A close-up tick on a black background accompanied by the word apocalypse… On the cover of its latest issue dated August 8, the American weekly The Nation is sounding the alarm: Lyme disease, spread by the famous dust mites parasites, progresses in an uncontrolled way. The United States alone now accounts for 476,000 new cases … each year. According to the non-profit organization FAIR Health, which regularly dissects US data from private health insurance, Lyme disease diagnoses increased by 357% in rural areas and 65% in urban areas between 2007 and 2021, with an acceleration over the recent period.
In Europe too, the pressure is growing. “We now see ticks in places where they did not evolve before, confirms Professor Jeanne Brugère-Picoux, veterinarian and member of the National Academy of Medicine. One example among others: twenty or thirty years ago , we did not see them in the Bauges region, between Annecy and Aix-les-Bains. Today, they are part of the landscape”. Doctors know this and they treat the resulting damage, from erythema migrans to the most problematic Lyme arthritis.
Nathalie Boulanger, medical entomologist, leads a research team on vector-borne diseases transmitted by ticks at the University of Strasbourg. It confirms the trend. “In the United States, on the East Coast, we are seeing a large expansion of Lyme disease cases, which are spreading to the Great Lakes and increasingly penetrating Canadian lands. In France, even if certain regions, such as the Grand Est or the Limousin, are more affected than others, the cases have generally increased in recent years”, she explains in a recent symposium, organized in the premises of the Academy of agriculture of France.
Is this a “real” increase or a reflection of better patient and medical awareness? Probably a bit of both, says the specialist. As with Covid, the more tests we carry out, the more positive patients we find. However, other reasons undoubtedly contribute to the proliferation of ticks, starting with the increase in the animal reservoir. Deer (highly valued by female ticks that take up to 100 times their weight in blood) have seen their population increase significantly in recent years. As do rodents. “In the forest of Sénart in the Paris region, you will find for example many squirrels from Korea, former pets filled with ticks”, observes Jeanne Brugère-Picoux.
By modifying his environment, Man therefore has a share of the responsibility in the current situation. It acts even without knowing it on many levels. The fragmentation of land, for example, seems to concentrate animals (cervids, rodents and ticks) in bits of forest where physical contact is made more easily. In another register, the stop – rightly – of the spreading of certain insecticide products in our forests has undoubtedly benefited ticks. As well as the evolution of certain forestry practices. “Less burning, more branches left on the ground after cutting… This creates great lodgings”, laments Jeanne Brugère-Picoux.
Even the greening of cities is sometimes problematic. Because near the green belts, the testimonies of citizens invaded by ticks accumulate. “Like bats and mosquitoes, these animals must be closely monitored,” warns Jeanne Brugère-Picoux. Especially since they can transmit diseases other than Lyme. This is the case, for example, of tick-borne encephalitis. “We are currently witnessing an increase in cases in several European countries and in particular in Switzerland. reach Spain, which makes surveillance necessary in the South of France”.
“Making Lyme disease a major public health issue is abusive, Professor Eric Caume recently reminded L’Express. There are currently no deaths listed; and less than 1,000 hospitalized patients per year in France “. However, the rise in cases forces us to adapt: ??new management of cuts in forests, reduction in the population of certain animals, research on possible tick predators (mushrooms, nematodes, etc.). Many options exist. But they are not yet the subject of a real plan of attack.
