Healthy hunting in central Africa

Abstract

People in contact with wild animals, and particularly nonhuman primates, are acutely at risk of zoonosis and should take steps to avoid infections. Despite only limited testing, we already know that more than 1% of rural Cameroonians are infected with wild primate T-lymphotropic viruses (PTLVs; Wolfe et al., 2005) and another 1% are infected with wild primate spumaviruses or simian foamy virus (SFV; Wolfe et al., 2004). In south-east Asia, a preliminary risk assessment found that about five in 1000 temple visitors risk infections with SFV from bites from temple macaques (Engel et al., 2006). There are also numerous cases of accidental laboratory infections with non-human primate pathogens such as PTLV, SFV, simian immunodeficiency virus (SIV) and others. Cross-species transmission of non-human primate pathogens to humans are not rare events; however, to avoid infections simple steps can be followed and such steps have been elaborated for laboratory workers (Guidelines to prevent simian immunodeficiency virus infection in laboratory workers and animal handlers, http://www.cdc.gov/mmwr/ preview/mmwrhtml/00001303.htm) and in rules and signs for people visiting tourist sites where interactions with monkeys occur (Fuentes, 2006). For people living in rural central Africa, such information is obviously more difficult to come by despite the high number of exposed individuals and the diversity of pathogens from a diverse number of wild primates. While the risk of infection is apparent, the health implications, for at least some of the viruses, are less clear. We do know that the ebola and monkeypox viruses, which can be transmitted through hunting and butchering of wild animals, have serious health effects. Additional research is however urgently needed to determine the effects of a number of other viruses, in particular the diverse PTLVs, one of which human T-Lymphotropic virus 1 (HTLV-1) can cause a form of blood cancer and inflammatory disease in 2–5% of people infected. Given that little is known about many of these pathogens and their effects, the threat posed by an infection may not outweigh the potential value of bushmeat as a food source or as a source of revenue to a hunter or butcher (J. Brashares, this vol.; M. C. Monroe & A. S. Willcox, this vol.). However, some methods for avoiding infections are not costly. For example, simple and easy-to-practise measures (M. C. Monroe & A. S. Willcox, this vol.) include avoiding contact between open wounds and animal blood and washing any bites, scratches or knife injuries. Of course, the best way to avoid infection with wildlife pathogens is by avoiding contact with wild animals altogether, an option with a high cost that will not be adopted in many villages in southern Cameroon given the low level of domestic animal meat production and the lack of dietary replacements (Koppert et al., 1993). The avoidance of certain species is a second option, with animals of any species found dead in the forest being the most important as they may transmit acute and deadly pathogens such as Ebola or anthrax. Nonhuman primates, in particular the great apes, would also be an important group to avoid as they share many pathogens with humans given our similar physiologies. As non-human primates rarely make up the majority of animals hunted at any one locality (rodents and antelopes are much more regularly captured in central Africa), avoiding primates does not necessarily have to be so costly as the hunting effort can be redirected into hunting of other species. Such a redirection of effort would benefit the conservation of the threatened non-human primates, although the redirection may affect the sustainability of hunting other species. It is important to ensure that the hunting of threatened species is not inadvertently encouraged or legitimized by promoting healthy hunting (P. Daszak, this vol.; M. C. Monroe & A. S. Willcox, this vol.). Some people may even use this as an argument against communicating healthy hunting information altogether, as has occurred with other programmes of harm minimization for illegal activities such