Scientists on Friday said they had found the first evidence of a biological link between the Zika virus sweeping Latin America and microcephaly, a severe deformation of the brain among newborns.

Laboratory tests found that the virus targeted key cells involved in brain development and then destroyed or disabled them, they said.

The findings are the first concrete evidence of a link between the mosquito-borne virus and microcephaly, which until now had been circumstantial, said Guo-li Ming, a professor of neurology at Johns Hopkins' Institute for Cell Engineering, and a co-leader of the research.