Covid-19: evidence of a massive infection of deer

Almost half of the deer in North America have been infected with the coronavirus! This is the very surprising finding of a study by the National Wildlife Research Center (NWRC), belonging to the United States Department of Agriculture. A previous study, dating from May 10, 2021, already showed that deer and hinds could be infected with the virus responsible for Covid-19 and that they were likely to transmit it to their congeners. This new analysis, published in preprint on July 29, 2021 (therefore not yet peer reviewed), would show that these animals are victims of a real coronavirus epidemic, becoming potential natural reservoirs for the virus.

A highly variable infection rate between the states of the North American country

NWRC researchers studied blood samples from 385 deer collected between January and March 2021 during wildlife monitoring activities in the United States, from four states in the north of the country (Michigan, Pennsylvania, Illinois and New York). . These animals were compared with samples from 239 deer from the same states collected between 2011 and 2020. 40% of samples collected in 2021 had neutralizing antibodies against the Sars-CoV-2 coronavirus, compared to only three samples from 2020 (collected in January ), only one from 2019 and none between 2011 and 2018. However, the infection rate was highly variable between states, from 67% of samples collected in Michigan to 7% of those in Illinois.

The number of these antibodies was also much higher in the samples from 2021 (reaching 80 to 100% in the neutralization tests performed) than those collected in 2020 and 2019 (around 36% neutralization). Such low neutralization rates could represent false positives due to immunity to other coronaviruses, the authors say.

Wildlife could become a major reservoir of the virus

This study represents the first detection of massive exposure to the coronavirus in wild animals. But the researchers do not know how these animals could have been exposed to the virus and offer several hypotheses. In particular direct exposure by humans during research or hunting activities, or through water sources contaminated by the virus.

But what worries experts the most is the possibility that these deer and other wildlife will become reservoirs for Sars-CoV-2, where the virus can mutate and then pass back to humans as potentially resistant variants. vaccines. They are therefore encouraging other researchers studying wild animals to include in their analyzes methods to detect the coronavirus and identify potential variants. To prevent Bambi and his family from becoming the source of the next pandemic.