We know: ticks are the cause of Lyme disease, which affects around 30,000 people each year in France. But this is not the only pathology caused by tick bites. These parasites can also cause tick-borne encephalitis. Thursday May 28, 2020, the Auvergne-Rhône-Alpes Regional Health Agency and the Ain prefecture thus alerted to the appearance of an outbreak of tick-borne encephalitis in 26 inhabitants of the department.
What is tick-borne encephalitis?
Also called tick-borne meningoencephalitis or verno-summer tick-borne meningoencephalitis (MEVE), this disease is caused by a virus transmitted by ticks: TBEV (“Tickborne Encephalitis Virus”, literally, “tick-borne meningoencephalitis virus”) . There are three types of this virus: European, Far Eastern and Siberian.
If 5,000 to 13,000 cases of tick-borne encephalitis are reported each year in the world, it is a rare disease in France: 20 cases are recorded each year.
Tick-borne encephalitis: how is the disease transmitted?
The virus causing this disease is transmitted to humans through the bites of infected ticks. Food-borne transmission is also possible through unpasteurized milk and dairy products from infected animals, although it is rarer.
This is also the preferred route in the case of the outbreak of tick-borne encephalitis identified in Ain: half of the people affected would have consumed cheeses made from raw goat’s and cow’s milk from a farm in the Oyonnax basin.
What are the symptoms of tick-borne encephalitis?
After contamination, the incubation period lasts one to two weeks. The disease then manifests itself suddenly, through the following symptoms:
- fever ;
- headaches ;
- chills ;
- digestive disorders.
In 20 to 30% of cases, the disease goes through a second phase, which is characterized by damage to the brain, in other words encephalitis. Symptoms that may appear include:
- prostration or restlessness;
- drowsiness;
- muscle tone disorders;
- loss of balance.
In 2 to 3% of cases, tick-borne encephalitis is fatal, and in 10 to 20% of cases, it can lead to sequelae, such as paralysis. The risks are even higher in children, since neurological sequelae related to tick-borne encephalitis are possible in about 50% of cases.
Tick-borne encephalitis: how to treat it?
There is no treatment for tick-borne encephalitis. The goal of disease management is to relieve symptoms. However, two vaccines prevent the disease: Ticovac® and Encepur®. They are recommended for people who live in areas where the disease is prevalent, namely Central Europe, Eastern and Northern Europe, China (Northeast and Northwest), South Korea , Japan, Kyrgyzstan, Mongolia and Eastern Russia. These vaccines can also be administered to travelers to rural or wooded areas of these regions, as well as to professionals working in forestry.
How to prevent tick-borne encephalitis?
To prevent this disease, it is necessary to protect yourself from tick bites. It is therefore advisable to avoid areas where these parasites proliferate, mainly between spring and autumn, which is the period most at risk, to wear covering clothes if you go to these areas, but also to carry out a self-examination when returning from these places at risk, in order to identify possible bites and remove ticks.
Sources: the sites of Public Health Franceof the’Pasteur Institute of Lille and of Vaccination Info Service.
Read also :
⋙ A serious pathology other than Lyme disease caused by ticks
⋙ Tick bites: an application to report them and better protect yourself
⋙ Lyme disease: how to recognize it and what are the treatments?