Serological evidence for human granulocytic ehrlichiosis in Western Austria

In order to evaluate the seroprevalence of human granulocytic ehrlichiosis in western Austria, sera from 357 Tyrolean blood donors were tested by an immunofluorescence assay. To assess the concomitant seroreactivity against Borrelia burgdorferi sensu lato, sera were further investigated by enzyme-linked immunoassay and Western blot. Thirty-two sera (9.0%) showed antibodies to Anaplasma phagocytophilum at a titre of 1:128 or higher, and 30 (8.4%) were seroreactive against Borrelia burgdorferi sensu lato. Infection with these two pathogens seems to occur in all Tyrolean districts except Landeck, the most upstream district of the Inn River Valley.