Dengue Cases May Exceed 30,000 In 2016

Government details stepped-up efforts, urges community to take immediate action

Singapore, 18 February 2016 – The number of dengue cases in 2016 may exceed 30,000 – higher than the record in 2013 when 22,170 cases were reported, unless immediate measures are taken to suppress the Aedes mosquito population.

Dengue Outlook in 2016

2 The high number of dengue cases expected in 2016 is due to a number of contributing factors, including warmer temperatures, mosquito population and circulating virus.

3 The El Niño weather phenomenon is the likely driver of the unusual high incidence of dengue cases at the start of 2016, outside of the typical dengue season. Studies have shown that El Niño events drive up the incidence of dengue on the global and regional scale. The warmer conditions due to the 2015 El Niño phenomenon support faster breeding and maturation cycles of the Aedes mosquitoes, and accelerate the multiplication of dengue viruses in mosquitoes.

4 NEA’s Gravitrap data has shown an increase in the Aedes aegypti mosquito population in our community since November 2015. Compared to the same period in January 2015, we have observed 50 per cent more Aedes aegypti mosquitoes caught in Gravitraps that have been deployed islandwide. The number of Aedes aegypti breeding found in homes during our regular inspections is also 50 per cent more compared to the same period in January 2015. These indicate an abundance of the mosquito vector in our community. The majority of breeding is found in homes, with the top breeding spots being domestic containers and flower pot plates/trays.

5 Additionally, the proportion of dengue cases due to the DENV-2 virus serotype has increased, replacing DENV-1 as the dominant virus and now accounts for about two-thirds of all dengue cases serotyped in Singapore. Historically, any change in predominant dengue virus serotype is usually followed by a spike in dengue cases.

6 This change in the main circulating dengue virus and the increase in mosquito population due to warmer temperatures may be contributing to the spike in dengue cases. Against a backdrop of low herd immunity amongst Singapore residents against dengue, the above development signals the increased possibility of a dengue outbreak in Singapore in 2016.

7 With the threat of Zika infection looming, it is critical to reduce the mosquito population. As the Zika virus is transmitted via the same Aedes mosquitoes, vector control remains the mainstay to prevent transmission of the Zika virus.

Overall Stepped-up Measures Taken by the Government

8 NEA is closely monitoring areas with active transmission of dengue and the transmission patterns. Together with the Inter-Agency Dengue Task Force (IADTF), as well as all Town Councils, we have been continuing efforts to rid public areas and housing estates of potential mosquito breeding habitats.

9 As of 31 January 2016, NEA has conducted over 126,000 inspections islandwide and uncovered more than 1,900 instances of mosquito breeding. The majority of the breeding is still being found in homes, with most breeding habitats found in domestic containers and flower pot plates/trays.

10 NEA has also been focusing on areas with higher potential for dengue transmission such as construction sites. As of 31 January 2016, NEA detected mosquito breeding in 12 per cent of the over 600 inspections conducted at construction sites. NEA has issued more than 10 construction site related Notices to Attend Court and more than 10 Stop Work Orders.

11 In preparation for the increase in dengue cases, NEA has also stepped-up its outbreak response plan in 2016. Refer to Annex A for more information on these stepped-up measures.

12 The Ministry of Health (MOH) has advised all medical practitioners on early diagnosis and close monitoring of dengue patients and suspected Zika cases. MOH has been working with the medical community to ensure that dengue is detected and appropriately managed in the primary care setting, and that all confirmed Zika infection cases will be admitted to a public hospital until they recover and test negative for the virus. All hospitals have guidelines on the admission and management of patients with dengue fever and Zika virus infection.

‘Do the Mozzie Wipeout’ Campaign 2016

13 While the Government and its stakeholders continue with efforts to keep the mosquito population in check, members of the community and stakeholders are urged to play their part to keep dengue cases down.

14 NEA has brought forward the annual ‘Do the Mozzie Wipeout’ Campaign 2016, ahead of the traditional dengue peak season, in view of the dengue outlook in 2016. The campaign will be launched islandwide, in partnership with the People’s Association (PA), on Sunday, 28 February 2016, to signify a concerted community effort. It will be led by Mr Masagos Zulkifli, Minister for the Environment and Water Resources, and Adviser to Tampines Grassroots Organisations (GROs), at the North East District, together with Mr Tan Chuan Jin, Minister for Social and Family Development and Adviser to Marine Parade GRC GROs, at the South East District, Ms Denise Phua, Mayor and Adviser to Kampong Glam GROs, at the Central Singapore District, Ms Low Yen Ling, Mayor and Adviser to Bukit Gombak GROs, at the South West District and Er Dr Lee Bee Wah, Adviser to Nee Soon South GROs at the North West District. The campaign calls for the community to take appropriate precautions to prevent mosquito breeding by practising the 5-step Mozzie Wipeout to clear their homes and premises of mosquito breeding. Starting from 28 February 2016, a concerted effort by all over a 14-day period will cover two rounds of the mosquito breeding cycle, and thus make a decisive collective impact towards suppressing the mosquito population.

15 The ‘Do the Mozzie Wipeout’ Campaign will be complemented by PA grassroots volunteers who will disseminate the information by stepping-up patrols and house visits at the hotspots and surrounding precincts to spread dengue prevention messages in the months ahead. More than 5,000 grassroots leaders and PA Community Emergency and Response Teams (CERT) volunteers will conduct the house visits targeting yellow and red dengue cluster areas.

16 To date, NEA has trained more than 5,800 Dengue Prevention Volunteers (DPVs), comprising grassroots leaders, CERT members, students, senior citizens and residents. These volunteers help to advise residents on the common mosquito breeding habitats and dengue prevention tips during house visits and community events, and check for potential breeding areas in common areas in their neighbourhoods. Refer to Annex B for roles of residents and DPVs in preventing dengue.

17 To heighten vigilance and collective action in cluster areas, more dengue alert banners will be deployed in cluster areas at strategic locations.

Health Advisory

18 MOH advises the public to seek medical attention immediately if they feel unwell and have a fever, especially if they live in an active dengue cluster. If they are diagnosed by the doctor to have dengue, they should follow the doctor's advice and ensure that they have adequate rest and drink enough water to prevent dehydration. They should also protect themselves and their household members from mosquito bites, e.g. by using mosquito repellent, mosquito coils, mosquito nets and by wearing long-sleeved shirts and pants. Those who develop symptoms such as fever, skin rashes, joint and muscle pains, headaches and red eyes after returning from a Zika-affected area should consult a doctor immediately and inform the doctor of the areas that they have travelled to.

19 The latest updates on the dengue situation can be found at the Stop Dengue Now Facebook page, www.dengue.gov.sg or the myENV app. For more information on Zika, please visit www.moh.gov.sg.

MINISTRY OF HEALTH

NATIONAL ENVIRONMENT AGENCY

PEOPLE'S ASSOCIATION

ANNEX A

NEA’S STEPPED-UP DENGUE OUTBREAK RESPONSE PLAN

1. Enhanced Vector Surveillance – Islandwide Gravitrap Surveillance

Gravitrap surveillance has been extended from 4,000 traps to about 30,000 traps across 5,000 HDB blocks, and the data collected will guide source reduction efforts. Another 20,000 traps will be rolled out to the remaining 3,000 HDB blocks by June 2016. The data collected will provide lead indicators for more targeted preventive control at areas with higher mosquito population.

2. Enhanced Case and Virus Surveillance – Stepped-up Diagnostic and Laboratory Capability

Since 2015, NEA has also enhanced epidemiological investigation to identify potential sources of infection other than registered residential addresses, such as workplaces or areas of congregation. This enhancement has helped us broaden our approach to tackle possible nodes of dengue transmission.

As NEA continues to provide dengue diagnostic services to primary healthcare clinics and hospitals, with the expected increase in the number of cases, test requests are expected to surge. NEA has increased the number of laboratory staff and extended operating hours to process the higher diagnostic test load by mobilising staff from other research groups.

NEA also performs serotyping and sequencing of dengue cases to provide information on the virus situation. Virus serotype switches are monitored very closely in virus surveillance, as they are known to be associated with an increase in the number of cases and risk of outbreaks. This capability is also an important one in the face of the Zika virus threat, as it will help to detect any cases of the virus in Singapore.

3. Prevention and Control – Risk Stratification

NEA’s inspection statistics showed that construction sites have the propensity of breeding mosquitoes with high density of larvae. In 2013, NEA detected mosquito breeding in 10 per cent of the inspections conducted at construction sites. However, with stringent inspection and enforcement measures imposed upon construction sites, NEA had detected mosquito breeding in about eight per cent of the inspections conducted at construction sites in 2015.

While construction sites detected with mosquito breeding or poor housekeeping continue to face stringent penalties including Stop Work Orders (SWOs) and prosecution in Court, NEA had stepped up its dengue control efforts against construction sites in 2015 as shown below:

a. Stepped-up inspection by the formation of dedicated construction site teams – inspection frequency at large construction sites was stepped up from quarterly to monthly.

b. Since April 2015, NEA started publishing the list of sites issued with SWO on the dengue microsite to serve as a deterrent to contractors to encourage them to upkeep their sites and prevention mosquito breeding. The publication will also encourage contractors to promptly take action to remove conditions favourable for mosquito breeding and limit the potential of secondary infections in the area.

c. Screening - For construction sites with dengue transmission, NEA is requesting for contractors to put in place a temperature screening regime to pick out cases earlier, encourage application of insect repellent for both dengue-infected and healthy workers and encourage dengue-infected workers to sleep under bed-nets or in air-conditioned sick bays to prevent further mosquito bites.

4. Prevention and Control - Inter-agency Preparedness

The cornerstones of source reduction and killing of adult mosquitoes (especially infected ones) remain our key strategy. In light of the impending epidemic, NEA is intensifying its outbreak preparedness and will need the support of all stakeholders. In anticipation of a possible rise in the number of cases, the annual mobilisation of the Inter-Agency Dengue Task Force (IADTF) members and the community to conduct source reduction was brought forward to January, instead of the usual April period. Various IADTF members have begun to activate their outbreak response plans.

5. Cluster Management – Use of Technology

NEA has been addressing the risk of roof gutters being potential mosquito breeding grounds. As these structures could be conducive and productive breeding habitats for the Aedes mosquito, if the roof gutters are defective, NEA requires home owners to repair them or remove them altogether. An Order under Section 17 of the Control of Vectors and Pesticides Act (CVPA) may be served on the owner to ensure that any defective roof gutter is repaired.

For safety reasons, only the first level roof gutters at landed homes are generally considered safe for inspection using a ladder without additional safety equipment. For higher level roof gutters, we use inspection poles that are equipped with cameras for inspections. For roof gutters that are non-amenable to inspection by inspection poles, Bacillus thuringiensis israelensis (Bti) misting is carried out to destroy any potential mosquito breeding in the gutters.

NEA continues to leverage science and technology to improve its dengue control programme. To overcome the limitations faced by our officers, NEA has been conducting a trial on the use of radio-controlled aerial inspection crafts (RAIC) for the surveillance of roof gutter conditions since September 2014. The trial has shown that the RAIC is capable of accessing high places and providing good visuals of problematic areas. We plan to expand the trial to test out an RAIC that will be able to deposit Bti larvicide, which kills mosquito larvae into roof gutters. This trial is expected to end in the second quarter of 2016.

6. Outbreak Management – Increased Manpower

To manage the projected dengue outbreak, NEA will be engaging additional temporary officers to augment the regular vector control workforce and enhance the management of dengue outbreak. With the looming threat of Zika virus introduction into Singapore, the additional manpower and resources will ensure minimal disruption of dengue control work. Besides helping out with ground inspection, logistics and Gravitrap deployment in clusters and surveillance sites, some of these officers will also be deployed to inspect non-residential premises e.g. schools, places of worship, bus interchanges, MRT stations etc. together with the regular officers.

ANNEX B

ROLES OF RESIDENTS AND DENGUE PREVENTION VOLUNTEERS IN PREVENTING DENGUE

Residents

- Practise the 5-step Mozzie Wipeout on alternate days.

- Apply repellent and wear long-sleeved shirts and pants.

- Spray insecticide in dark corners of the home such as under the bed and sofa, and behind the curtains.

- Cover up toilet bowls, sinks and gully traps and ensure there is no stagnant water at home before leaving for vacation.

- Seek medical treatment early if feeling unwell.

- Participate in dengue prevention campaigns in the neighbourhood

Dengue Prevention Volunteers

- Dengue Prevention Volunteers complement NEA’s outreach efforts, in helping to disseminate the knowledge of dengue prevention among residents and the community, so that the latter can carry out these efforts on a sustained basis.

- Dengue Prevention Volunteers help to:

o Heighten awareness among residents on the current dengue situation.

o Advise residents on the potential breeding habitats during house visits and community events, and remind residents to remove stagnant water in their homes.

o Encourage residents to incorporate dengue prevention steps in their daily routines.

o Educate residents on the importance of ULV misting to eradicate adult mosquitoes and encourage them to allow NEA officers to conduct misting, and spray insecticides in dark corners of their homes on their own.

o Share information about mosquitoes including characteristics of Aedes mosquitoes, symptoms of dengue fever, how dengue is transmitted and how residents can look after themselves to stem dengue transmission:

- Advise residents to apply insect repellent to protect themselves, especially for those living in cluster areas.

- Encourage residents showing symptoms suggestive of dengue to see their GPs early to be diagnosed.

- Educate residents infected with dengue to protect themselves from mosquito bites by applying repellent and wearing long-sleeved tops and long pants to stem further dengue transmission.

o Check for potential breeding areas in common areas in their neighbourhood.

o Encourage fellow residents to participate in dengue prevention activities in their neighbourhood.

NEA welcomes more volunteers from the community to join us. Interested members of the public can do so by contacting our dengue hotline at 1800-X-DENGUE (1800-933-6483), emailing dengue@nea.gov.sg, or signing up through the ‘Stop Dengue Now’ Facebook page.