Cases of tick-borne encephalitis are worrying the authorities in England. A viral disease transmitted by ticks, which looks like the flu at first but which can lead to potentially fatal neurological sequelae. What symptoms? Should we be afraid of it in France? Info and map.
Three cases tick-borne encephalitis (probable or confirmed) were recorded in England since 2019, alert theUK Health Security Agency (UKHSA) in a statement dated April 5, 2023. Tick-borne encephalitis virus (TBEV) is a tick-borne virusparasites (also called “wood lice”) that bite mainly between spring and autumn. This virus is also present in France, especially in the east of the country and in Auvergne-Rhône-Alpes, and elsewhere in the world. Tick-borne encephalitis may or may not be asymptomatic. “In humans, only 10-30% of infections cause meningitis or encephalitis. The rest of the time, the symptoms are of the type flu-like and therefore go unnoticed“, explains Gaëlle Gonzalez, author ofan article published in Frontiers in microbiology. Tick-borne encephalitis therefore remains very rare and the risk to the general public in the UK remains very low.wishes to reassure the authority, which nevertheless wished strengthen its surveillance and recommended modifying testing in hospitals so that any further cases could be detected quickly and the origin of those cases determined. Should we be afraid In France ? What are the health risks ? Is it deadly? Is there vaccines to protect yourself from it?
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 the tick-borne encephalitis virus present in France?
Yes, even if France is a country of low incidence, reassures the High Council of Public Health in a June 2020 report, the virus is present in France in regions such as Alsace, Lorraine, Savoie and Haute-Savoie, according to ANSES. According Public health France, about 20 cases of tick-borne encephalitis have been identified each year in France. Also, cases of human contamination by the tick-borne encephalitis virus through food were observed in the spring of 2020: 43 people living in Ain suffered from meningitis, meningoencephalitis or flu-like symptoms caused by contamination with the tick-borne encephalitis virus, reports ANSES in a press release dated October 4, 2022. They had all consumed raw milk goat cheese. It was the first known food-borne infection in France. In France, current surveillance of tick-borne encephalitis is based on the National Reference Center (CNR) arboviruses but does not allow an exhaustive and detailed collection of cases; these are notified to the European Center for Disease Prevention and Control (ECDC), which provides annual monitoring in Europe.
Map of tick-borne encephalitis: in which countries is it present?
5,000 to 13,000 cases of tick-borne encephalitis are reported every year around the world. The virus is present (non-exhaustive list):
- In Germany (Länder in the south of the country: Bayern, Baden-Würtenberg, Thüringen, Sachsen, Saarland, Rheinland-Pfalz, Hessen and Niedersachsen)
- In Austria
- In Estonia (west of the country)
- In Finland (coastal regions and archipelagos in the south of the country
- In Switzerland (except the cantons of Ticino and Geneva).
- Out of Europeit is to be discussed on a case-by-case basis in: China (North-East and North-West), South Korea, Japan, Kyrgyzstan, Mongolia, Eastern Russia.
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.
Sources:
– Tick-borne encephalitis, Public Health France, June 14, 2022
– Tick-borne encephalitis, Pasteur Institute of Lille
– Tick-borne encephalitis: trace the origin of cases of transmission via cheese, ANSES, October 4, 2022
– Site of the International Vaccination Center, AirFrance
– Tick-borne encephalitis detection in England, UK Health Security Agency