Julio Godoy
BERLIN, Jun 13 2008 (IPS) – Climate change induced by global warming is provoking health hardships in Europe, especially through new, prolonged allergies, authorities say.
The most important new allergy affecting Europeans is being caused by ambrosia artemisiifolia, popularly known by several names, including common ragweed, annual ragweed, bitterweed, blackweed, or, more telling, hay fever weed.
The plant was native to North America, but was brought to Europe several decades ago, according to German biologists and health authorities. But with the recent, steady rise in temperatures in Europe, the plant, which grows to about a metre in height, has spread in Germany, France, Hungary, Italy and other European countries.
The plant s pollen is known to provoke hay fever, characterised by sneezing, runny nose, itching eyes, and even heavy attacks of asthma and conjunctivitis. Cases of skin infection provoked by ambrosia have also been reported.
Because the plant blooms during the summer and until October, it is prolonging the normal European allergy season by at least two months, Thomas Duemmel, meteorologist at the Free University of Berlin told IPS.
Duemmel said other allergenic plants, such as birch, alder, hazel, and horse chestnut flourish in the early spring and until mid-May. Now, with ambrosia added, the allergy season starts early in March and can go on until October.
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The higher temperatures of recent years have prolonged the blossom season of all these plants, thus worsening the allergenic affections of millions of people, Duemmel said.
The proliferation of ambrosia is particularly worrisome in health terms, because one single tree can produce up to one billion pollen, which, helped by wind, can spread hundreds of kilometres, Duemmel added.
We have to stop the proliferation of ambrosia, because the plant produces one of the most allergenic pollen known, said Stefan Nawrath, biologist and ambrosia expert at the Institute for Ecology, Evolution and Diversity at the University of Frankfurt, some 450 kilometres south of Berlin.
Ten grains of the ambrosia pollen per one cubic metre of air are enough to cause headaches, rhinitis, and even asthma, Nawrath told IPS.
The state-owned Julius Kuehn Institute for botanical research points out that ambrosia has been the most allergenic plant in North America.
In an official research paper, the institute says that ambrosia, because of its late blossoming, is unfertile in cooler regions of the world, and therefore cannot proliferate. The paper adds that given rising temperatures associated with climate change, it is important to research which climatic conditions make possible the fertilisation of ambrosia s seeds.
The health worries caused by ambrosia are so serious that several German health agencies have approved a plan to exterminate the plant. The health of millions is at stake.
Nawrath told IPS that in some regions in countries like France and Italy, at least 12 percent of the population is allergic to ambrosia s pollen. Ambrosia can also be a plague for agriculture, because it reduces productivity of fields.
In Germany, the incidence of allergies caused by environmental change has markedly increased since the post-war era.
According to official health reports, the percentage of the West German population suffering from hay fever or other forms of pollinosis went up from 20 percent for those born between 1942 and 1951 to 27 percent for those born between 1962 and 1971.
The German Society of Allergology and Immunology goes further, and says that today a third of the country s population suffers from one form of allergy or other. In its White Book on Allergies in Germany , the society says allergies have dramatically increased in recent years.
By now, deaths caused by allergenic asthma are more numerous than those caused by traffic accidents, the society says.
This increase in allergic diseases is necessarily linked to changes in the environment, says Heidrun Behrendt, director of research on allergology and immunology at the Technical University in Munich, 500 kilometres southeast of Berlin.
The genetic disposition for allergies cannot increase substantially within a given population, Behrendt said in an interview. Therefore, we have to look for explanations for the increase of allergic diseases in environmental changes.
In her most research, Behrendt and her team found that so-called pollen dependent lipid signallers (PALMS, after its German name) trigger allergic diseases by provoking interaction between allergen pollen and airborne chemical pollutant particles, such as auto emissions.
We could prove that pollen corns and air pollutants set free the PALMS, and are therefore an explanation for the recent increase of allergies, Behrendt said.
According to Behrendt s study, PALMS activate infected cells and suppress immune cells in human organisms, thus opening the way for allergies. This finding could explain why people suffer more from allergies in regions with high concentrations of air pollutants, either in urban zones with dense automobile traffic or near intensive chemical industries.