Evolution of ragweed pollen concentrations, sensitization and related allergic clinical symptoms in Parma (northern Italy)

The pollen released in the atmosphere by the ragweed represents a question of public health in several European countries. In Italy, the ragweed is mostly distributed in the North. In our region (Emilia Romagna), the presence of ragweed was not described yet if not occasionally, but this plant is thriving well in the North of the Po river. The aim of our study was to estimate the concentration trends of ragweed pollens in the air of Parma starting from 1992 until 2008 and to describe the clinical related situation. The aerobiological surveillance was made with the methods standardized by the Italian Association of Aerobiology. We analyzed 19,468 outpatients affected by respiratory disease. The patients studied address our clinical Center, mainly with pathologies respiratory, most of them with allergic origin. To detect the existence of significant trends and correlations since, we used the non-parametric tests with SPSS software. Our observations showed that since 1995, the year until when pollens of ragweed were only sporadically observed in the air of Parma, there has been a significant increase in ragweed pollens. Among the patients addressed at our clinical Center, 876 patients had positive SPT (skin prick test) for ragweed pollen with respiratory illnesses, all polysensitized. Besides, we found a significant increase in patients with positive SPT for the ragweed, and among these, the increase in the asthma has been significant. On the basis of our results, we expect, in the absence of intervention from public authorities, a more significant increase in the positive subjects and an aggravation of the symptoms related to the presence of ragweed pollen in the air of Parma.