Approximately 60 percent of emerging infectious diseases of humans are zoonotic, that is, those diseases that are transmitted from animals to humans. Of these, 72 percent originate from wildlife, including Anthrax, Ebola, Hendra, HIV/AIDS and monkey pox, as well as Nipah, rabies, severe acute respiratory syndrome (SARS), simian foamy virus and West Nile virus. Emergence of these diseases is particularly worrisome to governments, leaders and world societies given that they carry multidimensional impacts to economic growth, food security, livelihoods and public health, as well as to social order, international trade and travel, and tourism revenue.
While complex in nature, the factors that contribute to the emergence of infectious diseases includes ecosystem changes associated with rising human populations, increasing demands for animal proteins, unsustainable natural resource consumption and losses of biodiversity, habitat fragmentation and encroachment. Alterations to natural living systems impair ecosystem functions and increase the likelihood of diseases to affect all species within the ecosystem, including domestic animals, wildlife, humans and plants.
There are cultural and socioeconomic determinants behind the consumption of bushmeat. For instance, for hundreds of years, African societies have been eating wildlife for nourishment. Furthermore, studies show that between 30 to 80 percent of protein intake in rural households in Central Africa comes from wild meat. More specifically, it is estimated that over 4.5 million tons of bushmeat is extracted annually from the Congo basin. Also, the financial returns from hunting wildlife are higher than average local wages given that in some parts of Africa bushmeat prices can be up to 10 times higher than beef, thus providing strong incentives to engage in this activity regardless of risks. In view of this, the strong international push to significantly increase economic development aid to Africa (and Asia) as well as promoting alternative livelihoods and food resources seems all the more justified.
As for wildlife trade, some studies indicate that rapidly rising incomes of a voracious middle-class in emerging market economies, coupled with clearing of forest owing to increasing natural resource consumption and agricultural expansion, the rise of resource extractive industries in Africa and Asia, and more sophisticated hunting weaponry are driving the increase in trade in wild animals. In China, for example, demand for wildlife meat, scales and exotic skins command cash prices in the order of US$150 to US$250 per kilogram, which, if compared to the average incomes of forest-dwelling households in Southeast Asia, allows for a better understanding of the monetary motivations behind this lucrative practice. Finally, the estimated global value of wildlife trade for consumption or recreational purposes is between 10 and 20 billions US dollars per year, according to local civil society groups.
The impetus behind the study of classical and novel infectious diseases arising from wildlife may in some part be related to the accumulating body of evidence demonstrating that up to 66 viruses have been isolated from 11 bat families and that some of these isolates have been implicated in recent disease events not previously known to the medical and veterinary health communities. As a whole, keeping the above in mind, it seems fair to ascertain that the butchering and consumption of bushmeat, wildlife farming, marketing and trade can be considered high risk practices that increase human exposure to potentially pernicious pathogens from wildlife.
Given that in the last fifteen years the world has witnessed increasing emergence of infectious diseases such as SARS in early 2003 in China, H5N1 Avian Influenza from 2004 to 2010 mainly in Southeast and South Asia, Egypt, but also in Europe and Africa, and Pandemic Influenza H1N1 in 2009 in North America, there is worldwide fear that more animal-borne diseases will strike in the future. Now more than ever, it has become clear that to be capable of addressing high-impact disease threats and hazards that arise at the interface shared by animals, humans and ecosystems, health systems around the globe will require international and regional cooperation, national political commitments, intersectoral collaborations, timely and transparent communication, and sustained infrastructure and capacity-building exercises, especially in countries bearing the brunt of disease flare-ups.
At the 'World Forest Week' celebrated on 4-8 October 2010 at the Food and Agriculture Organization of the United Nations (FAO) in Rome, Italy, a side event entitled "Hunting, wildlife trade, livelihoods and forestry management" during which a series of recommendations were developed to deal with the abovementioned important issues: (1) Enable community-based wildlife management programmes and (2) improve science-policy links. While the former faces obstacles and structural limitations, the latter makes intuitive sense. The thrust behind better linkages between science and policy is that, first, researchers and scientists need to know a great deal about what goes on in the policy world to investigate and theorize intelligently, and policymakers will profit if they can get analysis and advice from researchers and scientists who have expertise on matters that policymakers (and their constituencies) care about, and, second, researchers and scientists have a responsibility to investigate vital real-world issues, and especially controversial ones. This is why governments, funding organizations and societies devote considerable economic resources to supporting a robust academic and scientific community, as well as a dynamic international system composed of specialized technical agencies.
In the end, it is essential to comprehensively address the social, cultural and economic dimensions of pertinent stakeholders in different societies engaged in these complex issues, so that the solutions that arise can be inclusive of their situations and grounded on the prevalent realities on the ground.