A recent study published in mBio reveals that rats can be infected with Alpha, Delta, and Omicron variants of SARS-CoV-2, with wild rats in New York City being exposed to the virus. The findings emphasize the importance of monitoring rat populations for potential secondary transmission to humans. The study’s principal investigator, Dr. Henry Wan, stresses the need for better understanding of the role animals play in pandemics to safeguard both human and animal health.
A new study has demonstrated that rats are susceptible to infection with Alpha, Delta, and Omicron variants of SARS-CoV-2Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the official name of the virus strain that causes coronavirus disease (COVID-19). Previous to this name being adopted, it was commonly referred to as the 2019 novel coronavirus (2019-nCoV), the Wuhan coronavirus, or the Wuhan virus.” data-gt-translate-attributes=”[{“attribute”:”data-cmtooltip”, “format”:”html”}]”>SARS-CoV-2, the virusA virus is a tiny infectious agent that is not considered a living organism. It consists of genetic material, either DNA or RNA, that is surrounded by a protein coat called a capsid. Some viruses also have an outer envelope made up of lipids that surrounds the capsid. Viruses can infect a wide range of organisms, including humans, animals, plants, and even bacteria. They rely on host cells to replicate and multiply, hijacking the cell's machinery to make copies of themselves. This process can cause damage to the host cell and lead to various diseases, ranging from mild to severe. Common viral infections include the flu, colds, HIV, and COVID-19. Vaccines and antiviral medications can help prevent and treat viral infections.” data-gt-translate-attributes=”[{“attribute”:”data-cmtooltip”, “format”:”html”}]”>virus that causes COVID-19First identified in 2019 in Wuhan, China, COVID-19, or Coronavirus disease 2019, (which was originally called "2019 novel coronavirus" or 2019-nCoV) is an infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). It has spread globally, resulting in the 2019–22 coronavirus pandemic.” data-gt-translate-attributes=”[{“attribute”:”data-cmtooltip”, “format”:”html”}]”>COVID-19. Moreover, wild rats in the New York City municipal sewer systems and elsewhere in the city have been exposed to SARS-CoV-2. The study was published recently in mBio, an open-access journal of the American Society for Microbiology.
“Our findings highlight the need for further monitoring of SARS-CoV-2 in rat populations for potential secondary zoonotic transmission to humans,” said study principal investigator Henry Wan, Ph.D., Professor and Director of the Center for Influenza and Emerging Infectious Diseases at the University of Missouri. “Overall, our work in this space shows that animals can play a role in pandemics that impact humans, and it’s important that we continue to increase our understanding so we can protect both human and animal health.”
Rats are widely distributed in urban communities in the United States. For example, New York City alone has approximately eight million wild rats. These wild rats have ample opportunities to interact with humans. Two previous studies suggested that rats in Asia (Hong Kong) and Europe (Belgium) were exposed to SARS-CoV-2; however, it is unknown which SARS-CoV-2 variant these rats were exposed to in both studies.
In the new study, the researchers set out to determine whether the SARS-CoV-2 virus in humans has been transmitted to the rat population in urban areas of the United States, specifically New York City, and if so, which SARS-CoV-2 variant caused those infections. The researchers also set out to determine whether (and which) SARS-CoV-2 variants in NYC can cause infections in rats.
“In Fall of 2021, U.S. Department of Agriculture (USDA) Animal and Plant Health Inspection Service (APHIS) sampled Norway rats (Rattus norvegicus) in New York City to look for evidence of SARS-CoV-2 infection,” said study coauthor Tom DeLiberto, D.V.M., Ph.D., SARS-CoV-2 Coordinator at USDA APHIS Wildlife Services. “Two trapping efforts were conducted during September and November with permission from the NYC Department of Parks and Recreation in and around locations surrounding wastewater systems. Most of the rats were trapped in city parks within Brooklyn, although some were captured near buildings outside of park boundaries.”
Biologists collected and processed samples from 79 rats for virological studies and genomic sequencing. The researchers found that the rats were exposed to SARS-CoV-2 and showed a possible link to the viruses that were circulating in humans during the early stages of the COVID-19 pandemic. Specifically, 13 of 79 rats (16.5%) tested positive. “To the best of our knowledge, this is one of the first studies to show SARS-CoV-2 variants can cause infections in the wild rat populations in a major U.S. urban area,” Dr. Wan said.
To further investigate rat susceptibility to SARS-CoV-2 variants, the researchers conducted a virus challenge study and showed that Alpha, Delta and Omicron variants (variants found in humans) can cause infections in rats (wild-type Sprague Dawley rats), including high replication levels in the upper and lower respiratory tracts and induction of both innate and adaptive immune responses. Susceptibility to infection varied by type of variant.
“Our findings highlight the need for further monitoring of SARS-CoV-2 in rat populations to determine if the virus is circulating in the animals and evolving into new strains that could pose a risk to humans,” Dr. Wan said. “SARS-CoV-2 virus presents a typical one-health challenge which requires collaborative, multisectoral and transdisciplinary approaches to fully understand such challenges.”
Reference: “SARS-CoV-2 Exposure in Norway Rats (Rattus norvegicus) from New York City” by Yang Wang, Julianna Lenoch, Dennis Kohler, Thomas J. DeLiberto, Cynthia Y. Tang, Tao Li, Yizhi Jane Tao, Minhui Guan, Susan Compton, Caroline Zeiss, Jun Hang and Xiu-Feng Wan, 9 March 2023, mBio.
DOI: 10.1128/mbio.03621-22
Source: SciTechDaily
