dengue Fever caused by the bites of Aedes mosquitoes. Dengue first appeared in Singapore in 1960, with 70 hospitalized cases and one death. Since then, incidence of the disease has tended to reach serious levels at intervals of one to five years. In the late 1980s, there were only a few hundred dengue cases annually. However, this started to rise in the 1990s, reaching a high of 5,258 cases in 1998. Although the number was brought down to 673 in 2000, it started climbing again with a total of 9,459 cases in 2004. In October 2005, it reached a record high of 12,000 cases with 19 deaths.

An inter- ministerial committee was formed to tackle the dengue problem. One of the outcomes was the setting up of an inter- agency body headed by the National Environment Agency. It launched its Mozzie Attack Campaign, entailing community- level activities, whereby residents clean up their estates and train household members and maids to detect and eliminate potential mosquito- breeding sites.

A few days after an infected Aedes mosquito bites a healthy person, the person develops a fever. This is infectious only in the sense that if an Aedes mosquito bites him, it will pick up the virus in the blood and pass it on when it bites another person. The fever does not spread directly from person to person.

Symptoms of dengue include a high fever lasting five to seven days, rashes, severe headache, muscle and joint pains, nausea, vomiting, fatigue and diarrhoea. Usually rashes appear as red dots on the skin on the limbs and are due to bleeding under the skin.

The dengue virus has four strains: serotypes 1, 2, 3 and 4. Getting infected with one serotype does not protect you against the others. In fact, getting a second dengue infection, particularly with serotype 2, can lead to an even worse illness such as Dengue Haemorrhagic Fever and Dengue Shock Syndrome, which can be fatal.

Photo credit: National Environment Agency