The veterinary use of diclofenac and vulture conservation in Spain: Updated evidence and socio-ecological implications.

Diclofenac is a non-steroidal anti-inflammatory drug (NSAID) used in livestock farming, with lethal effects on vultures when reaching high concentrations in the carcasses they feed on. There are evidences showing that it caused the decline of >95% of vultures of the Gyps genus in Southern Asia until its ban in 2006. In March 2013 two veterinary drugs containing diclofenac were authorized in Spain. The scientific and conservationist communities alerted on the foreseeable risks to European vulture populations based on previous experiences. Several risk assessments modelled the expected impact on vultures, and media campaigns were launched to ban the veterinary use of diclofenac. Here, we evaluate the situation of Spanish vultures after seven years (2013-2019) since the marketing authorisation of the veterinary use of diclofenac was granted. The present assessment takes into consideration the awareness measures adopted to avoid an inappropriate use of the drug, the results of the monitoring programs performed both for vultures and livestock in the wild and from toxicological tests, as well as the review of the published models on the expected mortality of vultures. The measures adopted seem to have been adequate and have avoided impacts at vulture population level despite the finding of one cinereous vulture lethally intoxicated by diclofenac in 2020. In view of the results, we discuss the different situations from the veterinary use of this drug between Southern Asia and Spain. Finally, surveillance priorities and future prospects are proposed to prevent risks from possible changes in the current circumstances, regarding the use of diclofenac and other NSAIDs potentially harmful like flunixin.