Zika by Donald G. McNeil Page B

realized rats and fleas were the problem. Even rat diseases are spread by people—rats ride with loads of grain coming to market from outside the city, for example. Jewish and Christian markets might be separate; Jewish markets might not be as connected to the agrarian countryside as Christian ones were. Wells are dug in neighborhoods, so Jews and Christians often drew water from different wells. If one neighborhood was dying and another was not, the well-poisoning theory could seem plausible.
    Fish are a logical target to blame for cholera. Vibrio cholerae is a water-borne bacterium. Sewage, not fish flesh, spreads these bacteria. But they do live in filter feeders like oysters, and New York’s harbor in those early days was so famously full of huge oysters that they were a standard food of the poor. So, while fish were probably completely innocent, shellfish possibly were not, even though polluted drinking water was the real problem.
    The “AIDS is a gay lifestyle disease” rumor was ridiculous, even more so when doctors realized within a year or two that the syndrome was the same as “slim disease,” which was all over Central and East Africa. But it took another two years to find the virus that caused it. And rumors persist when prominent people endorse them. Peter H. Duesberg, a respected molecular biologist at the University of California at Berkeley, insisted for almost a decade that recreational drugs and the first HIV medicine, AZT, were the real causes of the symptoms and death. And more than a decade later, when the disease was widespread in South Africa, that country’s president, Thabo Mbeki, read “AIDS denialist” websites and refused to let public hospitals offer antiretroviral triple therapy, saying it was a plot by Western pharmaceutical companies to sell pricey drugs to Africa.A 2008 study by Harvard researchers estimated that his policy had led to 365,000 deaths, including those of 35,000 babies.
    There were so many Zika rumors, with so many facets, that my editors asked me to write one long piece wrapping them up and explaining why they weren’t true.
    The kernel of truth behind the mosquito one was that Oxitec, a British company founded by Oxford scientists, had bred a genetically modified male mosquito. It sought out and mated with female mosquitos but had a gene that shortened its own life and, more importantly, was passed on to all their offspring and caused 95 percent of them to die before reaching adulthood. (Oxitec was already modifying Aedes aegypti mosquitoes because they spread dengue, which had been raging through the Asian and African tropics for decades and in Brazil since 1981.) Oxitec had recently done field trials in Brazil, with the largest release taking place in Piracicaba. That created headlines because the words “genetically modified” make many people nervous, in Brazil as in Brooklyn. But Piracicaba is 1,700 miles from Recife, the microcephaly epicenter—about the distance from New York to Bismarck, North Dakota. Mosquitoes fly less than a mile in their lifetimes. Besides, the numbers the company bred and released were meant to cover a few neighborhoods. They were a drop in the ocean of billions, even trillions, of mosquitoes infesting South America. Also, male mosquitoes drink flower nectar, not blood. They don’t bite people. Moreover, Oxitec had undergone earlier field trials—in the Cayman Islands, Malaysia, and Panama. There had been no microcephaly outbreaks.
    The Roundup rumor I heard from a former newspaper colleague I hadn’t seen in many years. She wrote a long passionate email to a neighbor of hers, who happened to be my former mother-in-law, who forwarded it to me.
    â€œMy conspiratorial reporter’s brain,” it began, “has been ruminating through the Zika virus panic about whether those birth defects might have another cause.”
    She had long followed environmentalists’ efforts to get