“How La Niña Could Affect the Spread of Zika” | National Geographic
Many public health experts have discussed the impacts of El Niño on human health. Now National Geographic's Gulnaz Khan has shifted the lens to the potential impacts of La Niña:
This year, one of the strongest El Niño events on record affected weather patterns worldwide, bringing with it major flooding and severe drought that impacted the health of millions. El Niño has ended, but scientists are now monitoring for the onset of its counterpart, La Niña, which may create conditions that exacerbate the spread of mosquito-borne diseases like Zika virus.
La Niña is characterized by the cooling of ocean surface waters in the equatorial Pacific and affects many of the same regions as El Niño. Based on previous years, this means above-average rainfall and potential flooding in southern Africa, Southeast Asia, and northern South America, and drier than average conditions in eastern Africa and the west coast of South America. There's a 55 to 60 percent chance La Niña will develop during the upcoming months, according to an August forecast from NOAA.
This is a public health concern because certain climatic factors like temperature, relative humidity, and rainfall are strong environmental drivers of vector-borne disease transmission, said Courtney Murdock, assistant professor in the Department of Infectious Diseases at the Odum School of Ecology. This means the abundance and survival of pathogens such as Zika virus may ebb and flow with changes in weather caused by La Niña.