The beautiful days return and with them, the fear of stings or bites by small animals. Nature walks expose us to different small animals that scare us for the diseases they can transmit to us. The tick is one of the most mentioned mites. We give you an update on this microscopic animal, the real danger it represents, as well as what to do if you realize that you have been bitten by a tick.
What is a tick?
The tick belongs to the mite family. If 50,000 species are now listed, scientific hypotheses estimate the number of different species of ticks at more than one million. In France, around forty species have been identified, including:
- the sarcopte, responsible for scabies,
- Varroa, a bee parasite,
- the various mites living in the dust of our houses and likely to cause allergies,
- and Ixodes ricinus, whose name is primarily associated with Lyme disease.
Their optimal growth conditions correspond to an environment where the humidity is between 60 and 80%, and at a stabilized temperature between 26 and 32 ° C.
Ticks feed in different ways, but the most prevalent in the media, Ixodes ricinus, is a blood-sucking mite. It is during her meals – only one at each stage of her life – that she can transmit the viruses, bacteria or parasites that she carries.
The tick’s meal lasts between 3 and 10 days, depending on its stage of development. In adulthood, only the female takes blood: the male, only intended for reproduction, does not feed.
Bacteria that can be transmitted by Ixodes ricinus are bacteria of the genus Borrelia, responsible for Lyme disease, also called Lyme borreliosis. But the tick can also transmit other microorganisms such as:
- Bacteria Anaplasma phagocytophilum, known as agents of veterinary diseases since 1932, but only since 1990, as a vector of zoonosis,
- The Rickettsia helvetica, responsible for fevers, headaches and skin rashes,
- The protozoan Babesia, responsible for babesiosis, a disease similar to malaria,
- Or the virus that causes tick-borne encephalitis, a disease manifested by severe neurological symptoms (paralysis and convulsion), with frequent sequelae.
How likely is it to get sick from a tick bite?
First, not all ticks are dangerous to human health. Just as not all mosquito species transmit malaria, ticks do not carry any pathogen.
Then a tick infected with Borrelia in the larval stage, will remain infected throughout its life. But less than 1% adult females pass the bacteria on to their offspring. And the percentage of infected ticks is not uniform throughout France. For those carrying Lyme disease, the percentage varies between 0 and 20%.
Moreover, a tick, even infested with pathogens, does not necessarily infect the host on which it feeds. A study carried out in the Netherlands estimated the risk of developing Lyme disease following an infected tick bite that made its entire meal at 14%. The risk drops to 2% when the tick is extracted before 4 days of fixation. Please note, these figures are only valid for Lyme disease. Indeed, in the case of bacteria, transmission is not immediate. It is completely different for viruses that are immediately transmitted.
Finally, we must also rely on the action of the immune system : If it can happen that a pathogen is transmitted, the body can successfully block the infection and prevent the onset of the disease.
Since 2020, the presence of certain ticks in the south of France during the summer has worried CIRAD (Center for International Cooperation in Agricultural Research for Development) in Montpellier. This is the species Hyalomma marginatum, called a striped-legged tick. These ticks have been present in Corsica for several decades, but only recently on the continent. The concern stems from the fact that it can carry Crimean Congo hemorrhagic fever through a virus. But to date, no case has been detected in France.
The risk of falling ill is ultimately low compared to the many sometimes alarmist speeches to which the media expose us. Over the period 2009-2019, between 25,000 and 68,500 cases of Lyme borreliosis were diagnosed. This wide range comes from the fact that the disease is not linked to specific signs.
How do you know when you’ve been bitten by a tick?
Ticks are often found behind the ears, in folds such as the elbow, knee or groin, and on the ankles. Fixing the tick is not painful because its saliva is anesthetic, and goes unnoticed. The only way to know if you’ve been bitten by a tick is to do a body inspection after going out.
But it is far from simple: the tick is a blackish / grayish ball in light relief measuring only between 1 and 3 mm before meal. Only very keen attention can give you a chance to smell the tick by running a finger across the surface of the skin. In people with a lot of moles, some of them raised, this may seem mission impossible. Obviously, after several days, the tick having fed, it will be more visible and you will have a better chance of spotting it, but also the chances of disease transmission.
What if we identify a tick on the skin?
You have to remove the tick as quickly as possible with a suitable tool: a tick remover. This utensil is an essential part of the first aid kit because it is designed to remove the tick completely and without crushing it, which could facilitate the spread of pathogens which it may carry. The use of tweezers gives a much more random result.
You have to place the hook of the puller under the tick and then turn (regardless of the direction, even if you often find it indicated that you have to do it clockwise: the goal is to “unscrew” tick and not shoot).
The methods of asphyxiation of the tick with ether or with another product are completely ineffective or even counterproductive because this promotes the regurgitation of saliva and therefore possible contamination. It is also unnecessary to bring a flame near the skin.
If your procedure has failed and a piece of the animal remains in the skin, go to a doctor or the emergency room (however, your vital prognosis not being engaged, you are not given priority) for a complete removal of the animal.
Disinfect then where the tick lodged, and write down the day of the bite as a reminder and monitor the affected area for a few days. No significant redness should develop. For the other illnesses mentioned above, it is the onset of fever or body aches within 48 to 72 hours that you should watch out for.
If this is the case, consult a doctor immediately, specifying the date of the bite. In the case of the appearance of a significant redness, it must be taken into account as such because it can disappear after 3 days, even in the event of illness. And a blood test can only be done a few days after the injection because if it is done too early, the antibodies will not yet have been secreted by the body.