Bushmeat: a disease risk worth taking to put food on the table?

Authors


Correspondence
D. Wilkie, International Conservation, Wildlife Conservation Society, Bronx, NY 10460, USA. Email: dwilkie@wcs.org

Eating bushmeat places both people and wildlife at risk. Across west and central Africa, forests empty of wildlife but still scattered with villages suggests that bushmeat hunting may be a significantly greater threat to the ‘health’ of wildlife populations than to the health of people. That said, understanding whether or not people perceive hunting, butchering and eating wild animals as a health risk sufficient to change their behavior is important as it may offer, through a concern for public health, a new avenue for reducing unsustainable hunting and improving the conservation status of endangered species such as chimpanzees.

Unfortunately, interpreting the results of LeBreton et al.'s (2006) study in terms of the relevance to conservation is a challenge.

First, people are notoriously poor at evaluating and acting on health risks (cf. Sheldon Krimsky's work on risk assessment and communication at Tufts University; Krimsky & Plough, 1988). For example, although over 5000 people in the US die each year by falling out of their beds and only 100 die from infection with the West Nile virus, sales of mosquito traps and repellent are soaring, but sales of bed frames have not declined (W. Karesh, pers. comm.). Moreover, although zoonotic diseases such as anthrax, plague and rabies are typically virulent and among the most dangerous to humans, most are the result of people living in close proximity with domestic animals, not hunting wildlife for food. Human immunodeficiency virus (HIV)-1, severe acute respiratory syndrome (SARS), Ebola and Marburg are notable exceptions. A major challenge that epidemiologists face is estimating the number of contact events required for a zoonotic disease of wildlife to become established in a human population. Without this information it is impossible to assess the risk to the public and the likelihood that individuals will perceive the risk as sufficient to alter their behavior. For example, if the probability of transmission of a zoonotic disease is 1 in 200 contacts with bushmeat, then it is an acute public health risk and may be perceived as a personal risk by individual hunters, butchers, traders and consumers. If, on the other hand, the risk is 1 in 500 000 contacts, although still a public health concern, it is unlikely that individuals would perceive the risk as sufficient to take precautions or stop hunting and eating bushmeat.

Second, the interviews were conducted after rather than before public health education sessions on HIV – that no doubt talked about disease transmission via body fluids. Consequently, interviewees' voiced concerns about the risks of contact with wildlife body fluids may have less to do with ‘real’ fears and more to do with recent exposure to this mechanism of disease transmission.

That said, the authors' results show that the dietary benefits of eating bushmeat appear to outweigh concerns about the medical risks associated with the practice, as almost all those interviewed ate (98%) and butchered (83%) bushmeat and most men hunted (77%). Moreover, although 2003 interviewees (74%) perceived contact with the blood of wildlife as risky, only 66 hunters (3% of those that perceived a risk) and 65 butchers reported taking precautions; the vast majority apparently did not. In table 2, perception of risk appears to slightly reduce the probability of butchering wildlife, but overall the level of perceived risk appears insufficient to modify behavior. This is not surprising as many ethnic groups in central Africa often believe that illness has supernatural rather than biological origins. Whether health education that explicitly demonstrates that biological rather than supernatural origins of disease would alter behavior is a question worth answering.

Equally perplexing is the contrary influence of education level and wealth (proxied by house roof construction quality). Although these two factors are typically positively correlated, in this study better-educated individuals reported butchering and eating more bushmeat, whereas wealthier individuals reported hunting, butchering and eating bushmeat about half as often. Why better-educated individuals would eat more bushmeat is unclear. The influence of wealth is congruent with other studies (Apaza et al., 2002; Starkey, 2004; Wilkie et al., 2005) that suggest bushmeat is an inferior good in economic terms and that consumption declines with increasing wealth. Given this, economic development may have a positive effect on both public health risk from wildlife diseases and the conservation status of wildlife consumed for meat.

Whether public health education is a route to reducing bushmeat hunting and consumption remains an open question. The authors' contend that ‘the high percentage of individuals … who already report taking steps to avoid infections suggests that the population may be receptive to public health campaigns which discuss the health risks of hunting and butchering’. Yet, their data show that only 3% of those who perceived contact with the blood of wildlife as risky took precautions. Even the authors acknowledge the limits of relying on health education to alter behavior when they note, in the discussion, that until the supply of domestic animal substitutes rises to meet demand for animal protein, rural families living in proximity to wildlife will continue to hunt and consume bushmeat.

From a conservation perspective, these results suggest that enforcing existing laws that protect threatened and endangered species and halting commercial hunting in logging concessions will be more effective in conserving great apes and other rare species than public health education, particularly in places where the meat of domesticated animals is more expensive than bushmeat and people are poor.

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