Ragweed allergy: Aggressiveness of the pollen depends on the region

A mild winter, rain at the right time and lots of sun: the conditions for ragweed are ideal this year. The Austrian pollen warn service predicts that ragweed allerrigker will be a particularly heavy burden this season.

It is not only in this country that the flowering of the weeds, which started in August, is causing problems for people. In Europe, more than 33 million people suffer from a ragweed allergy. Researchers predict an increase to 77 million cases by 2060 due to climate change.

Differently aggressive

Teams from MedUni Vienna, University of Vienna and BOKU Vienna have now discovered that the origin of the ragweed pollen can be aggressive to varying degrees – depending on the geographic and climatic region, depending on the level of environmental pollution.

mouse experiment

Ragweed (Ambrosia artemisiifolia) is a highly allergenic plant whose pollen causes hay fever in sensitized people and can lead to asthma, explained MedUni Vienna. The multi-university research team exposed mice to pollen collected in different geographic regions. It was found that a small amount – 180 pollen grains in all – is sufficient to trigger an allergic reaction, much less than the high concentrations of pollen found in the air during the seasonal flowering season.

Extended flowering time, more pollen

Due to climate change, the flowering period in Europe is longer and the plant can spread to more northerly areas. But the regional origin of the pollen also determines the severity of the allergic reaction. “Our study shows that pollen from different environments can be differently aggressive. So not only airborne pollen concentrations, but also intrinsic (internal) changes related to the environment could alter the pollen’s sensitization ability and cause worse allergic symptoms.” , explained the lead researcher and coordinator of the “Atopica” project, Michelle Epstein from MedUni.

Environmental influences affect stress

“We now know that the aggressiveness of the pollen changes due to environmental influences. The next steps are further characterization of the pollen, particularly at the molecular level, in order to clearly identify the composition of allergenic components,” added Wolfram Weckwerth from the Department of Functional and Evolutionary Ecology the University of Vienna. “Controlling ragweed is a major public health concern and an adaptation strategy to mitigate and manage the effects of climate change,” emphasized Gerhard Karrer, a botanist at the University of Natural Resources and Life Sciences.

Pollen season is likely to be more intense

The ragweed season starts in August and lasts throughout the fall, but with global warming the season is getting longer. According to the researchers, the influence of climate change and other environmental factors also very likely includes a number of other pollen-producing plants.

Also economic impact

The annual economic burden of allergic asthma in the EU is already estimated at up to 151 billion euros.

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