The virus is linked to shrunken brains in unborn children, leading to severe brain damage or death.
It has spread to more than 20 countries, and has caused panic in Brazil where thousands of people have been infected.
There is currently no vaccine or cure, and diagnostic testing is difficult.
The search for a vaccine is being led by scientists at the University of Texas Medical Branch.
They have visited Brazil to carry out research and collect samples, and are now analysing them in a suite of high-security laboratories in Galveston.
But they warn that although a vaccine could be ready for testing in two years, it may be another decade for it to be approved by regulators.