Long distance transport of ragweed pollen as a potential cause of allergy in central Italy.
BACKGROUND
Ambrosia pollen is an important allergen in North America and, as recently discovered, in some European countries. In Italy, the most affected area is the northeast, whereas ragweed has not been reported in the central and southern parts of the country.


OBJECTIVE
To identify the source of ragweed pollen detected in Florence and Pistoia in central Italy.


METHODS
Ragweed pollen data were collected in Florence and Pistoia for a 6-year period (1999-2004). The relationship between pollen counts and local ground prevalent wind directions was evaluated with analysis of variance and the least significant difference test. Weather conditions were also evaluated on a large-scale circulation pattern by analyzing weather maps and air mass back trajectories.


RESULTS
A highly statistically significant relationship between daily prevailing wind direction and pollen count was found in the period under investigation; the ragweed pollen peaks were recorded when winds from northeast in Florence and north-northeast in Pistoia were observed. The synoptic weather situation and the path of back trajectories suggest an area around southern Hungary as a possible source of Ambrosia pollen. Furthermore, the pollen count was above the clinical threshold several times in both Florence and Pistoia.


CONCLUSIONS
Several factors indicate that the detection of ragweed pollen in central Italy is due to long distance transport. Taking into consideration the high allergenicity of Ambrosia pollen, the present findings, if confirmed, suggest that the number of sensitized individuals might significantly increase in the near future.
Cecchi
Lorenzo
L
Interdepartmental Centre of Bioclimatology, University of Florence, Florence, Italy. lorenzo.cecchi@unifi.it
Lorenzo
Cecchi
C
Morabito
Marco
M
Marco
Morabito
M
Paola Domeneghetti
Maria
M
Paola
Domeneghetti Maria
DM
Crisci
Alfonso
A
Alfonso
Crisci
C
Onorari
Marzia
M
Marzia
Onorari
O
Orlandini
Simone
S
Simone
Orlandini
O
D031164:Ambrosia / Q000254:growth & development*; D000818:Animals; D006967:Hypersensitivity / Q000209:etiology*; D007558:Italy; D011058:Pollen / Q000254:growth & development*; D014919:Wind