Mosquitoes are attracted by several factors, including the presence of carbon dioxide, heat, odours and movement. The female mosquito requires a blood meal in order to reproduce. There are many mosquito species; some species bite during daylight hours, and some are more active from dusk to dawn.
Personal protection measures during travel
When travelling in areas with malaria it is advisable to wear loose-fitting clothes with long trousers and long sleeves in the evenings. Travellers to areas with a risk of dengue fever infection should cover up during the day if possible, as the mosquitoes that transmit dengue fever bite during the day.
In tick-infested areas, trousers should be tucked into socks to prevent ticks from crawling up the legs.
Avoid dark blue clothing when travelling in Africa in areas where tsetse flies exist.
Clothing can be treated with an insecticide (e.g. permethrin), which kills insects, including ticks, on contact. Permethrin is available in formulations designed to be sprayed on to clothing.
DEET based repellents are the most effective; they have been widely tested under field conditions, and have been used for more than 50 years. DEET is available in several concentrations.
DEET-containing preparations should not be used in babies younger than 2 months of age. They can be used in concentrations up to 50% in pregnant or breast-feeding women, and in infants and children older than 2 months. Care should be taken to ensure that repellents are not ingested, and that they do not come into contact with the eyes or mouth.
Repellents should be reapplied at regular intervals, after swimming and in hot, humid conditions when they may be removed by perspiration. When both sunscreens and repellents are used, the repellent should be applied over sunscreen.
Research and extensive clinical experience indicate that DEET is very safe when used according to the manufacturer’s instructions.
Insect repellent: Advice for travellers
Use only on exposed areas of skin.
Remove with soap and water when the repellent is no longer needed.
Do not spray directly on the face, and wash hands after application to avoid contact with lips and eyes.
Do not apply to cuts, abrasions or irritated skin.
Sunscreen that is combined with repellent should usually be avoided.
Follow manufacturer’s instructions when applying repellents to babies and infants.
Screening and mosquito nets
Travellers staying in accommodation without screening should sleep under a net to avoid being bitten at night.
Nets should be impregnated with permethrin (or other contact insecticides); most nets have been treated prior to purchase. Nets may need to be impregnated with permethrin again after six months of use; long-lasting insecticide nets will generally not need treating frequently.
Contact insecticides will kill insects landing on the net and therefore increase the effectiveness.
Treatment of insect/tick bites
Arthropod bites usually appear as small, red, raised papules that itch. Application of a cold compress to the bite site may provide relief from pain or itching.
Local swelling can be reduced by the topical application of a mild steroid cream. Antihistamine tablets can be taken to relieve itching.
Mosquito bites should not be scratched and should be kept clean and dry to avoid infection.
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