Working Together to Address the Zika Outbreak in Singapore

3.01 pm

The Minister for Health (Mr Gan Kim Yong): Madam, on 27 August 2016, Singapore detected its first confirmed case of locally transmitted Zika virus infection. As of noon yesterday, 333 persons have tested positive for Zika, including eight who are pregnant, and involving seven clusters. Most of the patients have recovered and are no longer symptomatic. Although we had been expecting it, many Singaporeans were concerned when Zika cases first emerged in Singapore. Their anxiety is understandable, given that Zika is little known here. We have learnt much over the last two weeks. Allow me to give the House an update on the situation.

First, what is Zika? Zika is not a new disease. The first documented case of Zika was in Africa in 1947. The first reported large outbreak occurred in 2007, in Micronesia. Zika was unknown in the Americas until last year when a number of cases were reported in north-eastern Brazil. By now, 72 countries and territories have reported evidence of Zika virus transmission. On 1 February 2016, the World Health Organization (WHO) declared that the recent cluster of microcephaly cases in Brazil, which are suspected to be linked to Zika, constituted a Public Health Emergency of International Concern.

Zika is transmitted via the Aedes mosquito, which can also carry the dengue and chikungunya viruses. Zika can also be spread through sexual transmission in some cases.

About four out of five persons infected with the Zika virus will not have symptoms. They are asymptomatic. The rest will only have mild symptoms, which include fever and rash, and other symptoms such as red eyes and joint pain. On rare occasions, patients may also develop Guillain-Barré Syndrome (GBS), a disease that temporarily affects the nervous system.

Zika is, however, of concern among pregnant women. A small number of babies born to pregnant women with Zika infection may develop microcephaly, a congenital condition that affects the development of the brain. Research is still ongoing to better understand the association between Zika and microcephaly.

We had expected Zika to come to Singapore sooner or later, given the large volume of travel in and out of Singapore. When it did, we also expected to see local transmission, because of the presence of Aedes mosquitoes here. Hence, we have put in place an action plan with a three-pronged approach: first, preparing for Zika; second, responding to initial cases; and third, managing Zika in the long term. Let me first talk about preparations for Zika. We prepared for Zika on a few fronts.

First, the Ministry of Health (MOH) worked with the National Environment Agency's (NEA) Environmental Health Institute to put in place a sentinel surveillance programme for Zika two years ago. We partnered about 200 clinics island-wide to collect blood samples from selected patients with symptoms associated with Zika, which are quite similar to dengue, and tested them for the Zika virus.

From January this year, we stepped up our surveillance and testing efforts and increased the number of samples tested for Zika to more than 500 a month, a majority of them from people who had no travel history to Zika-affected areas. Close to 4,000 samples were tested between February and August, before the first confirmed case happened. All the test results then were negative. At the same time, we strengthened our laboratory capabilities to facilitate the testing and management of patients.

As a second layer of defence, we kept our doctors, especially our general practitioners (GPs), abreast of the developments on Zika. Our GPs are the first line of care for most Singaporeans. They have been helpful in alerting us to unusual disease patterns. We have also made Zika a notifiable disease under the Infectious Diseases Act from January this year, so that MOH would immediately be alerted if any doctor or laboratory in Singapore detects a case of Zika.

Third, we sought to reduce the risk of importation of Zika. We issued travel advice to outbound travellers to Zika-affected areas and inbound travellers returning from these areas.

Fourth, we stepped up public education and issued health advisories. In early February, we set up the Clinical Advisory Group (CAG) on Zika and Pregnancy, to develop a health advisory for pregnant women, and also to advise doctors on the clinical management of pregnant women with Zika. An interim clinical guidance was issued in mid-April.

Fifth, we strengthened our operational readiness for an outbreak. In January this year, MOH worked with partner agencies to prepare our operational plans in case of an outbreak. In July, we conducted a multi-agency exercise where we simulated the import of an infectious disease into Singapore. This exercise involved a wide range of partner agencies, including the Ministry of Trade and Industry (MTI) and the Ministry of Manpower (MOM). Meanwhile, we continued to monitor global developments related to Zika closely to obtain regular updates on the situation worldwide.

Madam, on 12 May, a man was hospitalised after he fell ill upon returning from Brazil. On 13 May, he tested positive for Zika, and the patient was quickly isolated at the Communicable Diseases Centre (CDC) at Tan Tock Seng Hospital (TTSH). We screened the patient's household members, and NEA deployed a larger team of officers to conduct intensive vector control operations in the area around his home in Watten Estate. Residents in the area were given Zika information leaflets and were advised to seek medical attention should they develop symptoms of fever and rash. We also asked the clinics in the vicinity to look out for Zika-like symptoms. The man was discharged after he tested negative for the Zika virus and recovered. No other cases were subsequently linked to this case and the virus was successfully contained.

Three months later, in the evening of 22 August, MOH was alerted by a GP from the Sims Drive Medical Clinic on an unusual increase in cases of fever, rash and joint pain that had tested negative for dengue and chikungunya. The next day, MOH arranged with the GP to refer new cases with similar symptoms to the CDC.

On 25 August, that is, two days after, we approached the supervisor of a nearby construction site for records of workers who had recently been unwell, so that they could be investigated further.

The following day, a lady visited the same GP clinic with similar symptoms and was referred to the CDC, as was arranged with MOH. She was confirmed as Zika-positive on 27 August. Three other patients were preliminarily tested positive that day, pending confirmation tests. That very evening, MOH announced all four cases of locally transmitted Zika cases – one confirmed and three pending confirmation.

Following this, we alerted the GPs in the Aljunied Crescent and Sims Drive area to specifically look out for patients with Zika-like symptoms, and advised residents in the area to see their doctors if they had such symptoms. NEA also intensified vector control operations in the vicinity.

By now, MOH and NEA have moved beyond the surveillance phase, to actively detect cases and identify clusters to manage the spread of Zika.

To determine the extent and the locations of the spread, we not only looked out for new cases, but also looked backwards in time to investigate past cases in the vicinity. As a number of such cases were construction workers, we went back to the construction site on 27 August to trace and test workers who had recently recovered from fever, and also assessed and tested new patients. We obtained most of the results by the next day and included them in our subsequent announcement.

This active back-tracing was why the number of confirmed Zika cases increased from one reported on 27 August to 41 on 28 August. This sudden jump was surprising to some people, who wondered if these cases had, in fact, been detected earlier but held back by MOH. In reality, the number of confirmed new Zika-positive patients – and I repeat – new Zika-positive patients, increased only by five. The other 36 were from our proactive back-tracing of workers at the construction site. Many of them have already recovered from the sickness.

Through the back-tracing, we also checked the onset of symptoms to determine the epidemiology of the outbreak. The analysis showed that the earliest case had onset of symptoms on 31 July. Some people misinterpreted this as MOH having known of the first Zika-positive case since 31 July. This is not so. As I explained, we only confirmed the first locally transmitted Zika case on 27 August, and we released the information the same evening. We subsequently identified new clusters beyond Aljunied and Sims Drive and we provided updates daily.

Assoc Prof Daniel Goh asked how we manage construction sites and dormitories. MOM and NEA have stepped up the engagement of construction sites and dormitory operators to intensify their vector control efforts to prevent mosquito breeding.

MOM has also reminded employers and dormitory operators to encourage workers to seek medical attention and notify their supervisors, should they feel unwell. Measures such as temperature taking have limited effect for Zika since a majority of infected individuals are asymptomatic, that is, they do not run a temperature. As Zika is a mosquito-borne disease, the key strategy is vector control.

I would also like to assure Assoc Prof Daniel Goh that our primary healthcare system is accessible to foreign workers, should they need to see a doctor. The cost of their treatment will be borne by their employers.

Let me now explain our approach towards Zika going forward and how we are going to manage Zika in the long term. As more cases and clusters emerge, our efforts are focused on vector control. Minister Masagos will speak on this later.

Isolation of patients has limited effect as 80% of those with Zika are asymptomatic, that means they have no symptoms. Secondly, there are already mosquitoes in the community carrying the virus. Hence, we now no longer isolate patients. Hospitalisation of Zika patients is also not necessary as we have found that most cases have mild symptoms. Patients will be hospitalised only if it is clinically necessary.

We had also reviewed our policy on the testing of suspect cases. Initially, we were focused on the clusters in order to quickly assess the nature and extent of the outbreak to guide our strategy. We therefore provided free testing for those with symptoms who lived, worked or studied in the areas that were affected.

As more cases were found in other parts of Singapore, we extended Zika testing beyond the clusters and now provide a subsidy to all Singaporeans with Zika-like symptoms at the public healthcare institutions.

Many pregnant women are understandably anxious about Zika. We are paying particular attention to them because of the possible risks to their foetuses if they are infected by Zika.

The Clinical Advisory Group for Zika and Pregnancy had, on 30 August, updated its guidelines on the health advisory, testing and clinical management for pregnant women. These were aligned with WHO guidelines which advise that Zika testing for asymptomatic pregnant women is not routinely recommended. However, WHO's guidelines do recommend testing for symptomatic pregnant women and those whose male partners had tested positive for Zika. Symptomatic pregnant women and those whose male partners have tested positive should seek the advice of their doctors. They will be provided with free Zika tests at both public and private healthcare institutions if their doctors assess that testing is needed.

Pregnant women who are tested positive for Zika will be referred by their doctors to an obstetric or maternal-foetal medicine specialist for counselling and subsequent follow-up. Regular ultrasound scans will be carried out to monitor the development of the foetus. Zika infection does not always result in abnormal foetal development. It is, therefore, important that pregnant women be appropriately advised and monitored by the relevant specialists. Babies born with microcephaly will be supported and cared for, just as we do for babies with other congenital conditions.

The People's Association (PA) has also worked with NEA and specially arranged for insect repellents to be available to pregnant women at community clubs island-wide since last Saturday. We hope this is helpful.

Mr Christopher de Souza and Mr Png Eng Huat asked how we could raise public awareness of Zika. Public awareness is one of the most critical elements in our fight against Zika and we have undertaken multiple efforts on this front.

Since January this year, we have kept the public updated on Zika developments through the media and the MOH website, providing information on precautions to take when travelling to Zika-affected areas.

Since 27 August, we have shared information with the media and the public on a daily basis. I would like to thank the media for following the news closely, taking the effort to understand the issues and presenting the news on Zika in a clear and accurate way.

The Ministry of Communications and Information (MCI) has set up a microsite on Zika with useful and easy-to-read infographics and videos on "What is Zika?", providing advice to pregnant women, as well as the latest updates on the Zika situation in Singapore. MCI has also produced some interstitials on Zika, which have been broadcast on free-to-air channels, starting from last week. NEA has also set up a website with statistics on Zika infections and clusters. NEA, in collaboration with the grassroots organisations, has continued its outreach to the community through information leaflets and posters on Zika and dengue. This has gone hand-in-hand with their vector control operations.

In Chua Chu Kang, for example, with the support of NEA, students from Pioneer Junior College and the Institute of Technical Education (ITE) College West, grassroots leaders and volunteers, we visited 134 blocks in my constituency on 4 September, to share with residents information on Zika and what they can do. And I am sure many other Members have done the same.

I have no doubt that we will be able to learn more about the Zika virus through global and local research efforts. The National Public Health Laboratory has worked with the Agency for Science, Technology and Research’s (A*STAR's) Bioinformatics Institute to complete the sequencing of the Zika virus found in two patients here and shared their results publicly. We cannot tell at this moment whether the viruses found here cause more or less severe disease than those in South America. Further research will be needed to shed light on this.

We can also expect more test kits to be on the market in future. They will need to undergo field trials, be validated by laboratory professionals, and approved by regulators to ensure they are safe, and the results are reliable before they are available for use.

Currently, there is no specific anti-viral treatment or approved vaccine for Zika. Early-stage human trials have commenced for experimental vaccines. There are also ongoing research efforts in Singapore on Zika. But testing and translating these to practical clinical use will take time.

Mr Alex Yam asked whether the Ministry will consider setting up a National Zika Registry. We will study this carefully. Meanwhile, we are already tracking Zika, which is a notifiable disease. Microcephaly has been tracked by the National Birth Defects Registry since January 1993. We will work with our doctors to monitor the outcomes of babies born to women with Zika over time. Madam, allow me to say a few words in Mandarin, please.

(In Mandarin): [Please refer to Vernacular Speech.] Mdm Speaker, most people infected with the Zika virus will only have mild symptoms and can recover without treatment. However, Zika infection is a concern among pregnant women as some babies born to pregnant women with Zika infection may be at risk of developing microcephaly.

We provide free Zika tests for the symptomatic pregnant women and those whose male partners have tested positive for Zika. Doctors will provide counselling to pregnant women who tested positive for Zika and closely monitor the development of the foetus.

MOH has been working closely with NEA to intensity vector control and eradicate mosquito breeding grounds. We also stepped up public education.

To further reduce the risk of transmission of Zika, we must take a whole-of-society approach in our fight against Zika. It is not NEA's job alone. Each one of us also has a part to play. I believe that as long as we work together, we can win the battle against Zika.

(In English): Let me continue to conclude in English. Madam, Ms Tin Pei Ling asked if there are useful insights learnt from managing and communicating the latest Zika incident. I would like to share three learning points.

First, it is important to be transparent and timely in sharing accurate information. This is why we released regular updates on Zika, in order to keep the public apprised of the situation. This also prevents rumours and untruths from spreading and creating confusion and suspicion.

Second, a whole-of-Government response is key. MOH and the Ministry of the Environment and Water Resources (MEWR) are grateful that we have had strong support from our healthcare partners and professionals, Government agencies such as NEA, MCI, MOM and PA, in responding to this outbreak.

Lastly, but even more importantly, a whole-of-Government approach is still not enough. We need a whole-of-society approach. I am grateful to many grassroots leaders and volunteers who helped to reach out to fellow residents on Zika and I want to thank all Singaporeans for helping us on the ground to eliminate mosquito breeding sites.

Madam, there is still much to do, and all of us need to play our part in the fight against Zika. It is still early days to ascertain what the long-term trend of Zika infections will be. We cannot afford to be complacent, even if we see day-to-day numbers coming down.

Even as NEA continues its vector control efforts, each one of us should do what we can to reduce the spread of Zika by taking personal precautions against mosquitoes and checking for mosquito breeding in our homes and our workplaces. I urge all Singaporeans to continue to remain vigilant and do our part, to protect Singapore against Zika.

Madam, the journey in our fight against Zika is likely to be a long one because of the presence of Aedes mosquitos here. Even if we can control the present outbreak, we will need to continue to guard against imported cases, as the Zika virus is still circulating among many countries, including several in this region. Therefore, as we tackle Zika, life must go on. By working together, I am confident that we can succeed in managing Zika in the long term.

Mdm Speaker: As the Minister for the Environment and Water Resources will be making a related Statement, I will take all clarifications after that Statement has been delivered. Minister Masagos.

3.22 pm

The Minister for the Environment and Water Resources (Mr Masagos Zulkifli B M M): Madam, the Minister for Health has given an account of the Zika outbreak, and the clinical management of patients diagnosed with Zika in Singapore. I will now highlight the mosquito control measures my Ministry and NEA have undertaken to control the mosquito population prior to and during the outbreak.

As everyone knows by now, Zika and dengue are conveyed by the same mosquito – the Aedes aegypti. Our key strategy for dengue control, and now Zika, is source reduction – the detection and removal of breeding habitats and larvae. This integrated vector management strategy is in line with WHO's recommendations and remains especially critical now, as we are in the traditional dengue peak season.

Using a risk-based approach in NEA's vector control, our officers conduct pre-emptive checks and vector control efforts as precautionary measures in areas identified with high Aedes mosquito population. When a dengue or Zika cluster is identified, we intensify our source eradication efforts by partnering the community and premise owners to eliminate mosquito breeding habitats. Fogging is also conducted to kill the mosquitos as an additional measure to quickly curtail the transmission of dengue or Zika.

Following the Zika outbreak, we have heard calls for fogging to be conducted at various residential estates. Currently, NEA carries out indoor spraying of insecticides and outdoor fogging or misting to kill adult mosquitoes in the Zika clusters. This is the same thing we do in the dengue clusters. These measures are helpful in the clusters because they have infected adult mosquitoes which must be destroyed before they bite and infect more people. However, it would not be wise to conduct fogging indiscriminately outside of the clusters as a preventive measure.

Firstly, fogging is only effective if the chemical has direct contact with the mosquitoes. This means that fogging will have to be repeated frequently as new batches of mosquitoes continue to emerge from breeding habitats that are not removed. Routine fogging is not a sustainable vector control measure. Secondly, the right chemical and sufficient number of fogging guns needs to be deployed to achieve an effective kill. Thirdly, the overuse or indiscriminate use of chemical treatment may cause the build-up of resistance in the local mosquito population. Fogging should only be used when there are Zika or dengue clusters or when the adult mosquito population is observed to be high so that we can mitigate the situation quickly and, again, I qualify, it is only effective when worked together with source eradication.

I just read an article in The Economist where experts fighting the same Aedes aegypti mosquito in Florida have come to the same conclusion that fogging on its own is not effective and that the only real solution is, in fact, "boots on the ground". And this is the best way to destroy the breeding habitats. Given that this particular mosquito, the Aedes aegypti, likes to be around humans, lives in crowded places, and lay eggs in clean water, the only way to mitigate the risk of dengue or Zika is to prevent the mosquito from emerging in the first place. Indeed, human blood is needed by the female Aedes mosquitoes to lay eggs and breed. They will go everywhere where there is human blood to feed on and water to breed their offspring.

That is why our NEA officers' boots have been on the ground for years to eradicate breeding spots in accessible and public areas. That is why we have to emphasise repeatedly that every household must also constantly do the necessary ground actions to remove potential breeding spots in their own homes where it is not easily accessible to our officers.

Why does Singapore remain vulnerable? I would like to share that we remain vulnerable to dengue and other mosquito-borne diseases for a few reasons.

Firstly, the dengue cases have been increasing globally. WHO reported 2.2 million cases in 2010, and this number has increased to 3.2 million last year.

Secondly, we are in a dengue-endemic region and there are four different dengue virus serotypes circulating concurrently. Historically, we notice a change in the predominant virus is usually followed by a spike in dengue cases.

Thirdly, a large proportion of our population lacks immunity to dengue and other mosquito-borne diseases as a result of intensive mosquito control in the past decades. In many other countries where dengue is endemic, the affected are often children. This is not the case in Singapore, which is good. Our success has, therefore, and however, paradoxically lowered our herd immunity so that disease transmission occurs easily even with a very small mosquito population.

Fourthly, our region's constantly warm climate and high humidity allow the mosquitoes to breed all year round. The warmer climate also supports faster breeding and the maturation cycle of the mosquitoes, which contribute to a higher population and the spread of diseases.

Finally, our high population density is very helpful to the breeding of Aedes aegypti. This specific mosquito, as I have mentioned, has adapted particularly well to our urban environment because it loves human beings, compared to animals, and likes to breed, mate and feed near human dwellings.

We must acknowledge that all these extraneous factors make it impossible to eliminate the Aedes aegypti here. Indeed, if we had done anything less, dengue and Zika would have spread throughout the whole island more quickly and thoroughly. Therefore, we are far from helpless and can do much to mitigate the risks.

We have put in resources for surveillance. NEA has deployed about 37,000 Gravitraps around Singapore and this number will reach 48,000 by the end of the year. These Gravitraps will allow us to identify areas with a large Aedes aegypti population and take targeted mosquito control measures proactively even if there are no dengue or Zika cases. This sort of risk-based, preventive surveillance work will go on well ahead of any peak transmission season.

Inspections and enforcement have also been useful. Dr Tan Wu Meng has asked for the number of site checks conducted by NEA and the proportion of mosquito breeding habitats found.

Around 850 officers are deployed daily to do inspections island-wide. Between January and July this year, we conducted about 748,000 inspections – 638,000 of these inspections were in homes and 4,400 in construction sites. More than 10,000 breeding habitats were destroyed during these inspections – about half were in homes and about 5% in construction sites. Besides conducting preventive surveillance, we inspect all the premises and public areas within the cluster, conduct indoor spraying of insecticides and outdoor fogging to kill adult mosquitoes, as well as oiling of breeding habitats to kill any mosquito larvae.

For the construction sites, we have stepped up enforcement actions and penalties over the years in addition to imposing fines. In 1998, we passed the Control of Vectors and Pesticides Act (CVPA) which allows us to impose Stop Work Orders (SWO) for worksites repeatedly found with poor housekeeping and mosquito breeding habitats.

The number of SWOs imposed on errant sites increased from 2013 as a result of a tightened regime. Between January and July this year, NEA issued around 50 SWOs, 410 Notices to Attend Courts and also proceeded with over 40 Court prosecutions of errant contractors for repeat offences.

Since 1999, NEA has required all construction sites exceeding $50 million in project value to employ full-time Environmental Control Officers (ECO) while sites between $10 million and $50 million are required to employ part-time ones. There are now around 2,750 ECOs to ensure good housekeeping and proper mosquito control measures in the construction sites all over Singapore.

This combination of measures – onsite ECO, outreach, inspections, fines, SWOs – has helped us to bring about a significant reduction in the percentage of inspected construction sites found with mosquito breeding – from 30% in the 1990s to 11% in 2013 to about 9% today.

While NEA has given attention to construction sites, I must reiterate that a large number of mosquito breeding sites is, in fact, still found in homes. Earlier this year, given the potentially large number of dengue cases as well as the impending threat of Zika, the NEA renewed the call for everyone to safeguard our own home. Since 14 March 2016, NEA has taken enforcement action against all the home owners found with mosquito breeding, regardless of whether the homes are within the existing dengue clusters, and2,200 households were fined between January and July this year.

While the current strategy has kept the mosquito population here low, we are exploring new methods to further tackle the mosquito problem. I recently announced plans to trial a novel method of suppressing the mosquito population through the release of male Aedes aegypti mosquitos carrying Wolbachia to mate with wild female Wolbachia-free Aedes mosquitos. Eggs produced from the mating between the male Wolbachia-carrying Aedes aegypti mosquito and a wild female Aedes aegypti mosquito will not hatch.

The trial follows a four-year intensive study and comprehensive risk assessments by NEA's Environment Health Institute (EHI), and support shown by the WHO, the United States (US), Australia, and so on. From October 2016, male Wolbachia-carrying Aedes aegypti mosquitos will be released in three selected sites. If successful, this will complement our existing mosquito control efforts and eventually lead to the suppression of the Aedes aegypti mosquito population and a possible curtailment of dengue or Zika transmission. That said, the Wolbachia technology is not a silver bullet. It will take some years before we can deploy it at scale. And with or without this kind of breakthrough, I want to stress that everyone must still continue with source reduction efforts.

Actions after Zika outbreak. Our mosquito control strategy has helped us to suppress dengue over the years and I will now address the questions raised by Mr Christopher de Souza, Mr Dennis Tan and Assoc Prof Daniel Goh, to show that this same strategy has prepared us well to tackle our Zika challenge now.

Following MOH's announcement of the first locally transmitted Zika case on 27 August 2016, we immediately alerted the 27 members of our Inter-Agency Dengue Taskforce (IADTF). Every day, around 300 NEA officers, contractors and volunteers carry out vector control efforts and outreach in these clusters. As of 11 September 2016, more than 31,000 premises in the various Zika clusters have been inspected for mosquito breeding. More than 200 mosquito breedings have been detected and destroyed in the clusters.

In the Zika clusters, thermal fogging outdoors and indoor spraying of premises have been carried out to kill adult mosquitoes and the drains have been flushed to remove any stagnant water as an added precaution.

At this point, I would like to thank the residents in the Zika clusters for their show of support and cooperation to our officers. They willingly opened up their homes for our officers to do their inspections and helpfully pointed out areas of concern to them for action. Again, we need everyone to step up and forward to help take good care of our homes and neighbourhoods so that we can all maintain good health.

NEA has also inspected the construction sites and workers' dormitories in the Zika clusters. An SWO) was issued to the construction site at Sims Drive on 27 August 2016 to curtail the local Zika transmission as the site had failed to maintain satisfactory housekeeping and to eliminate potential mosquito breeding habitats.

NEA has, in fact, been working regularly with the Singapore Contractors Association (SCAL) and Senior Minister of State Amy Khor recently met them again to drive home the point that their construction site supervisors would need to be more vigilant about mosquito control and to look out for any workers with Zika symptoms. With the threat of Zika, all SCAL members will be conducting Mozzie Wipeout exercises in their sites in the next few weeks.

NEA has also served CVPA orders to four dormitories to impose stricter requirements on them to maintain good housekeeping, check for mosquito breeding, clear stagnant water regularly, carry out thermal fogging if the mosquito population is high, and mandatory residual spraying in their premises on a quarterly basis.

Communication is key in any public health situation. Together with MOH, we have provided updates of our efforts and actions through the daily media briefings. Up-to-date information on the Zika clusters has been put up on the NEA website since last Wednesday. We have also engaged our community partners to conduct extensive outreach to the residents in the Zika clusters.

Over the past two weekends, outreach activities supporting the Mozzie Wipeout Movement Against Zika were conducted all over Singapore to remove stagnant water in common areas, dispose of discarded receptacles properly, and distribute Zika information leaflets to the residents. Let me reiterate our gratitude for the support of the public and our partners and the many volunteers who have worked tirelessly with us.

Mdm Speaker, we are on the right track. Our strategy of rigorous mosquito control efforts and coordinated public education has been commended by WHO and US' Centers for Disease Control and Prevention.

Everyone – the Government agencies, premises owners, businesses, residents, the community – has a role in our fight against dengue and Zika. Home owners, please "Do the Mozzie Wipeout". Contractors and dormitory operators, please maintain proper housekeeping. Town Councils, please help eliminate potential breeding sites in the common areas and undertake fogging sensibly. It is our insurance against a widespread outbreak.

Let us all continue together to keep our boots on the ground, keep calm and carry on. Mdm Speaker, in Malay, please.

(In Malay): [Please refer to Vernacular Speech.] We are on the right track. Our strategy of rigorous mosquito control and our well-coordinated public education efforts have been commended by WHO as well as the US' Centers for Disease Control and Prevention.

Everyone – the Sovernment agencies, premises owners, businesses, residents, the community – has a role in our fight against dengue and Zika.

For home owners, let us continue to perform the steps to "Do the Mozzie Wipeout". For the contractors and dormitory operators, please maintain proper housekeeping at the building sites and dormitories. For the Town Councils, please help to eliminate the potential breeding sites in the common areas and undertake fogging sensibly. All these efforts are our insurance against a widespread outbreak. Let us all continue to keep our boots on the ground, keep calm and carry on in our fight against this disease.

Mdm Speaker: Ms Foo Mee Har.

3.43 pm

Ms Foo Mee Har (West Coast): I have two supplementary questions for the Minister of the Environment and Water Resources. I would like to ask the Minister what additional measures would the Ministry contemplate implementing to prevent mosquito breeding in vulnerable locations, such as construction sites and workers' dormitories. For example, would the Minister consider more stringent measures, such as introducing a new regime requiring all construction contractors, large and small, to engage authorised pest controllers to conduct independent checks and treatments at the construction sites?

Under this arrangement, the Government could spell out specific maintenance and housekeeping standards that all contractors must abide by or risk suspension of their operations until they comply.

All construction sites would need to display clearance reports by these independent pest controllers at the construction sites so that the public can see that they have got a very systematic regime, and it is conducted by independent controllers, something like what was implemented by the Building and Construction Authority (BCA) on the lift maintenance scheme.

Mr Masagos Zulkifli B M M: I thank the Member for the questions. I think, firstly, we should not go overboard by implementing more measures and also adding more costs when we can do things well publicly. The combination of the CVPA measures, which include having an ECO on site for those construction sites exceeding $50 million and a part-time one every two weeks for those between $10 million and $50 million, we think this is sufficient.

Again, I would like to stress the importance of having the support of all the premises owners, including construction site supervisors, so that they do not let their eyes off the ball. Sometimes, there are dry seasons; the rain may not fall and, therefore, there may not be any mosquitoes. But the Aedes aegypti mosquito can breed any time of the year.

Therefore, we must never let our vigilance down. We are thankful that the Singapore Contractors Association (SCAL) continues to encourage the supervisors to be on the look-out, always be on their toes, so that whether it is their site or their workers, they must care for them enough not to allow the mosquitoes to breed and, therefore, spread Zika or dengue.

We have also extended our CVPA to the dormitories because it is a good precautionary measure, although this is not a construction site. The workers live there and they may also spread or transmit to one another. Therefore, CVPA will require the dormitory owners to step up their housekeeping of the premises as well as misting quarterly, to ensure that mosquitoes, if they were ever to exist in that place, will die if they were to land on the walls, because this is where most of them would be during the nights when they are resting. So, we must continue to work with them. We will monitor. And if these actions are not sufficient, if WHO or other experts tell us to do other things that will help us to fight it, we will definitely take it up.

Mdm Speaker: Mr Alex Yam.

Mr Alex Yam (Marsiling-Yew Tee): Madam, first of all, I thank the Ministers for their comprehensive Statements. Please also allow me to place on record my appreciation to the MOH and NEA officers for their hard work on the ground since the start of the Zika infection.

A couple of questions for MOH. First of all, are we able to ascertain, at this point, the origin of this particular local transmission? Secondly, I understand from the Minister's Statement that there was a look-back exercise. I would like to ask what we did with the look-back cases that were Zika-positive. Were these patients informed that they were Zika-positive and was this particular exercise helpful in reducing the spread of Zika further?

On microcephaly which is perhaps the most visual and the most frightening aspect of Zika, are there any other causes of microcephaly in babies and how many non-Zika microcephaly cases have there been in Singapore since the tracking began in 1993? Also, in terms of public awareness that both the Ministers spoke about, have both the Ministries ascertained what the level of public awareness on Zika is at this moment, and what more can the Government do to stress the whole-of-society approach to containing Zika and preventing vector breeding?

Last of all, a question for the Minister for the Environment and Water Resources. Under CVPA, from the start of this year, how many section 36 orders have been served to inspect vacant or non-cooperative households in premises in dengue or Zika areas?

Mr Gan Kim Yong: Madam, I can answer some of the questions first and then I will allow my colleague to answer. First, Mr Alex Yam asked about the origin of the local transmission. I presume he is asking about the first case locally. It is very difficult to determine the first case of Zika because Zika is not transmitted from person to person. From epidemiological studies, it is very difficult to trace who passes on to who because there is an intermediary factor and, that is, the mosquito. We are unable to trace the mosquito for obvious reasons. Therefore, we do not know who is the first so-called index case.

We also have to be quite careful not to identify the person with the earliest onset of symptoms on 31 July as the first case. It may well not be because, again, 80% of the patients actually do not have symptoms. So, it is not necessary that the first person with symptoms is the first case. I hope I have addressed the Member's question. So, the answer is we do not really know who the index case in this outbreak is.

Secondly, Mr Alex Yam asked about the look-back exercise. The look-back exercise was important to us in order to have a sense of how wide the cluster was and how many patients were involved, to allow us to determine very quickly rather than to have to wait for further cases to be investigated, and to size up the situation. We decided to look back to allow us to have a quick assessment of the size of the cluster and to also allow NEA to focus its efforts where it matters. It is helpful in that sense.

For patients who are tested positive, we do inform them. And for those who are still symptomatic, we isolated them in the beginning, as I had explained earlier. They were hospitalised for us to observe them, as we wanted to be sure that they did not have complications either. By the time of the look-back, in fact, most of the patients in the look-back exercise had already recovered. They were no longer symptomatic because, in the look-back exercise, we looked quite far backwards and many of them had already recovered. We were just approaching them and asking them whether they were ill before, what their symptoms were and when their symptoms started. That is how we did the look-back exercise.

On microcephaly, Zika is not the only cause of microcephaly. Microcephaly can be due to a number of factors. It could be due to genetic and environmental factors, such as Down Syndrome, exposure to drugs and alcohol, rubella, as well as other infectious diseases. Even before we encountered the first case of Zika, microcephaly cases were present in Singapore. Over the last five years, we had, on average, between five and 12 microcephaly cases per 10,000 live births. For these patients with microcephaly, we continue to provide support and manage them in the same way as we manage children with congenital conditions.

Mr Alex Yam also asked about the level of public awareness. Those of us who have done home visits would know that the level of awareness is very high among the public. Every door that we knock on, I always tell them, "I want to remind you about Zika." They will say, "Yah, Zika I heard of it. I read about it in the newspapers. I watched the TV." Most of them are aware of Zika. Based on a recent survey by MCI, more than 90% of Singaporeans found it easy to access information with regard to Zika. And we will continue to raise public awareness. Because research on this is still on-going, our knowledge of Zika is still very limited, in terms of scientific knowledge. There will be new discoveries and developments, and we need to continue to engage the public and keep them informed of these new developments.

Mr Masagos Zulkifli B M M: Mdm Speaker, there was a question about section 36. To date, this year, before the detection of Zika, there were 13 section 36 orders served and, after Zika, 24 such orders were served. Of these 24, three were found with breeding but with very few larvae.

Mdm Speaker: Ms Tin Pei Ling.

Ms Tin Pei Ling (MacPherson): First of all, because part of MacPherson was part of the first general cluster, I would like to also thank MOH, NEA, the Town Councils, pest control workers and grassroots leaders for their relentless efforts in the anti-Mozzie and anti-Zika efforts. Thank you.

I have got a few questions. First of all, I would like to ask if Zika is now considered endemic in Singapore and if a full eradication is even possible. Second, I note that WHO has praised Singapore and that we have also complied with the guidelines, in terms of how we can support and advise pregnant women in Singapore, I am wondering if more help can be given to them.

Until there is greater research and clarity in whether the local strain of Zika will cause more or less damage, in terms of pregnant women and the foetuses, I believe pregnant women will continue to be worried throughout the months of pregnancy. So, would regular tests be made available to all pregnant women during the pregnancy? And for those who have exhibited symptoms and tested positive, would MOH subsidise the expected increase in cost, given the anticipated increase in scans and other follow-ups needed to ensure the well-being of the foetuses?

Thirdly, is the current testing capacity enough to deal with the demand in case of a national outbreak again – hopefully not – and whether there is a need to increase the capacity for testing? Finally, will there be funds specially set aside to conduct Zika research? This is especially so, given that mosquitoes are considered endemic in the tropical countries like ours?

Mr Gan Kim Yong: Madam, whether Zika is endemic in Singapore, I think it is too early to say. It is actually not productive for us to discuss on terminology, whether it is endemic or otherwise. Our immediate task is to focus on vector control, do our level best, try to eradicate as much as we can and, if not, to minimise as much as we can. That is our immediate task, and we should focus on this. I certainly hope that Zika will not be endemic. But it is something that we will have to monitor over a longer period of time before we can make a definitive assessment.

On pregnant ladies, WHO did not recommend regular routine testing for non-symptomatic pregnant women because, to test them, there is a very narrow window. You have to test them while they are infected. After a period of time, when their infection has recovered, it will be very difficult to detect whether the lady has been infected before. Therefore, the window is very narrow, and it is not practical to keep testing the lady every day, every week, or every other week. WHO did not recommend regular testing for those who are non-symptomatic. Our Clinical Advisory Group also advised against it.

For symptomatic pregnant women, the advice is for them to consult their doctors because each case is different, their risk factors are also different. So, it is better for them to consult their doctors. How often they need to be tested and monitored, their doctors will be able to advise them accordingly.

Ms Tin also asked about the additional cost. For treatment in our public healthcare institutions, they will always have access to our subsidy framework. If they are subsidised patients, and if they are unable to afford the cost, especially for the lower-income families, MediFund is available for them, whether for the test or the treatment.

Ms Tin asked about the capacity for testing. We have sufficient capacity, in the meantime, to handle the daily testing that we are encountering, and we also have measures put in place to increase the capacity, if need be.

On research funding, it is an area that we are also interested in. Our National Medical Research Council (NMRC) has funds to support meaningful research with regard to Zika. It is something that we are discussing with the researchers and if they have worthwhile projects, they can put these up to NMRC, and we will support them accordingly.

Mdm Speaker: Assoc Prof Daniel Goh.

Assoc Prof Daniel Goh Pei Siong (Non-Constituency Member): I have three questions, two for the Minister for Health. The first one is whether the 36 construction workers were discovered to be infected in the look-back exercise, whether they went to a clinic and, if they did, why were the clinics not able to detect an uptrend in the Zika symptoms and report that to MOH?

The second question is: what processes are in place to ensure construction site contractors would report large numbers of workers who display symptoms of dengue or Zika infection to MOH in a timely manner and, if none exists, whether there should be such processes?

For the Minister for the Environment and Water Resources, whether, other than size, the location of construction sites should be considered for more stringent surveillance, namely, how close the sites are to residential areas?

Mr Gan Kim Yong: Madam, first, on the question of the 36 patients we detected in the look-back exercise, some of them went to the clinics. But the symptoms were very mild. So, very often, the clinics may not be able to identify them as having potential Zika infection. Members would remember that I had explained how we identified the first case. It was because of a GP clinic that had identified a large number of patients with similar symptoms, and they were not able to determine the cause of the symptoms. They had tested the patients for dengue and chikungunya, and they were not able to determine what infection the patients had. And so, they alerted us. That is part of our surveillance system.

As I had also explained in my reply, our primary care system is, in fact, on the frontline of our surveillance. They are more sensitive because they are trained and on the lookout for unusual trends. If they identity trends like what I mentioned earlier, they will alert us and then, we would go in and investigate.

In addition to the GP network that we work with to identify unusual trends, we also have a sentinel surveillance system, where we work with partner GPs and our polyclinics to monitor and test selected samples regularly to ensure that even if they have no significant symptoms, if we are not able to determine the cause of the symptoms, we also test them for Zika to make sure that we are able to identify Zika infections if it is transmitted in the community.

Most of the clinics, when they do testing, under normal circumstances, the focus is on imported cases as well. So, if they see symptoms that resemble Zika, even if they are light symptoms, they would check the travel history. If the patient has been to Zika-infected countries, then alarm will be raised. And they would then inform us. That is also part of the system to track imported cases. That was how the first case in Watten Estate was discovered, because he had a travel history to Brazil. When he returned, we discovered that he had symptoms. Therefore, we sent his blood for testing, and we discovered Zika that way.

The Member's second question on a large number of patients in the construction sites, again, as I had explained, the key gatekeeper is our primary care system. We work through our GPs when they notice unusual trends, whether it is Zika or any other infection. We are on the lookout not just for Zika but also other potential infectious diseases, including diseases that we may not be aware of as well. So, our frontline GPs are the most important. When they see cases that they have doubts about, or when they see patterns that are unusual which they cannot explain, they will usually alert MOH, and we will work together with them to find out the truth. This was how we discovered a locally transmitted case in the first instance.

Mr Masagos Zulkifli B M M: On the question of whether we should focus more on construction areas near residential sites, Singapore is a very built-up area. So, most construction sites are around homes. Therefore, it is not the primary factor why we go to that site or not. We have risk factors. And now, indeed, we have extended the coverage to beyond the construction sites to the dormitories where the workers come from.

Mdm Speaker: Mr Dennis Tan.

Mr Dennis Tan Lip Fong (Non-Constituency Member): Madam, I have one question for Minister Masagos. It is a very quick question. Regarding what the Minister said about the male Wolbachia mosquito experiment, what is the expected time frame for this experiment before the Ministry decides to introduce it on a bigger scale?

And I have one quick question for the Minister for Health. Is the Minister able to confirm whether the current strain of virus in Singapore is similar to the one in Brazil and if that is not known yet, when does he expect to know whether it is the same strain?

Mr Masagos Zulkifli B M M: We are calibrating the Wolbachia mosquitoes, so to speak, from October onwards, for about six months. Singapore is a very unique built-up area. In other areas, they just have to fly horizontally. We have to know whether these mosquitoes will fly high and how high and whether they will survive long enough in our urban environment. So, after six months, if successful – and I hope it is successful so that we do not have to recalibrate again – we can then deploy them across for small-scale study and field suppression trials. And then if successful, we will roll it out for higher-risk areas. The whole programme will take up to 2020.

Mr Gan Kim Yong: Madam, let me just make a correction. Earlier on, I said that based on a study, more than 90% of people find it easy to find the information on Zika. Actually, the survey was done by the feedback unit Reaching Everyone for Active Citizenry @ Home (REACH), and not by MCI. That is the correction.

Just now, Mr Dennis Tan asked about the strain of the current Zika virus in Singapore. Our scientists – the A*STAR scientists as well as the National Public Health Laboratory scientists – have worked together to sequence the virus and based on their analysis, the Singapore strain that we have discovered so far, came from the Southeast Asian strain, which is not the same as the strain in Brazil. In fact, the strain in Brazil is a later strain that was derived from the Asian strain. So, the strain that we have is an earlier generation, which means that it has been circulating in Asia even before Brazil had a Zika outbreak. So, this is the current strain that we have identified. But research is still ongoing.

Mdm Speaker: Mr Christopher de Souza.

Mr Christopher de Souza (Holland-Bukit Timah): Madam, I would like to ask Minister Masagos: can fogging be done at more areas? Also how effective is fogging and are there any side effects to fogging?

Mr Masagos Zulkifli B M M: As I mentioned in my Statement just now, fogging is effective if done properly, if done by a licensed professional. We have to fog when there is a cluster because it means that there are adult mosquitoes infecting the population or to prevent those mosquitoes which are not yet infecting from infecting. So, that is the primary reason why we do fogging. But we cannot just do fogging. I know everyone likes fogging because it is very visual, everyone can see it and everyone feels better, but it does not solve the problem.

It must be done together with source eradication, whether it is a construction site or our homes. Indeed, at our homes, whenever the fogging is done, they close up their homes. And, therefore, it does not get into the homes.

The other thing we could do is misting, which means that in some Town Councils as well as dormitories, we do misting to make the chemical stick on the wall and it lasts longer. But we cannot do this very often either. As I mentioned just now, there are also side effects of using the same chemical over and over again so frequently that the mosquitoes may become immune to those insecticides. And this has already happened. In fact, some insecticides are not used at all nowadays because we have overused them.

A word of caution for everybody and I am glad that, as I watched my phone, the headlines that are coming out are that there are many myths to fogging and we hope that we are doing accurate, better fogging than just more fogging.

Mdm Speaker: Dr Tan Wu Meng.

Dr Tan Wu Meng (Jurong): Madam, two supplementary questions for the Minister for the Environment and Water Resources. The first relates to the Minister's answer just now on the number of venues where breeding sites were destroyed. The Minister said that half were in homes. Another 5% were in construction sites. Would the Minister be able to share in what other areas, besides these, can these sites of breeding be found?

The second question relates to a back-of-the-envelope calculation that I did, based on the figures the Minister provided. The Minister mentioned that about 5,000 breeding sites were found in the 638,000 homes that were assessed. That adds up to about one breeding site per 128 homes. On the other hand, the 5% figure means 500 breeding sites were found out of 4,400 construction sites studied. That means about one in nine construction sites has mosquito breeding sites discovered and destroyed.

In light of this, would his Ministry consider taking an even more robust approach to stamping out mosquito breeding sites in construction sites, especially since my own Clementi residents have expressed concern every time a new construction site comes up nearby? Anecdotally, I can share that, on walkabouts, my residents and I also find that we are more likely to get bitten by mosquitoes when we are near a construction site that has active construction activity.

Mr Masagos Zulkifli B M M: Madam, I wish the mosquitoes can calculate as well. But mosquitoes do not calculate. They just go to where there are humans and there is water to breed. And whether it is a construction site or a home, it should be of equal concern to us.

The real difference is accessibility. For construction sites, our officers can come in anytime. They can impose appropriate orders on them to clean up, put in the right officers, and step up on their housekeeping. But we cannot say similarly for homes. Therefore, even in terms of per home basis, we are actually far better than what has been prescribed by WHO. We should not rest on our laurels.

Every mosquito that hatches, a female mosquito will hatch a further 300 eggs. They grow exponentially. We just leave the breeding untouched. Therefore, whether it is home or construction site, we must be as vigilant, and I think we also should educate our constituents that it is not just about the construction site. We will do our best to suppress the source of breeding if it occurs there. But everyone must do their part to make sure they do the five "mozzie wipeout" steps as a daily habit to ensure that they do not give the mosquitoes a chance to breed.

Mdm Speaker: Ms Joan Pereira.

Ms Joan Pereira (Tanjong Pagar): Mdm Speaker, NEA has been conducting intense inspections, not just in public housing estates but also in condominiums when asked to assist, and my condominium managements are really, very appreciative. However, when asked to share their findings with the condominium managements, NEA rejected the request. Would NEA consider sharing such information so that it can be a community effort for follow-up action?

Mr Masagos Zulkifli B M M: May I clarify with the Member what kind of information is not shared?

Mdm Speaker: Ms Joan Pereira.

Ms Joan Pereira: Like when they visit the homes, if they are found to have bred mosquitoes, can such information be shared with the condominium managements?

Mr Masagos Zulkifli B M M: Even for public housing, our Housing and Development Board (HDB) flats, we do not specify which unit exactly where the breeding happens. It is enough for the information that, in this particular building or block, that is a cluster, because there is more than one and there is a chance that it was infected by one or the other. Therefore, it is enough for people to take heed and to know that some form of transmission is happening and take more precaution to go round their house to eradicate the source of breeding.

Therefore, I think it is not important to know the exact unit. That is taken care of by NEA. That is their role. Everyone's role is to ensure that there is no breeding at home and then, if there are adult mosquitoes, particularly seen in large numbers in the condominium, to do the fogging as appropriate.

Mdm Speaker: End of clarification time. Introduction of Government Bill. Minister for Manpower.