Zika in the Americas

Health officials warn women not to get pregnant because Zika can cause devastating birth defects. (Photo by Beth Murphy/GroundTruth)

Zika virus is now in dozens of countries, including the United States. GroundTruth’s Beth Murphy documents the Zika epidemic in Puerto Rico, exploring how climate change is affecting mosquito-borne diseases, here and around the world. We also hear from GroundTruth fellow Lucas Dantas, who has returned to his home city of Fortaleza, Brazil, to find out how Zika is putting even more strain on poor families.

Dahiana Santana shows a sonogram of the baby she's carrying. She worries she might have contracted Zika during her pregnancy, but she never received her test results. (GroundTruth Films)
Dahiana Santana shows a sonogram of the baby she’s carrying. She worries she might have contracted Zika during her pregnancy, but she never received her test results. (GroundTruth Films)

Behind the Science

Mosquito bites result in more than a million deaths each year, according to the World Health Organization. That’s because they’re the primary carriers of diseases like malaria, dengue fever – and the Zika virus. Scientists say climate change is affecting the life cycles of mosquitoes and, as a result, could be amplifying the spread of Zika.

“Climate change has profound impacts on public health, including infectious diseases,” says physician and epidemiologist Barry Levy. “Warmer temperatures increase the breeding season and also the rate at which mosquitoes multiply. It’s of great concern that climate change may impact the spread of Zika virus.”

It’s not just Zika that doctors are worried about, as the climate gets friendlier for disease-carrying mosquitoes.

“There are places, for example, in East Africa where malaria never occurred because they were at higher elevations and now that temperatures are warmer, malaria is occurring for the first time,” Levy says. A 2014 study found that “future climate warming will result in a significant increase in malaria cases in densely populated regions of Africa and South America, unless disease monitoring and control efforts are boosted and sustained.”

The impact of this rise in infectious diseases won’t be felt equally. Women and children are more vulnerable, and poor countries and poor people will be hit harder.

“Climate change is a risk multiplier in many ways, and a number of diseases already occur more frequently in children and some of them also occur more frequently in women,” said Levy. “In addition, in terms of raising awareness of the population about how mosquitoes breed, about steps that people individually can take, these are resources that are not as available in many of the low-income countries.”

Warming temperatures aren’t the only way climate change is affecting mosquito life cycles. The increased storms associated with climate change can lead to more flooding and standing water, which mosquitoes require in order to breed. Conversely, if climate change exacerbates drought, as it has in Brazil, people without access to running water will store water, which can become a mosquito breeding ground.


  • Managing producer: Rachel Rohr
  • Health & environment editor: Marissa Miley
  • Filmmaker: Ed Kashi
  • Consulting editor: Nathan Tobey
  • Sound designer: Robert Andersson
  • Executive editor: Charles Sennott

Special thanks to Mildred Rivera in Puerto Rico, Zoe Sullivan in Brazil, Nathan Tisdale of GroundTruth Films, and to Tom Devlin, Phil Redo, Bob Kempf and Doug Shugarts at WGBH.