The rampant veterinary use of non-steroidal anti-inflammatory drugs (NSAIDs) namely Aceclofenac, Ketoprofen and Nimesulide has renewed the concerns of ornithologists about their potential threat to the recovery of vulture population in the country.
These three drugs which are widely used by veterinarians to treat cattle are found to be toxic for vultures, known as king scavengers.
Diclofenac has long been established as a key reason for wiping out an astonishing 99.9 percent of the vulture population in early 1990s and was also banned in the country. However, with studies pointing out the lethal effects of NSAIDs like Aceclofenac, Ketoprofen and Nimesulide on vultures, the ornithologists have now called for a complete ban on these drugs.
“As per the studies, there is enough evidence that these three drugs are toxic for vultures and poses a big challenge for ongoing conservation programmes for vulture population. We had last year written to the Union Health Ministry demanding a ban on these drugs. We have also written to the Drugs Controller General of India and the Department of Animal Husbandry and Dairying, Government of India to regulate the use of these drugs till a ban is imposed,” said Dr Vibhu Prakash, head Jatayu Conservation Breeding Centre, Pinjore and Principal Scientist, Bombay Nature History Society while talking to The Pioneer.
Dr Prakash said, “After the ban, the usage of Diclofenac has reduced drastically over the years though its usage is still reported in some parts of the country. In the absence of Diclofenac, the veterinarians are now using drugs like Aceclofenac, Ketoprofen and Nimesulide to treat cattle. Unfortunately, these drugs are being sold without any prescription also.”
“A study released this year on White-Rumped Vultures, which is a critically endangered species, concluded that the ban on Diclofenac alone will not help save vulture in the Indian subcontinent. In addition to Diclofenac, at least Nimesulide and Aceclofenac should be banned for veterinary use to conserve White-Rumped Vultures,” he said.
The study conducted on four White-Rumped Vultures, found dead in Gujarat in 2019, had shown that all the vultures were exposed to veterinary drug Nimesulide, through the carcasses of cattle they consumed before death.
“Uric acid deposits, as crystals or powder, were observed in the internal organs of all four vultures although intensity was different. The uric acid deposition observed in the viscera in all the four vultures during post-mortem and elevated levels of Nimesulide residues in the organs and gut content were responsible for the mortality of these scavengers in Gujarat during 2019,” the study stated.
In many developed countries, like the USA, UK, Canada, Australia, New Zealand and Japan, Nimesulide is not permitted for human use due to its high risk of liver damage.
Notably, White-Rumped Vultures are notified as critically endangered species on the IUCN (International Union for Conservation of Nature) red list of threatened birds globally. This vulture species among others had suffered an extremely rapid population decline primarily as a result of feeding on carcasses of animals treated with the veterinary drug Diclofenac in the country.
In October 2020, eight White-Rumped Vultures, six of them captive-bred at JCBC Pinjore, were reintroduced into the wild for the first time in India under the vulture conservation and breeding programme.
TK Roy, ecologist and Asia Waterbird Census (AWC) Delhi state-coordinator said that Diclofenac was banned in 2006 but other substitutes of this drug are being widely used by veterinarians across the country.
He said that Aceclofenac when administered to livestock very rapidly metabolizes and converts into Diclofenac and poses the same risk to vultures. Ketoprofen also has the same toxic effect as Diclofenac to vultures. Surveys of livestock carcasses in India have found toxic levels of residual Ketoprofen. Vultures have also died after feeding upon their staple diet – cattle carcasses – that had traces of Nimesulide, he said.
In such a scenario, the authorities concerned should put in place a strategy to restrict the use of all vulture-toxic drugs in the county, Roy added.
According to the experts, Meloxicam remains the only drug that is not fatal to the vulture population.
A previous study on availability of the vulture-toxic drug, Diclofenac, and other NSAIDs in South Asia had pointed out “Diclofenac still accounted for 10–46 percent of all NSAIDs offered for sale for livestock treatment in 2017 in India, suggesting weak enforcement of existing regulations and a continued high risk to vultures. Availability of meloxicam increased in all countries and was the most common veterinary NSAID in Nepal (89.9 percent in 2017). Although the most widely available NSAID in India in 2017, meloxicam accounted for only 32 percent of products offered for sale.”
Dr Vibhu Prakash said that since the banning process of three NSAIDs, which are toxic to vultures, is likely to take time, there is a need to regulate their use and spread awareness about their harmful effects.
He said, “We have started the awareness campaign in around 100-km radius of JCBC Pinjore with an aim to restrict their usage and ensure that treatment of livestock is done by qualified veterinarians only. The area of 100-km radius is also monitored to ensure a safe environment for vultures.”
“Apart from this, we recommend the use of Meloxicam which is not fatal to the vulture population,” he added.
The vulture, known as king scavengers plays a key role in the environment as ecosystem service provider as it feeds on carrion and keeps the natural environment clean and controls spreading viral diseases from decaying carrions.
Till the early 1990s, the population size of Gyps vultures in India and Nepal alone was estimated to be about 40 million (four crore) and the number declined to below one lakh. The population of Gyps species common to the region-the Oriental White-Backed, the Long-Billed and the Slender-Billed vultures- had declined by over 97 percent since the 1990s, and that of the Oriental White-Backed vultures by 99.9 percent.
The overall cause of the decline had been identified as the Diclofenac drug, which was given to livestock as an anti-inflammatory drug.
Over the years, the Government of India has set up eight breeding centres for vultures and its action plan for Vulture Conservation (APVC) 2020-2025 advocates establishing more such centres in different parts of the country to slowly stabilize the population of vultures.