Risk of veterinary diclofenac and other veterinary pharmaceuticals to South American avian scavengers

Avian scavengers provide important ecosystem services, including the consumption of animal carcasses that otherwise would remain in the environment. Conserving this group of birds is critical and begins by understanding the threats they face. Diclofenac, a non-steroidal anti-inflammatory (NSAID) used in livestock, was the cause of vulture population declines in the Indian subcontinent in the 1990’s (Oaks et al. 2004). Despite this association that led to banning it in Southeast Asia, diclofenac was approved for use in Spain in 2013. In a recent study, residues of diclofenac and other NSAIDs were found in 3.07% of livestock carcasses in vulture feeding stations in Spain. The same study found NSAID residues in 14/389 avian scavenger carcasses (Herrero-Villar et al. 2020). Further, a Cinereous Vulture, classified as ‘near threatened’ by the International Union for Conservation of Nature, was found dead with elevated diclofenac levels (Herrero-Villar et al. 2021). Despite an increased understanding about NSAID risks to Old World Vultures, a knowledge gap exists for NSAID threats to New World avian scavengers in South America, who provide the same critical ecosystem services than in other parts of the world (Santangeli et al. 2022). Therefore, understanding key threats and how to mitigate them is paramount.

Aims and objectives

The overall goal is to evaluate the risk of NSAIDs to avian scavengers in South America. The country of focus will be Argentina given ongoing work in different avian scavenger species, overlap between livestock and avian scavengers, and preliminary knowledge on approved veterinary pharmaceuticals containing diclofenac.

1. Summarize current knowledge about NSAID effects to South American avian scavengers and identify data gaps
2. Understand the use of NSAIDs in livestock species in Argentina
3. Identify hotspot areas of avian scavenger exposure to NSAIDs through livestock
4. Quantify the risk of avian scavengers in Argentina to NSAIDs

Methodology

1. A systematic review and meta-analysis of NSAID effects to South American avian scavengers will be conducted, and current evidence and knowledge gaps summarized.
2. A survey will be delivered to livestock veterinarians in Argentina. The survey will include questions related to type, volume, and indications of NSAID use, as well as carcass disposal practices. Questions will be in the native language (Spanish) and will be presented in different formats (online, telephone, or in person).
3. A risk map will be developed to determine the spatial overlap between livestock and avian scavenger presence. Data to inform this aim will be a combination of data from (2), previously published field observations, spatial data including land-use data and farm locations, as well as new field observations of avian scavengers' presence at or near livestock farms.
4. A risk assessment combining data from the previous aims will be conducted to quantify the risk of avian scavengers to NSAIDs in Argentina. This assessment will also incorporate an evaluation of potential risk management strategies to mitigate this threat.

The student will acquire skills in evidence synthesis, survey and study design, risk assessment, data analysis, spatial epidemiology, and avian field ecology.

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This project will be based in Bristol Veterinary School.

Please contact [Email Address Removed] for further details on how to apply.

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