The National Environment Agency (NEA) is seeking community support in our collective dengue prevention efforts, as we enter the traditional peak dengue season. 529 dengue cases were reported in the week ending 16 May 2020, higher than the 300 to 400 weekly cases that we have seen for the first four months this year. As we enter the warmer months ahead, the increased risk of higher transmission of dengue is a concern, due to the accelerated breeding cycle and maturation of the Aedes mosquito vectors, as well as the shorter incubation period of the Dengue virus.
Of the 821 dengue clusters notified this year, about 84 per cent have been closed, with the concerted efforts of our partners and the community. The 189-case cluster at Jurong West Street 91, 183-case cluster at Begonia Drive, 154-case cluster at Elias Road, 148-case cluster at Jalan Bangau, 124-case cluster at Ang Mo Kio Avenue 3, and 106-case cluster at Gangsa Road, were closed in the first four months of the year. However, there are still large dengue clusters located at Pavilion Circle (153 cases), Woodleigh Close (136 cases) and Westwood Avenue (104 cases), where intensive vector control efforts are ongoing.
From January to April this year, NEA conducted about 310,000 inspections for mosquito breeding islandwide, and uncovered more than 6,400 mosquito breeding habitats.
Continuing dengue home inspections to safeguard public health
During this Circuit Breaker period, NEA has continued with home inspection efforts to remove mosquito breeding in large dengue cluster areas, in order to help break disease transmission. NEA officers performing dengue home inspections are equipped with personal protective equipment (PPE), and take necessary precautions to protect themselves and homeowners/ occupiers during the course of their work. These include not reporting to work if unwell, strict temperature tracking regime, and sanitising their hands before and after every home inspection. Residents staying at dengue cluster areas are strongly urged to cooperate with NEA officers and facilitate their checks.
Focused efforts on mosquito breeding and preventive efforts in homes, to break the transmission chain
We have observed a 50 per cent increase in Aedes mosquito larval breeding found in homes over the past three years, compared to in the preceding three years. During the Circuit Breaker period, NEA continues to detect mosquito breeding in homes, despite residents spending most of their time at home, and having more opportunities to remove mosquito breeding habitats. Homeowners and occupants are urged to pay attention to any mosquito breeding or adult mosquitoes present in homes, and to take the necessary steps to prevent or remove them. This includes regularly doing the Mozzie Wipeout and removing any stagnant water from homes, applying mosquito repellent to protect themselves from mosquito bites, and spraying insecticide at mosquitoes harbouring at home.
With more people staying home, there is a higher risk of disease transmission within housing estates, especially in areas where the population of the Aedes mosquito vector – a day biter – is high. Besides good housekeeping to prevent mosquito breeding within their own premises, residents can also take simple, proactive steps against adult mosquitoes in the environment, to help break the transmission chain. This includes preventive spraying of insecticide in dark corners of the home, such as under the bed and sofa, behind the curtains, and in the toilets. NEA has published two educational videos to guide residents on the spraying of aerosol insecticide at home (https://youtu.be/8Omrqokv1s4), and what to do if one lives in a dengue cluster area or sees mosquitoes at home (https://youtu.be/JU_pM1_Uls8).
Besides spraying insecticides, another effective self-help measure is the use of mosquito repellent by residents to protect themselves from mosquito bites. Since early May 2020, NEA has worked with the Ministry of Health (MOH), Polyclinics and General Practitioners (GPs), to provide over 300,000 bottles of mosquito repellent for distribution to patients with suspected dengue. Persons with suspected dengue or infected with the Dengue virus should apply mosquito repellent regularly, to protect their loved ones and others living around them, to help break the disease transmission chain. Those showing symptoms suggestive of dengue should see a doctor for timely diagnosis and management.
Focused efforts at construction sites
Preventive surveillance has also been stepped up at construction sites, given their closure during the Circuit Breaker period. Before the start of the Circuit Breaker, construction site operators have been instructed to maintain a minimum workforce to perform housekeeping and facilitate pest control services within the sites. Since then, NEA has increased audits at construction sites, to ensure that vector control measures are in place. Of the 1,514 construction and Additional & Alteration (A & A) work sites, NEA is prioritising audits at those sites within dengue cluster areas and within residential areas. 50 per cent of these have been inspected to-date. From January to April this year, 31 summonses and two Stop Work Orders (SWOs) were issued to construction sites, and two contractors will be charged in court for repeat offences.
Adapting dengue prevention efforts for Circuit Breaker period
NEA brought forward the launch of the National Dengue Prevention campaign to March this year, ahead of the traditional mid-year peak dengue season, to raise the dengue alert early and facilitate pre-emptive measures to mitigate the increase in dengue cases in the coming months. Whilst grassroots events and physical outreach activities have been suspended during the Circuit Breaker period, NEA has increased public engagement efforts over digital and social media platforms, in addition to working with community partners, to disseminate dengue prevention tips and reminders via their social networks and chatgroups.
To better reach and alert residents in targeted dengue cluster areas, NEA has started to use SMS blasts since April 2020. As visual cues in neighbourhoods have been found to be effective in enhancing dengue awareness, more dengue alert banners have been put up at dengue cluster areas with 10 or more reported cases, and we will also start to display posters at lift lobbies of some public housing blocks to alert residents of the ongoing dengue clusters. Recently, in partnership with the People’s Association (PA) in the distribution of reusable masks, close to one million dengue prevention leaflets were also distributed directly to residents, as part of our extended outreach and timely reminders to the community to take necessary precautions against dengue.
NEA has been working intensively with key stakeholders from various Government agencies in the Inter-Agency Dengue Task Force (IADTF), Town Councils (TCs) and construction site management, on sustained environmental management efforts during the Circuit Breaker period. NEA is also working with the Ministry of Manpower (MOM) and operators of dormitories to ensure that vector control measures are in place, as most dormitory residents are staying indoors, as well as conducting outreach to these workers through their vernacular mediums.
Residents living in areas with more Aedes mosquitoes are at higher risk of being bitten and infected with the Dengue virus. Information about locations with higher Aedes aegypti mosquito population and dengue clusters can be found on the NEA website and myENV app.