Serological evidence of Ehrlichia infection in Swedish Lyme borreliosis patients

We studied sera from patients who had participated in a prospective study o f borreliosis in Sweden and had acquired tick bites in areas of the country with a high prevalence of granulocytic ehrlichial infections in animals. T he sera were examined for IgG anti Ehrlichia antibodies by an indirect immu nofluorescence assay using locally isolated bovine Ehrlichia antigen. Confi rmation of the serological results was done at the Unite des Rickettsies, M arseille, France. Three out of 37 of the investigated patients and 1 out of 100 investigated healthy blood donors had significant antibody titres to g ranulocytotropic Ehrlichiae. No patient or blood donor had specific antibod y titres to Ehrlichia chaffeensis. These data suggest that Scandinavian Ehr lichia species can infect and evoke immunological response in tick-exposed humans.