Coronavirus in animals: Asiatic lions remain isolated in Chennai zoo; Are wild cats more vulnerable to infection

The coronavirus’ defining feature is its spike proteins, using which it begins the process of binding itself with the host cell. (Representational image)

Coronavirus and lions: Chennai’s Vandalur Zoo saw 9-year-old lioness Neela dying of an infection, suspected to be caused by coronavirus, last week, and soon after, the infected Asiatic lions at the zoo were isolated and put on an antibiotic regime. Since Neela’s death, Bhopal-based National Institute of High Security Animal Diseases has found samples of nine lions to be positive. According to a report in IE, Tamil Nadu CM M K Stalin visited the zoo to take stock of the situation, and also asked authorities to ensure vaccination of all staff members at the zoo. This marked the first instance of a lion testing positive for the infection in the country.

However, last week, at Bhagwan Birsa Biological Park located in Ranchi, a 10-year-old tiger died, and as per officials, was suffering from fever. While the tiger’s Rapid Antigen Test came back to be negative, the viscera of the tiger was sent to Bareilly’s Indian Veterinary Research Institute. Amid this, other animals at the biological park were also being tested.

Does this mean that lions and tigers are particularly vulnerable to this virus? The coronavirus’ defining feature is its spike proteins, using which it begins the process of binding itself with the host cell. This binding is done using a protein called ACE2 receptor among the hosts, and there are differences in the extent to which different species express this receptor. This difference is what determines the vulnerability of a species to the virus. Studies have found that domestic cats as well as their mighty wild relatives express ACE2 in a more significant manner as compared to other species, and it has also been found that ACE2 of cats is similar to that of humans.

A paper published in PLOS Computational Biology last December had studied 10 different species and their ACE2 receptors, and found that apart from humans, ferrets were the most vulnerable species to getting infected by coronavirus, followed by cats and civets.

Another study published in PNAS last August had carried out a genomic analysis of 410 species to understand their relative risk of coronavirus infection. It found that primates like chimpanzee and rhesus macaque were at very high risk, while black lemur was found to be at high risk. According to this study, cats were at a medium risk, and dogs were found to be at low risk.

A research conducted in August last year looked at tissues collected from six cats and one tiger, and found that there was a wide expression of ACE2 receptors in their gastrointestinal tracts. However, this expression was found to be more prominent in cats than tigers.