Tis the season! From April to October, ticks are particularly active in natural environments, especially in forests. In the woods, damp bushes, but also in meadows, gardens and parks, this mite is discreet, but you have to be wary of it. Indeed, ticks are potential carriers of the bacteria responsible for Lyme disease. So be careful, but don't panic:only 20 to 30% of ticks are infected. In order to protect yourself, it is important to know the preventive measures to adopt and what to do in the event of a tick bite.
Ticks are found all over the world. They are the main vectors of pathogens responsible for infectious diseases in Europe, including Lyme disease.
Lyme disease is transmitted by the bite of a tick infected with Borrelia burgdorferi sensu lato , a bacterium of the spirochete family. In Europe, the most widespread vector is the Ixodes ricinus tick. , present in most metropolitan areas except for very dry areas. This tick lives in wooded areas, tall grass, but also gardens and parks. Thus, while bites are often associated with forest walks, a quarter of them occur in gardens.
The main vector of infectious pathologies is therefore a hard tick, a mite of the Ixodidae family. :in France, more than 9 out of 10 ticks removed from humans are Ixodes ricinus . They live preferably in temperate climates, but have a great ability to adapt to altitude and humidity.
The tick is still considered absent at an altitude above 1200-1500 m. These blood-sucking parasites also show flexibility in terms of temperature:their activity is reduced for temperatures above 25°C and below 7°C, the temperature at which they go into hibernation. Their period of activity is therefore seasonal, peaking in spring and autumn. However, the theory that you cannot get bitten by a tick in winter is not entirely correct, as ticks can also be active in winter depending on weather conditions.
The main recommendation to avoid tick bites is prevention, whether you are in the garden or in the forest. Simple gestures are enough most of the time to avoid a bite. We tend to think spontaneously of the undergrowth or the countryside, but ticks are also rampant in the city, especially since green spaces are more and more frequent there.
It is best to walk on trails and avoid tall grass, wear a hat, closed shoes and long clothes, put on your T-shirt, sweater, etc. in the pants and the bottom of the pants in the socks or boots. This last point prevents ticks from getting inside the clothes. The color of clothes should preferably be light. This is because light colors make ticks more visible. For children, whose head is at the height of the brush, wearing a cap helps to avoid punctures of the scalp.
To deter ticks, a few natural molecules are being studied, to avoid the use of synthetic products. Mention may in particular be made of 2-undecanone (BioUD) from tomato; decanoic acid (Contrazek) also called capric acid – an oily derivative from coconut or palm nuts; geraniol, Margosa or neem (Neem) extract and lavender extract. The other essential oils are generally little or not recommended, because they are very volatile.
Finally, it is also useful to check its direct environment, garden or courtyard, which may harbor ticks. A few simple precautions can greatly reduce the risk of bites. We can mention in particular the fact of cutting tall grass and brush around the house, and mowing the lawn; remove dead leaves and weeds from the lawn and along the edge of wood reserves; provide woodchip or gravel paths between wooded areas and lawns, patios and play areas. Paths should be at least 3 meters wide, theoretically preventing ticks from crossing; set up playgrounds away from trees, in a sunny place; stack the wood carefully, sheltered and dry. This can keep rodents away, which attract ticks.
Finally, some aromatic herbs are natural repellents, such as garlic, rosemary, bay leaf, mint or even lemon balm. The smell of certain flowers such as chrysanthemum, lemongrass geranium or wormwood also keeps these pests away.
There are few tick repellents, these include mosquito repellent. But an update of knowledge concerning their effectiveness against tick bites was carried out in 2018. Four molecules are recognized as being effective in repellents against these parasites.
On the one hand, we can use DEET-based products, and those based on icaridin. They are to be applied to areas of the body not protected by clothing, avoiding the face. The scientific names of active ingredients listed on product labels may vary from product to product:DEET is also called “N,N-diethyl-m-toluamide”; icaridin is also called “picaridin” or “KBR 3023”. The duration of protection against tick bites is generally shorter than that against mosquito bites.
It is imperative to choose a product according to age. So before 6 months, no chemical solution should be used, a mosquito net on the stroller being sufficient.
Between 6 months and 12 years, the product must be labeled 10% or less in DEET. The duration of the protection does not exceed 3 hours and is limited to one application per day for children under 2 years old. The application can increase to three times for older children. Icaridin-based products must be labeled 20% or less, knowing that their duration of protection varies with their composition:between 3 to 5 hours for 10% and between 8 to 10 hours for 20%.
For ages 12 and up and adults, DEET-based products must contain 30% or less. The duration of protection is 6 hours maximum. For icaridin products, they must be labeled "20%" or less. The duration of protection varies in the same way as before.
On the other hand, the durations of effectiveness are only averages taken from tests carried out in the laboratory in humans and sometimes in mice. They do not take into account certain parameters that can influence their effectiveness.
The other two molecules are PMD (P-menthane-3, 8-diol), a natural compound extracted from eucalyptus Corymbia citriodora , and IR35/35 (N-butyl, N-acetyl-3 ethylaminopropionate). Synthesized in Germany in 1969, this product was marketed from 1973. Colorless and practically odorless, but it alters plastic materials.
Small precision:if the protection must also be against the sun, it is advisable to start by applying the sunscreen and to wait 15 minutes so that it penetrates the skin. This limits the absorption of the insect repellent.
Last point, clothing impregnation, with dedicated repellents, can be effective. This complements the use of skin repellents. Permethrin is used in particular. The product can be applied in sprays on the outer face of clothing; it then retains its effect for 6 weeks. When a mosquito or tick approaches the treated tissue, or lands or crawls on it, permethrin irritates it, prompting it to move away before it has had a chance to sting or bite. /P>
Repellents are potentially toxic products that should be used with caution, but never on children under 16 or pregnant women. It is then possible to impregnate your clothes with white vinegar diluted with water.
The whole body should be inspected, paying particular attention to the sites where the skin is thinnest, such as the armpits, the folds of the knee, the genital areas, the navel, the ear canals and the scalp. It is preferable that the examination be carried out as quickly as possible. This examination must be meticulous, because the stage of the vector most often involved is the nymph, which measures only 1 to 3 millimeters. It is recommended to repeat this examination the next day, because the tick, engorged with blood, will be more visible.
In addition, it is also advisable to take a bath or shower as soon as possible, ideally within 2 hours of outdoor activity, to check for the presence of ticks. This will also remove any ticks that may not be firmly attached to the skin.
Finally, it is useful to examine his equipment (backpack, coat, etc.) and his pets. This precaution aims to avoid introducing a tick into the house.
The first thing to do is to remove the tick as quickly as possible using a tick remover (avoid the use of alcohol or ether, which may cause the tick to regurgitate). Indeed, the longer a tick remains attached, the more likely it is to transmit the bacteria. The tick puller allows the extraction of the tick by rotation-traction perpendicular to the skin. It is especially important to avoid crushing the abdomen of the tick. This tick remover, marketed in particular in pharmacies, exists in small size for the nymph stage of these parasites and in large size for adults. Kits in three sizes are also available.
The bitten area must then be disinfected and monitored for a month in search of erythema migrans (clinical manifestation of Lyme disease, requiring a medical consultation, as well as fever or very intense fatigue).
It should be noted that, as part of the plan to fight against Lyme disease, started in 2016 in France, 5 clinical reference centers (CR MVT) have been created, for better management of patients with difficulties in diagnosis.
If there is an antibiotic treatment against Lyme borreliosis, but no vaccine (even if serious leads are considered), it is exactly the opposite for tick-borne meningoencephalitis (FSME, abbreviation from German):there is a vaccine for FSME, but no treatment once the disease has developed.
After a tick bite infected with the FSME virus, the transmitted infection most often causes no symptoms. In a minority of people, flu-like symptoms (fever, pain in the limbs) occur between 2 and 28 days after the bite. These symptoms disappear after a few days, after which the person is immune for life.
But in 5 to 15% of sick people, meningitis appears 4-6 days later, the infection can spread to the brain (meningoencephalitis).
Ticks infected with the FSME virus are present in many European countries (Austria, Slovenia, Switzerland, Bavaria, etc.). About 1% of ticks are infected with the virus. There has been a marked increase in recent years. However, the majority of infections are silent, which explains the relatively low incidence of FSME. However, all people living or staying temporarily in endemic areas are at risk of contracting FSME. This disease can sometimes leave sequelae and even lead to death in rare cases. Vaccination is a reliable way to limit the risk of FSME.
The complete basic vaccination against FSME requires three injections (=three doses). Two injections, at an interval of 1 to 3 months, already provide temporary protection. The third injection provides long-term protection. Depending on the vaccine, it should be done 5 months or 9 to 12 months after the second dose. If vaccine protection is urgent, the doctor or pharmacist can opt for a rapid vaccination schedule. The FOPH of Switzerland recommends a booster every 10 years.
Since 2015, CIRAD has been studying the tick Hyalomma marginatum , regularly observed on the Mediterranean coast of mainland France. The exact origin of this species, present in Corsica for several decades, but of recent installation on the continent, is still unknown. Unlike the species Ixodes ricinus , this tick is not a vector of the bacteria responsible for Lyme disease, but it can transmit the Crimean-Congo hemorrhagic fever virus, a virus not yet detected in France.
Today observed in the areas of scrubland or dry hills of the Mediterranean coast of several French departments - Pyrénées-Orientales, Aude, Hérault, Gard, Bouches-du-Rhône, Var -, as well as in the south of the Ardèche , it seems to have been progressing for 5 years in these Mediterranean regions which are favorable to it. The researchers state:"We are studying its establishment, its ecological niche, and its tolerance to various temperatures, humidities, rainfall patterns, to understand the factors that explain its spread . For this reason, we are interested in any reports made by breeders or individuals who would recognize it .
This tick attaches itself to certain animals, and accidentally to humans, when they are immobile, and much more rarely when they are in motion. It is found in fields or scrubland from March to August. Unlike other species of ticks waiting for a host on a blade of grass, it moves towards the host it locates by the vibrations of the ground and by its breathing. Its movements are of the order of a few meters. But once attached to an animal, it can then be transported over long distances and thus extend its distribution area.
This tick is not dangerous in itself:its bite can cause irritation that persists for a few days, if the tick has not been removed quickly. However, an infectious agent can be harbored by the tick and occasionally be transmitted through the bite. But not all ticks carry these infectious agents and not all bites are infectious.
Hyalomma marginatum can transmit the Crimean-Congo hemorrhagic fever virus (CCHFV) to humans. Although positive serologies have recently been reported in cattle in Corsica, this virus has never yet been detected on the continent. On the other hand, it is widespread in Africa, Asia, the Middle East and Turkey, where it has recently caused an epidemic. In Europe, it is present in Crimea, Romania and the Balkans, from Greece to Albania. It recently made its appearance in Spain. Let's stay vigilant with the upcoming holidays, the good weather and the upcoming trips...
