Phyloproteomic and functional analyses do not support a split in the genus Borrelia (phylum Spirochaetes)

Background The evolutionary history of a species is frequently derived from molecular sequences, and the resulting phylogenetic trees do not include explicit functional information. Here, we aimed to assess the functional relationships among bacteria in the Spirochaetes phylum, based on the biological processes of 42,489 proteins in reference proteomes of 34 Spirochaetes species. We tested the hypothesis that the species in the genus Borrelia might be sufficiently different to warrant splitting them into two separate genera. Results A detrended canonical analysis demonstrated that the presence/absence of biological processes among selected bacteria contained a strong phylogenetic signal, which did not separate species of Borrelia. We examined the ten biological processes in which most proteins were involved consistently. This analysis demonstrated that species in Borrelia were more similar to each other than to free-life species (Sediminispirochaeta, Spirochaeta, Sphaerochaeta) or to pathogenic species without vectors (Leptospira, Treponema, Brachyspira), which are highly divergent. A dendrogram based on the presence/absence of proteins in the reference proteomes demonstrated that distances between species of the same genus among free-life or pathogenic non-vector species were higher than the distances between the 19 species (27 strains) of Borrelia. A phyloproteomic network supported the close functional association between species of Borrelia. In the proteome of 27 strains of Borrelia, only a few proteins had evolved separately, in the relapsing fever and Lyme borreliosis groups. The most prominent Borrelia proteins and processes were a subset of those also found in free-living and non-vectored pathogenic species. In addition, the functional innovation (i.e., unique biological processes or proteins) of Borrelia was very low, compared to other genera of Spirochaetes. Conclusions We found only marginal functional differences among Borrelia species. Phyloproteomic networks that included all pairwise combinations between species, proteins, and processes were more effective than other methods for evaluating the evolutionary relationships among taxa. With the limitations of data availability, our results did not support a split of the arthropod-transmitted spirochaetes into the proposed genera, Borrelia and Borreliella

Regarding the identification of Rhipicephalus ticks in the western Mediterranean: a comment on Gago et al. (2022)

Dear Editor, I read with attention the paper by Gago et al. (2022) that appeared in a recent issue of Ticks and Tick-borne Diseases with the title “Patterns of adult tick parasitization of coexisting European (Erinaceus europaeus) and Algerian (Atelerix algirus) hedgehog populations in eastern Iberia” (https://www.sciencedirect.com/science/article/pii/S1877959 × 22001509). I would like to call your attention to several concerning issues I found in the paper, namely (i) the lack of reliable identifications of the ticks, (ii) the questionable statistical treatment of weather data, and (iii) the poor Methods section, lacking adequate explanations of the protocols; and (iv) the absence of supplementary material including the database of the study and availability of voucher tick specimens..

An Agenda for Research of Uncovered Epidemiological Patterns of Tick-Borne Pathogens Affecting Human Health

The panorama of ticks and tick-borne pathogens (TBP) is complex due to the many interactions among vertebrates, vectors, and habitats, occurring at different scales. At a broad spatial range, climate and host availability regulate most tick processes, including questing activity, development, and survival. At a local scale, interactions are obscured by a high indeterminacy, making it arduous to record in field surveys. A solid modelling framework could translate the local/regional empirical findings into larger scales, shedding light on the processes governing the circulation of TBP. In this opinion paper, we advocate for a re-formulation of some paradigms in the research of these outstanding cycles of transmission. We propose revisiting concepts that faced criticisms or lacked solid support, together with the development of a conceptual scheme exploring the circulation of TBP under a range of conditions. We encourage (i) an adequate interpretation of the niche concept of both ticks and vertebrate/reservoir hosts interpreting the (a)biotic components that shape the tick’s niche, (ii) an assessment of the role played by the communities of wild vertebrates on the circulation of pathogens, and (iii) the development of new approaches, based on state-of-the-art epidemiological concepts, to integrate findings and modelling efforts on TBP over large regions

Libro: Ticks of the Southern Cone of America: Diagnosis, Distribution, and Hosts with Taxonomy, Ecology and Sanitary Importance

Este libro escrito por Santiago Nava, José Venzal, Daniel González-Acuña, Thiago Martins y Alberto A. Guglielmone, supone una adición fundamental al conocimiento que se ha venido acumulando sobre las garrapatas que colonizan el Cono Sur de América. En un formato adecuado para su lectura o consulta, los autores presentan tanto descripciones como abundantes ilustraciones, de una extraordinaria calidad, de las especies de garrapatas pertenecientes a las familias Ixodidae y Argasidae que ha sido citadas para la zona.Asociación Parasitológica Argentin

Garrapatas. Un vector emergente en España

Las garrapatas constituyen un grupo de artrópodos de inmensa importancia en la Salud Pública por actuar como vectores de una amplia variedad de agentes patógenos. Todas las especies son parásitos temporales obligados y deben alimentarse de sangre de los vertebrados para completar su ciclo vital. Tienen un ciclo vital complejo, que en la familia Ixodidae consiste en tres estadios diferentes, que pueden alimentarse en tres hospedadores vertebrados diferentes, mientras que en la familia Argasidae pueden ser hasta 9 estadios distintos. Las primeras son conocidas normalmente como “garrapatas duras” como oposición al nombre común de los argásidos, conocidas como “garrapatas blandas”..

Ticks and tick-borne pathogens on the rise

Editorial.Peer Reviewe

Towards a multidisciplinary approach to the study of tick-borne diseases

Editorial.Peer Reviewe

A global set of Fourier-transformed remotely sensed covariates for the description of abiotic niche in epidemiological studies of tick vector species

[Background]: Correlative modelling combines observations of species occurrence with environmental variables to capture the niche of organisms. It has been argued for the use of predictors that are ecologically relevant to the target species, instead of the automatic selection of variables. Without such biological background, the forced inclusion of numerous variables can produce models that are highly inflated and biologically irrelevant. The tendency in correlative modelling is to use environmental variables that are interpolated from climate stations, or monthly estimates of remotely sensed features. [Methods]: We produced a global dataset of abiotic variables based on the transformation by harmonic regression (time series Fourier transform) of monthly data derived from the MODIS series of satellites at a nominal resolution of 0.1°. The dataset includes variables, such as day and night temperature or vegetation and water availability, which potentially could affect physiological processes and therefore are surrogates in tracking the abiotic niche. We tested the capacities of the dataset to describe the abiotic niche of parasitic organisms, applying it to discriminate five species of the globally distributed tick subgenus Boophilus and using more than 9,500 published records. [Results]: With an average reliability of 82%, the Fourier-transformed dataset outperformed the raw MODIS-derived monthly data for temperature and vegetation stress (62% of reliability) and other popular interpolated climate datasets, which had variable reliability (56%-65%). The transformed abiotic variables always had a collinearity of less than 3 (as measured by the variance inflation factor), in contrast with interpolated datasets, which had values as high as 300. [Conclusions]: The new dataset of transformed covariates could address the tracking of abiotic niches without inflation of the models arising from internal issues with the descriptive variables, which appear when variance inflation is higher than 10. The coefficients of the harmonic regressions can also be used to reconstruct the complete original time series, being an adequate complement for ecological, epidemiological, or phylogenetic studies. We provide the dataset as a free download under the GNU general public license as well as the scripts necessary to integrate other time series of data into the calculations of the harmonic coefficients.Parts of this work were supported by EU FP7 ANTIGONE project number 278976.Peer Reviewe

Evolution of Tick Vaccinology Highlights Changes in Paradigms in This Research Area

Ticks and tick-borne diseases affect human and animal health worldwide. Although some tick-protective antigens have been identified and characterized, further research is needed for the development and application of effective anti-tick vaccines, which currently are unavailable for human protection. To study the trends and gaps in anti-tick vaccine approaches, herein we used scientometric analysis to evaluate several aspects of tick vaccinology. Co-authorship and citations networks pointed out two main research fronts, one focused on the laboratory protocols driving the recognition of candidate antigens and the other devoted to field experiments of protection against ticks. The analysis demonstrated the prominence of research in European countries on the topic. The scientometric approach allowed the recognition of isolated teams working casually on the topic, the lack of cooperation between middle- and low-income countries, and the need for sustained and integrated research. Most important, we identified a considerable lack of new candidates for vaccine development, as well as the participation of African and Asian countries. These results provide significant insights obtained from bibliographical analysis, suggest the strength and weaknesses in this field of research, and highlight new directions to advance in the development of effective vaccines for the control of tick infestations and tick-borne pathogens