Chennai Zoo Lions infected with Delta variant of COVID-19, reveals genome sequencing

According to the Genome sequencing results of the lions which tested COVID-19 positive at the Chennai Zoo, four samples have been identified as "Delta" variants of the virus.

As per the World Health Organization(WHO), this variant showed higher transmissibility and reduced neutralisation(by antibodies). This variant is first said to have been detected in India in late 2020. Variants of the SARS-CoV-2(infection) have been emerging and circulating around the world throughout the COVID-19 pandemic.

In two batches, eleven samples from the Chennai zoo lions were sent for testing. The  ICAR-National Institute of High-Security Animal Diseases (NIHSAD), Bhopal was sent four samples on May 24 and seven samples on May 29 and of the total samples, nine tested positive and it was reported on June 3 and the lions have been under treatment since then. 

“Genome sequencing of four of the samples was done at NIHSAD, Bhopal. Analysis of the sequences shows that all the four sequences belong to Pangolin lineage B.1.617.2 and are Delta variants as per WHO nomenclature” said the Director ICAR-NIHSAD. It was added that on May 11 2021, the WHO classified B.1.617.2 lineage as a variant of concern (VOC). 

The Arignar Anna Zoological Park locally known as Vandalur Zoo housed 15 lions out of which two(lion and lioness) passed away due to COVID-19.

According to the deputy director of the Zoo, eight out of the thirteen lions are COVID-19 positive at present. While four of them are said to be completely safe, two are asymptomatic, and two are showing occasional lack of appetite owing to age.

“Temperature checks, eating patterns and food data of 53 different animals are being monitored on a regular basis. Few tigers showed appetite issues, but they were fine after we replaced beef with chicken. But even these tigers’ results returned negative. Rest all animals are okay” Naga Sathish Gidijala, IFS, Deputy Director, AAZP told Zee media. 

While the mystery over how the captive big cats got infected with the deadly virus remains unsolved, experts and vets advising the Zoo suspect human-animal(man to single lion) transmission followed by animal-animal(lion to multiple lions) transmission.

Based on a discussion between experts, the transmission from man-animal seems to have happened, despite animal keepers and feeders having worn PPE suits and followed precautions.

On the possibility of animal-human transmission, they felt that it could not be ruled out. Citing existing information, they said that only know cases of animal-man transmission are said to be from bats.

Even in the case of pet dogs getting infected, the team feels that dogs got infected from humans and not vice versa. They feel that lion-lion transmission is likely, whereas there are no known cases of dog-dog transmission. 

AAZP authorities have been providing treatment to the animals and following protocols in consultation with experts from Tamil Nadu Veterinary and Animal Sciences University (TANUVAS), Veterinarians of Hyderabad Zoo and Bronx Zoo.