SAO PAULO -- Brazil's Health Ministry says it's received reports of 6,158 cases of microcephaly nationwide since the Zika virus outbreak started in October of last year. But only 745 of those have been confirmed so far.
The latest figures released by the ministry on Wednesday show that 1,182 cases have been discarded and 4,231 are still being investigated.
Last week the ministry said a total of 5,909 microcephaly cases had been reported.
Microcephaly is a rare defect that causes newborns to have unusually small heads and damaged brains.
Investigators are trying to determine if the sudden jump in reports of microcephaly cases is linked to the outbreak of the Zika virus.
