Mosquito Bite Prevention in Sri Lanka: A Practical Guide

Sri Lanka has several mosquito-borne illnesses worth taking seriously — dengue first and foremost, but also chikungunya, occasional Zika, and rarely Japanese encephalitis in agricultural areas. Most cases in travelers are dengue, and prevention is the same regardless of which disease you’re worried about: don’t get bitten.

This article is the practical, day-to-day version of that advice.

Know your mosquito

The Aedes mosquitoes that carry dengue and chikungunya are small, dark, and have white striped markings on their legs. Two things to know:

• They bite during the day, with peaks at dawn and dusk. Most people associate mosquitoes with the evening, which is when malaria mosquitoes bite — but malaria has been eliminated in Sri Lanka. Aedes is the relevant species, and it bites in daylight.
• They breed in tiny amounts of standing water. A discarded yoghurt pot, a flower-pot saucer, a clogged gutter, a coconut shell on the beach. Standing water near where you’re staying is the source.

The repellent that actually works

The gold standard is DEET, twenty to thirty percent concentration. Higher percentages last longer; you don’t need above thirty for adult use. Alternatives that work nearly as well:

• Picaridin (also called icaridin): twenty percent. Doesn’t smell as harsh as DEET, doesn’t damage plastics.
• IR3535: twenty percent. Mild on skin, good for children.
• Oil of lemon eucalyptus (PMD): thirty percent. Plant-derived, effective, but shorter-lasting and not for children under three.

Citronella and most “natural” repellents don’t last more than thirty to sixty minutes and aren’t reliable for serious mosquito areas.

Apply after sunscreen, not before. Reapply every four to six hours during the day, more often if you’re sweating or swimming. Pay attention to ankles, the back of the neck, behind the ears, and the back of the hands — the spots people miss.

Clothing

Long, light, loose. Light colours seem to attract fewer mosquitoes than dark ones. Permethrin-treated clothing is the next level — you can buy clothes pre-treated, or treat your own with permethrin spray. Permethrin lasts through several washes and is excellent for shirts, trousers, socks, and hats. Don’t apply it to skin.

Where you sleep

The single best thing you can do is sleep with air conditioning or a strong fan on. Mosquitoes are weak fliers and avoid moving air. Many places in Arugam Bay are open-air bungalows — beautiful, but not ideal for mosquito control. If your room doesn’t have AC or a fan over the bed:

• Use a bed net (mosquito net), tucked in
• Use a plug-in repellent device or mosquito coils overnight
• Close screens at dusk if you have them

Around where you’re staying

Look for standing water and empty it. Your hosts will usually keep on top of this, but a fresh check of your immediate area never hurts. Common breeding spots:

• Plant pot saucers
• Tyres lying around
• Buckets, basins, kettles left outdoors
• Blocked drains
• Open water storage containers
• Pool covers with rainwater collected on them

Special considerations

• Pregnant travelers should be especially careful because of Zika, which can cause birth defects. Talk to a travel medicine doctor before traveling.
• Children need lower-concentration repellents (under thirty percent DEET, under twenty percent picaridin) and should not have repellent applied to their hands (which end up in mouths) or near their eyes.
• People with allergic reactions to bites should keep oral antihistamines on hand. Severe reactions warrant a doctor visit.

This article is general health information and not a substitute for medical advice.