A nationwide seroprevalence study of Francisella tularensis in Denmark

IF 3.4 2区医学 Q2 INFECTIOUS DISEASES

Ticks and Tick-borne Diseases Pub Date : 2026-03-01 Epub Date: 2026-03-13 DOI:10.1016/j.ttbdis.2026.102625

Freja Gustafsson , Lasse Fjordside , Lene Holm Harritshøj , Bitten Aagaard Jensen , Christian Erikstrup , Dorte Kinggaard Holm , Susanne Gjørup Sækmose , Karen Angeliki Krogfelt , Charlotte Sværke Jørgensen , Helene Mens , Anne-Mette Lebech

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引用次数: 0

Abstract

Background

Francisella tularensis is the causative agent of tularaemia. The incidence of tularaemia has increased in Europe in recent years. Due to the non-specific symptoms and diverse clinical manifestations, potential underreporting may exist. Additionally, the recent expansion in tick-borne pathogens could have increased the risk of F. tularensis transmission. We therefore aimed to estimate the seroprevalence of F. tularensis in Danish blood donors and tick-exposed individuals.

Methods

Plasma samples from healthy blood donors collected in 2022 (n=999) from all five administrative regions in Denmark, samples from blood donors from the Capital region collected in 2024 (n=200), and samples from tick-exposed individuals diagnosed with Lyme borreliosis (n=200), were screened for F. tularensis IgG using a commercial ELISA test. Positive samples for IgG were further tested using an in-house agglutination diagnostic assay measuring total F. tularensis antibodies and tested for Brucella antibodies to control for cross-reactivity.

Results

A total of 31/1399 samples were confirmed for F. tularensis antibodies resulting in an overall seroprevalence of 2.2% (CI [1.5;3.3]). All F. tularensis positive samples were negative for Brucella antibodies. The seroprevalence ranged from 1.0%-4.0% within the Danish regions with no significant regional differences. In the Capital region the seroprevalence was 1.0% in 2022 compared to 2.5% in 2024 (P-value 0.45). No significant difference in seroprevalence between blood donors and tick-exposed individuals was observed.

Conclusion

The seroprevalence of F. tularensis in Denmark was modest and comparable to other European countries. The study indicates that tularaemia may be underdiagnosed in Denmark.

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丹麦全国土拉菌血清流行率研究

背景土拉菌是土拉菌血症的病原体。近年来，土拉菌病在欧洲的发病率有所上升。由于症状的非特异性和临床表现的多样性，可能存在潜在的漏报。此外，最近蜱传病原体的扩大可能增加了土拉菌病传播的风险。因此，我们的目的是估计丹麦献血者和接触蜱虫的个体中土拉菌的血清患病率。方法采用商业ELISA检测方法，对2022年丹麦5个行政区健康献血者（n=999）、2024年首都地区献血者（n=200）和诊断为莱姆病的蜱接触者（n=200）的血浆样本进行土拉螺旋体IgG检测。采用内部凝集诊断法对IgG阳性样本进行进一步检测，检测土拉菌总抗体，并检测布鲁氏菌抗体，以控制交叉反应性。结果共检出31/1399份土拉菌抗体，血清总阳性率为2.2% （CI[1.5;3.3]）。所有土拉菌阳性标本布鲁氏菌抗体均阴性。丹麦各地区血清阳性率为1.0%-4.0%，无显著地区差异。首都地区2022年血清阳性率为1.0%，2024年为2.5% （p值0.45）。在献血者和接触蜱虫的个体之间没有观察到明显的血清阳性率差异。结论丹麦土拉菌的血清阳性率较低，与欧洲其他国家相当。该研究表明，土拉菌血症在丹麦可能未被充分诊断。

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来源期刊

Ticks and Tick-borne Diseases INFECTIOUS DISEASES-MICROBIOLOGY

CiteScore

6.90

自引率

12.50%

发文量

185

审稿时长

6-12 weeks

期刊介绍： Ticks and Tick-borne Diseases is an international, peer-reviewed scientific journal. It publishes original research papers, short communications, state-of-the-art mini-reviews, letters to the editor, clinical-case studies, announcements of pertinent international meetings, and editorials. The journal covers a broad spectrum and brings together various disciplines, for example, zoology, microbiology, molecular biology, genetics, mathematical modelling, veterinary and human medicine. Multidisciplinary approaches and the use of conventional and novel methods/methodologies (in the field and in the laboratory) are crucial for deeper understanding of the natural processes and human behaviour/activities that result in human or animal diseases and in economic effects of ticks and tick-borne pathogens. Such understanding is essential for management of tick populations and tick-borne diseases in an effective and environmentally acceptable manner.