A 16.5% percentage of mice caught in New York tested positive for COVID. This could mean that more than 1.3 million mice may have been infected.
A new research carried out in New York has revealed the presence, in the Big Apple, of more than one million mice positive for Coronavirus, the virus responsible for the COVID-19 pandemic. The estimate derives from the percentage of rats caught and positive results during a study carried out specifically, with the data projected on the total number of mice that populate the metropolis (over eight million). The researchers also determined that these animals are susceptible to the Alpha, Delta and Omicron variants, 3 of the 5 variants reported as “worrisome” by theWorld Health Organization. The main danger is in the mutations that the virus can undergo as it passes between the various animals, producing new variants, potentially capable of infecting humans, through the “spillback”. To date the transition from man to animal, and back to human being, has been identified in only one in a mink farm in Denmark; in fact, scholars believe that it is a very rare event. But the gigantic amount of mice present in large urban centers and the various opportunities for contact with citizens increase this danger. A team of US experts led by experts from the University of Missouri, in collaboration with scientists from the Viral Diseases Branch of the Walter Reed Army Institute of Research, Yale University and USDA APHIS Wildlife Services. The scholars, led by Xiu Feng Wan, director at the Center for Influenza and Emerging Infectious Diseases, reached their conclusions after carrying out two different studies. In the first test the biological samples of mice captured in New York were analysed, above all not far from the sewers and parks, while in the second they analyzed in laboratory the susceptibility of mice to various variants of SARS-CoV-2.
As for the tests on mice, carried out between September and October of 2021, workers from the Animal and Plant Health Inspection Service (APHIS) at the United States Department of Agriculture (USDA) studied 79 of them, with the objective of analyzing the positivity to IgM and IgG (neutralizing) antibodies. Well, 13, 16.5%, are positive for SARS-CoV-2. Specifically, to a strain of type B that circulated among people when the pandemic was in its infancy. By projecting this figure onto the entire population of brown mice or Norway rats (Rattus norvegicus), or eight million mice, Wan and colleagues determined that about 1.3 million mice could test positive. Norway rats, which are widespread, could have come into contact with the virus in sewage water, contaminated objects and food or by air, in the homes of infected people. It is known that many animals can be infected by dogs, cats, mink, tigers, lions, leopards, monkeys and deer. The main danger of this spread is the spillback, or the passage of the virus from man to animal and then the return to the human being, perhaps with dangerous mutations. So far, though, there’s been little evidence of this happening, but the fact that so many positive mice are so many is a worrying fact. The details of the research have been published on mBio della mBio dell’American Society for Microbiology.