Ambrosia in Nederland

Objective

To determine the degree of ragweed sensitization in Dutch patients and the current spread of ragweed plants and pollen in the Netherlands.

Design

Descriptive.

Method

A group of 250 patients in whom an allergy was suspected was tested for specific IgE using a panel of inhalation allergens (Phadiatop) and an extract of ambrosia pollen. There were 50 samples per season: autumn of 2004, 2005, and 2006 and the spring of 2005 and 2006. The distribution of Ambrosia plants was determined by observations both by professionals (FLORON foundation) and by a network of volunteers throughout the Netherlands (www.natuurkalender.nl).

Results

Ragweed-specific IgE was demonstrated in 7.2% of the 250 tested patients. Among the patients who reacted positively in the Phadiatop inhalation allergy screening, this figure was 16%. Ragweed-specific IgE was more often present in those patients that were sensitized to mugwort pollen. Ambrosia plants were found in most parts of the Netherlands. The plant is mainly found in gardens where it was likely introduced by means of bird seed. Until now, Ambrosia pollen counts were low and did not usually exceed 10 pollen/m³ in the last 17 years.

Conclusion

Although at present both the degree of ragweed sensitization and the daily number of ragweed pollen in ambient air appear to be relatively low, future years may show whether ragweed develops into a major cause of hay fever symptoms at the end of summer in the Netherlands.

This supplementary information is presented as submitted by the corresponding author. It has not been copy-edited and NTvG does not guarantee the accuracy of the data.