A veterinary anti-inflammatory drug, ketoprofen, can be lethal to Indian vultures that eat the carcasses of treated livestock, an international team of scientists has said.
The scientists, whose study published in the Royal Society's journal Biology Letters, carried out safety tests on the drug in India and found that doses administered to cattle were sufficient to kill vultures.
The pain reliever had been proposed as a replacement for diclofenac, which scientists say brought some species of Asian vulture to the brink of extinction. The study said it causes the birds to suffer acute kidney failure within days of exposure. This is the same toxic effect caused when vultures feed on the carcasses of animals treated with diclofenac.
Researchers had thought that ketoprofen would be less harmful because it metabolised faster by cows, and converted within hours into a form that is not dangerous to vultures.
Richard Cuthbert from the Royal Society for the Protection of Birds, who led the study involving researchers from many conservation organisations, including the Bombay Natural History Society, carried out tests on the more common species of vultures, using them a surrogate for endangered Asian vultures, the BBC reported.
Their tests showed that meat from animals that had been treated with ketoprofen could be lethal for the birds.
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Rhys Green, a zoologist from the University of Cambridge said the findings were important. "This reveals that a veterinary drug that some pharmaceutical companies in the Indian subcontinent would like to sell more of is not safe for vultures, which have already been reduced to very low levels by diclofenac."
"Ketoprofen isn't a big problem for vultures at the moment because little is used. But it would hamper efforts to restore vulture populations if its level of use increased to rival that of diclofenac." "We'd like to know of more safe alternatives... And we're asking the Indian pharmaceutical industry to step up and test them," Dr Cuthbert said.
The Indian government has banned the production of veterinary diclofenac, but there was still a problem with vets using human diclofenac in cattle. "It's still cheaper than meloxicam," Dr Cuthbert said, adding "but the price of meloxicam is coming down... As more companies produce it."