A Pyrenean black vulture, the first scavenger bird intoxicated by diclofenac to be detected in Europe

    Specialists from various institutions detected the first case of diclofenac poisoning in a black vulture (Aegypius monachus) in Europe, specifically in Spain, a crucial location for the conservation of European populations of scavenger birds. It is urgent to adopt preventive measures when confirming that the veterinary use of this drug represents a real danger for European vultures.


    Several conservation organizations and scientific institutions, both Spanish and European, have been warning for years about the risk posed to vultures by exposure to diclofenac. The alarm is more than justified, since this non-steroidal anti-inflammatory drug (NSAID), in its veterinary use, was the cause of one of the greatest ecological disasters of recent times. During the 1990s and early 2000s, a dramatic population decline of at least three species of Asian vultures was detected, driving them to near extinction (>99%). This was due to diclofenac poisoning after ingesting carrion from domestic animals treated with this drug shortly before his death.

    In a study published on April 5 in the scientific journal Science of the Total Environment, the poisoning of a scavenger bird in Europe is revealed for the first time. In addition, it is the first case reported in a black vulture, a threatened species classified in Spain as "Vulnerable". It is a specimen born in 2020 in the colony established in the Boumort National Hunting Reserve (Lleida Pre-Pyrenees).

    This work, whose authors are all specialists from various Spanish entities, including the Instituto de Investigación en Recursos Cinegéticos (IREC – CSIC, UCLM, JCCM), confirms for the first time as a real danger that vultures in Europe can die after ingesting carrion from domestic animals previously treated with diclofenac.

     

    Black vulture fledgling found dead in the nest poisoned by diclofenac (Photo: Agents Rurals de Catalunya).

    Collaboration, a decisive factor

    The previous work that has allowed the confirmation of this case of diclofenac poisoning dates back to September 24, 2020, the day of the death of the black vulture born that same year in Boumort and that a few days before had started the first flights. The GPS transmitter that the animal carried allowed the team from the Group for the Rehabilitation of the Native Fauna and its Habitat (GREFA) in charge of monitoring this colony to interpret this information and locate the corpse of the specimen.

    The coordination of GREFA with the groups of Rural Agents (GEVA and GSM), as well as with the Department of Territory and Sustainability of the Generalitat de Catalunya and the technical team of the Boumort Reserve, made possible the rapid transfer of the carcass of the black vulture to the Vallcalent Fauna Center, in Lleida, where the necropsy was carried out and the samples were extracted for later analysis.

    In fact, it was the anatomopathological analyzes carried out at Noah's Path, in Elche, and the toxicological ones carried out by the IREC Wildlife Toxicology Group, those who have confirmed the death of this black vulture from diclofenac poisoning. On the one hand, the histopathological analysis revealed a widespread visceral gout without signs of other pathologies present, a lesion indicative of intoxication by NSAIDs such as diclofenac. Finally, the toxicological analysis confirmed the presence of diclofenac at concentrations sufficient to explain the death of the animal. In this analysis, different analytical techniques were used to rule out other toxins that could be involved in the death of the black vulture. However, after conducting the analyzes in triplicate, only the presence of diclofenac was detected in liver and kidney.

     

    Detection of this case of diclofenac poisoning has been possible thanks to collaboration between GREFA, IREC, the Rural Agents of Catalonia, the Department of Territory and Sustainability of the Generalitat of Catalonia and the Boumort Reserve; to histopathological analyzes and to a toxicological analysis in triplicate.

    Precautionary measures

    There is a possibility that this individual fed on carrion from cattle previously treated with diclofenac during its first flights or that it became intoxicated through the food provided by its parents in the nest.. Although it is true that neither the parent adults nor other marked individuals that had been feeding at the Boumort supplementary feeding point were affected.

    On the other hand, intoxicated black vulture may have ingested a diclofenac injection site, where higher diclofenac levels can be maintained compared to other tissues where the NSAID has been distributed. It is important to emphasize that in this specific case the poisoning was detected because the animal belongs to a closely monitored population. Therefore, it is possible that there are other cases of diclofenac poisoning that have not been detected to date.

    The authors of the study consider it necessary to apply regulatory measures to prevent vultures from having access to carcasses and remains of cattle treated with diclofenac. It is advisable to carry out routine checks of the carrion provided at supplementary feeding points, analyzing these samples in search of NSAIDs and other drugs for veterinary use to avoid events like this.

    In addition, the population trend of these species should be monitored regularly to detect declines related to diclofenac poisoning quickly and avoid catastrophes such as those that occurred in Asia. In the event that these preventive measures are not carried out with all the guarantees, recommend a moratorium on the veterinary use of diclofenac and use other non-toxic NSAIDs for these birds as an alternativesuch as meloxicam.

    The scientific publication of this research is available at: