Human granulocytic anaplasmosis in northeastern Italy.

Sporadic cases of human granulocytic anaplasmosis (HGA) have been reported in areas with a high prevalence of tick-borne diseases (TBDs) in Europe. We aimed at estimating the sero-prevalence of A. phagocytophilum and other TBDs in northeastern Italy in outpatients with a history of recent tick bite or suspected TBD. In the 1-year study, 79 patients were enrolled and 30 (38%) received a diagnosis of TBD: 24 (30%) with Lyme disease and 5 (6%) with HGE. Our findings indicate the presence of HGA in northeastern Italy; so, since co-infection with Lyme disease appeared to be frequent, physicians assessing patients after a tick bite should consider HGA in the diagnosis.