(CNN) In just one week, Zika cases in Singapore have gone from zero to 258, raising concerns about a potential rapid surge in cases across Asia. A recent study estimates that roughly 2.6 billion people in the region and Africa could be at risk of contracting the virus, which has been linked to the neurological disorder microcephaly in unborn babies. It's not yet clear why Zika has spread so suddenly in Singapore. Many of the cases are thought to be locally-transmitted by the Aedes aegypti mosquito. On Saturday, Singapore's Ministry of Health said analysis of two cases found they had likely evolved from a strain of Zika that was already circulating in Southeast Asia. Malaysia confirmed its first case of Zika infection in a 58-year-old woman -- who had visited her daughter in Singapore -- on September 1. The country reported its first locally-transmitted case on September 3, with authorities expecting more to come.Surge in Zika cases in Singapore has raised concerns in the regionA new study shows that 2.6 billion people across Asia and Africa could be at risk
"In _, you have megacities with populations between five to 10 million people. "When you have high populations of people and mosquitoes, it's a good recipe for both dengue and _ to spread," he added. Khan wants his team's research to help governments with less-developed infrastructures and fewer health facilities to be able to deploy their resources effectively if they ever had to face a _ epidemic. "It's also a call to the broader international community to say that assistance is need to address _ as a global epidemic," he said.