Newtonian mechanics predicted that there should be a planet inside the orbit of Mercury which they named Vulcan to explain Mercury’s anomalous precession of its perihelion, but it turns out that what was really going on was due to the curvature of spacetime predicted by General Relativity.
It would be pretty wild if Planet X didn’t exist at all either and we found out that General Relativity was wrong instead.
#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
The findings of this case report do not provide absolute proof that Zika virus causes microcephaly. The standard criteria for proving causation (with modifications) are still those that were formulated by Robert Koch in 1890, which require the isolation of the causative organism, reinfection of a susceptible person in whom the characteristic disease develops, and then repeated isolation of the organism. However, Koch’s criteria are difficult to apply, particularly for rare, devastating, and untreatable manifestations of an illness.[^3]
Zika Virus and Microcephaly • 2016 Feb 10 • Eric J. Rubin, M,D., Ph. D., Michael F. Greene, M.D., and Lindsey R. Baden, M.D. • The New England Journal of Medicine
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