Reverse transmission of COVID-19 to animals may not be fatal: Experts
New Delhi: Since the news of a tiger testing positive of COVID 19 in Bronx zoo, New York broke out, there has been a whispered panic among people about the virus transmitting to animals.
Shedding some light on the particular case, Dr Ashraf, Chief Vet, Wildlife Trust of India (WTI) termed it 'reverse zoonosis' as the disease was transmitted back to animal from a human. He further explained that all major taxa (bovine, feline, canine, porcine, bat, civets, many other taxa including chicken and other birds) have their own list of Coronaviruses that are sometimes transmissible to other taxa.
Dr Ashraf does not see this reverse transmission as a threat to the life of tigers or other cats but humans picking up the infection from an animal could be fatal. He said, "Since this CoV-19 virus is a mutant that has jumped the host to cause disease in humans, the severity of it causing disease in other species (if they get infected) would be less."
Originated in Wuhan, China, COVID-19 caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is a part of the family of Coronavirus, which is considered to be zoonotic or zoonoses diseases.
While explaining the zoonotic transmission, Professor Mahendra Pal, Ex-Professor of Veterinary Public Health, Department of Microbiology, Immunology and Public Health, Addis Ababa University, Ethiopia, said, "There have been no cases of human to animal transmission except one in the US. There are possibilities that a novel Coronavirus infected person may transmit the infection to pets."
According to Professor Pal's research and notes, "We are still learning about this virus, but we know that it is zoonotic, and it appears that it can spread from people to animals in some situations."
Soon after the Bronx zoo case, Indian wildlife authorities issued an advisory, asking all zoos, sanctuaries and tiger reserves to be on high alert and the Central Zoo Authority addressed the chief wildlife wardens of all the states and Union Territories to monitor animals 24x7 through CCTV cameras and observe their behaviour or symptoms indicating Coronavirus.
Vivek Menon, Founder & CEO, Wildlife Trust of India appreciated government's quick response and said that the transmission is possible, if at all, would be from the caretakers in zoos and rescue centres or when forest officers or staff are addressing conflict animals by tranquilisation.
Referring to a recent experimental study (April 8), Menon said that cats can pick up the infection airborne and not dogs, pigs, chicken and ducks. In that sense, all felids are potential candidates for getting infected, but the disease (if at all) would be mild.
According to Menon, India hasn't reached the stage of recommending PPEs for zookeepers. He said, "PPEs are for self-protection from getting infected. We need to follow such precautions only if you suspect your animals or keepers to be infected. As of now, it would be enough if they can stop keepers with respiratory symptoms from coming for work. Additionally, they can be advised to wear a mask while entering cubicles, holdings, or night shelters of felids for feeding and cleaning."
Unlike Menon, Latika Nath, a Biologist and wildlife conservationist thinks PPE including masks, gloves and sanitised footwear are all necessary to protect captive animals from contracting the infection.
Latika further explained that the animals in zoos are solely dependent on human for food and all other needs. So it becomes necessary to ensure that all workers entering cages are certified COVID-19 free. She recommended that the "PPE protocol is a must for all people - not to protect the people but to protect the mammalian species within the Park."
Latika also stressed upon the special training programmes for zoo staff at the time in prevention and also monitoring for early identification of symptoms in all mammalian species in zoos.
She also suggested intensive programmes for risk communication and community outreach programmes to teach both forest department staff and residents of villages within parks and in the buffer areas of parks.