New paper highlights need for greater research and surveillance of NSAID poisoning in non-Gyps raptors

A Short Communication entitled “Non-steroidal anti-inflammatory drugs (NSAIDs) as a hidden threat to scavenging raptors beyond Gyps: A call for wider research and surveillance” (here) was published on 9 September in the Journal Environmental Toxicology and Pharmacology, highlighting the lack of knowledge of the causal mechanisms behind NSAID poisoning in non-Gyps vultures and other raptors.

The research confirms that the premature stop codon in the CYP2C19 gene, thought to explain diclofenac sensitivity in Gyps vultures (Adawaren et al. 2024), is present only in Gyps vultures (including Cape G. coprotheres, White-backed G. africanus, Eurasian Griffon G. fulvus and Himalayan Griffon G. himalayensis).

However, the study also highlights evidence of lethal NSAID toxicity in non-Gyps species such as cinereous vultures Aegypius monachus, Steppe eagles Aquila nipalensis and black kites Milvus migrans, even though these species are thought not to carry the same genetic mutation. Population declines of non-Gyps species (such as Egyptian Vulture Neophron percnopterus, Red-headed Vulture Sarcogyps calvus and Bearded Vulture Gypaetus barbatus) coinciding with the Asian vulture crisis further point to NSAID exposure as a wider threat beyond Gyps.

Lead author Kane Colston from the University of Bristol commented “This finding suggests that NSAID sensitivity in scavenging raptors, at least beyond Gyps vultures, cannot be explained by this mechanism, and that additional toxicological pathways and sublethal effects are likely involved. We call for increased surveillance, including genetic, pharmacokinetic and toxicological monitoring of non-Gyps scavengers, to establish species-specific risks and thresholds.”

Colston continued “There is a need to develop non-invasive alternatives such as tissue cultures for toxicological testing of new and existing NSAIDs. Furthermore, beyond direct mortality, we also need to consider chronic, low-dose NSAID exposure, which could affect reproduction, behaviour and survival and thus lead to population declines of affected species.”

These findings strengthen SAVE’s long-standing call for the removal of all vulture-toxic NSAIDs from veterinary practice, and for urgent action to expand monitoring and research beyond Gyps vultures to safeguard other threatened scavenging raptors.

Compiled by Kane Colston

References

Adawaren, E.O., Labuschagne, C., Abera, A. and Naidoo, V. 2024. A premature stop codon in the CYP2C19 gene May explain the unexpected sensitivity of vultures to diclofenac toxicity. Toxicol. Appl. Pharm. 482, 116771. https://doi.org/10.1016/j. taap.2023.116771.

Colston, K., Mifsud, K., Rooney, N., Grande, J.M. and Bueno, I. 2025. Non-steroidal anti-inflammatory drugs (NSAIDs) as a hidden threat to scavenging raptors beyond Gyps: A call for wider research and surveillance. Environ. Toxicol. & Pharmacol. 119, 104817