Anaplasma phagocytophilum in Ixodes ricinus ticks and human granulocytic anaplasmosis seroprevalence among forestry rangers in Białystok region.

PURPOSE Human granulocytic anaplasmosis, former ehrlichiosis, is a tick-borne zoonosis of increasing recognition. The aim of the study was: 1) to assess the prevalence of Anaplasma phagocytophilum infection in Ixodes ricinus ticks collected in recreational forests in Bialystok vicinity, the capital of podlaskie voivodship; 2) to evaluate the prevalence of IgG and IgM antibodies to A. phagocytophilum among forestry rangers from the same region. RESULTS Of the 372 ticks examined, 54 (14.5%) yield the positive PCR reaction. The highest prevalence was detected in females, up to 27.8% (37/133), almost one third lower in males--9.2% (13/142), followed by nymphs--4.1% (4/97). Human seropositivity study revealed IgG antibodies against A. phagocytophilum in 9 out of 231 individuals (3.9%). No IgM antibodies were found. Sixty-seven individuals 67/231 (29%) reported erythema migrans. IgM anti-Borrelia burgdorferi antibodies were detected in 32 out of 121 (26.4%) persons tested, IgG--in 43 out of 231 (18.6%). CONCLUSIONS The data obtained show relatively low A. phagocytophilum seroreactivity among professionally exposed to tick group of forestry workers despite high A. phagocytophilum infection level in the competent vector--I. ricinus ticks.