Brazilian health officials believe a mosquito-borne virus has caused brain damage in around 2,400 babies, leading six states in the country to declare an emergency. The virus, called Zika, was discovered around 70 years ago in Africa, The Washington Post reported, and can cause “serious neurological complications or even death”. The country’s health ministry last month said it found the virus during an autopsy on a baby that had microcephaly, a condition that results in an abnormally small head.

Health officials are now telling couples not to get pregnant, CNN said. Last year, there were only 147 cases of microcephaly, compared with the 2,400 this year. Rio de Janeiro, where the 2016 Olympics are due to be held, has also been hit by the virus.