The recent surge in cases of dengue fever is indeed cause for concern. According to press reports, dengue fever claimed 13 lives in the first three weeks of January 2007 alone.

Deputy Health Director-General Ramlee Rahma was quoted as saying that five more dengue fever deaths were reported in Selangor in the third week of this year, bringing the total death toll to 13 nationwide.

In the third week of January, Malaysia has reported 1,423 suspected cases, of which 403 had been confirmed as dengue fever. Selangor and Kuala Lumpur remained the places with the biggest number of cases reported, with 574 and 312 suspected cases respectively.

What is dengue fever?
Dengue fever is a flu-like illness spread by the bite of an infected mosquito. Dengue hemorrhagic fever is a severe, often fatal, complication of dengue fever.

Dengue and dengue hemorrhagic fever are caused by any of the dengue family of viruses. Infection with one virus does not protect a person against infection with another.

How does it spread?
Dengue is spread by the bite of an Aedes mosquito. The mosquito transmits the disease by biting an infected person and then biting someone else. The most common Aedes species is Aedes aegypti, a domestic, day-biting mosquito that prefers to feed on humans.

Where is it found?
Dengue viruses occur in most tropical areas, mainly in Asia, Africa, the Pacific, Australia, the Americas, and the Caribbean basin. Dengue is most common in cities but can also be found in rural areas. It is rarely found in mountainous areas above 4,000 feet.

Signs and symptoms

Basically, dengue commences with high fever and other signs as listed above for 2 to 4 days. The temperature then drops rapidly and intense sweating takes place. After about a day with normal temperature and a feeling of well-being, the temperature rises abruptly again. Rashes (small red bumps) show up on the arms, legs and the entire body simultaneously along with fever. However, rashes rarely occur on the face. The palms of the hands and soles of the feet may be swollen and bright red. Although the patient may feel exhausted for several weeks, most cases of dengue take approximately one week to recover. Once a person recovers from dengue, he or she will have antibodies in their bloodstream which will prevent him or her from having a relapse for about a year.

Treatment
There is no specific treatment to shorten the course of dengue fever. Medications are given to alleviate the signs and symptoms. The patient may be required to be sponged down with water at room temperature using a wet, squeezed out towel for about 20 minutes at a time. This will help to help lower the high temperature. Ice water should not be used for this purpose. However, bed rest is essential to a speedy recovery and the patient should consume plenty of water which will help to alleviate the illness.

Patients should be kept in a room that has screens to prevent mosquitoes from entering or else under mosquito netting until the second period of fever has subsided. Hence, mosquitoes cannot bite them. If the patient is bitten then the dengue virus may be transmitted to the mosquito and then to another host.

Most dengue infections result in relatively mild illness, but some can progress to dengue hemorrhagic fever. With dengue hemorrhagic fever, the blood vessels start to leak and cause bleeding from the nose, mouth, and gums. Bruising can be a sign of bleeding inside the body. Without prompt treatment, the blood vessels can collapse, causing shock. Dengue hemorrhagic fever is fatal in about 5% of cases, mostly among children and young adults.

The time between the bite of a mosquito-carrying dengue virus and the start of symptoms averages 4 to 6 days, with a range of 3 to 14 days. An infected person cannot spread the infection to other persons but can be a source of dengue virus for mosquitoes for about 6 days.

Who is at risk?
Typically, anyone who is bitten by an infected mosquito can get dengue fever. Risk factors for dengue hemorrhagic fever include a person’s age and immune status, as well as the type of infecting virus. Persons who were previously infected with one or more types of dengue virus are thought to be at greater risk for developing dengue hemorrhagic fever if infected again. Dengue is diagnosed by a blood test.

Contributing factors

The emergence of dengue as a major public health problem has been most dramatic in the western hemisphere.

Several factors contribute to the resurgence of dengue fever:

• No effective mosquito control efforts are underway in many countries with dengue.
• Public health systems to detect and control epidemics are deteriorating around the world.
• Rapid growth of cities in tropical countries has led to overcrowding, urban decay, and substandard sanitation, allowing more mosquitoes to live closer to more people.
• The increase in non-biodegradable plastic packaging and discarded tyres is creating new breeding sites for mosquitoes.
• Increased travel is helping people infected with dengue viruses to move easily.

Prevention and Control
At present, the only method of preventing and controlling dengue fever is to eradicate the mosquito population. There are a number of ways to combat the vector mosquitoes:

• Eliminate any sources that may collect water such as tins, bottles, food containers and old tyres. Mosquitoes breed easily in any source of stagnant water.
• Cover all containers to prevent egg-laying female mosquitoes access to them.
• Implement proper solid waste disposal.
• Appropriate insecticides can be added to water containers and man-made ponds. The insecticides can prevent mosquitoes breeding for several weeks. However, they must be re-applied as per directions.
• Always clean and check drains to ensure they are not blocked especially during the rainy season.
• Breed small mosquito-eating fishes in an artificial pond to eradicate the mosquito larvae.
• Fog your compound regularly. Consult your pest management professionals for further details.
• Mosquito traps

In addition to the above, you can also prevent mosquitoes from being attracted to you:

• Avoid wearing dark and tight clothing because mosquitoes are attracted to dark colours. Wear loose, white and long clothes, which cover the whole body. Mosquitoes find it difficult to bite through loose clothes than tight fitting clothes.
• Sleep under mosquito netting or in a room which has mosquito screens on the windows. Mosquitoes are unlikely to bite you in an air-conditioned room and under strong fans.
• Mosquito coils are also useful to help prevent mosquitoes from entering the room. Apply mosquito repellants. Avoid reduce outdoor activities during morning and late afternoon because Aedes mosquitoes are daytime feeders.

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