New England Complex Systems Institute. "New doubts on Zika as cause of microcephaly." ScienceDaily. ScienceDaily, 24 June 2016.
Source: New England Complex Systems Institute
"Brazil's microcephaly epidemic continues to pose a mystery -- if Zika is the culprit, why are there no similar epidemics in other countries also hit hard by the virus? In Brazil, the microcephaly rate soared with more than 1,500 confirmed cases. But in Colombia, a recent study of nearly 12,000 pregnant women infected with Zika found zero microcephaly cases. If Zika is to blame for microcephaly, where are the missing cases?"