Diclofenac - Ecological Effects

Ecological Effects

Use of diclofenac in animals has been reported to have led to a sharp decline in the vulture population in the Indian Subcontinent, 95% decline in 2003, 99.9% decline as of 2008. The mechanism is, it is presumed, renal failure, a known side effect of diclofenac. 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 diclofenac. At a meeting of the National Wildlife Board in March 2005, the Government of India announced it intended to phase out the veterinary use of diclofenac. Meloxicam is a safer candidate to replace use of diclofenac. It is more expensive than diclofenac, but the price is coming down as more drug companies begin to manufacture it.

"The loss of tens of millions of vultures over the last decade has had major ecological consequences across the Indian Subcontinent that pose a potential threat to human health. In many places, populations of feral dogs (Canis familiaris) have increased sharply from the disappearance of Gyps vultures as the main scavenger of wild and domestic ungulate carcasses. Associated with the rise in dog numbers is an increased risk of rabies" and casualties of almost 50,000 people. The Government of India cites one of those major consequences as a vulture species extinction. A major shift in transfer of corpse pathogens from vultures to feral dogs and rats can lead to a disease pandemic causing millions of deaths in a crowded country like India; whereas vultures' digestive systems safely destroy many species of such pathogens.

The resulting multiplication of feral dogs in India and Pakistan has caused a multiplication of leopards feeding on those dogs and invading urban areas looking for dogs as prey, resulting in occasional attacks on human children.

The loss of vultures has had a social impact on the Indian Zoroastrian Parsi community, who traditionally use vultures to dispose of human corpses in Towers of Silence, but are now compelled to seek alternative methods of disposal.

Diclofenac has been shown also to harm freshwater fish species such as rainbow trout.