A year ago, the most pressing concern leading up to the Olympics this summer in Brazil was that swimmers and sailors would compete in Rio’s sewage-laden Guanabara Bay. Today, one fear looms above the rest as the country prepares to welcome the world for the games this summer: Zika.
A year since it emerged from northeast Brazil and grabbed international headlines, the mosquito-borne Zika virus is still “spreading explosively,” the World Health Organization says. So far, an estimated one million people have been infected across Latin America, from Paraguay to Mexico. Unchecked, the WHO has warned, the disease could infect four million more before the year is out. Its symptoms include fevers, rashes, joint pain and, in pregnant women, the possibility of a child born with microcephaly—a birth defect that leads to abnormally small heads and underdeveloped brains. The disease is nowhere near as deadly or virulent as, say, Ebola, but it inspires a similar horror and the CDC has advised pregnant women to avoid travel to epidemic regions.
“The problem with Zika is that, for one particular target population, it is very bad,” says Scott Weaver, the scientific director of the Galveston National Lab at the University of Texas and one of the few researchers who studied Zika before the current outbreak. “Your perspective gets distorted when you see babies with microcephaly. It’s heartbreaking.” In Brazil, officials have reported 5,000 cases of microcephaly so far.
Brazilian authorities are working around the clock, but it’s doubtful the epidemic will be contained by the start of the Games in August. “We do not have a vaccine for Zika yet,” Brazilian president Dilma Rousseff told the press earlier this year. “The only thing we can do is fight the mosquito.”
That, unfortunately, is not a simple proposition.
The fight against disease-ridden mosquitos is a battle nearly as old as civilization. Ancient Egyptians consumed vast amounts of garlic to ward off mosquitos while they built the pyramids; Romans drained swamps to combat malaria outbreaks; the U.S. cleared mosquito-infested jungle to protect workers constructing the Panama Canal. And yet, as each outbreak of West Nile in New York or malaria in South Sudan shows, controlling mosquitoes is a fight we’re nowhere near winning.
The enemy in Brazil is Aedes aegypti. One millimeter long, black and white, and thirsty for human blood, Ae. aegypti is not only the main transmitter of Zika—it’s also the biggest vector of yellow fever, chikungunya, and dengue, a.k.a. bone break fever. Over its history, this particular species has been the ferrier of untold human suffering, filling city morgues from Philadelphia to Buenos Aires, changing the course of wars, and felling presidents and peasants.
Because of the mosquito’s prevalence across the Americas, from Philly to Patagonia, even cities thousands of miles from Rio are at risk of an outbreak this summer, experts say. “They’re like hurricanes,” says Gordon Patterson, a historian of mosquito control at the Florida Institute of Technology, referring to the outbreaks. “We don’t know where they’re going to hit, but there’s a storm out there on the horizon.”
This year, governments and charities across the world will spend hundreds of millions of dollars fighting mosquitos. And still, a million people will likely die from mosquito-borne diseases. To stop an illness like Zika, humanity has to best one of its oldest enemies. Is it even possible for Brazil—a single nation and only “newly industrialized,” according to economists—to kill or subdue a swarm of millions of tiny mosquitos and stop an epidemic?
Well, the country’s done it before.
This is the first section of an online feature at Outside Magazine.