The toads Rhinella spp. are in constant contact with humans and domestic animals and are commonly parasitized by ticks, which are also potential vectors of pathogenic microorganisms, such as apicomplexans and rickettsia. However, little is known about microorganisms associated with toad ticks. In this work, we molecularly evaluated the presence of Rickettsia spp. and hemogregarines in ticks of Rhinella horribilis and R. humboldti in the Colombian Caribbean, finding two different species of Rickettsia: the colombianensi strain and one close to R. bellii. In the case of hemogregarines, since only 18S gene sequences are available, it is difficult to define species and place them correctly in a phylogeny, but most of our samples show a 99% identity with Hemolivia stellata, while others identical to each other seem to form another clade within this genre. All collected ticks were identified as Amblyomma dissimile, representing the first time that H. stellata was recorded in this tick. The prevalence of both microorganisms was very high, which makes it necessary to generate robust phylogenies to clarify their taxonomic diversity and to correctly define their ecological role and pathogenicity, which should be taken into account in amphibian conservation plans and veterinary medicine.

The primary aim of this study was to evaluate the performance of four DNA extraction methods on a collection of 200 sub-optimally stored Ixodes ricinus ticks from Southeastern Norway (177 nymphs, 11 males and 12 females). The methods were ammoniium hydroxide hydrolysis of homogenised or intact ticks and two commercial silica membrane-based kits, the QIAGEN Blood and Tissue kit and the QIAGEN Mini kit. DNA was evaluated by spectrophotometry, fluorometry, agarose gel electrophoresis and quantitative PCR. The second aim was to compare methods of evaluating the yield and purity. All four extraction methods provided amplifiable DNA, but the yield was variable (median 151 ng, range 0.13 to 4500 ng). DNA yields were not significantly different across the methods. Nine of 200 samples were inhibitory, all of which were ammonium hydroxide extracts of homogenised ticks. DNA purity, as judged by A_260/280 ratios, was low; it was highest (mean = 1.63) for the Qiagen Blood and Tissue kit with the other methods showing values averaging 1.44. DNA yield measurements using qPCR, fluorometry (Qubit), drop spectrophotometry (NanoDrop) and gel electrophoresis (E-gels) correlated poorly, r ranging from <0 to 0.9 with no systematic pattern (average 0.4), probably reflecting the effects of low purity, low concentrations and differing amounts of single- and double-stranded DNA. Neoehrlichia mikurensis and Borrelia burgdorferi s.l. were detected in 5 and 13% of samples, respectively by qPCR. Our findings indicate that for the purposes of qPCR analysis, ammoniium hydroxide hydrolysis of intact ticks, a very cheap and simple method is as good as any of the other methods tested.

The distribution range of the taiga tick, Ixodes persulcatus, has increased in the last decade in Northern Europe. We performed samplings at nine locations in Nordland County, east and northeast of Brønnøysund, south of the Arctic Circle in July 2023. Four of 62 ticks collected were identified as I. persulcatus (one female, two males and one nymph), the remaining were identified as Ixodes ricinus (9 females, 2 males and 47 nymphs). This is the first report of I. persulcatus in Norway. Given the importance of I. persulcatus as vector of Borrelia burgdorferi sensu lato and more pathogenic subtypes of the tick-borne encephalitis virus, more research should be done focusing on its distribution, ecology and associated pathogens in Norway.

Background: Borrelia burgdorferi sensu lato (s. l.) and Neoehrlichia mikurensis are the most prevalent pathogenic bacteria found in Ixodes ricinus in Norway. Here we evaluate the prevalence of both bacteria and the density of infected ticks, key factors to assess the human infection risk. The study was performed in one location in southern Norway. Results: An overall prevalence of 12% for B. burgdorferi s. l. and 8% for N. mikurensis was found. The most prevalent B. burgdorferi s. l. genospecies was Borrelia afzelii , followed by Borrelia burgdorferi sensu stricto and Borrelia garinii. The highest density of infected nymphs with B. burgdorferi s. l. was in May and the lowest was in November. In the case of N. mikurensis , the highest density of infected nymphs was found in September and the lowest in November. B. burgdorferi s. l. prevalence was negatively correlated with tick density. Conclusions: Our results highlight the importance of assessing not only pathogen prevalences but also tick population densities. Extended periods of surveillance in questing ticks are necessary to understand the intricate dynamics of ticks and tick-borne pathogens.