A 34-month-old tigress, which was brought from Nandankanan in Odisha, died of an unknown disease, the third such death of Royal Bengal Tigress, in Alipore zoo in south Kolkata, triggering concerns among animal lovers in West Bengal.

The tigress, which was born in February 2023 at Nandankanan in Odisha and brought to Kolkata in August that year, was found dead in her cage in the Alipore Zoological Gardens on Wednesday.

Alipore Zoological Gardens director Tripti Sah said a postmortem was done and the viscera tests were being conducted to ascertain the causes of the untimely death of the young tigress.

According to sources at the zoo, the tigress was suffering from an infection caused by a haemoprotozoan parasite. She was admitted to the zoo's health facility recovery centre where she died. The parasite is transmitted by ticks or biting flies, leading to fever, anaemia and jaundice. These parasites also affect livestocks.

A viscera test will confirm the exact cause of death, sources said.

Her death takes the toll to three in just three months. In September, the zoo witnessed two such deaths.

Biswajit Roy Chowdhury, a prominent Indian wildlife conservationist, photographer, and environmentalist, expressed concern over the death of a sub-adult tigress. "I suspect that some parasites within the zoo are responsible for the recent deaths," he said.