Singapore has confirmed 56 cases of locally transmitted Zika virus infection, while ramping up health screenings and mosquito control efforts.
All 56 people either lived or worked in the Aljunied Crescent or Sims Drive area of Singapore and had no record of traveling to Zika-affected regions recently, according to a release by the Ministry of Health. Of the 41 people confirmed on Sunday as infected with Zika, 34 have already fully recovered.
"We expect to identify more positive cases," the official statement said. "Given that the majority of Zika cases are asymptomatic or mildly symptomatic, and mosquitoes in the affected areas may already have been infected, isolation of positive cases may have limited effect to managing the spread."
The first case was a 47-year-old Malaysian woman who developed symptoms last Thursday and tested positive for Zika on Saturday. Foreign workers at a construction site on Sims Drive comprised 36 of the cases.
"Whenever you have one local case that is not imported, you are very likely to see more cases already hiding in the community," Jasper Chan, clinical assistant professor at the University of Hong Kong's Department of Microbiology, told CNBC's "Squawk Box."