Use of diclofenac in animals has been reported to have led to a sharp decline in the vulture population in the Indian subcontinent – a 95% decline by 2003[29%] and a 99.9% decline by 2008. The mechanism is presumed to be renal failure; however toxicity may be due to direct inhibition of uric acid secretion in vultures. Vultures eat the carcasses of livestock that have been administered veterinary diclofenac, and are poisoned by the accumulated chemical, as vultures do not have a particular enzyme to break down. Three endemic vulture species Gyps bengalensis, Gyps indicus and Gyps tenuirostris are critically endangered following dramatic declines in South Asia resulting from exposure to diclofenac, a veterinary drug present in the livestock that they scavenge. Extensive research has identified the cause of the decline to be 'diclofenac', a non-steroidal anti-inflammatory drug (NSAID) used to treat livestock
Then vultures rapidly started disappearing from the landscape. A study in 2004 solved the mystery of why the vultures were vanishing. A veterinary drug called diclofenac was the main, if not the only, cause of vulture declines.
The manufacture of the veterinary diclofenac, as an anti-inflammatory treatment for livestock, was outlawed in India in 2006. This was followed by bans in Nepal, Pakistan and most recently in Bangladesh. The government bans in these countries has formed a key response to the crisis, and the latest evidence shows that diclofenac levels are beginning to come down.
However, diclofenac is still being found in cattle carcasses. Diclofenac formulated for humans is not banned and is still available. So there is still a lot more to do to prevent equally dangerous human diclofenac formulations as well as other untested veterinary drugs, being used in its place. Diclofenac is so devastating that we do not have many years if our threatened vultures are to be saved. Removing diclofenac and expanding the captive breeding centers are the only ways to save the birds.
Vultures provide a crucial ecosystem service through the disposal of livestock carcasses and their loss has had huge socio-economic impacts across the Indian Subcontinent. Without vultures, hundreds of thousands of animal carcasses have gone uneaten—left to rot in the sun, these pose a serious risk to human health. Livestock carcasses provide a potential breeding ground for numerous infectious diseases, including anthrax, and most worryingly, the loss of vultures has resulted in an increase in the number of feral dogs around carcass dumps—the bites of which are the most common cause of human rabies in the region. The near absence of vultures has also encouraged the proliferation of pest species, such as rats.
Final Year B. Pharm.