Réseau national de surveillance aérobiologique (RNSA)
Le Plat du Pin
11, chemin de la Creuzille
Common ragweed (Ambrosia artemisiifolia L.) is a noxious agricultural weed whose particularly large production of highly allergenic pollen has a substantial negative effect on public health. In the 1860s, the plant was inadvertently introduced from North America into several regions of the world, where it has gradually established and spread. Its primary vector of introduction in Europe was red clover seeds, probably from Pennsylvania. Ragweed was later re-introduced repeatedly in many places at different times. However, it did not become really invasive until the second half of the 20th century when it spread to human-disturbed habitats, such as agricultural and non-agricultural fallow lands, urban and roadway developments, etc. Ragweed pollinosis was described in the United States and its causal mechanism recognized between 1866 and 1872, but the earliest cases were not reported in France until the 1950s, and their prevalence has increased dramatically since the early 1980s. The prevalence of ragweed sensitization now exceeds 2.5% in all European countries except Finland. Hungary has the highest sensitization rate (53.8% of positive skin tests) followed by Denmark, the Netherlands, and Germany with rates from 14.2% to 19.8%. In France, the prevalence of ragweed pollinosis in the Rhône-Alpes region is believed to have risen from 9.2% in 2004 to 13% in 2014 and possibly even 21% in some places.