Deforestation, hunting and the ecology of microbial emergence

Abstract

Understanding how novel microbes enter into the human population is perhaps the fundamental goal of the study of emerging infectious diseases (EID). The frequency at which microbes will emerge is determined by the diversity of microbes present in the environment, the level of contact between a potential host and this microbial diversity and the susceptibility of the novel host to infection. While a range of microbial media exist, including soils, plants and animals, the greatest emergence risks come through contact with media, such as wild vertebrates, that share susceptibility characteristics with humans and live in regions of high microbial diversity. Lowland tropical forests provide a rich environment for emergence due to their combination of high vertebrate and microbial biodiversity. Human activities that occur in lowland tropical forests, such as ecotourism, logging, and the hunting of wild vertebrates have the potential to increase the frequency of microbial emergence. Of these and other activities considered, hunting and the processing of bushmeat, particularly from nonhuman primates, involve the greatest level of risk for the transmission of microbes. While human hunting in lowland tropical forests poses a serious threat for microbial emergence, it is by no means alone among contemporary human behaviors in doing so, sharing risk characteristics with activities as diverse as lab microbiology, wildlife veterinary work, and modern food production practices.