If a Pig Coughs in Mexico the Whole World Should Hear It

We should not be breathing a sigh of relief because the H1N1 pandemic appears to be abating. 1 Rather, we should be alarmed by the specter of future, potentially more disastrous, outbreaks of zoonotic diseases (diseases transmissible from animals to humans) that ‘swine flu’ portends. Such consternation is warranted given that (a) over 60% of all pathogens currently known to cause disease in humans have an animal origin, 2 (b) over 75% of emerging human pathogens are zoonotic, 2 and (c) zoonoses are twice as likely to be associated with emerging disease in humans compared to nonzoonotic pathogens. 2 Since emergence is precipitated by population growth, global trade and travel, urbanization, agriculture, and climate change, 3,4 the threat posed by zoonotic diseases is only going to increase. Our vulnerability to outbreaks of zoonotic diseases is aggravated by traditional anthropocentric clinical- and laboratory-based disease surveillance systems that are capable of detecting zoonotic threats only after a disease has already emerged (and potentially become established) in human populations. 4 This shortcoming is illustrated by the fact that H1N1 was only identified in people two months after the initial human outbreak, 5