Lyme disease in Italy, 1983-1996

This paper is a brief review of the epidemiology of Lyme disease in Italy. The first case of the illness was identified by Crovato in Liguria in 1983. In the following years, many other cases have been reported from all Italian regions with the exception of Valle d'Aosta, Basilicata and Calabria. The exact number of cases in our country is not known because Lyme disease was not a notifiable disease until 1990, but on the basis of literature data, at least 1324 cases have been observed in the fourteen-year period 1983-1996. Friuli-Venezia Giulia, Veneto and Trentino-Alto Adige are the main regions involved. Only few cases of illness have been described in Mid and Southern Italy and in the Islands (6.0%). No reports exist on Lyme disease in animals. There is, however, serological evidence of infection of domestic and wild animals. The causative agent, Borrelia burgdorferi sensu lato, was first isolated from Ixodes ricinus ticks by Cinco in Trieste in 1977. Since then many other strains, belonging to three different genomic species (B. burgdorferi sensu stricto, B. garinii and B. afzelii), have been isolated from humans, reservoir hosts and ticks. Cases were reported for all age-groups, more frequently in females, following the typical seasonal course, with a marked seasonality from spring to autumn, when ticks are more active. Erythema chronicum migrans was the most frequent manifestation of LD. Several studies have been conducted on groups at risk (forest workers, gamekeepers, etc.). In contrast to the high prevalence of antibodies to B. burgdorferi sensu lato in the groups at risk (up to 27.2% for forest workers), the seroprevalence of the healthy population is, in general, lower.