The Zika virus, now detected in 42 countries, is only the latest in a series of diseases establishing a new normal for pandemics. Sars ravaged South China in 2003, Middle East Respiratory Syndrome (Mers) shocked the Middle East in 2012, and Ebola devastated west Africa in 2014. We have seen avian influenza emerge in new geographies alongside mosquito-borne viruses, such as Chikungunya. Over the past 50 years, more than 300 infectious pathogens have either newly developed or reemerged in places where they had never been seen before.
These trends raise questions: Why are infectious diseases occurring with such frequency? Why are pandemics the new normal? The increased rate of outbreak is typically framed as a failure of the health system. Indeed, that is a critical component. But the conditions that allow for outbreak in the first place are rooted in environmental change.