The Tick-Borne Diseases STING study: Real-time PCR analysis of three emerging tick-borne pathogens in ticks that have bitten humans in different regions of Sweden and the Aland islands, Finland

Cronhjort, Samuel; Wilhelmsson, Peter; Karlsson, Linda; Thelaus, Johanna; Sjödin, Andreas; Forsberg, Pia; Lindgren, Per-Eric

doi:10.1080/20008686.2019.1683935

Cited by 8 publications

(8 citation statements)

References 29 publications

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“…Samples with a cycle threshold (Ct) value higher than 30 were considered negative [ 40 ]. To confirm the initial putative findings of F. tularensis (Tul4+ samples), subsequent qPCRs were performed using the Francisella qPCR assays in Table 1 [ 40 , 41 , 42 , 43 ]. In brief, the DNA was pre-amplified (due to the limited amount of DNA) using the RepliG midi kit (Qiagen, Hilden, Germany), according to the manufacturer’s instructions.…”

Section: Methodsmentioning

confidence: 99%

Co-Occurrence of Francisella, Spotted Fever Group Rickettsia, and Midichloria in Avian-Associated Hyalomma rufipes

et al. 2022

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The migratory behavior of wild birds contributes to the geographical spread of ticks and their microorganisms. In this study, we aimed to investigate the dispersal and co-occurrence of Francisella and spotted fever group Rickettsia (SFGR) in ticks infesting birds migrating northward in the African-Western Palaearctic region (AWPR). Birds were trapped with mist nests across the Mediterranean basin during the 2014 and 2015 spring migration. In total, 575 ticks were collected from 244 birds. We screened the ticks for the species Francisella tularensis, the genus Francisella, and SFGR by microfluidic real-time PCR. Confirmatory analyses and metagenomic sequencing were performed on tick samples that putatively tested positive for F. tularensis during initial screenings. Hyalomma rufipes was the most common tick species and had a high prevalence of Francisella, including co-occurrence of Francisella and SFGR. Metagenomic analysis of total DNA extracted from two H. rufipes confirmed the presence of Francisella, Rickettsia, and Midichloria. Average nucleotide identity and phylogenetic inference indicated the highest identity of the metagenome-assembled genomes to a Francisella-like endosymbiont (FLE), Rickettsia aeschlimannii, and Midichloria mitochondrii. The results of this study suggest that (i) FLE- and SFGR-containing ticks are dispersed by northbound migratory birds in the AWPR, (ii) H. rufipes likely is not involved in transmission of F. tularensis in the AWPR, and (iii) a dual endosymbiosis of FLEs and Midichloria may support some of the nutritional requirements of H. rufipes.

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Section: Methodsmentioning

confidence: 99%

Co-Occurrence of Francisella, Spotted Fever Group Rickettsia, and Midichloria in Avian-Associated Hyalomma rufipes

et al. 2022

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“…holarctica or as sentinels for tularemia [ 36 , 38 , 41 , 43 , 44 , 47 , 54 , 57 , 58 , 59 , 60 , 61 ]. The role of ticks and mosquitoes for the transmission of tularemia in Europe likely differs between countries and is still under investigation [ 22 , 26 , 37 , 39 , 41 , 55 , 62 , 63 , 64 , 65 ].…”

Section: Tularemia In Germanymentioning

confidence: 99%

Francisella tularensis Subspecies holarctica and Tularemia in Germany

et al. 2020

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Tularemia is a zoonotic disease caused by Francisella tularensis a small, pleomorphic, facultative intracellular bacterium. In Europe, infections in animals and humans are caused mainly by Francisella tularensis subspecies holarctica. Humans can be exposed to the pathogen directly and indirectly through contact with sick animals, carcasses, mosquitoes and ticks, environmental sources such as contaminated water or soil, and food. So far, F. tularensis subsp. holarctica is the only Francisella species known to cause tularemia in Germany. On the basis of surveillance data, outbreak investigations, and literature, we review herein the epidemiological situation—noteworthy clinical cases next to genetic diversity of F. tularensis subsp. holarctica strains isolated from patients. In the last 15 years, the yearly number of notified cases of tularemia has increased steadily in Germany, suggesting that the disease is re-emerging. By sequencing F. tularensis subsp. holarctica genomes, knowledge has been added to recent findings, completing the picture of genotypic diversity and geographical segregation of Francisella clades in Germany. Here, we also shortly summarize the current knowledge about a new Francisella species (Francisella sp. strain W12-1067) that has been recently identified in Germany. This species is the second Francisella species discovered in Germany.

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“…In Sweden, the presence of Bartonella spp. in ticks has been investigated in two studies: one on 167 ticks [29] collected in central Sweden and the second on 1663 ticks collected in Sweden and the Åland Islands, Finland [30]. Both studies failed to demonstrate Bartonella spp.…”

Section: Discussionmentioning

confidence: 99%

Bartonella spp. seroprevalence in tick-exposed Swedish patients with persistent symptoms

et al. 2021

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Background Bartonella spp. are emerging pathogens transmitted by arthropod vectors, possibly including ticks. We have investigated signs of bartonellosis in Swedish patients with presumed tick-bite exposure and symptom duration of at least 6 months. Methods Serological testing for Bartonella henselae and Bartonella quintana was performed in 224 patients. Symptoms, tick exposure, evidence of co-infection and previous treatments were evaluated. Seropositive patients were compared to a matched group (twofold larger and negative serology) from the same study cohort. Results Seroprevalence was 7% for B. henselae and 1% for B. quintana, with one patient testing positive to both agents. Tick bites were reported by 63% of the patients in the seropositive group and 88% in the seronegative group and presumed tick exposure was more common in the seronegative group. Animal contact was equally common in both groups, along with reported symptoms. The most common symptoms were fatigue, muscular symptoms, arthralgia and cognitive symptoms. Exposure to co-infections was evenly distributed in the seropositive and seronegative groups. Conclusions Antibodies to Bartonella were more common in this cohort of patients than in cohorts of healthy Swedish blood donors in previous studies but lower than those in blood donors from southern Europe. Positive Bartonella serology was not linked to any specific symptom, nor to (suspected) tick-bite exposure. Graphical abstract

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The Tick-Borne Diseases STING study: Real-time PCR analysis of three emerging tick-borne pathogens in ticks that have bitten humans in different regions of Sweden and the Aland islands, Finland

Cited by 8 publications

References 29 publications

Co-Occurrence of Francisella, Spotted Fever Group Rickettsia, and Midichloria in Avian-Associated Hyalomma rufipes

Co-Occurrence of Francisella, Spotted Fever Group Rickettsia, and Midichloria in Avian-Associated Hyalomma rufipes

Francisella tularensis Subspecies holarctica and Tularemia in Germany

Bartonella spp. seroprevalence in tick-exposed Swedish patients with persistent symptoms

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