In Rennes there was a “sentinel” pollinarium for the best treatment of allergies

Perched on top of the library, the Rennes Pollinarium looks like a garden like any other. It is here that fifteen types of pollen with the most allergenic pollen in the region are grown, tracked every day by a botanist and then alerted to the public.

“Currently, willow and hazel stand out the most. In two weeks, we will have foxtail herbs and scent spot,” says Hervé Tyger, a botanical gardener from Rennes.

In front of him, on large plantations flooded with sunlight, grow ryegrass, timothy grass, feather grass, bulbous couch grass, fragrant fluff, as well as birch, oak, hazel, and willow.

Each plant was taken from the wild, within a radius of 20 kilometers around Rennes, on the four cardinal points. “The idea is to have more genetic variation because every plant doesn’t emit pollen at the same time,” the botanist explains to AFP, pointing at the stamens, the pollen sacs. “If we shake it a little, we see very yellow pollen grains in the form of very fine dust. That’s what causes allergies,” he continues.

The male fertilizing element of a flower, the pollen falls on the pistil of a female flower of the same species to fertilize it and form a fruit. It consists of tiny grains with a diameter of several tens of micrometers, the thinnest and lightest, carried by the wind, most likely to enter the respiratory tract and cause allergies.

Botanist Hervé Tiger notes his observations after studying stamens at the Pollinarium in Rennes, March 18, 2022. (AFP – Damien MEYER)

Every morning, Hervé Tiger examines the flowering of selected species together with allergists. “The goal is to visually observe pollen release. We look to see if there are stamens, and mark in a small notebook the start and end dates of the release, the main thing is to observe the entire first release in order to raise the alarm, ”he said.

– “Prevention tool” –

The information is then checked by an allergist, entered into a centralized database in Nantes ( and distributed to the public. In Rennes, there are 1,300 patients and doctors in the database, registration is free. “Each zone has its own warnings, because allergenic plants are not necessarily the same everywhere,” the gardener clarifies.

There are twenty pollinariums in France, four of which are in the process of opening. The first began operating in Nantes in 2012. It was allergists who came up with this “watchdog” remedy, believing that there was too much difference between the symptoms noted in their patients (rhinitis, asthma, conjunctivitis, etc.) and the pollen detected by atmospheric sensors in cities that are less sensitive at the very beginning of the emission. .

“This is a very interesting preventive tool from a public health point of view,” says Mikael Puliken, an allergist and referent at the Rennes Pollinarium. “Because of this, you know very precisely when to take and when to stop taking antihistamines. It also allows you to identify the pollen that causes respiratory allergies,” he continues.

Hazelnut stamens at Rennes Pollinarium, March 18, 2022 (AFP - Damien MEYER)
Hazelnut stamens at Rennes Pollinarium, March 18, 2022 (AFP – Damien MEYER)

In addition, treatment for the first gram of pollen in the air is “more effective than treatment in the midst of an allergic crisis,” the doctor adds. He highlights “an increase in the prevalence of allergies in 30 years, the WHO even predicts that one in two people will be allergic in 2050.” In France, pollen allergy affects 10 to 20% of the population.

Ultimately, the goal is to traverse the entire territory of pollinariums with about a hundred structures.

“Global warming and pollution are increasing the amount of pollen in the air,” recalls Julia Maguero, who is in charge of partnerships at the Association of Sentinel Pollinators of France (APSF). In fact, heat lengthens the length of pollen seasons. “People are more and more affected throughout the year, whereas before they were from February to September,” she elaborates, adding that “pollution also increases the allergenic potential of pollen, leading to more and more respiratory diseases.

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