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Perfect Storm of Perfect Plagues

Guess what else global climate change can do? Create a perfect epidemiological storm with enough power to take heretofore innocuous diseases and turn them into perfect plagues. A new study in Plos ONE reveals how extreme climatic conditions can alter normal host-pathogen relationships, causing a "perfect storm" of multiple infectious outbreaks to trigger epidemics with catastrophic mortality.

Outbreaks of canine distemper virus (CDV) in lions in 1994 and 2001 resulted in unusually high mortality of lions in Tanzania's Serengeti National Park and Ngorongoro Crater. In the past, CDV epidemics caused little or no harm to the lions. But the outbreaks of 1994 and 2001 were preceded by extreme droughts that caused Cape buffalo to become heavily infested with ticks. When the lions ate the buffalo, they consumed unusually high levels of tick-borne blood parasites.

In the drought years, the CDV suppressed the lions' immune systems and also combined with the heavy levels of blood parasites. The merger created a fatal synergy. In 1994 more than 35 percent of Serengeti lions died. About the same number perished in the Ngorongoro Crater in 2001.

Unspoken but implied: Our own little witch's brew of ticks and viruses is waiting for wetter or hotter or dryer or fierier years to come together and make us suffer too… The world is too complicated for the simpletons who've been running it and, alas, there is no bloodsucker that feeds on stupidity.

Julia Whitty is Mother Jones' environmental correspondent, lecturer, and 2008 winner of the Kiriyama Prize and the John Burroughs Medal Award.

Posted by Julia Whitty on 06/26/08 at 3:22 PM | Comments (5) | Email | Print

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