With the return of warm weather comes warmer rays and wildflowers… but also ticks that carry Lyme disease. It is also in the coming weeks that we will have to be most wary of these nasty critters.
“Ticks start moving very early. They are most active in the spring and early summer, says Jade Savage, professor of biology at Bishop’s University. They do not like extreme heat and drought. This is why it is quieter during the very hot, very dry summer months. It starts again in the fall. »
You have to be particularly vigilant in the spring because there are a lot of ticks at the nymph stage, which is an intermediate stage between the larva and the adult tick. “The nymph is much smaller than the adult tick. So small that it’s possible it’s been attached for 24 hours and has been missed,” Ms. Savage points out.
The risk of transmission of the bacteria responsible for Lyme disease occurs mainly after 24 hours of attachment.
The big culprit is the blacklegged tick. In recent years, its territory has been expanding. Initially limited to the United States, it progressed to Estrie and Montérégie. They are now found further north, as far as Quebec.
The good side is that people are more aware, more vigilant. More of them are adopting protective measures, observes the professor.
It is therefore a question of wearing long sleeves and entering the bottom of the pants in the socks. It is obviously less tempting in the middle of summer, when it is hot. Repellents such as 20% DEET or icaridin can then be used.
“As DEET is potentially neurotoxic, it is not recommended for children,” says Dr. Mirabelle Kelly, microbiologist and infectious disease specialist at the CIUSSS de l’Estrie. The Canadian Pediatric Association recommends icaridin 10% instead. »
There are clothes impregnated with a repellent, permethrin, which are also effective.
“The main thing is to watch yourself after an activity and take a shower so that the tick, if it’s not yet attached, falls off with the water,” says Dr. Kelly.
For many years, doctors have prescribed antibiotics, such as doxycycline and amoxicillin, to treat Lyme disease once it has set in.
“What’s different is that for about five years we’ve had secondary prophylaxis, we’ve been using doxycycline for prevention after a bite,” says Dr. Kelly. There are four criteria that must be met: the head must have been attached for more than 24 hours, there must be relatively credible proof that it was indeed a tick, the treatment must be sought within three days of the removal of the tick and that we are in a region where the prevalence of the disease is sufficient to justify the use of prevention. »
There is another new element: Pfizer and Valneva have undertaken clinical trials on a new Lyme disease vaccine to test its efficacy and safety.
“A vaccine had come on the market in the 1980s-1990s, Lymerix,” notes Dr. Kelly. In the early 2000s, there was a class action lawsuit organized by vaccinated patients who had joint pain. The studies did not show that it was necessarily the vaccine that was responsible: there were no more cases of joint pain in the vaccinated than in the non-vaccinated. But it hurt the marketing of the vaccine. The company just decided to drop the marketing. »
Quebec could participate in studies on the new vaccine. “We have been approached to participate, but we are still in the process of being approved,” says Dr. Kelly. If it works, we would start studying this summer in Granby, Sherbrooke and Montreal. »
While waiting for this vaccine, people should learn how to identify and remove ticks correctly. “It has to become a collective skill, removing a tick, without having to ask a medical professional. »
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