Hunters key to early detection of zoonotic diseases, study finds

By Dr. Priyom Bose, Ph.D.Feb 7 2024Reviewed by Benedette Cuffari, M.Sc.

To prevent future health crises, monitoring the emergence of zoonotic diseases in wild meat value chains is essential. In this regard, the role of community hunters is crucial, as they can report early signs of possible disease in game animals.

Study: An experimental game to assess hunter’s participation in zoonotic diseases surveillance. Image Credit: Virrage Images / Shutterstock.com

Background

Since the mid-twentieth century, zoonotic diseases have caused 60% of emerging disease events. More recently, wildlife has been suspected to be the original reservoir of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causal agent of the coronavirus disease 2019 (COVID-19) pandemic.

Wild animal hunting and trade facilitate human-wildlife interactions and spillover events. Community-based surveillance can provide early warning and aid in limiting the spread of a zoonotic disease. However, research has shown that local communities perceive the risk of disease transmission from animals to humans differently.

About the study

In a recent study published in BMC Public Health, researchers designed an experimental game (EG) to better understand the response of community hunters when encountered with signs of zoonotic diseases in game animals.

EGs provide important insights into the decision-making of a group of individuals. These “players” are confronted with hypothetical scenarios and are asked to choose among different options. Observations from EGs are compared to game theoretical predictions, which assume players to be rational utility-maximizers.

In the forested area of Gabon in central Africa, an EG was developed and tested that mimicked the implementation of a community-based surveillance system. Voluntary reports of hunters were used to monitor zoonotic diseases in wildlife.

Both subsistence and commercial hunters were included in the EG. The key aim was to identify the characteristics of hunters, surveillance, and epidemiological processes that could influence their probability of participating in wildlife disease surveillance.

A total of 88 hunters were divided into nine groups, each comprising five to 13 players. Over 21 rounds of the EG were performed, each of which involved a hunting trip simulation where the payers were likely to capture a wild animal with clinical signs of zoonotic disease.

When signs of the zoonotic disease were visible, the participants were asked to report or sell/consume the animal. Reporting meant lower hunting revenue but also a lower probability of the spread of a zoonotic disease, which could benefit the entire community.

Key findings

A false alert, defined as a flagged case not caused by a zoonotic disease, led to reduced case reports in the subsequent round. Concerning hunter characteristics, those who engaged in agricultural activity, in addition to hunting, flagged suspected cases more often than their counterparts. The number of potential case reports rose with each round, thus suggesting a greater inclination to report throughout the game.

In the game-theoretic model, participation in surveillance was associated with positive externalities. Relevant information benefits the community as a whole; however, it comes at a cost for the reporting player, which could lead to sub-optimal participation in reporting. The game sessions corroborated this theoretical hypothesis.

The subsequent reduction in reports followed by a false report was due to false reports reducing the anticipated benefit of reporting. Prior research has shown that from a societal point of view, false alerts are acceptable as long their costs do not exceed the benefits of accurate disease detection.

In the future, community engagement programs should highlight the utility of periodic false alerts. This will help maintain regular surveillance and its proper functioning in the event a zoonotic disease emerges.

Players engaging in agricultural work were more likely to flag suspected cases of zoonotic disease than their counterparts. For these hunters, agriculture often accounts for a significant portion of household income, thereby reducing their reliance on hunting revenue to support their families. Thus, economic dependence on wild meat likely governs the decision to participate in surveillance systems.

Conclusions

The current study highlights the usefulness of EGs in enhancing our understanding of hunters’ willingness to participate in zoonotic disease surveillance. Extending the game to include all potential actors of surveillance along the wild meat value chains could provide helpful information to better manage the risks stemming from zoonotic diseases.