Protecting yourself from mosquitoes when travelling

A mosquito that bites a sick person swallows the germ, then passes it on to the next person. Daytime mosquitoes (Aedes) transmit dengue, chikungunya, Zika and yellow fever. Evening and night-time mosquitoes (Anopheles) transmit malaria. Other night-time mosquitoes, in rural areas of Asia, transmit Japanese encephalitis.

• Malaria: a preventive medicine, or a standby treatment to take with you, depending on the region.
• Yellow fever: a vaccine, sometimes required to enter a country.
• Japanese encephalitis: a vaccine for some stays in Asia, especially long stays or stays in the countryside.
• Chikungunya: a vaccine, from age 12, if there is an outbreak at your destination or for a long stay in a risk area.
• Dengue: a vaccine, only for people who have already had dengue.

A repellent does not kill mosquitoes: it masks the skin odours that attract them. Effective products contain:

• DEET, at least 20 to 30%, at most 50% for adults;
• icaridin (or picaridin), around 20%;
• citriodiol, or oil of lemon eucalyptus;
• IR3535.

Some products sold in Switzerland and tested in the laboratory: Anti Brumm Forte (DEET 28%), Anti-Brumm Ultra Tropical (DEET 50%), KIK Activ (DEET 20%), Nobite Extreme (DEET 30% and icaridin 20%), Anti Brumm Classic, Night and Kids (icaridin 20%), SENSOLAR ZeroBite (icaridin 20%), Anti Brumm Naturel (citriodiol 31%).

Apply enough, without forgetting your ankles, the back of your neck and your ears: most travellers apply far too little. Reapply it as directed on the label and after swimming. Avoid the eyes, the mouth and wounds.

With sunscreen: sunscreen first, then the repellent 15 to 20 minutes later. DEET slightly reduces the effect of sunscreen: use SPF 30 to 50.

Children: DEET is well tolerated from 2 months of age, icaridin from 6 months, according to Swiss experts. Citriodiol is not used under 3 years of age. Put the product on your hands, then on the child's face, never on the child's hands. For babies, a mosquito net over the cot or pushchair is still the best protection.

Pregnancy: DEET is well tolerated. Malaria is more dangerous during pregnancy. Swiss experts also advise against regions where chikungunya, Zika or dengue are circulating. See a doctor before any trip.

Permethrin kills or stuns mosquitoes and ticks that land on the fabric.

1. Work outdoors or in a well-ventilated room.
2. Lay out or hang up the clothes.
3. Spray from about 30 cm away, especially sleeves, collars, cuffs and trouser hems.
4. Leave to dry for at least 2 hours.

Also treat hats, mosquito nets and sheets. The effect lasts several weeks and several washes: follow the instructions. Never on the skin, and not on underwear. Keep out of reach of children.

Plug-in insecticide diffusers are used indoors, mosquito coils only outdoors. Tuck the mosquito net in well under the mattress.

Garlic, vitamin B1, perfumes and alcohol do not protect against bites. Nor do ultrasonic devices, electronic wristbands, apps or yeast.

1. Fever in a malaria area, or in the year after you return: see a doctor the same day. Ask for a malaria test, even if you are taking preventive treatment.
2. For fever, take paracetamol. No aspirin or ibuprofen until dengue has been ruled out: they increase the risk of bleeding.
3. Drowsiness, confusion, seizures, bleeding, difficulty breathing: go to the emergency department straight away.

Keep taking your malaria prevention medicine until the end of the course, even after you return.

In Switzerland, emergencies: 144. Abroad: the local emergency number.