In a joint statement, the Ministry of Health (MOH) and National Environment Agency (NEA) said 24 of the new cases are linked to the Aljunied Crescent/Sims Drive/Kallang Way/Paya Lebar Way cluster.

They added that two cases have no known links to any existing cluster, but did not specify where these cases were located.

Meanwhile, the National Public Health Laboratory has worked with A*STAR’s Bioinformatics Institute to complete the sequencing analysis of the Zika virus found in two patients from the Aljunied Crescent/Sims Drive cluster, and the analysis indicated that the virus belongs to the Asian lineage and likely evolved from the strain that was already circulating in Southeast Asia, MOH and NEA said.

They added that the virus from these two patients was not imported from South America, and that more details will be released shortly from the research team.

NEA said it has been continuing with vector control operations in high-risk areas such as Aljunied Crescent, Sims Drive, Paya Lebar Way and Kallang Way.

As of Sep 2, 57 breeding habitats – comprising 32 in homes and 25 in common areas or other premises – have been detected and destroyed in these clusters, the agency said. NEA officers and grassroots volunteers are also continuing with outreach in the expanded cluster areas like Paya Lebar Way and Kallang Way.

Vector control operations and outreach efforts are also being carried out in Bedok North Avenue. NEA said that as of Sep 2, 26 breeding habitats in Bedok North Avenue – comprising 17 in homes and 9 in common areas or other premises – have been detected and destroyed. Mosquito control measures are ongoing, while NEA officers are continuing with outreach in this cluster as well.

Indoor spraying of insecticides, outdoor fogging, and oiling and flushing of drains are also underway in these two cluster areas. “In such areas with active transmission, outdoor fogging and indoor spraying and misting are both necessary because there may be infected adult mosquitoes in both outdoor and indoor areas that need to be destroyed before they bite and infect more people,” NEA said.

“These methods are, however, only effective if the insecticide has direct contact with the mosquitoes, and thus have to be repeated frequently as new batches of mosquitoes will continue to emerge until all breeding habitats are found and removed. Hence, routine fogging is not a sustainable vector control measure – source reduction is still a more effective and sustainable strategy.”

Meanwhile for non-cluster areas, NEA said that the most effective mosquito-control measure remains as source reduction, through detecting and removing breeding habitats and killing larvae, “as it eliminates the mosquitoes at the most vulnerable stage of their life cycle”. This is in line with WHO’s recommendations for vector control.

The statement on Saturday said that community outreach activities are being conducted across the island over these two weekends to urge all residents to join in the collective efforts in the fight against the mosquito-borne virus.

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