Two cases of tick-borne transmitted tularemia on Southern Zealand, Denmark

Francisella tularensis is a zoonotic bacterium which causes the infection tularemia. It colonizes invertebrates and vertebrates, counting wildlife animals and rodents. Humans can become infected through several pathways including contaminated food, water, and handling animals and due to bites from vectors. Ticks are known to cause tularemia in humans, though their role as a disease transferring vector is not well understood. We describe two case reports of tularemia transferred by ticks on Southern Zealand, Denmark. Case 1: A 49-year-old woman presented with lymphadenopathy and an unhealed sifting wound after a tick bite. Serology tests for F. tularensis were initially negative but turned positive five weeks after symptom onset, when abscess drainage was performed. Gentamicin and ciprofloxacin treatment improved the patient’s clinical condition, and she completely recovered. Case 2: A 74-year-old man presented with malaise, fever, and an abdominal ulcer allegedly caused after a vector bite. CRP and leukocytes were increased, while serology tests for F. tularensis were negative. Doxycycline treatment improved the patient’s clinical condition, and he completely recovered. Three weeks after symptom onset, renewed serology tests for F. tularensis were positive.