Proving that the Zika virus causes microcephaly

When the Zika virus was first discovered in Uganda in the 1940s, it was thought to be harmless. It caused a rash and, in some cases, a slightly elevated temperature. But in the past few months in Brazil, it has been linked with something far worse: microcephaly (an abnormally small brain and head) in newborn babies. In adults an increased incidence of a rare neurological disorder called Guillan-Barre syndrome has also been linked with Zika infection. This is associated with muscles weakness, paralysis and can be fatal. Zika is anything but harmless.