An Anonymous Coward writes:
The Zika virus has been known for quite some time, but it gained notoriety recently due to its possible linkage to birth defects.
Science News has a summary report on Zika virus: https://www.sciencenews.org/article/special-report-heres-what-we-know-about-zika
A report on the studies of its possible linkage to microcephaly, a birth defect of babies with undersized and underdeveloped brains: https://www.sciencenews.org/article/how-zika-became-prime-suspect-microcephaly-mystery
In short, studies are continuing, evidence is mounting, but still not quite a confirmation.
According to Snopes [snopes.com]:
"Speculative reports connecting Monsanto and pyriproxifen as culprits had no basis in any accepted science or research and, at worst, served to exacerbate unfounded fears about larvicides during a mosquito-borne disease outbreak. To date, medical research hasn't reached any firm conclusions about why a decades-old virus (Zika) potentially led to a sudden increase in microcephaly cases; however, the use of a similarly decades-old larvicide (pyriproxyfen) as the only cause was dismissed by experts across several related fields as improbable and without merit."