Sick Days

May 28, 2017
By Damond Benningfield


U.S. winter temperature outlook for 2015-2016. Credit: National Oceanic and Atmospheric Administration

We all know that El Niño can have a big impact on the United States. It generally brings cooler, wetter weather to the southwest and the Gulf coast, and drier conditions to much of the rest of the country. And that may have a bigger impact on daily life than just whether you’re likely to need an umbrella. It could change the odds that you’ll get sick.

El Niño is caused by a rise in water temperature in the eastern Pacific Ocean, near the equator, which causes more water to evaporate from the surface. As the water vapor moves around the globe, it can change climate patterns from Canada to Australia.

There’s evidence that the change can bring an increased risk of certain diseases. In Brazil, for example, the extra rainfall from the last El Niño brought more mosquitoes, which increased the risk of malaria, Zika, and other diseases.

And, a study in 2016 found a slight link between El Niño and diseases in the United States. Researchers compared El Niño events to hospital records in different regions of the country. They found that in the western states, El Niño corresponded to a slight increase in the rate of diseases carried by bugs and rodents -- especially those transmitted by ticks. But there was a slight drop in the rate of admissions for diseases of the digestive system.

On the other hand, there was a slight increase in gastrointestinal afflictions in other parts of the country, but a decrease in some other types of diseases. So El Niño could affect your chances not just of getting wet, but of getting sick.