Guidelines for Addressing Disease Risks in Wildlife Trade

Introduction

For thousands of years, humans have been using wildlife for commercial and subsistence purposes. Wildlife trade takes place at local, national and international levels, with different forms of wildlife, such as live animals, partly processed products and finished products. Wildlife is a vital source of safe and nutritious food, clothing, medicine, and other products, in addition to having religious and cultural value. Wildlife trade also contributes to livelihoods, income generation and overall economic development.

However, wildlife trade can have detrimental effects on species conservation, depleting natural resources, impoverishing biodiversity and degrading ecosystems (Morton et al., 2021). Wildlife trade, whether legal or illegal, regulated or unregulated, can pose threats to animal health and welfare. It also presents opportunities for zoonotic pathogens to spill over between wildlife and domestic animals, and for diseases to emerge with serious consequences for public or animal health and profound economic impacts (IPBES, 2020; Swift et al., 2007; Smith et al., 2009; Gortazar et al., 2014; Stephen, 2021; Stephen et al., 2022; FAO, 2020). The risk of pathogen spillover and disease emergence is amplified with increased interaction between humans, wildlife and domestic animals. The risk of pathogen spillover has also been exacerbated by climate change, intensified agriculture and livestock production, deforestation, and other land-use changes. Wildlife trade is also a risk to ecosystem biodiversity via the introduction of invasive species (Wikramanayake et al., 2021). Therefore, increased effort must be put into understanding the potential consequences of the wildlife trade, mapping and analysing the adjacent risks, and implementing strategies to manage those risks. Reducing wildlife-trade risks not only helps to limit disease but also minimises the negative effects of invasive species. Between 1960 and 2021, invasive alien species caused estimated cumulative damage of around 116 billion euros across 39 countries in the European Union alone, despite strict import regulations (Haubrock et al., 2021). The effect of invasive species is extremely apparent.

Factors contributing to disease emergence and pathogen transmission vary depending on which forms of wildlife are traded. For example, live animals present higher risks than processed products. And while all animals can host infectious agents, some species carry pathogens with a higher zoonotic spillover potential. Disease risks also vary depending on the setting, for example, whether farm or market.

Wildlife-trade-related welfare impacts also vary across activities, including, but not limited to:

• capture

• transport

• holding

• killing and slaughter.

Impaired animal welfare can lead to stress and immunosuppression, potentially increasing an animal’s susceptibility to pathogens in the environment and the severity of infection, thereby increasing the number of subsequent onward pathogen transmission events. For example, keeping animals in poorly managed holding facilities or transporting live animals in cramped conditions leads to high levels of stress and provides greater opportunity for pathogen transmission. Hygiene and biosecurity are therefore critical to minimising risk in situations which cause stress.
Disease risks may be further exacerbated by mixing wildlife from various geographic locations or by mixing wildlife with domestic and peri-domestic animal species, as this provides opportunities for pathogen transmission between animals that would not normally be in contact. The relative level of interactions between species varies with the complexity of wildlife supply chains, which are often informal and less regulated than domestic animal supply chains.
Intensification of existing uses and emergence of new uses for wild species may also lead to new interfaces that modify pathogen spillover risks.

While pathogens do not discriminate between legal and illegal forms of trade, interventions to prevent disease emergence or reduce pathogen transmission are likely to be more effective in legal supply chains and markets, where regulations are more likely to be enforced. Illegal wildlife trade, by comparison, intrinsically involves illicit or non-standard practices and brings higher risk. Hence, reducing pathogen spillover from illegal wildlife trade relies on efforts to combat wildlife trafficking and limit illicit activities and high-risk practices.

Animal trade practices create multiple interfaces between humans, wildlife and domestic animals. They interact multiple times along the supply chain, such as during capture, farming, handling, storage, slaughter, processing, sale, transportation, relocation and translocation. Additional points of contact are created when animals are used for display at zoos and exhibitions, in traditional rites, for medical research or as companion animals. An assessment of the wildlife trade system in which these interfaces occur identifies the main stakeholders and the trade-offs between different interests (e.g. economic, health and conservation) inherent in this complex system. Risk assessment then identifies key hotspots and weaknesses where risks are greatest (Keller et al., 2011). The results can then inform the development of risk-management strategies targeted at key stakeholders and the hazards assessed to be greatest.

Decisions related to disease risk management within wildlife trade are complicated not only by the sector’s diversity but also by competing interests, such as sustaining economic development, conserving biodiversity and protecting the health of the public and of domestic animals. It is important to take a holistic approach when assessing wildlife trade systems, since focusing on singular hazards ignores these trade-offs. A One Health approach should be applied to wildlife trade. In other words, consideration should be given to biodiversity conservation, animal welfare, national and international regulations on threatened and endangered species, and reduction and management of risks to human and animal health.

Although domestic-animal risk analysis approaches can be adapted to wildlife trade, they can be insufficient because the latter is a highly complex system with a wide range of stakeholders and activities. These activities include local hunting, transboundary movement of wildlife as companion animals, farming and distribution of wildlife along large and complex supply chains, and marketing and consumption of wildlife specimens and products. The types of markets and points of sale involved may not come under the same level of scrutiny as domestic livestock markets dealing in animals destined for the food chain. Therefore, specialised approaches to risk analysis are needed for wildlife trade.