A group of Argentinian physicians claims a toxic larvicide rather than Zika is to blame for the huge spike in babies born with microcephaly in Brazil, according to an article on the Becker's Hospital Review website.
In 2014, the Brazilian government added pyriproxyfen to water tanks to control mosquito populations.
The Argentinian report claims past outbreaks of Zika virus have not been accompanied by spikes in birth defects, and the areas with the highest use of pyriproxyfen are the ones experiencing the greatest concentrations of microcephaly.
The Brazilian government has dismissed the claims, according to The Telegraph.