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Table 1.  

Pathogen or tick Tick life stage
Adult females Adult males Nymphs Larvae Not identified Total
Borrelia burgdorferi sensu lato 29 3 159 1 2 194
B. afzelii 10 1 115 1 2 132
B. garinii/B. bavariensis 7 1 24 0 0 32
B. burgdorferi sensu stricto 3 0 12 0 0 15
B. valaisiana 5 1 8 0 0 14
B. lusitaniae 1 0 1 0 0 2
B. spielmanii 3 0 3 0 0 6
Co-infections 0 0 4 0 0 4
Rickettsia spp. 14 0 69 37 0 120
   R. helvetica 12 0 56 36 0 104
   R. monacensis 1 0 6 1 0 8
   Candidatus R. mendelii 1 0 3 0 0 4
   New endosymbiont 0 0 1 0 0 1
   Candidatus R. thierseensis 0 0 1 0 0 1
   Not identified 0 0 2 0 0 2
   Candidatus Neoehrlichia mikurensis 5 1 46 1 1 54
   Anaplasma phagocytophilum 1 0 29 0 0 30
Babesia spp. 3 0 20 5 0 28
   B. microti 3 0 18 0 0 21
   B. divergens 0 0 1 0 0 1
   B.. venatorum 0 0 1 5 0 6
Relapsing fever borreliae            
   B. miyamotoi 1 0 20 2 1 24

Table 1. Tickborne pathogens detected in different life stages of ticks after tick bite, Austria, 2015–2018

Table 2.  

Variable Not infected, n = 457   Infected, n = 25 p value
No. or mean ± SD Median, % (IQR) No. or mean ± SD Median, % (IQR)
   M 214 46.8   12 48.0 1.000
   F 243 53.2   13 52.0 NA
Age, y 48.7 ± 14.5 48.5 (36.8–59.1)   52.4 ± 14.0 54.0 (42.9–58.6) 0.216
Use of repellent 17 3.7   2 8.0 0.258
No. ticks 1.3 ± 1.2 1.0 (1.0–1.0)   2.4 ± 3.8 1.0 (1.0–2.0) <0.001
Time, tick bite to blood test, d† 4.3 ± 4.0 4.0 (2.0–6.0)   3.9 ± 2.1 3.0 (2.0–5.0) 0.645
Duration of tick attachment, d 1.0 ± 2.9 1.0 (0.0–2.0)   1.2 ± 1.2 1.0 (0.0–2.0) 0.668
Tick location            
   Left leg 119 26.0   15 60.0 <0.001
   Right leg 130 28.4   13 52.0 0.022
   Left arm 53 11.6   6 24.0 0.106
   Right arm 55 12.0   4 16.0 0.530
   Head/neck 21 4.6   1 4.0 1.000
   Abdomen/chest 71 15.5   4 16.0 1.000
   Genital/pelvic area 111 24.3   5 20.0 0.811
   Back 46 10.1   4 16.0 0.314
   Antimicrobial drug‡ 30 6.6   0 0.0 0.39
   PCR positive 62 13.6   11 44.0 <0.001
   IgG§ 57 12.5   6 24.0 0.08
   IgM§ 30 6.6   2 8.0 0.58
   IgG and IgM§ 23 5.0   2 8.0 0.37
   History of erythema migrans 84 18.0   8 32.0 0.15
Tick engorgement            
   None 180 39.5   4 16.0 <0.001
   Slightly/partially 219 48.0   10 40.0 NA
   Fully 57 12.5   11 44.0 NA

Table 2. Comparison of persons infected and not infected with Borrelia burgdorferi sensu lato after tick bite, Austria, 2015–2018*

*IQR, interquartile range; NA, not applicable. †Time between tick bite and first blood test. ‡Received within 4 weeks before tick bite. §Presence of Borrelia-specific antibodies at the first visit.

Table 3.  

Parameter p value OR (95% CI)
Sex 0.818 0.90 (0.38–2.15)
Age 0.662 1.01 (0.98–1.04)
No. ticks 0.048 1.18 (1.00–1.39)
Tick PCR positive for B. burgorferi 0.001 4.39 (1.78–10.84)
Tick engorgement    
   Fully <0.001 9.52 (2.79–32.45)
   Slightly/partially 0.229 2.09 (0.63–6.98)
   Not engorged NA 1 (NA)

Table 3. Multiple logistic regression analysis for assessing risk for infection with Borrelia burgdorferi sensu lato after tick bite, Austria, 2015–2018*

*NA, not applicable; OR, odds ratio.


Infections With Tickborne Pathogens After Tick Bite, Austria, 2015-2018

  • Authors: Mateusz Markowicz, MD; Anna-Margarita Schötta, BSc; Dieter Höss, MD; Michael Kundi, PhD; Christina Schray, MD; Hannes Stockinger, PhD; Gerold Stanek, MD
  • CME / ABIM MOC Released: 3/18/2021
  • Valid for credit through: 3/18/2022, 11:59 PM EST
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Target Audience and Goal Statement

This activity is intended for infectious disease specialists and other physicians who care for patients at risk for Borrelia infection.

The goal of this activity is to evaluate variables associated with a higher risk for Borrelia infection after a tick bite.

Upon completion of this activity, participants will:

  • Assess characteristics of tick bites in the current study
  • Analyze results of molecular screening of ticks in the current study
  • Distinguish the rate of positive testing for Borrelia among patients in the current study
  • Evaluate risk factors for a positive Borrelia infection in the current study


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  • Mateusz Markowicz, MD

    Medical University of Vienna
    Vienna, Austria


    Disclosure: Mateusz Markowicz, MD, has disclosed no relevant financial relationships.

  • Anna-Margarita Schötta, BSc

    Medical University of Vienna
    Vienna, Austria


    Disclosure: Anna-Margarita Schötta, BSc, has disclosed no relevant financial relationships.

  • Dieter Höss, MD

    Private Medical Office
    Thiersee, Tyrol, Austria


    Disclosure: Dieter Höss, MD, has disclosed no relevant financial relationships.

  • Michael Kundi, PhD

    Medical University of Vienna
    Vienna, Austria


    Disclosure: Michael Kundi, PhD, has disclosed the following relevant financial relationships:
    Served as an advisor or consultant for: AVIR Green Hills Biotechnology AG; Valneva SE; Vivaldi Biosciences Inc.
    Received grants for clinical research from: Pfizer Inc.

  • Christina Schray, MD

    Medical University of Vienna
    Vienna, Austria


    Disclosure: Christina Schray, MD, has disclosed no relevant financial relationships.

  • Hannes Stockinger, PhD

    Medical University of Vienna
    Vienna, Austria


    Disclosure: Hannes Stockinger, PhD, has disclosed no relevant financial relationships.

  • Gerold Stanek, MD

    Medical University of Vienna
    Vienna, Austria


    Disclosure: Gerold Stanek, MD, has disclosed the following relevant financial relationships:
    Served as an advisor or consultant for: Valneva SE

CME Author

  • Charles P. Vega, MD

    Health Sciences Clinical Professor of Family Medicine
    University of California, Irvine School of Medicine


    Disclosure: Charles P. Vega, MD, has disclosed the following relevant financial relationships:
    Served as an advisor or consultant for: GlaxoSmithKline


  • Thomas J. Gryczan, MS

    Emerging Infectious Diseases 


    Disclosure: Thomas J. Gryczan, MS, has disclosed no relevant financial relationships.

CME Reviewer

  • Hazel Dennison, DNP, RN, FNP-BC, CHCP, CPHQ, CNE

    Associate Director, Accreditation and Compliance
    Medscape, LLC


    Disclosure: Hazel Dennison, DNP, RN, FNP-BC, CHCP, CPHQ, CNE, has disclosed no relevant financial relationships.

 Medscape, LLC staff have disclosed that they have no relevant financial relationships.

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Infections With Tickborne Pathogens After Tick Bite, Austria, 2015-2018

Authors: Mateusz Markowicz, MD; Anna-Margarita Schötta, BSc; Dieter Höss, MD; Michael Kundi, PhD; Christina Schray, MD; Hannes Stockinger, PhD; Gerold Stanek, MDFaculty and Disclosures

CME / ABIM MOC Released: 3/18/2021

Valid for credit through: 3/18/2022, 11:59 PM EST


Abstract and Introduction


The aim of this prospective study was to assess the risk for tickborne infections after a tick bite. A total of 489 persons bitten by 1,295 ticks were assessed for occurrence of infections with Borrelia burgdorferi sensu lato, Anaplasma phagocytophilum, Rickettsia spp., Babesia spp., Candidatus Neoehrlichia mikurensis, and relapsing fever borreliae. B. burgdorferi s.l. infection was found in 25 (5.1%) participants, of whom 15 had erythema migrans. Eleven (2.3%) participants were positive by PCR for Candidatus N. mikurensis. One asymptomatic participant infected with B. miyamotoi was identified. Full engorgement of the tick (odds ratio 9.52) and confirmation of B. burgdorferi s.l. in the tick by PCR (odds ratio 4.39) increased the risk for infection. Rickettsia helvetica was highly abundant in ticks but not pathogenic to humans. Knowledge about the outcome of tick bites is crucial because infections with emerging pathogens might be underestimated because of limited laboratory facilities.


Ticks are vectors for a variety of tickborne pathogens that cause human disease[1]. The diversity of tickborne pathogens has increased extensively in recent years, supported by progress in the molecular identification of microorganisms[2]. Clinical studies on the health-related impact of many emerging tickborne pathogens are scarce and information on the epidemiology is limited.

We undertook a comprehensive observational study in Austria to assess the incidence of recognized tickborne infections by applying clinical, serologic, and microbiological endpoints. We conducted a detailed risk analysis of contracting Lyme borreliosis. Our objective was to investigate whether variables such as confirmation of Borrelia burgdorferi sensu lato in ticks, duration of tick attachment, engorgement of ticks, and number of simultaneous tick bites have an impact on the risk for infection. Furthermore, we wanted to know whether the localization of a given tick bite and any previous contact with B. burgdorferi s.l. can affect this risk.