Prolonged course of tick-borne ulceroglandular tularemia in a 20-year-old patient in Germany--case report and review of the literature

Methods: A 20-year-old female patient presented with painful axillary lymphadenopathy. She reported a tick bite five months ago in her right hand followed by fever, chills and regional lymphadenopathy. Empiric antibiotic treatment with doxycyclin and ciprofloxacin had led to defervescence but no change in painful lymph node swellings. Surgical removal of a cubital lymph node had already been performed three months after the tick bite. Methods: Laboratory findings were normal except for moderate elevation of C-reactive protein. Serology confirmed the suspected clinical diagnosis of ulceroglandular tularemia. Retrospective real-time PCR (markers fopA and tul4) for Francisella tularensis from the previously removed lymph node (paraffin tissue blocks) was negative. Methods: Clinical presentation and serological test results were consistent with a prolonged course of tick-borne ulceroglandular tularemia associated with reactive lymph node swelling. The patient requested surgical removal of the painful axillary lymph node. Histology showed reticulocytic, abscess forming lymphadenitis with pseudotuberculosis type of granulomatosis and negative acid-fast staining. Blood culture, capture ELISA and real-time PCR for Francisella tularensis performed on material from the lymph node preparations were negative. A complete recovery was achieved without renewed antibiotic treatment.

Conclusions: According to recent seroprevalence studies, the emergence of tularemia as a rare zoonosis in Germany is clinically underestimated. This case report illustrates possible appearance of the disease in other than known risk groups (e.g. hunters, lumbermen). Ectoparasites like infected ticks have to be considered as vectors, even in non-endemic regions.