For many of us, warmer days bring outdoor pursuits, such as hiking, biking and so much more. They also signal the return of little parasitic mites called ticks, whose bites can have severe consequences for our health through the transmission of various infectious agents. The most common infections caused by tick bites are Lyme disease* (Lyme Borreliosis), generally treatable with antibiotics, and tick-borne encephalitis** (TBE), which is rarer than Lyme disease with 5000 to 13 000 cases reported globally each year. Although there is no vaccine against Lyme disease, one does exist against TBE and it is recommended for anyone residing in or travelling to areas where the disease is prevalent. In Europe, the TBE vaccination is recommended in Austria, Czech Republic, Estonia, Finland, Germany, Latvia, Lithuania, Poland, Slovakia, Slovenia, Sweden, Switzerland and Western Russia.

Ticks live all year round but are most active between March and November. They are generally found in damp, wooded areas and grassy fields, either in the long grass or on plants close to the ground. On human bodies, ticks like warm, moist areas where the skin is thin: behind the ears, around the neck, under the armpits, on the navel, in the groin, behind the knees or on the inner thighs. A careful inspection after any outing is essential.

How can I protect myself?

You can protect yourself from tick bites by following these few simple steps:

• Cover up: wear a long-sleeved top, long trousers, long socks, and closed-toe shoes. Choose light-coloured clothes, as ticks will be more visible on them.
• Spray your clothes, shoes, and skin with tick repellent (available in pharmacies).
• Examine your body whenever you might have been exposed to ticks (after a walk in the woods, a picnic on the grass, etc.).

What should I do if I have been bitten by a tick?

Don’t apply a salve or lotion as this could cause the release of the Borrelia bacterium, that is present in tick saliva and causes Lyme disease. Remove the tick immediately and carefully by:

• Using a tick-remover tool/card or fine-tipped tweezers.
• Grasping the tick as close to the skin’s surface as possible without squeezing the tick. (Do not rotate the tool but pull outwards with steady, even pressure).
• Disinfecting the skin on and around the bite.
• Keeping an eye on the bite area for around six weeks.

Contact your doctor if:

• You have been bitten by a tick and are pregnant or immunocompromised (immunosuppressive treatment, HIV, etc.).
• Your child under the age of eight has been bitten.
• The tick remained implanted in your/their skin for more than 36 hours or you were unable to remove it.
• You don’t know when it became implanted but it was full of blood at the time of extraction.
• A red rash, which does not itch, develops and spreads around the bite site (more than 3 days and up to several weeks afterwards).
• You have symptoms such as unexplained pain, fever or fatigue, joint pain, neurological disorders, or the appearance of a red rash elsewhere in the days and weeks following the bite.

If you are worried about a possible tick bite or have flu-like or unusual symptoms after being bitten by a tick, please consult your doctor or a pharmacist.

Also don’t hesitate to contact the Medical Service if you have any questions: infirmary.Service@cern.ch

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Further information:

General information on Lyme disease and TBE – OFSP (available in French only)
General information on tick bites

Mapping the risk of tick bites in France – INRAE (available in French only)
Mapping the risk of tick bites in Switzerland – OFSP (available in English and French)

Vaccination against TBE in France (available in French only)
Vaccination against TBE in Switzerland (available in French only)

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*https://piqure-de-tique.ch/la-borreliose-en-bref/ (automatic translation available in English)

**https://piqure-de-tique.ch/la-fsme-en-bref/ (automatic translation available in English)