Continuing mortality of vultures in India associated with illegal veterinary use of diclofenac and a potential threat from nimesulide

Abstract

The collapse of South Asia's Gyps vulture populations is attributable to the veterinary use of the non-steroidal anti-inflammatory drug (NSAID) diclofenac. Vultures died after feeding on carcasses of recently-medicated animals. The governments of India, Nepal and Pakistan banned the veterinary use of diclofenac in 2006. We analysed results of 62 necropsies and 48 NSAID assays of liver and/or kidney for vultures of five species found dead in India between 2000 and 2012. Visceral gout and diclofenac were detected in vultures from nine states and three species: Gyps bengalensis, Gyps indicus and Gyps himalayensis. Visceral gout was found in every vulture carcass in which a measurable level of diclofenac was detected. Meloxicam, an NSAID of low toxicity to vultures, was found in two vultures and nimesulide in five vultures. Nimesulide at elevated tissue concentrations was associated with visceral gout in four of these cases, always without diclofenac, suggesting that nimesulide may have similar toxic effects to those of diclofenac. Residues of meloxicam on its own were never associated with visceral gout. The proportion of Gyps vultures found dead in the wild in India with measurable levels of diclofenac in their tissues showed a modest and non-significant decline since the ban on the veterinary use of diclofenac. The prevalence of visceral gout declined less, probably because some cases of visceral gout from 2008 onwards were associated with nimesulide rather than diclofenac. Veterinary use of nimesulide is a potential threat to the recovery of vulture populations.

Potential threat to Eurasian griffon vultures in Spain from veterinary use of the drug diclofenac

“…) and nimesulide (Cuthbert et al . ). It has been suggested that NSAIDs that are nephrotoxic to a particular bird species are those with long elimination times from the plasma in that species (Hutchinson et al .…”

“…There is also circumstantial evidence of nephrotoxicity of diclofenac to the steppe eagle Aquila nipalensis (Sharma et al 2014). Hence, it is possible that obligate and facultative scavenging birds other than Gyps vultures are affected by diclofenac as well as by other nephrotoxic NSAIDs, such as ketoprofen (Naidoo et al 2010) and possibly also by flunixin (Zorrilla et al 2015) and nimesulide (Cuthbert et al 2016). It has been suggested that NSAIDs that are nephrotoxic to a particular bird species are those with long elimination times from the plasma in that species (Hutchinson et al 2014).…”

Percentage of faecal excretion of meloxicam in the Cape vultures (Gyps corprotheres)

“…The safety of meloxicam has since been demonstrated in the G. bengalensis, G. indicus and G. coprotheres (Swan et al 2006a). As a result of the advocacy on the use of meloxicam and the concurrent ban on the sale of diclofenac for veterinary use, the previous rate of decline has been slowed with the population finally showing a small degree of recovery (Cuthbert et al 2011, Cuthbert et al 2016. For example in Pakistan, there was an increase vulture nesting sites from 11 observed during a survey conducted between 2010-2011 to 34 between 2011-2014 (Murn et al 2015).…”

Metabolism of aceclofenac in cattle to vulture‐killing diclofenac

“…Among these, experimental safety testing shows that one is vulture‐toxic (ketoprofen) (Naidoo et al , ) and another is vulture‐safe (meloxicam) (Swan et al ; Swarup et al ). Two others are almost certainly toxic given that elevated residues of these drugs have been found in dead vultures with clinical signs of NSAID poisoning (flunixin [Zorrilla et al 2014] and nimesulide [Cuthbert et al ]).…”