NEW YORK — Already Public Enemy No. 1, the rodent population roaming New York City poses a new threat as researchers reveal millions of rats could carry the virus that causes COVID-19.
New research Thursday raises the question of possible animal-to-human transmission in one of the Big Apple’s largest population groups: rats. Previous research has already shown that the virus can live in household pets, zoo big cats, and wild deer.
The rat-catching team that published research in the American Academy of Microbiology journal mBio found that wild rodents are susceptible to the virus and, through further laboratory studies, determined that they can contract several of its variants.
THE POPULATION OF RATS IN NEW YORK IS ALREADY KNOWN
“To our knowledge, this is one of the first studies to show that SARS-CoV-2 variants can cause infections in wild rat populations in a major urban area in the US,” said Dr. Henry Wan, of the University of Missouri, said.
The team behind the research captured 79 rats in the fall of 2021, mostly in Brooklyn parks. Samples from the groups of rodents were tested and 13 (16.5%) tested positive, the study found. Expanding the animal positivity rate to the estimated city-wide rat population of the study (8 million), it can be speculated that as many as 1.3 million rats could display an immune response to COVID-19.
Robust rodents that they are, rats that received the virus within a laboratory setting did not show extreme reactions to SARS-CoV-2. Despite the high levels of viral RNA within the animals’ noses and lungs, none experienced weight loss or other significant reactions.
Of the three variants, Alpha, Delta and Omicron, the rats appeared susceptible to all three, the researchers found through the additional “virus challenge study.” However, Delta replicates “more efficiently” than the other two in rats.
A review of the data by the Los Angeles Times takes the implications a step further, saying the findings suggest that rats could not only be a source of reinfection for people, but could also become a source of new variants that they could pose problems for humans along the way, potentially.
“Several studies have suggested that fragments of the SARS-CoV-2 genomes were identified in wastewater systems and that the prevalence of SARS-CoV-2 in wastewater systems coincides with outbreaks in resident human populations” , the study explained.
“However, no evidence has shown that SARS-CoV-2 viruses in sewage are infectious, suggesting that sewage rats may have been exposed to the virus through airborne transmission, for example by overlapping living spaces with humans or indirect transmission from unknown fomites, for example, contaminated human food residues”.
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Its researchers warn that much more study is required to understand the full implications of any possible threat to people. Their ever-growing population, which has skyrocketed in recent years and caught the attention of the city’s mayor, makes the rodents a clear threat if a transmission link between rats and humans can be established.
“Rats likely play an important role in the evolution of the Alpha, Delta, and Omicron variants, which has the potential to result in the emergence of novel rat variants that are naive to the human population and may contain harmful properties for humans.” humans,” the research team said.
The threat of future mutations or virus strains among rat populations requires additional monitoring, Dr. Wan said, for the protection of “human and animal health.”
For its part, the New York City Department of Health noted the following:
“While the Department of Health was not involved in this research study, we know that other animals have been infected with SARS CoV-2. This study suggests that Norway rats and laboratory rats may also be susceptible to infection by the virus. SARS-CoV-2 virus, but at this time there is no evidence to suggest that infected rats transmit the virus or pose a COVID-19 threat to New Yorkers,” the Department of Health said in a statement.
