[Human granulocytic anaplasmosis: an autochthonous tick-borne disease with a potentially severe course].

Human granulocytic anaplasmosis (HGA) is caused by Anaplasma phagocytophilum. In the Netherlands, the bacterium is present in a few percent of Ixodes ricinus ticks, but only a specific subvariant is associated with human disease. Although the infection is often asymptomatic, the clinical course can be severe and unpredictable. Here, we describe three recent Dutch cases: two autochthonous cases with a severe course and one case acquired in the United States. All patients recovered rapidly after initiation of doxycycline following the final diagnosis. Awareness of tick-borne diseases other than Lyme disease is important for healthcare professionals in primary, secondary, and tertiary care, as well as for supporting (laboratory) specialties such as clinical chemistry and medical microbiology.