Prevalence of Whipple's disease in north-western Italy.

Whipple's disease (WD) is a rare systemic infection due, in genetically susceptible individuals, to Tropheryma whipplei, a heterogeneous Gram-positive actinobacteria. Although it has already been recognised that WD affects mainly middle-aged Caucasian men, the prevalence of WD is virtually unknown. The annual incidence of WD in the general population is said to be less than 1 per 1,000,000, but scientific evidence for these figures is still lacking. On the basis of the number of patients recorded with a diagnosis of Whipple's disease in the regional registers for rare diseases of Lombardia, Liguria and Piemonte-Valle d'Aosta regions, we studied the prevalence of WD in the north-western part of Italy. Forty-six patients with Whipple's disease were recorded in these regions (13 females; mean age at diagnosis 52.1 ± 11.1 years). Since 16,130,725 inhabitants live in these four regions, prevalence of WD in the general population is 3/10(6) and almost 30% of the patients are females. WD is certainly a rare disease but it also affects women in a considerable proportion of cases.