We think it’s time to remind you about dengue fever… again.
The tropics and the rainy season… One unique combination that reminds us of dengue fever. Indonesia is an endemic region of dengue fever. This disease can be found in almost every region and anytime of the year, with a higher incidence during rainy season, which is generally October to April (the highest incidence usually is during February and March), because it gives a better habitat for the vector, the mosquito, to breed. For information about the disease, the symptoms and others, go to our archive. In this article we’ll discuss more about mosquito bite prevention.
DEET. This remains the gold standard of currently available mosquito and tick repellents. Comparison studies suggest that DEET preparations are the most effective insect repellants now available. Recommended concentration:
- 35 % or more for adults who are in high risk regions for prolonged periods
- 20% – 35% for most adults and children over 12 years old, provides complete protection for an average of 5 hours
- 10% or less for children ages 2 to 12, but some experts believe that these are safe even for infants over two months old.
DEET has been used for more than 40 years and is safe for most children when used as directed.
Remember! The effectiveness of DEET varies from individual to individual and depends on climate changes. For example, it can be washed off during swimming or by rain. High temperatures make it less effective. DEET, particularly in very high concentrations, can also dissolve plastics, including those used in glasses, watches and some synthetic clothing. DEET then should not be put on clothing.
Overexposure to DEET at any age has produced toxic effects, including itching, rash and in severe cases, irritability, insomnia, and confusion. It should be noted, however, that it has been intensively studied for 40 years and used in billions of applications. Only 50 such toxic reactions have been reported and most of them resolved without any consequences.
When applying DEET, the following precautions should be taken:
- Do not use on the face and apply only enough to cover exposed skin on other areas.
- Do not over apply and do not use under clothing.
- Do not apply over any cuts, wounds or irritated skin.
- Parents or an adult should apply repellent to a child and not let the child apply it to him or herself. Parents or an adult should first put DEET on their own hands then apply it to the child. Avoid putting DEET not only near the child’s eyes and mouth, but also on the hands (since children frequently touch their faces).
- Wash any treated skin after going back indoors.
- If using a spray, apply DEET outdoors–never indoors. Spray repellents should not be applied inside or directly on anyone’s face.
Other Insect Repellent Products
- Soy-based Bite Blocker, is safe for infants and gives protection that averaged over an hour and a half.
- Citronella – or mixed oil based products, protects for an average of 20 minutes or less.
- Synthetic insect repellent IR3535, provides protection for 20 minutes to an hour.
- Repellent containing eucalyptus, offers protection that averages 2 hours and is a good alternative, particularly for children.
- Bayrepel, a piperidine derivative, mainly used in Europe, may prove to be very protective.
- Bath oils, all wristbands (including those that contain DEET or emit sound), garlic and vitamin B1, are proved to offer very little protection or none at all.
Permethrin. It is an insect repellent used as a spray for clothing and bed nets, which can repel insects for weeks when applied correctly. Electric vaporizing mats containing permethrin may be very helpful. A permethrin solution is also available for soaking items, but should never be applied to the skin. Side effects from direct exposure may include mild burning, stinging, itching and rash, but in general, this agent is very safe and its use may even reduce child mortality rates from malaria. Travelers allergic to chrysanthemum flowers or who are allergic to head-lice scabicides should avoid using permethrin.
Other Preventive Measures. Other preventive measures include:
- Wearing trousers and long-sleeved shirts, particularly at dusk. One survey suggested that this measure may significantly reduce the incidence of mosquito-born disease.
- Sleeping only in screened areas.
- Air-conditioning may reduce mosquito infiltration. Where air-conditioning is not available, fans may be helpful. Mosquitoes appear to be reluctant to fly in windy air.
- Don’t wear perfumes.
- Minimizing skin exposure after dusk.
- Washing hair at least twice a week.
- Burning citronella candles reduces the likelihood of bites. Indeed, burning any candle helps to some extent, perhaps because the generation of carbon dioxide diverts mosquitoes toward the flame. Smoke from burning certain plants, including ginger, beetle nut and coconut husks, have also reduced mosquito infiltration, but the irritating and toxic effects on the eyes and lungs may be considerable, such as the citrosa plant. To date, no evidence shows much benefit but such methods are not harmful.
For people living in Indonesia, the health department recommends to prevent mosquito breeding sites. Mosquitoes usually lay their eggs on still water. It is advised to:
- Drain out water from desert coolers/window air coolers (when not in use), tanks, barrels, drums, buckets etc.
- Remove all objects containing water (e.g. plant saucers etc.) from the house.
- Collect and destroy discarded containers in which water collects e.g. bottles, plastic bags, tins, used tyres etc.
- In case it is not possible to drain out various water collections or to fully cover them, use temephos, an insecticide, (brand name Abate) 1 part per million according to the local guidelines to prevent larvae from developing into adults.