Varying clinical picture and course of human granulocytic ehrlichiosis. Twelve Scandinavian cases of the new tick-borne zoonosis are presented

In the twelve clinical cases of human granulocytic ehrlichiosis (HGE) so far identified in Scandinavia (ten in Sweden, two in Norway), clinical presentation varied from a mild febrile illness to a severe septic condition with such systemic complications as acute respiratory distress syndrome (ARDS). Laboratory verification was based on PCR (polymerase chain reaction) in ten cases, and on serology in two cases. Sequence analysis of 16S rDNA showed the infectious agents to belong to the Ehrlichia phagocytophila genogroup. Seroprevalence data indicate widespread human exposure to granulocytic Ehrlichia; mean seroprevalence, 15-20% of 1,000 clinical sera from tick-exposed patients (mainly from Sweden and Norway). Proposals for diagnostic criteria and procedures, and case management are presented in the article.