Tick-borne encephalitis: symptoms, mortality, map of France

I’tick-borne encephalitis progresses throughout Europe and is, since May 2021, a notifiable disease. Transmitted by ticks during a bite, this infection affects the brain and the spinal cord. In 40% of cases, it may be responsible for “neurological sequelae for several years”, remember French Public Health. A thirty cases are notified in France every year. 94% were hospitalized. No deaths have been recorded to date.

Map of tick-borne encephalitis cases in France

There Haute-Savoie is the department that reported the most cases between 2021 and 2023. The Auvergne-Rhône Alpes region is now a important area of ​​circulation of the viruswith massifs particularly at risk, such as Drill. The circulation zone of the virus reached in the south Ardechea department that should be the subject of particular vigilance.

What are the symptoms of tick-borne encephalitis?

Symptoms of tick-borne encephalitis are similar to other causes of meningitis and may include:

• A high fever
• Nausea and vomiting
• Of the headache
• A neck stiffness (torticollis)
• pain when looking at bright lights
• A confusion or reduced consciousness
• Sudden weakness or loss of movement in the arms and legs
• Speech disorders

The public is reminded that they should consult a general practitioner if he does not feel well after a tick bite and needs to seek emergency medical attention if he or someone he knows has the symptoms listed above.

Tick-borne encephalitis is transmitted to humans duringa tick bite of the kind Ixodes carrier of the virus during his blood meal. The infectious viral particle measures approximately 50 nm in diameter. The tick bites mainly between spring and autumn, during agricultural work, walks in the forest or in gardens. Transmission through raw dairy products (raw milk, raw milk cheese) is possible. Two virus subtypes can infect humans: the Eastern subtype And the Western subtype.

Is tick-borne encephalitis fatal?

Tick-borne encephalitis can cause severe, life-threatening brain damage, at the level of the brain, of the membranes which surround the brain and the spinal cord. The tick-borne encephalitis virus is deadly for 2 to 3% of patientssays the British Health Security Agency.

“The diagnosis is based on the search for specific antibodiesin serum and cerebrospinal fluid“, reports the Pasteur Institute of Lille.

What treatment to treat tick-borne encephalitis?

There is no specific treatment. Treatment is strictly symptomatic, in particular to treat fever and headaches. The course of tick-borne encephalitis is favorable in most cases.

Is there a vaccine to prevent tick-borne encephalitis?

Vaccination against tick-borne encephalitis is recommended for travelers who must stay in rural or forested areas in endemic regions (Central, Eastern and Northern Europe, Northern Central Asia, Northern China, Northern Japan) from spring to autumn. In addition, people who work in a forest environment, and who are therefore particularly exposed, can be vaccinated. Two vaccines are available in France under the name of Ticovac^® And Encepur^®. The vaccination schedules are as follows:

► Ticovac® : three injections at M0, between M1 and M3, then between M5 and M12. There is a pediatric presentation that can be used in children aged 1 to 15 years old.

► Encepur® (usable from the age of 12): three injections at M0, between M1 and M3, then between M9 and M12.

For these two vaccines, the 1st booster should be done 3 years after the 3rd dose, before possible re-exposure to the tick-borne encephalitis virus.

What prevention to reduce the risk of tick-borne encephalitis?

To protect yourself from this disease, the only prevention is not to expose yourself to tick bites:

• Avoid areas where ticks are abundant from spring to fall
• Cover up if you have to enter these areas
• Using repellents on the skin and insecticides on the clothes
• Examine yourself carefully when you return from work or a walk and extract the ticks attached to the skin
• In endemic areas, it is also necessary avoid consuming raw milk (or its derivatives such as cheese) since milk can contain viruses. Prefer pasteurized milk.