Singapore's first and largest Zika cluster in Aljunied declared closed

NEA officers pouring oil in drains while the Town Council has engaged contractors to fumigate the precint of Bishan St 12 on Sept 7, 2016.
NEA officers pouring oil in drains while the Town Council has engaged contractors to fumigate the precint of Bishan St 12 on Sept 7, 2016. PHOTO: LIM SIN THAI

Singapore's first and largest Zika cluster, which was in the Aljunied area and had nearly 300 cases, has been declared "closed" by the authorities after it went two weeks without any new reported case.

Only two clusters now remain: one in Ubi Avenue 1 with four cases, and another in Jalan Chengkak/Jalan Raya with three cases.

The Aljunied Crescent/Sims Drive cluster was closed on Oct 9 after seven weeks, said the National Environment Agency (NEA) yesterday. But the area will still be kept under close surveillance until the end of the month, it added.

"The surveillance period takes into account the incubation period of the Zika virus and the lifespan of the Aedes mosquito," it said, urging residents to be alert and continue stamping out mosquito breeding habitats.

"There could still be asymptomatic or mild, undiagnosed cases which might fuel further transmission of the virus if there are mosquitoes in the vicinity," said the NEA.

Singapore's first locally transmitted Zika case came to light on Aug 27, and led to an all-out effort to curb the disease's spread.

In recent weeks, the number of new Zika cases has been falling steadily, along with that of dengue cases. There were 11 new Zika cases reported last week, down from the 62 new cases in a week a month ago.

"The collective effort by NEA and the community has managed to rapidly contain what could have been a major epidemic," said founding director Duane Gubler of the emerging infectious diseases programme at Duke-NUS Medical School.

Both Zika and dengue are transmitted by the same Aedes mosquito and have similar symptoms. These include fever, rash and joint pains. But Zika infections tend to be milder, with four in five patients showing no symptoms at all.

On Monday, the Health Ministry (MOH) said it will no longer issue updates each time there is a dengue fatality. "The issuance of a press release for each dengue-related death does not serve any added public health purpose," it said in response to queries from The Straits Times.

In general, there are fewer than 10 dengue deaths on average a year, with eight deaths so far this year.

Starting next year, statistics on dengue-related deaths will be published in a quarterly report instead. This will be made available on the ministry's website and the official dengue website.

MOH said NEA already has the practice of starting mosquito control operations when it is notified of dengue infections, and this will continue. "NEA also informs Singaporeans of dengue clusters so that they can take the appropriate measures to eradicate mosquito breeding and protect themselves," it said.

A version of this article appeared in the print edition of The Straits Times on October 19, 2016, with the headline 'Singapore's first and largest Zika cluster in Aljunied declared closed'. Print Edition | Subscribe