Mosquito Bite Avoidance
Avoidance of mosquito bites should always be considered as the first line of defence against mosquito-borne infections, especially malaria, dengue fever, chikungunya, zika and yellow fever.
Different types of mosquito bite at different times of day, and transmit different infections so mosquito bite preventive measures are advisable at all times.
The mosquitoes which spread malaria tend to bite between dusk until dawn.
Bite avoidance measures to prevent malaria should start before dusk and continue until after dawn.
Mosquitoes responsible for spreading other diseases e.g. yellow fever, dengue fever and zika virus, tend to bite during the day.
Insect Repellents
Various different repellents are available, repelling a wide range of different types of insect. DEET is the preferred choice.
DEET (N,N-Diethyl-m-tolumide)
DEET is widely considered the most effective broad spectrum repellent against mosquito bites. Research and significant clinical experience has concluded there is a low risk of adverse effects when DEET is applied in accordance with manufacturer instructions.
DEET is available in different concentrations and the duration of protection varies depending on the given concentration: 20% DEET between 1 to 3 hours, 30% DEET up to 6 hours, 50% DEET up to 12 hours. Duration of protection does not increase with concentrations above 50% DEET.
DEET is recommended for all individuals over the age of 2 months, including pregnant woman (unless known to be allergic).
DEET should be used on all exposed areas of skin. Care should be taken to avoid ingestion or inhalation during application.
DEET is water soluble and should be reapplied after washing/swimming or sweating. DEET should be applied after sunscreen. A higher sun protection factor (SPF) sunscreen should be applied to compensate for DEET-induced reduction in SPF.
DEET concentrations above 50% do not increase duration of protection and should not be used on skin, but can be used on clothing.
DEET may damage synthetic materials e.g. clothing made from man-made fibres, plastic watches/glasses and care should be taken to avoid contact with DEET.
Icaridin (Picaridin)
Icaridin (KBR3023) (1piperidinecarboxylic acid, 2-(2 hydroxyethyl)-,1-methyl-propylester) is available in various concentrations and should be used in accordance with the manufacturers’ instructions.
The mosquito repelling efficacy of 20% Icaridin is comparable to 20% DEET. Consequently, a concentration of at least 20% Icaridin should be used to protect against mosquito-borne diseases.
Lemon Eucalyptus (p-menthane 3,8 diol, or PMD)
Lemon eucalyptus 30% gives protection similar to 30% DEET but it is reported to provide a shorter period of protection than DEET.
3-ethlyaminopropionate (IR3535)
3-ethlyaminopropionate (IR3535) (20%) is less effective at repelling Anopheles mosquitoes than DEET and Icaridin (KBR3023), so should not be recommended for bite prevention in malarias regions.
Oil of Citronella
The repellent properties of products containing oil of citronella are very short lived. They are not recommended for insect bite protection. Citronella has been withdrawn in Europe.
Clothing
Mosquitoes cannot bite through loose clothing. Covering up with clothing reduces the amount of skin that can be bitten i.e. high necked clothing with long sleeves and trousers or long skirts. Clothing can be thin, loose and light weight in hot environments. Exposed areas of skin should be covered with an insect repellent that contains no less than 20% DEET or suitable alternative.
For added protection, clothing can be impregnated or sprayed with pyrethroid insecticides such as permethrin. Kits and spray are available to buy from outdoor/travel suppliers; the manufacturer's instructions should be followed. Frequent washing of these garments will reduce the insecticides effectiveness.
Mosquito Nets
The protection afforded by mosquito nets against mosquitoes and other biting arthropods is greatly enhanced by using a net impregnated with a pyrethroid insecticide. Nets can be retreated; the manufacturer's instructions should be followed when washing or retreating bed nets with insecticides. There are many different styles of net available although all provide the same protection. It is important to choose a net that best suits the type of travel. Below is a list of some nets available.
Bell Shaped Net
Can be used indoors or outdoors.
Comes with hanging kit so can be adapt for individual use easily.
Available in double and single.
Wedge Shaped Net
Suitable for travellers on the move as has only one hanging point so can be put up and taken down without too much difficulty.
Can be used outdoors.
Available in double and single.
Box Net
Suitable for travellers staying in one location for period of time.
Box net requires at least six hanging points so cannot be put up or taken down with ease.
Available in double and single.
Mosquito nets should be inspected for holes prior to using them. If a hole is apparent then this can be mended using a mosquito net repair kit, a needle and thread or simply by using duct tape.
Nets should be tucked under mattresses or ground sheets to avoid entry of insects into the bedding area. The net should allow sufficient space that skin does not rest directly against the net, mosquitoes can still bite through it.
Room Protection
Rooms with mosquito screens on windows and doors should be checked to ensure that there are no holes in the screens allowing insects entry. If beds nets are not used, screens must be kept closed at all to avoid insect entry into rooms.
Air conditioning used properly and constantly provides a sealed environment and insects are less likely to enter such rooms.
Pyrethroid products such as plug-ins or candles/coils may be used in addition to bed nets and/or mosquito screens but should not be solely relied upon. Plug-ins require electricity and will not work with an unreliable electricity supply. In these situations insect repelling candles, methylated burners, cones and coils are alternatives, though they are not recommended for indoor use.
Fallacies
There are a number of measures cited as protective against mosquito bites which are unreliable including the following:
Herbal remedies – have not been tested for their ability to prevent or treat malaria and should not be used.
Homeopathy – lack any scientific proof in either preventing or treating malaria. In addition, the Faculty of Homoeopathy does not promote the use of homeopathic remedies for malaria prevention.
Tea Tree Oil – there is no evidence to suggest tea tree oil is effective at repelling mosquitoes.
Buzzers – (emitting high frequency sound waves) are ineffective as mosquito repellents. Companies selling them have been prosecuted and fined under the UK Trades Descriptions Act and they should not be used.
Vitamin B1 and Vitamin B12 – there is no evidence that these repel mosquitoes.
Garlic and yeast extract - there is no evidence that these repel mosquitoes when taken orally (or topically!).
Environmental Issues
One of the most effective ways to control mosquito populations that transmit disease is to reduce the number and types of mosquito breeding habitats. All mosquitoes require a water source to lay their eggs. To effectively reduce larval hatching it is important to check for mosquito breeding sites. In tropical areas where mosquitoes tend to be problematic the spraying of breeding sites is practised. In households and/or hotels it is important to get rid of any standing water i.e. if watering plants tip water out of saucer etc.
Patient Information Leaflet
Download the Mosquito Bite Avoidance for Travellers Leaflet.
Disclaimer: This information has been developed for educational purposes only. It is not a substitute for professional medical advice. Should you have questions or concerns about any topic described here, please consult your healthcare professional.
