Science & Technology

Livestock not susceptible to novel coronavirus: study

Ferrets, cats highly susceptible to being infected

 
By Rajeshwari Sinha
Last Updated: Thursday 16 April 2020
SARS-CoV-2 replicated poorly in pigs Photo: Needpix

The novel coronavirus (SARS-CoV-2) replicated poorly in livestock animals like pigs, chickens, ducks and dogs, show initial results of a joint study conducted by three Chinese institutes, published in journal Science on April 8, 2020.

Ferrets and cats, however, were permissive to the infection, according to the study by the Academy of Agricultural Sciences, National Institute for Viral Disease Control and Prevention and National High Containment Laboratory for Animal Diseases Control and Prevention.

The study aimed to understand whether the virus could be transmitted to other animal species that could then become reservoirs of the infection. It also studied the behaviour of the virus in animals that are in close contact with humans.

Many experts think SARS-CoV-2 originated in bats and were trasferred to humans via pangolins.

The study used virus samples from two areas: One was isolated from an environmental sample from the Huanan Seafood Market in Wuhan (from where the first-known case originated) and the second was isolated from a human patient.

The animals being investigated upon were inoculated through intranasal routes, following which viral RNA quantification and virus titration studies were carried out to detect the presence of viral Ribonucleic acid (RNA) or the virus.

The virus was detected in the nasal turbinate (shell-shaped networks of bones, vessels and tissues), soft palate and tonsils of ferrets — a domesticated species of the European polecat.

It was not found on the other organs that were tested, including the trachea, lung, heart, liver, spleen, kidneys, pancreas, small intestine and brain.

The virus could, thus, replicate in the upper respiratory tract of ferrets without causing any death or disease in the animal, according to the study.

The study also suggested that ferrets could be used as model candidates in laboratories for the testing of anti-viral drugs or be used as vaccine candidates for COVID-19.

On examining cats and dogs, the study found that the virus replicated efficiently in the former, with younger cats being more prone to the virus.

It could also transmit between cats via the airborne route.

This could be one reason why a tiger — that belongs to the cat family —  contracted the virus at the Bronx Zoo in New York city on April 5, 2020.

Dogs, however, were found to have a low susceptibility to the virus, with similar observations for pigs, chickens and ducks.

An earlier study, conducted after the Severe Acute Respiratory Syndrome (SARS) disease outbreak in 2003, showed animals like pigs and chickens did not play a role as amplifying hosts for SARS-CoV, the virus responsible for the outbreak.

Pigs and chickens used for experiments, inoculated intravenously, intranasally, ocularly and orally with the SARS coronavirus, did not develop any clinical signs.

There were were no signs of any pathological changes evident from a postmortem analysis. The study was published in journal Emerging Infectious Diseases in 2004.

More research was needed, however, to establish linkages in livestock animal production settings, despite the findings on the SARS-CoV-2.

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