El Nino Climate Pattern May Influence Disease Outbreaks Globally

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http://www.scientificamerican.com/article.cfm?id=el-nino-climate-pattern

Certain disease outbreaks, including some of the worst pandemics of the 20th century, are linked to weather patterns in the Pacific Ocean, according to new research. Scientists said tracking these climate changes can help officials anticipate and plan for surges in illnesses.

The El Niño-Southern Oscillation (ENSO) cycle causes ripples through the global climate, changing rainfall and air currents. These shifts, in turn, can cause disease carriers to interact in new ways, creating novel pathogens. Weather changes can also increase the number of people exposed to a disease, increasing the likelihood of an outbreak.

El Niño is the warm phase of the ENSO, characterized by unusually high sea surface temperatures along the equator in the Pacific, lasting between nine months and two years, according to the National Oceanic and Atmospheric Administration.

The temperature changes seem small -- usually 0.5 to 1 degree Celsius -- but they can alter rainfall patterns all over the world. "It's a shift in the large-scale dynamics of the tropical atmosphere," said Jon Gottschalck, head of forecast operations at NOAA's Climate Prediction Center. "It's not regular, and it's not predictable. They call it an oscillation, but it's an aperiodic oscillation."