Allergenicity of ragweed species which have been recorded in Israel
Ragweed species (Ambrosia spp.: Asteraceae) include a number of species which are known invasive alien plants in some regions of the world. In Israel six alien Ambrosia species have been reported over the last 30 years. These include A. confertiflora (EPPO A2 List with a restricted distribution in Israel), A. grayi (currently under eradication in Israel), A. psilostachya (absent in Israel since 2017), A tenuifolia (a rare non-native species in Israel), A. artemisiifolia (a transient species in Israel) and A. trifida (previously transient, absent in Israel since 2015). Ragweed pollen is known to cause allergic reactions in humans, e.g. pollinosis (hay fever). To test the effect of pollen from four Ambrosia species on people already suffering from allergies, pollen was collected from A. confertiflora and A. tenuifolia and extracts were prepared, and pollen extracts were purchased for A. artemisiifolia and A. trifida. Allergy tests (skin prick allergy tests) were conducted between 2012-2013 on 163 participants aged between 16 and 60 years. Participants in the experiment were tested for reaction to pollen extracts from the four Ambrosia species plus a water control. Sensitivity to Ambrosia extracts was recorded in 22.7 % of the studied population. Patients reaction to A. confertiflora was three times stronger compared to the three other Ambrosia species. A. trifida had the lowest reaction in patients.
Yair Y, Sibony M, Confino-Cohen R, Rubin, Shahar E (2019) Ragweed species (Ambrosia spp.) in Israel: distribution and allergenicity. Aerobiologia 35, 85-95.