Genome analysis of over 1,500 white-tailed deer
The study showed that the Corona 19 virus develops three times faster in deer than in humans, and transmission of the virus between humans and deer has been confirmed, raising concerns about the emergence of new mutations in deer paws. This is content published in Health Day, a medical web journal based on an unpublished dissertation by Ohio State University researchers published in Nature Communications on the 28th (local time).
Deer serve as viral reservoirs for viruses to reproduce and multiply, making them ideal hosts for ongoing mutations. Once the virus circulates among deer, it can spread to other wildlife and livestock, as well as to humans.
A study that analyzed the genomes of more than 1,500 white-tailed deer in Ohio, USA, found at least 30 cases of human-to-deer transmission of the virus. Andrew Bowman, professor of veterinary medicine at Ohio State University (OSU), one of the study team, said: “In general, interspecies transmission is rare, but in this case, 30 cases of interspecies transmission were confirmed, although the sample was small.” “It is not surprising that there is growing evidence that people can become infected.
The researchers analyzed nasal swabs from 1,522 white-tailed deer that grazed in 83 of Ohio’s 88 counties between November 2021 and March 2022. More than 10% of the samples tested positive for the COVID-19 virus. At least one positive case was found in 59% of the 83 counties tested.
Researchers who reported finding cases of white-tailed deer infestations in nine Ohio states in late 2021 confirmed that this was not a local event after expanding their investigation to all of Ohio. Professor Bowman said: “At the time, it was thought that this phenomenon only occurs in cities because deer come into closer contact with people, but many benign deer also occur outside the city.”
The researchers also found antibodies to the coronavirus from previous infections in the deer’s serum. About 23.5% of Ohio’s white-tailed deer have had at least one case of COVID-19, researchers estimate.
The researchers collected 80 genome-wide sequences from samples that are markers of a group of mutations in the COVID-19 virus. Delta mutations and alpha mutations have also been discovered, which were once very popular among humans.
The genetic structure of the delta variant found in deer was of the same lineage as the delta variant at its peak in humans. The researchers said this points to interspecies transmission between humans and deer, with deer-to-deer transmission occurring in herds in several counties.
“There are also timing differences in what we found,” Bowman said. In humans, delta became predominant in deer when delta prevalence peaked, and alpha became predominant in deer when it was no longer common in humans. “Therefore, there are concerns that deer act as repositories for mutations that have been lost in humans,” he said.
The researchers also found results confirming that vaccination would help prevent severe or serious illness in the event of a COVID-19 outbreak caused by deer. Vaccinated Siberian hamsters have been exposed to deer coronavirus but have not been infected.
Professor Bowman was concerned that the rate of evolution of the Corona 19 virus, which is common in deer, could be faster in humans. “Deer are not only infected with SARS-CoV-2 and serve as reservoirs for it, but the rate of evolution can be much faster,” he said. According to the analysis method developed by the research team, the rate of evolution of coronavirus in white-tailed deer is not only three times higher than that of humans, but also shows various mutational abnormalities.
However, no case has been reported of a deer-derived strain causing a significant outbreak in humans. The long-term implications of this accelerated evolution remain to be seen, the researchers say, as no significant phenotypic changes have been observed in animal models using white-tailed deer-derived viruses.
However, the risk remains. There are 30 million deer grazing in the United States. The virus likely continues to circulate among the animals, as 70 percent of Ohio deer are still uninfected, according to the report. “Having a deer as a host can lead to things we should be wary of,” Bowman said. “It could also be by infecting the host animal.”
The article can be found at the following link (https://www.nature.com/articles/s41467-023-40706-y).