Why El Nino Will Make the Zika Outbreak Even Worse

Zika has now spread to 28 countries in the Americas. It is showing no signs of slowing down.

“The outbreak continues to increase in Latin America and the Caribbean,” Dr. Marcos Espinal, Director of Communicable Diseases and Health Analysis, Pan American Health Organization, told a press conference last week. “We have not yet seen the peak.”

He estimated that Colombia will be the next country to be hardest hit by the outbreak, which generally causes mild sickness, but has also been linked to neurological disorders and a birth defect known as microsephaly when a pregnant woman contracts the mosquito borne virus.

“The expectation is that Colombia will see half million cases, he said. “We should expect to see cases of microsephaly in Colombia by June.”

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This is truly frightening. His comments suggest there is a ticking time-bomb of children who will be born with serious medical complications that could affect them for their entire lives.

And now, the World Health Organization is warning that the outbreak could be even worse than expected, thanks in large part to El Nino.

Zika is mostly spread by mosquitos (though there is evidence that it can be sexually transmitted as well.) El Nino is causing increased rainfall in much of Latin America and Caribbean. That, in turn, increases the availability of breeding grounds in which mosquitos thrive and multiply.

“We could expect more mosquitoes capable of spreading the Zika virus because of expanding and favorable breeding sites due to the weather effects of El Niño,” says Dr Raman Velayudhan, Coordinator, Vector Ecology and Management, Department of Neglected Tropical Diseases in a statement released by the WHO.

There is historic precedent for this. Back during the last extreme El Nino in 1997-98 Malaria rates increased exponentially in some countries. Like Zika, Malaria is a mosquito borne virus. And like this current El Nino, 1997-98 caused some extreme rainfall in Latin America. In Ecuador outbreaks of malaria increased by 440%.

Above-average rainfall is expected until mid 2016. During this time, mosquito control efforts are going to be particularly difficult. If mosquito control efforts are not commensurate with the scale of the challenge, we may very well see a surge in the number of cases of microsephaly in the coming year, as more and more babies are born.