo staff were unable to determine the source of these infections.

Humans did infect animals

So far and although the cause is sometimes unknown, it seems to be rather humans who infect animals. Thus, according to Angela Bosco-Lauth (Assistant Professor of Biomedical Sciences at Colorado State University, Fort Collins), humans are the suspected vector of infection in deer. On the other hand, “the probability that a human will contract the disease from a deer which he has just killed is quite minimal, although it cannot be completely excluded. “He added, highlighting the massive number of infections in the world, that” what we are seeing is unprecedented in history. What is even more worrying is the possibility of the appearance of a new variant, especially in domestic or farm animals. We have seen in particular with the delta variant that mutations appear quite easily and adapt to the host. “

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Angela Bosco-Lauth and her colleagues recently conducted experiments in cats, dogs, hamsters and ferrets. They observed a rapid progression of SARS-CoV-2, particularly in dogs and cats. In their study, published in early November in the journal Proceedings of the National Academy of Sciences, the authors suggest closely monitoring the development of SARS-CoV-2 in companion animals and other potential animal hosts.

Given that cats seem particularly susceptible to infection with this virus and that they live near humans, we would be in the presence of “a more likely context of transmission in both directions, between humans and animals, and which can give rise to variants ”, worries Angela Bosco-Lauth.

The US Center of Disease Control says humans can transmit Covid-19 to animals, including pets, zoos or farm animals like mink. The Agency emphasizes, however, that there is still no evidence that Covid-19 can be transmitted from animals to humans, with the exception of farmed mink.

Denmark culled millions of mink in 2020 to prevent a mutation that occurred after human-to-animal and animal-to-human transmission. The country then cremated 4 million of those mink that had first been hastily buried a few months earlier.

Caution is required for hunters

SARS-CoV-2 is not transmitted through the blood, and there is no evidence that a person can get sick from eating deer meat, but some states recommend that hunters take extra care when preparing food. base of white-tailed deer. The majority of these states advise them to follow the CDC’s recommendations for handling wild game, which advise against taking animals that appear sick or are found dead, to avoid cutting the spine and spinal tissue, not to consume the brains of a wild animal, and to wear rubber or disposable gloves.

For example, Wisconsin suggests wearing a mask and advises hunters to also limit handling or cutting of the lungs, throat, muzzle and nostrils. Massachusetts advises the wearing of a face mask, in addition to CDC guidelines. A Rhode Island state wildlife biologist told the Providence Journal that he recommended wearing a mask when handling deer in the field.

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Most states in the US recommend the Covid vaccine, which they see as the best way to protect against potential infection, even from animal sources.

Extra precautions are never unnecessary, said Angela Bosco-Lauth, adding that “wearing a mask to prevent other pathogens besides SARS-CoV-2 is a good idea”.

This article originally appeared on Medscape.com under the title COVID Spread Among Deer Causes Concern Over New Variants . Translated by Dr Claude Leroy.