Detailed study vital to track human-animal transmission cycle

Professor Ganesan spoke to DT Next and explained how critical this is in breaking the chain of transmission from animals to humans and tracing the formation of new variants.

What animals are susceptible to coronavirus infection? What is the difference between the strains affecting animals and humans?

• Coronaviruses are a large family comprising four genuses, namely, alpha, beta, gamma, and delta. So far, only alpha and beta coronaviruses are known to infect humans in addition to other animal species such as dogs, cats, cattle, camels, and bats. The gamma and delta genuses are only seen in birds. SARS-CoV-2 belongs to the genus beta coronavirus. SARS-CoV-2 can spread between people through aerosols and direct contact. SARS-CoV-2 infection is also noticed in animal species such as cats, lions, minks, etc. Infection from animals to humans and vice versa is possible. However, such transmission has not been documented by the scientific community. There are two prevailing theories on the origins of SARS-CoV-2 - the first states that the virus originated in bats and thereafter spread to humans. The second is that the virus is manmade.

How common is the infection in animals and is there any report indicating transmission between humans and animals?

• The first report of COVID in animals came in April 2020 when a tiger at New York’s Bronx Zoo tested positive for SARS-CoV-2. Thereafter, reports of RT-PCR positive cats, dogs, and minks from different parts of the world. In India, eight Asiatic lions at Hyderabad Zoo tested positive during April 2021. Following this, in June 2021, the lions at Chennai Zoo also tested positive for SARS-CoV-2. A small number of pet cats and dogs have also been reported to be infected across countries. The information regarding the prevalence of COVID-19 virus infection in pet dogs and cats in India is not available at this time. No data is available on transmission between pets and humans. Similarly, the carrier status of SARS-CoV-2 virus in the bat population found in India is yet unknown.

What is the way forward in protecting animals, both wild and captive?

• Vaccinations will become mandatory for pets and farm animals too. Countries like Russia have already started vaccinating the animals. This approach may prevent the animals from moving to ‘carrier status’ and help. This will go a long way in strengthening eradication programmes.

Will animals also get affected in the COVID third wave?

• A third wave is unavoidable, considering the rate of spread and vaccination. COVID in animals may also add to the burden. Hence, containment zones with full bio-security for the infected animal population are necessary. Total screening of suspected animals with RT-PCR will be useful in defining and categorising the containment areas.

Wildlife institutes, veterinary varsities, and zoos have started diagnosing and treating infected animals. Are they moving in the right direction?

• Treatment regimens face practical difficulties. The total elimination of COVID-19 from the endemic zone may not be a realistic goal soon. One approach involving both physicians and veterinarians is needed to control this pandemic.