The Public Health Impact of Climate Change

It’s official. The World Health Organization declared the Zika virus an international public health emergency on Monday. So far all known cases in the U.S. have been infected abroad, but the virus is expected to spread rapidly if nothing is done, partly due to warmer weather patterns that let mosquitos thrive.


The past year was the warmest on record and scientists say it is likely 2016 will be even warmer. The warming climate is likely linked to extreme weather conditions that we haven’t seen before, including drought, blizzards, heat waves and floods. These weather conditions are associated with public health concerns, including food insecurity, heat-related deaths and vector-borne infectious diseases. With climate change, health risks will intensify and some new ones will emerge.


Most recently we have seen the impact on the spread of the mosquito-borne Zika virus, which is linked to babies born with abnormally small heads and Guillain-Barre syndrome. Warmer weather allows mosquitos to reproduce faster, emerge earlier in the season, survive longer and spread further from the equator in regions in which they weren’t previously seen. The two types of mosquitos that carry the virus were not previously known to be in the U.S. but are now prevalent in many areas. Unlike more common mosquitos that bite at night, these two types bite in the daytime, when more people are outside. For the Zika virus, above normal temperatures and heavy rains in Brazil and Uruguay are providing optimal conditions for mosquito breeding and biting. Weather, coupled with lack of immunity in regions that have not been previously exposed to Zika, is resulting in new infections. While it has been suggested that it is overly simplistic to solely analyze the migration of mosquitos to determine how infectious diseases will spread – we need to think about how climate change affects human migration as well – the bottom line is that there will be an impact.

Source: U.S. Climate Resilience Toolkit.
Source: U.S. Climate Resilience Toolkit.

In addition to making changes to slow climate change, countries worldwide are going to have to build their infrastructure and health practices to slow or prevent the impact on public health. Telling women to refrain from having babies is not an appropriate long-term strategy, especially when the woman’s country severely restricts her reproductive rights already, with low access to birth control and abortion. Not to mention the potential economic costs to the country if the virus goes untreated for several years. Instead, greater use of mosquito nets and education campaigns to eliminate stagnant water, use of bug spray and wearing of long pants and sleeves are proper interventions while experts work to develop a vaccine.

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