Findings of and Government Responses to 
Recent Surveys on Prevention of Dengue Fever

 

INTRODUCTION

At the last meeting held on 17 March 2003, Members were briefed on the 2003 Anti-mosquito Campaign and an enhanced vector surveillance programme implemented by the Food and Environmental Hygiene Department (FEHD). This paper informs Members of the findings of ovitrap surveys conducted from January to April 2003 and a telephone survey on prevention of dengue fever, as well as the Government responses to these surveys.

ENHANCED DENGUE VECTOR SURVEILLANCE

Findings

2. The enhanced dengue vector surveillance programme was launched in January in 2003 to monitor the distribution of the Aedes albopictus at selected areas, evaluate the effectiveness of mosquito prevention and control work carried out by FEHD and other concerned departments, and provide surveillance information to effect necessary changes in mosquito control strategies and measures. 

3. Two different indices, namely, Area Ovitrap Index (AOI) and Monthly Ovitrap Index (MOI), are recorded. AOI indicates the extensiveness of the distribution of Aedine mosquitoes in a surveyed area while the MOI is the average of all AOIs within the same month, which reflects the territory-wide situation of Aedes albopictus. The indices are categorized into 4 different levels and announced each month through FEHD��s website and press releases. 

4. Appendix 1 shows all the MOIs and AOIs recorded from January to April 2003. It can be seen that the MOI surged from 1.4% in March to 11.4% in April, consistent with the seasonal pattern observed in the last three years. The figure for this April is much lower than that recorded last April (30.2%) (see Appendix 2) and the three-year average obtained from 2000 to 2002 (23.2%). Eight surveyed areas were found to have AOIs over 20% in April. They included Tai Po North (21.7%), Kennedy Town (22.0%), Tung Chung (22.2%), Kwai Chung (22.6%), Lo Wu (26.1%), Cheung Chau (36.4%), Wong Tai Sin Central (37.5%) and Ma Wan (39.3%).

Government Responses

5. We have expeditiously activated the cross-departmental response mechanism to contain the apparent rise in vectorial extensiveness in certain localities. FEHD and relevant departments have promptly mounted special control operations in the surrounding areas of Aedes-positive ovitraps. Intensive on-the-spot inspections have been conducted, followed by elimination of breeding sources and application of larvicides to potential breeding grounds that were non-removable. For those localities with serious infestation problems such as Ma Wan, FEHD has carried out extensive larval and adult control actions including fogging. All these special operations will continue until the ovitrap surveys concerned have shown negative results. 

6. On top of the locality-specific control operations, departments concerned will intensify mosquito control measures in public places, sites and venues under their purview throughout the territory. The wide-ranging measures include inspection for larval habitats, clearance of solid waste, removal or covering of containers, leveling of depressions, application of insecticides and larvicides, and installation of mosquito traps. The major operational targets set by concerned departments for the coming quarter are set out in Appendix 3

TELEPHONE SURVEY ON PREVENTION OF DENGUE FEVER

7. In December 2002, the Department of Health (DH) commissioned a territory-wide telephone questionnaire survey. It aimed to gauge public awareness of dengue fever and its preventive measures; the Government��s anti-dengue fever campaign and the community��s responsibility in preventing and controlling the disease. The survey was completed this April and its results were announced at a press conference on 1 May 2003.

8. Major findings of the survey are enumerated in Appendix 4. Overall, it is encouraging to note that the majority of the respondents were aware of the threat of dengue fever and its preventive measures. Nevertheless, only about 40% of the respondents indicated that they had taken anti-mosquito measures in the past 3 months. In the light of the survey findings, we will re-focus or enhance efforts on three fronts.

9. First, now that public awareness of dengue fever has been heightened, we need to impart more skills and introduce hands-on programmes to the public. In this connection, Home Affairs Department will seek to engage the community more in hands-on mosquito control operations through promotional activities at the district level. Education Manpower Bureau will likewise work with schools to arrange more practical sessions on prevention of mosquito breeding. We will also emphasize the need to put knowledge into practice in our media strategy and publicity measures to be launched. 

10. Second, we need to reach out to public housing residents, unemployed and retired persons to disseminate dengue-related information and help them protect themselves. In this connection, Housing Department will get across anti-mosquito messages to residents in public housing estates. We will also enlist the support of Social Welfare Department and Labour Department to do the same for retired and unemployed persons. 

11. Third, we need to raise public awareness of the penalty for mosquito breeding. Under Section 27 of the Public Health and Municipal Services Ordinance (Cap 132), any person allowing the breeding of mosquitoes in his premises commits an offence and is liable to a maximum fine of $25,000. Around 60 prosecutions have been instituted against mosquito breeding in the past four months. To prevent inadvertent breach of the law, we will step up publicity on the relevant statutory provisions, the enforcement actions taken by FEHD and the court rulings in this regard. 

CONCLUDING REMARKS

12. The Government will continue to monitor the situation closely, exercise vigilance over possible dengue infections in Hong Kong and take sustainable and proactive measures to reduce the threat of dengue vector to the community.


Health, Welfare and Food Bureau
Department of Health
Food and Environmental Hygiene Department
May 2003

 

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