Singaporeans are being warned to be on guard against dengue with the fever in its peak season.
There were 263 cases last week and 272 in the previous week, the highest figure for the year so far, according to the latest statistics from the National Environment Agency (NEA).
The warmer months of June to October are when dengue cases are higher due to the accelerated breeding and maturation cycles of the Aedes mosquitoes.
However, current figures are well below last year's highest weekly number of 891, in June.
As of Monday, there were 39 dengue clusters classified as high-risk areas. Six had a red-alert level, meaning there had been 10 or more cases in the previous fortnight.
At the top of the red-alert list were two clusters in Bishan - covering Bishan streets 22, 23, 24 and 25 - which have had 209 dengue cases in total.
The third most active cluster was Yishun Avenue 1, covering The Estuary condominium and blocks 816, 819 and 824 in Yishun Street 81. The area has had 33 dengue cases since the start of the cluster on May 12, with 27 of the cases at The Estuary.
The NEA said it had destroyed 32 mosquito-breeding habitats at the condo. Of these, 21 were in residential premises while the rest were in common and outdoor areas.
"Outdoor thermal fogging has been carried out to kill any adult mosquitoes in the common and outdoor areas," the agency said. "We also encourage residents to allow NEA officers to carry out indoor spraying."