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

Abstract

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.

Tularemia treatment: experimental and clinical data

“…Table 6 summarizes data from tularemia case series with a predominance of the UG or GL forms. Many other sporadic UG or GL tularemia cases have been reported in several countries but with similar findings than those reported in case series ( Pérez-Castrillón et al, 2001 ; Jackson et al, 2012 ; Sobolewska-Pilarczyk et al, 2014 ; Boone et al, 2015 ; Formińska et al, 2015 ; Calin et al, 2017 ; Pekova et al, 2017 ; Whitten et al, 2017 ; Haulrig et al, 2020 ; Kubiliute et al, 2021 ). The UG and GL forms are predominant worldwide, except in some countries such as Turkey (see below).…”

The clinical spectrum of tularemia—Two cases

“…Due to environmental and climatic changes the geographical distribution of vector-borne infections is changing and incidences increasing [ 6 ]. F. tularensis has been detected in increasingly new settings and in a wide range of wild species [ [1] , [2] , [3] ] and more cases have recently been reported from Sweden and a few cases from Denmark [ 1 , 7 , 8 ].…”

“…Fluoroquinolones, tetracyclines and aminoglycoside are all effective therapy for F. tularensis with cure rates varying between 60–100 % [ 11 ], because of the toxicity of aminoglycosides and the need for intravenous administration, tetracyclines and fluoroquinolones are first-line drugs for treatment of mild to moderate tularemia and should be given for 14–21 days depending on clinical status [ 4 , 12 ]. Some studies have reported tetracyclines to have higher rates of relapse compared to fluoroquinolones [ 7 , 11 ]. Our patients both reported marked improvement of symptoms following antimicrobial treatment and no relapse or subsequent complications were seen, but they also reported to be suffering from fatigue, myalgia or shortness of breath the following 2–3 months.…”

Laboratory Methods for Detection of Infectious Agents and Serological Response in Humans With Tick-Borne Infections: A Systematic Review of Evaluations Based on Clinical Patient Samples

“…The presence of the less virulent F. tularensis subsp. holarctica in European ticks has been described (19)(20)(21), but transmission of tularemia via ticks is relatively uncommon (53,75,76). Laboratory confirmation of tularemia consists of detecting the bacteria in a biological sample and/or detecting a specific antibody response.…”