That part of the story was quickly swept under the rug.
Brazilian state suspends chemical used to fight Zika over fears it may be behind brain defects
rt.com/news/332692-zika-brazil-chemical-larvicide/
Brazil State Bans Pesticide After Zika Claim
wsj.com/articles/brazil-state-bans-pesticide-after-zika-claim-1455584596
Brazil Ends Monsanto Linked Pesticide Use to Fight Zika After It’s Exposed as Cause of Birth Defects
thefreethoughtproject.com/brazil-suspends-pesticide-fight-zika-virus-exposed-dangerous-virus/
>Previous Zika epidemics did not cause birth defects in newborns, despite infecting 75% of the population in those countries. Also, in other countries such as Colombia there are no records of microcephaly; however, there are plenty of Zika cases.
Brazil Officials Focus on Sumitomo-Monsanto Pesticide Used to Fight Zika After It Was Exposed as a Possible Cause of Birth Defects
theinternationalreporter.org/2016/03/01/brazil-officials-focus-on-sumitomo-monsanto-pesticide-used-to-fight-zika-after-it-was-exposed-as-a-possible-cause-of-birth-defects/
“Pyriproxyfen is a growth inhibitor of mosquito larvae, which alters the development process from larva to pupa to adult, thus generating malformations in developing mosquitoes and killing or disabling them. It acts as an insect juvenile hormone or juvenoid, and has the effect of inhibiting the development of adult insect characteristics (for example, wings and mature external genitalia) and reproductive development. It is an endocrine disruptor and is teratogenic (causes birth defects).
“Malformations detected in thousands of children from pregnant women living in areas where the Brazilian state added pyriproxyfen to drinking water is not a coincidence, even though the Ministry of Health places a direct blame on Zika virus for this damage, while trying to ignore its responsibility and ruling out the hypothesis of direct and cumulative chemical damage caused by years of endocrine and immunological disruption of the affected population,” according to the report by Physicians in the Crop-Sprayed Towns.
Here someone from the WHO says it's perfectly safe:
npr.org/sections/goatsandsoda/2016/02/18/467138913/did-a-pesticide-cause-microcephaly-in-brazil-unlikely-say-experts
"Pyriproxyfen actually mimics a hormone found in invertebrates, so it basically interferes with their development, but mammals don't have that development process," Gordon says. "There's absolutely no concern for reproductive effects that have been raised for this chemical."
Plus, the Brazilian Ministry of Health directs state and city officials to use a mere 0.0003 ounces of the chemical per gallon of water. That concentration is enough to kill mosquito larvae, but it's much lower than what WHO has deemed to be a safe concentration in drinking water.
"It's miles below the sort of acceptable recommended doses or the maximum doses you would apply," Gordon says. "You'd have to drink hundreds of liters of water to get to anywhere near potentially risky level."
But Brazil being Brazil maybe some sloppy employee accidently put a lot more pyriproxyfen in the drinking water than there should have been.