The number of locally-transmitted Zika virus cases in Singapore jumped to 242 over the weekend, with most cases linked to the existing cluster in the city-state's east, the Ministry of Health (MOH) and the National Environment Agency (NEA) said.
Singapore added 91 new Zika cases since Friday, of which 83 cases were connected to the Aljunied Crescent, Sims Drive, Kallang Way and Paya Lebar Way areas.
There might also be a potential new cluster of infections in the Joo Seng Road area, where two cases have been confirmed, the government agencies said.
Another cluster of infections had also been confirmed in the Bedok North Avenue Three area, according to a Saturday statement.
Control of the Aedes mosquito population remained the primary solution to stem the spread of Zika, according to a joint MOH-NEA statement released on Sunday.
The National Public Health Laboratory and A*Star's Bioinformatics Institute released research at the weekend that showed Singapore's Zika infections were likely from an Asian strain of the virus that was already circulating in Southeast Asia, and not from a strain imported from South America.
Several countries, including the U.S., the U.K. and Australia, have issued travel advisories warning pregnant women to avoid nonessential travel to the Asian city-state.
Zika, which hit several South American countries hard, is mostly transmitted by Aedes mosquitoes but can also be spread through sexual transmission.
There is currently no treatment or vaccine to prevent Zika infection, which causes symptoms including a mild fever, rash, red eyes, joint pain and a headache. While symptoms of the virus are generally mild, Zika poses a significant threat to pregnant women as it has been linked to a birth defect known as microcephaly in unborn fetuses.
An August World Health Organization study also found that the Zika virus could be linked to the Guillain-Barre syndrome, an autoimmune disorder that affects the peripheral nervous system.