Rapid spread of Zika virus in the Americas raises alarm
Mosquito-borne disease linked to birth defect is pushing northward from Brazil
![boy holding baby with microcephaly](https://i0.wp.com/www.sciencenews.org/wp-content/uploads/2016/01/012116_mr_zika-main.jpg?fit=860%2C460&ssl=1)
AN OUTBREAK CONTINUES A Brazilian boy holds his baby brother, born in 2015 with a birth defect called microcephaly. Scientists believe the condition may be linked to maternal infections with the mosquito-borne Zika virus.
Felipe Dana/AP