Dengue Fever is a disease caused by dengue viruses which are transmitted to people by infected Aedes albopictus mosquito.

Aedes albopictus becomes infected when it bites a person who happens to be carrier of the dengue virus and after about 8 to 12 days can transmit the virus while biting a healthy person. 

Aedes albopictus can lay eggs in small containers such as tree holes, bamboo ends, cans, discarded tyres, and rock pools holding small amount of water.  Here are some preventive guidelines:  

1. Keep all drains free from choke.
2. Cover all containers that hold water to prevent mosquito from accessing the water.
3. Properly dispose articles that are able to collect water such as empty lunch boxes, cans and glass bottles.
4. Ensure that plastic sheets, canvas or tarpaulin used for weather protection in open areas are properly drained.  
5. Change water in vases at least once a week.
6. Avoid using saucers to hold water from potted plants.
7. Clear water in saucer of potted plants every week and clean saucers with brushes to remove mosquito eggs or larvae that may attach to the surfaces.
8. Clear the water accumulated on tray beneath refrigerator and air conditioners at least once every week.
9. Clear household garbage everyday by disposing them into refuse bins which are properly covered .
10. Wear long-sleeved clothes and long trousers when outdoors, especially in areas close to bushes, ponds, and wetlands.
11. Avoid going near shrubby areas where adult mosquitoes usually rest during the day.  The most active time of Aedes albopictus would be during daytime especially two hours after sunrise and a few hours before sunset.
12. In areas where there is likely to be mosquitoes, apply insect repellent containing DEET (N,N-Diethyl-meta-Toluamide)(Users should consult product safety information or physicians whether the repellents are safe for children or sensitive skin).
13. Install mosquito screens on windows.
14. Regularly inspect locations where it is likely to have drainage blocked by leaves and rubbish.  
15. Report to EMO if there is any defective surfaces and drainage. 

1. Fill the stumps at the vertical ends of bamboo scaffolds with sand or drill holes at the base to prevent them from holding water after raining. 
2. Use metal poles to replace bamboo scaffold if possible.
3. Cover all unused containers or buckets to prevent them from holding water.
4. Turn concrete carts upside down when not in use.  Alternatively, cover the carts with tarpaulin.
5. Remove unused tyres from site.  Alternatively, drill holes to drain away water if the tyres are used for anti-bumping purposes.
6. Sweep or drain away water from uneven floors or holes on the ground as frequent as possible.
7. Lift wells and pits should be properly drained off, especially after raining.
8. Remove all refuse on site as frequent as possible.
9. Use rubbish bins with properly lids to collect lunch boxes and empty bottles.
10. Cover all construction materials including pipes, boxes, toilet wares, etc. properly to prevent the accumulation of water.  Water trapped on the coverings must be removed at least once a week.
11. Stay away from bushes, tree shades, ponds and other wet areas.
12. Contractors should use the following checklist prepared by the Food and Environmental Hygiene Department for construction sites to ensure that their sites will not become breeding grounds for mosquitoes.
    

Weekly Mosquito Inspection Program for Construction Sites

Remarks:

1. The management of construction sites may design their own inspection program to meet specific needs

• Inspection personnel should be assigned to carry out weekly inspection. 
• If mosquito or potential breeding places for mosquitoes were found, immediate and appropriate follow up actions should be taken, including:

• Remove stagnant water
• Dispose of garbage properly
• Cover water containers properly, and keep empty containers upside down to avoid collecting water
• Fill bamboo stumps and uneven ground filled with sand, mud or cement
• Remove garbage from gullies to avoid choking
• Wrap up disused tyres or punch the tyres with large holes