CHENNAI: The renowned Arignar Anna Zoological Park, popularly known as Vandalur Zoo, has reported India's first animal death due to coronavirus infection. A young asiatic lioness Neela, 9, has succumbed to the disease mysteriously on Thursday evening at 6.15 pm. The big cat was asymptotic till a day before her death and the medical records of the animal showed no underlying comorbidities.
Meanwhile, eight more lions have also tested positive for Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes COVID-19. Out of them, the health condition of two lionesses Kavitha, 23, alias Viji and Bhuvana, 19, alias Sasi is said to be critical.
Vandalur officials told The New Indian Express that the number of positive cases may further go up as more samples are being collected and sent for laboratory testing. This is probably the largest COVID-19 cluster in a zoological park in the world.
Meanwhile, the death of Neela has rekindled the fear of backward transmission (humans to animals), which experts say may lead to reverse anthroponosis of novel strains, once it occurs may render current COVID-19 vaccines less effective. The virus may spill back and forth between humans and animals, thus forming a vicious loop with prolonged spread, recurrent infections and outbreaks, and continuing
fights with evolved viral strains.
For this reason, Hyderabad-based Centre for Cellular and Molecular Biology (CCMB), which is an animal SARS-CoV-2 virus sequencing centre recognised by Central Zoo Authority (CZA), has volunteered to conduct genome sequencing of the virus strain that killed Neela and infected others for better understanding of zoonotic transmission which would help in preventive measures and appropriate treatments.
"A nationwide consultation process has also been started by the senior officials involving domain experts and scientists," said Tamil Nadu government in a press statement on Friday evening.
Considering the potential risk to zoo's in-house veterinarians, Tamil Nadu Veterinary and Animal Sciences University (TANUVAS) has recommended against conducting a post-mortem on the carcass of Neela.
"We have safely incinerated the carcass after securing additional nasal swab and rectal swab samples of the animal, which would be useful for further analysis," said Debasis Jana, director, Vandalur Zoo, to The New Indian Express.
Early testing would have helped?
In May first week, eight Asiatic lions in Hyderabad's Nehru Zoological Park tested positive for COVID-19 and a week after a lion in Jaipur Zoo tested positive. During that time, as a precautionary measure, Vandalur Zoo authorities were mulling the idea of sending faecal samples of all big cats to CCMB for testing. However, the samples were not sent.
Until May 26, none of the big cats at Vandalur Zoo were exhibiting any symptoms of COVID-19. So, the authorities felt there was no need for testing. Rightly so, the conventional means of collecting samples fromthe nose and respiratory tract requires tranquilisation of the animal, which may compromise the immunity.
The situation changed drastically from May 26 which is when five lions in house number-1 in the lion safari area reported to show anorexia (loss of appetite) and occasional coughing. The first signs of COVID-19 outbreak. Immediately TANUVAS was notified, veterinarians of Hyderabad Zoo and also Bronx Zoo in the United States which had the previous experience of dealing with such cases, were consulted and appropriate treatment based on symptoms started. However, the 11 samples were sent to CCMB only on May 29 and the results arrived on June 3, the day when Neela died.
In defense, a zoo official told The New Indian Express, "We chose not to send faecal samples because it was not an established testing technique. For instance, we sent all three samples of Neela - nasal, rectal and faecal samples - to CCMB on May 29. The result of nasal and rectal swab samples tested positive for COVID-19, while faecal sample results came negative.
"After May 26, when lions started showing symptoms, we used a method called squeeze sampling where the animals will be put in a squeeze cage, which immobilizes it and the veterinarian takes the samples. This takes a lot of time and also causes stress to the animal. In fact, three other lions which were staying with Neela are still asymptotic.," the official said.
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A press statement from Vandalur Zoo on Friday said: "In order to ascertain whether or not the reported findings are in the nature of false positives or the animal could have died of comorbidities, samples were again collected on Friday and sent to the Indian Veterinary Research institute Bareilly and the Centre for Cellular and Molecular Biology, Hyderabad."
"Scrupulously following the precautionary measures"
The zoo said it has been scrupulously following the precautionary measures prescribed in various advisories issued by the Central Zoo Authority, the Central and the State Governments from time to time.
Prophylactic measures for the felids, mustelids, viverrids and primates as arrived at in consultation with the expert team of TANUVAS, veterinarians of Hyderabad Zoo and also Bronx Zoo, are being adhered to.
All the lions which have tested positive are under close observation and on prescribed treatment regimen by the in-house veterinary team in close coordination with expert team from TANUVAS. All animal keepers and helpers for these animal houses are vaccinated against Covid 19. A separate set of animal keepers are engaged for each group of lions.
PPE Kits are mandatory for the animal keepers, veterinary doctors and field staff visiting the area, the press release added.