COVID-19 News: University Of Missouri Study Shows That Rats In New York City Are Now Reservoirs Of The SARS-CoV-2 Virus!

COVID-19 News: Worrisome findings from study conducted by researchers from the Center for Influenza and Emerging Infectious Diseases, University of Missouri, Columbia-USA has revealed that almost all of the rat population in New York City are carry various variants of the SARS-CoV-2 virus and are now serving as zoonotic reservoirs of the virus. the researchers also warned that such similar occurneces could also be developing in other parts of the United States and also elsewhere in other countries and poses a serious threat.


 
Scientists from the USDA APHIS Wildlife Services National Wildlife Disease Program, Colorado-USA, from the Viral Diseases Branch of Walter Reed Army Institute of Research, Maryland-USA, Rice University Texas-USA and Yale University, Connecticut-USA were also involved in the study.
 
The study demonstrated that rats are susceptible to infection with Alpha, Delta and Omicron variants of SARS-CoV-2 and wild rats in the New York City municipal sewer systems and elsewhere in the city have been exposed to SARS-CoV-2.
 
According to the study team, millions of Norway rats (Rattus norvegicus) inhabit New York City (NYC), presenting the potential for transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) from humans to rats.
 
The study team evaluated SARS-CoV-2 exposure among 79 rats captured from NYC during the fall of 2021.
 
The study findings showed that 13 of the 79 rats (16.5%) tested IgG- or IgM-positive, and partial SARS-CoV-2 genomes were recovered from all 4 rats that were qRT-PCR (reverse transcription-quantitative PCR)-positive. Genomic analyses suggest these viruses were associated with genetic lineage B, which was predominant in NYC in the spring of 2020 during the early pandemic period.
 
In order to further investigate rat susceptibility to SARS-CoV-2 variants, the study team  conducted a virus challenge study and showed that Alpha, Delta, and Omicron variants can cause infections in wild-type Sprague Dawley (SD) rats, including high replication levels in the upper and lower respiratory tracts and induction of both innate and adaptive immune responses.
 
It was found that the Delta variant resulted in the highest infectivity.
 
The study findings indicate that rats are susceptible to infection with Alpha, Delta, and Omicron variants, and wild Norway rats in the NYC municipal sewer systems have been exposed to SARS-CoV-2.
 
The study findings highlight the need for further monitoring of SARS-CoV-2 in urban rat populations and for evaluating the potential risk of secondary zoonotic transmission from these rat populations back to humans.
 
The study findings were published in peer reviewed journal: mBio.
https://journals.asm.org/doi/10.1128/mbio.03621-22

The study team warned that host tropism expansion of SARS-CoV-2 raises concern for the potential risk of reverse-zoonotic transmission of emerging variants into rodent species, including wild rat species.
 
The team presented both genetic and serological evidence for SARS-CoV-2 exposure to the New York City wild rat population, and these viruses may be linked to the viruses that were circulating during the early stages of the pande mic. The findings highlight the reverse zoonosis of SARS-CoV-2 to urban rats and the need for further monitoring of SARS-CoV-2 in rat populations for potential secondary zoonotic transmission to humans.
 
Lead author, Henry Wan, Ph.D., Professor and Director of the Center for Influenza and Emerging Infectious Diseases at the University of Missouri told COVID-19 News reporters at Thailand Medical News, “Our study findings highlight the need for further monitoring of SARS-CoV-2 in rat populations for potential secondary zoonotic transmission to humans. 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."
 
It was noted that 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.
 
The study team 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.
 
Co-author, Tom DeLiberto, D.V.M., Ph.D., SARS-CoV-2 Coordinator at USDA APHIS Wildlife Services added, "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. 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."
 
The study team collected and processed samples from 79 rats for virological studies and genomic sequencing. The team 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.
 
Dr Wan commented, "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.”
 
D Wan concluded, "Our study 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. SARS-CoV-2 virus presents a typical one-health challenge which requires collaborative, multisectoral and transdisciplinary approaches to fully understand such challenges."
 
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