New study suggests rats, water buffalo and mountain gorillas can spread COVID-19 virus

A new study has identified various mammal species that can act as hosts to SARS-CoV-2 and spread the virus to humans. These include rats, water buffalo, and mountain gorillas. Read on to find out the other animal species that can cause secondary spillover to humans.

By: Longjam Dineshwori | | Published: February 24, 2021 6:54 pm

Scientists worldwide have different theories about the origin of the novel coronavirus, which led to the ongoing COVID-19 pandemic. The World Health Organization (WHO) expert team’s China mission also ended without finding the virus’ origin, but it concluded that it was ‘extremely unlikely’ that the virus escaped from a lab in Wuhan. The experts did agree the virus was most likely of animal origin and it probably crossed over to humans from bats, via an unknown intermediary animal species. Also Read - Delhi May Experience A Vaccine Shortage Following Weekend Lockdown Due To Covid-19 Surge

The WHO team, which included 10 independent foreign experts, spent 28 days in China to find clues about the animal origin of COVID-19. They conducted tests on thousands of samples from wild, farmed and domestic animals across China — but none of them had the SARS-CoV-2 virus. However, Professor Dominic Dwyer from University of Sydney, who was a member of the WHO team, said that some animal species which are thought to be susceptible to the virus – such as bamboo rats, ferret badgers and civets — were sold at Wuhan’s Huanan market, the site blamed as the source of the virus. Based on this observation, Dutch virologist and WHO team member Marion Koopmans said that farms supplying wild animals to Wuhan’s Huanan market should be investigated. Also Read - UK Covid variant doesn't lead to severe illness, death: Study

Preventing spillback infections important to contain COVID-19 pandemic

A new study, published on the bioRxiv preprint server, has underscored the importance of preventing spillback infections to contain the COVID-19 pandemic. The occurrence of spillback transmission of SARS-CoV-2 from humans to farmed mink, and secondary spillover from the mink (the new host) back into humans, was reported in Denmark and in the Netherlands. Also Read - COVID-19 Second Wave: Experts Suggest Strict Lockdown In India To Break Coronavirus Chain

Understanding the nature of the virus, and its susceptibility to a range of hosts is vital to prevent such secondary spillover to humans, the researchers noted, while cautioning that emergent strains may be more infectious than the existing ones. In fact, researchers have found the mink-derived variant less sensitive to neutralizing antibodies.

Several studies have therefore investigated the zoonotic capacity of various animal species for SARS-CoV-2, including predicting their susceptibility to Covid-19 infection and their capacities for onward transmission. A major bottleneck to these studies is the limited number of sequences for angiotensin-converting enzyme 2 (ACE2), a highly conserved cell surface receptor that the novel coronavirus uses to enter host cells. This ACE2 protein is found predominantly on the cell surface of all major vertebrate groups. In the new study, the researchers combined protein structure modeling with machine learning of species’ biological traits to predict zoonotic capacity of SARS-CoV-2 across 5,400 mammals.

While developing the new model, they considered several factors that increases susceptibility to SARS-CoV-2, such as the binding strength between virus receptor binding domain and host ACE2.

Animals that can become new hosts of coronavirus

The new model developed by researchers, including an Indian origin, was able to predict a high SARS-CoV-2 zoonotic capacity for many domesticated, farmed, and live traded animal species.

According to the model, Bubalus bubalis (water buffalo), rats, rodents, and bats have a high zoonotic capacity to act as new hosts of the SARS-CoV-2. Endangered species such as mountain gorillas and addax were also predicted to have a high capacity to cause spillback transmission to humans. Several computational models also predicted that Sus scrofa (pigs) are susceptibility to SARS-CoV-2, but animal-based experiments didn’t support it.

The researchers, therefore, noted that combining the results of theoretical models, statistical models, laboratory experiments, and real-world observations can help better understand the zoonotic capacity of SARS-CoV-2.

The study titled “Predicting the zoonotic capacity of mammal species for SARS-CoV-2” was authored by Ilya R. Fischhoff, Adrian A. Castellanos, João P.G.L.M. Rodrigues, Arvind Varsani, and Barbara A. Han.

Published : February 24, 2021 6:54 pm

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