“No, we don’t know if Zika is causing microcephaly. But we have no evidence it’s pesticides, either.”
#CorrelationDoesNotImplyCausation but it’s still probably a good idea to avoid getting bitten by mosquitoes if possible whether or not you’re pregnant, because malaria, dengue, West Nile, yellow fever, chikungunya, etc. are all generally terrible experiences.1
Others claim the real microcephaly culprit isn’t mosquitos carrying Zika, but the pesticides used to control those mosquitos.
But there’s no evidence to prove either of those theories, says David Morens of the National Institute of Allergy and Infectious Diseases at the National Institutes of Health. Still, he’s not completely dismissing the pesticide theory.
“It’s certainly plausible, but we haven’t heard enough scientific information to weigh in on whether it’s real,” Morens says. “I can say that what we’ve heard about these cases of microcephaly and the epidemic of Zika, and now the possible chemical or pesticide exposure, are claims and statements that don’t yet have scientific backing.”2
I haven’t really seen anything from reputable sources about the possibility that the insecticide pyriproxyfen is actually the cause of microcephaly in Brazil, not the Zika virus, but there’s nothing on the University of Hertfordshire’s Pesticide Properties Database that rules it out.
We have no data about whether or not pyriproxyfen is a mutagen or endocrine disruptor.3
pyriproxyfen • Pesticide Properties Database