Ills in the pipeline: Emerging infectious diseases and wildlife

In the recent film Contagion, a medical thriller released in fall 2011, the fictitious MEV-1 virus—passed from bat to pig to humans—spreads across the globe as easily as the common cold, killing millions of humans and causing mass hysteria as medical researchers race to find a cure. Though it's Hollywood hyperbole, the film holds a kernel of truth: Researchers believe that the close proximity of Malaysian hog farms to forested areas—the natural habitat for fruit bats—allowed the previously unknown Nipah virus to spill from bats into pigs and subsequently into people, resulting in more than 100 human deaths (Epstein et al. 2006). There is no doubt that in recent times we have seen an unprecedented number of emerging infectious diseases, defined by the Institute for Medicine as new, reemerging, or drug-resistant infections whose incidence has increased or whose incidence threatens to increase in the near future. Many of these have a wildlife origin (Taylor et al. 2001). While this jump may be due, in part, to increased vigilance and reporting, there is a general consensus that current global conditions are creating a situation that is very favorable to the transmission of microbes that cause diseases. (For reviews, see Daszak et al. 2001 and Keesing et al. 2010). Likewise, it's increasingly important that wildlife professionals become aware of how and why new infectious diseases spread and what, if anything, can be done to minimize impacts on wildlife.