Human granulocytic ehrlichiosis in Europe: clinical and laboratory findings for four patients from Slovenia.

Febrile illnesses following a tick bite in patients from Slovenia were evaluated for an ehrlichial etiology. A case of acute human granulocytic ehrlichiosis (HGE) was confirmed by seroconversion to the HGE agent or molecular identification of ehrlichial organisms. Acute infection with the HGE agent was confirmed in four patients. None of the patients had detectable antibodies to the HGE agent at their first visit, but polymerase chain reaction analysis was positive for three patients. All four patients subsequently seroconverted to the HGE agent as shown by high titers of antibody. Clinical features and laboratory findings were similar to those in reports from the United States, although the disease course was relatively mild in the Slovenian cases. All patients recovered rapidly and without sequelae, although only two received antibiotic therapy (of whom only one was treated with doxycycline). HGE is an emerging tick-borne disease in the United States and should now be included in the differential diagnosis of febrile illnesses occurring after a tick bite in Europe.