Epidemiology
The disease is regarded as extremely rare, with an incidence (new number of cases per year) of one case per million people. The patients are predominantly male (86% in a survey of American patients), although in some countries the rate of women receiving a diagnosis of Whipple's disease has increased in recent years. It occurs predominantly in those of Caucasian ethnicity, suggesting a genetic predisposition in that population.
T. whipplei appears to be an environmental organism that is commonly present in the gasterointestinal tract but remains asymptomatic. Several lines of evidence suggest that some defect - inherited or acquired - in immunity is required for it to become pathogenic. The possible immunological defect may be specific for T. whipplei, since the disease is not associated with a substantially increased risk of other infections.
The disease is usually diagnosed in middle age (median 49 years). Studies from Germany have shown that age at diagnosis has been rising since the 1960s.
Read more about this topic: Whipple's Disease