Chennai, Dec 18 : Tamil Nadu researchers have sounded a fresh warning over the continued threat posed by a banned veterinary drug to Indiaâ??s critically endangered vultures, after a major new study confirmed that diclofenac â?? prohibited nearly two decades ago â?? is still being used to treat livestock across several regions in the country.

The findings are part of the study: "The continued threat of toxic NSAIDs to Critically Endangered Gyps vultures in South Asia", conducted by 13 researchers between 2012 and 2024 and published recently in Bird Conservation International.

The study reveals that three Gyps species endemic to Asia â?? the white-rumped vulture, red-headed vulture, and long-billed vulture â?? continue to suffer population decline due to unintentional poisoning.

When these birds feed on carcasses of cattle treated with diclofenac, they suffer fatal kidney failure, a phenomenon identified as the primary cause of the rapid crash in vulture numbers since the 1990s.

Despite the Union governmentâ??s ban on veterinary use of diclofenac in May 2006 and additional restrictions on multi-dose vials in 2015, the drug is still being stocked illegally.

Researchers found that Rajasthan - a state where intensive conservation advocacy has not been undertaken - recorded the highest prevalence, with up to 25 per cent of surveyed pharmacies offering diclofenac.

Tamil Naduâ??s Vulture Safe Zones (VSZs) fared better, but enforcement challenges persist.

According to S. Bharathidasan, secretary of conservation organisation Arulagam, which helped survey VSZs in the state, more than 100 court cases have been filed against suppliers, manufacturers, and retailers. He said the diclofenac vials detected in Tamil Nadu originated largely from Karnataka, outside the VSZ, where conservation outreach remains limited.

The study also reveals that access to veterinary NSAIDs varies widely, with 64.3 per cent of pharmacies in Tamil Nadu and 100 per cent in Rajasthan offering them.

Much of the diclofenac found was stocked in 3-ml vials â?? legal for human use but illegal for veterinary treatment, making them a loophole for misuse.

While the Centre has additionally banned ketoprofen and aceclofenac since July 2023, Tamil Nadu has taken proactive steps by restricting the use of flunixin in key vulture habitats such as The Nilgiris, Erode and Coimbatore from 2019, and curbing ketoprofen as early as 2015.

However, researchers warn that banning known toxic drugs is not enough if untested substitutes with similar risks enter the market. They emphasised the need to curb pilferage of human-use vials for veterinary purposes and ensure strict enforcement, warning that vulture populations will remain vulnerable unless the illegal use of diclofenac is eliminated statewide and nationally.

/IANS