Some experts have raised questions over what is behind the Brazilian spike in microcephaly, particularly due to the absence of a similar surge in cases in other areas hit by the virus. Others have also suggested that it has been grossly over-reported in Brazil. The country has registered a total of 3,852 suspected cases, but of the roughly 1,200 investigated so far, just 462 have been confirmed. Evidence of Zika infection was found in just 41 of the affected babies.