[Candace]

If the spike in microcephaly is actually real and not just an artifact of better diagnosis (because it's now being looked for), the zika virus is the most probable cause.

http://www.who.int/mediacentre/factsheets/zika/en/

http://scienceblogs.com/insolence/2016/02/11/zika-virus-and-microcephaly-antivaccine-warriors-say-its-vaccines-that-did-it/