Risk of Mosquito-borne Virus Zika Spreading to Singapore

Dr Lim Wee Kiak asked the Minister for Health (a) what is the risk of the mosquito-borne virus Zika spreading to Singapore; (b) what measures are in place to prepare our public health services to tackle any outbreak; (c) whether any advisory has been sent to the medical community to alert and update them on the latest Zika outbreak; (d) whether Zika fever will be added to the list of notifiable diseases in Singapore; and (e) whether travel advisories will be issued to those who intend to visit the affected countries.

MOH has been monitoring the Zika virus situation closely. Zika virus infection is transmitted by the Aedes mosquito, identical to dengue. It is generally a mild and self-limiting illness, though recent reports from Brazil of an association with brain malformation in babies of mothers infected during pregnancy is cause for concern.

There is currently an outbreak of Zika virus infection occurring in the Latin America and Caribbean region since early 2015.

Sporadic cases of Zika virus infection have also been detected from several countries in Southeast Asia, including Cambodia, Indonesia, Philippines, East Malaysia and Thailand, in recent years but there have been no reports of outbreaks. On 19 January, Taiwan reported an imported case of Zika virus infection from Thailand.

There is an on-going surveillance programme for Zika virus infection in Singapore. While no cases have been detected so far, given that only one in five people infected with Zika virus displays symptoms and that the symptoms are generally mild, we cannot completely rule out the possibility that there are undetected cases in Singapore. Given the presence of the Zika virus infection in our region and the volume of travel by Singaporeans as well as tourists, it is inevitable that there will be imported cases of Zika virus infection into Singapore in time to come. Local transmission of the disease is also likely, as the Aedes mosquito vector is present.

To reduce the risk of importation, MOH and NEA have advised travellers to countries with local transmission of Zika virus infection to protect themselves from mosquito bites. Posters will be placed in airports for outbound travellers to serve as reminders. Due to concerns about the risk to the foetus during pregnancy, pregnant women are advised to reconsider travel plans to affected countries.

To facilitate early detection, returning travellers who had travelled to countries with local transmission of Zika virus infection are advised to seek medical attention if they develop symptoms. Posters will be placed at airports for inbound travellers to serve as reminders.

MOH has issued a medical circular to increase the awareness of Zika virus infection among the medical community. Zika virus infection has been included in the list of legally notifiable diseases. All medical practitioners and diagnostic laboratories are required to notify MOH of suspect and confirmed cases of Zika virus infection within 24 hours. Suspect cases of Zika virus infection will be tested by the National Public Health Laboratory (NPHL). MOH is also working with NEA to enhance their on-going laboratory surveillance for Zika virus.

If a case of Zika virus infection is detected in Singapore, vector control operations will be stepped up to prevent further transmission of Zika virus infection. MOH will also actively look for additional cases in high-risk areas in relation to the case. Confirmed cases will be admitted to a public hospital for further management and public health precautions will be taken to ensure that they are not bitten by mosquitoes. This is to minimise the risk of Zika spreading and becoming endemic in Singapore.

While MOH and NEA will take necessary steps to contain its spread, it may be challenging to prevent the disease from spreading and eventually becoming entrenched in Singapore, given the presence of the Aedes mosquito vector here. The mild, non-specific nature of the symptoms in the majority of infected patients will also make surveillance difficult. We urge the public to do its part by remaining vigilant and taking appropriate precautions to prevent mosquito breeding.