Claire Huang Channel NewsAsia 31 Aug 10;
SINGAPORE : The number of dengue, chikungunya and malaria cases in Singapore is falling.
The National Environment Agency (NEA) said this is due to the Integrated Vector Management system (IVM), introduced by the World Health Organisation.
The system helps stakeholders decide how to allocate their resources like manpower and collaborate with other agencies to control the disease.
Preventing mosquitoes from multiplying is the key to keeping dengue cases down. And with the IVM approach, NEA said it can also keep malaria and chikungunya at bay.
Tai Ji Chong, Head of NEA's Operations Environmental Health Department, elaborated: "For the case of dengue, the trend has been going down. In the past we have seen cyclical trends of dengue where it peaks every six or seven years, but from 2006 till today, we do not see that kind of trend anymore.
"In fact, for the last two years, the trend has been going down. With the IVM system in place for dengue, we apply the same system for chikungunya when it comes in, and as a result, chikungunya did not become endemic in Singapore."
And the strategy works. Dengue fever cases have gone down from 7,000 in 2008 to 4,500 in 2009.
Similarly, the number of chikungunya cases has gone down from 720 in 2008 to 340 cases in 2009.
NEA said the downward trend has continued this year, with a total of 22 local and imported chikungunya cases so far.
Malaria cases here also went down from 29 last year to just nine cases in the first 33 weeks of this year.
But NEA cautioned that the declining trend also means that the community has a lower immunity to that particular infectious disease.
Mr Tai said: "Like all infectious diseases, whenever it is very well-controlled, the more well-controlled it is, the more susceptible the population because they have no exposure."
This is why the public has to continue to play their part in keeping dengue and other infectious diseases at bay.
The success of the IVM approach in some countries is why the World Health Organisation (WHO) hopes it can get more governments to implement the system. And WHO hopes to convince them at the 2nd Asia-Pacific Dengue Workshop, which is taking place in Singapore.
However, Dr Raman Velayudhan, a scientist from the Control of Neglected Tropical Diseases at WHO, said it will be a challenge.
He said: "We are working with member countries to really advocate for IVM, what IVM is all about. It is basically an integration of vector control methods and for judicious use of the tools.
"Essentially how we are doing it is WHO works with member countries. We have regional committees which are now adopting IVM resolutions and at a later date, we hope that we would have had some of the resolution, maybe in a couple of years' time, looking at more and more evidences as they come in about IVM.
"Financially, the problems are there. The problem is how to scale up our implementation, how are we going to go about our training, at the regional level and at the country level and making sure that IVM is really adopted at the local level, because we need the planning, the implementation to work at communities. So communities have to make the decision and how we go about capacity building."
Dr Raman added that dengue is affecting 125 countries worldwide and this year alone, there have been outbreaks in close to 50 countries.
Close to 60 experts on dengue from more than 20 countries will share concepts and strategies for dengue control and management at the nine-day workshop. - CNA/ms
Dengue outbreak cycle broken: NEA
Number of cases falling since 2007, but disease still endemic to region
Grace Chua Straits Times 1 Sep 10;
THE six- to seven-year cycle of dengue outbreaks has been broken, and chikungunya and malaria have also been brought under control, the National Environment Agency (NEA) announced yesterday.
With dengue, the number of cases typically rises over a period of six years or so, and then climaxes in a major outbreak, explained Mr Tai Ji Choong, who heads operations at NEA's environmental health department.
Since the last major outbreak in 2005, the number of dengue cases has gone into a long decline - from 8,826 cases in 2007 to 7,031 in 2008, to 4,497 last year.
If the dengue cycle was playing to form, these numbers should have been rising instead of falling, Mr Tai said.
In the first 33 weeks of this year - and with the May-to-October dengue breeding season almost done - the number of cases stood at 3,015, lower than last year's total for the same period.
He attributed the year-on-year decline to the NEA's disease management approach, which involves public environment and health agencies working closely with water agency PUB, the Housing Board and other public and private groups.
Called 'integrated vector management', the approach also involves reducing the use of fogging chemicals so the dengue-carrying Aedes mosquito does not become resistant to them, and designing buildings and bus stops so that possible mosquito-breeding spots such as gutters and bamboo-pole holders are not a part of their design, Mr Tai said.
He was speaking on the sidelines of the second Asia-Pacific Dengue Workshop, organised by the World Health Organisation (WHO), the NEA and the Ministry of Foreign Affairs.
The workshop, attended by 58 participants from 23 countries, aims to promote integrated vector management in the region and train participants in better field and clinical surveillance. It began yesterday and ends next Wednesday.
By WHO statistics, 2.5 billion people are at risk of dengue; the Asia-Pacific region alone sees between 200,000 and 500,000 cases every year and more than 2,000 deaths from the disease.
But many developing countries lack the manpower and funds to deal with the complex disease, for which no vaccines or anti-viral drugs exist.
NEA chief executive Andrew Tan said, also on the sidelines of the workshop, that despite Singapore's disease control successes, it should not be complacent.
Dengue is endemic to the region, and changes to the environment here, such as the planting of trees and rooftop gardens, can inadvertently create new mosquito-breeding spots, for example.
Another challenge is that current methods of hunting down and destroying breeding spots are labour-intensive, he added.
To improve dengue control, the NEA is refining its risk-assessment maps and predictions, and studying ways to detect and kill mosquito larva more efficiently. It will also look at whether climate change shortens mosquitoes' breeding cycles.
At the dengue workshop, France's Pasteur Institute medical entomologist Paul Reiter suggested that releasing mosquitoes rendered genetically sterile could control the mosquito population and thus, dengue and other mosquito-borne diseases.
Mr Tan, when asked, said Singapore would be cautious about using such radical technology.
Two other diseases under control
Straits Times 1 Sep 10;
# CHIKUNGUNYA
Singapore's National Environment Agency (NEA) yesterday declared that the painful mosquito-borne disease chikungunya was not endemic here. But there had been cause for concern earlier because the viral illness, which first cropped up here through three imported cases in 2006, hit 718 people in 2008, partly as a result of a local outbreak.
Mosquito-control measures reduced the number to 341 last year, including 66 imported cases. This year, there have so far been seven local and 15 imported cases.
The NEA's integrated vector management programme controls both dengue and chikungunya, as it targets the same two species of mosquito, Aedes aegypti and Aedes albopictus.
# MALARIA
A malaria task force is reviewing and upgrading drains following malaria outbreaks in Sungei Kadut and elsewhere last year, when 29 people fell ill. In all, there were 168 cases, of which 29 were local.
So far this year, malaria cases have returned to normal levels, with nine local and 109 imported cases.
The malaria task force involves many public agencies, including the Ministry of Defence, the National Parks Board, the Ministry of Health and the Singapore Land Authority.
