Genetic diversity of Borrelia burgdorferi sensu stricto: Novel strains from Mexican wild rodents

Rhipicephalus sanguineus Complex in the Americas: Systematic, Genetic Diversity, and Geographic Insights

The Rhipicephalus sanguineus group encompasses at least 12 validated species of Palearctic and Afrotropical hard ticks, which are relevant in veterinary medicine and public health. The taxonomy of R. sanguineus s.s., has been particularly intensely debated, due to its wide geographic distribution, morphological variants, parasite-host associations, and its capacity and vectorial competence for the transmission of several pathogens. By sequencing mitochondrial markers, it was possible to identify the existence of multiple lineages, among which the Tropical and the Temperate lineages stand out, particularly in America. However, the northern limit between these lineages is not clear due to the lack of extensive sampling across Mexico. For this reason, the aim of the present study was to determine the genetic diversity and structure of the R. sanguineus group in Mexico and to compare it with the populations reported in the Americas, in order to propose the northern limit of the R. sanguineus Tropical lineage and the potential regions of sympatry with R. sanguineus s.s. The findings of this study now confirm the presence of R. sanguineus s.s. in Mexico, showing a subtle genetic structure and high genetic diversity throughout its distribution in the Americas. In contrast, the Tropical lineage seems to be genetically less diverse in its overall distribution in the Americas. The genetic diversity of these two independent lineages could have important epidemiological implications in the transmission of tick pathogens.

Borrelia in neotropical bats: Detection of two new phylogenetic lineages

The genus Borrelia encompasses 50 spirochetal species, several of which are pathogenic and have been detected in a wide range of mammals, especially rodents and cervids. Although the order Chiroptera is the second most diverse mammalian order, and borreliosis represents a human and veterinary health problem in endemic countries, few studies have previously reported infections of Borrelia in these flying mammals. For this reason, the aim of the present study was to detect the presence of, and to analyze the diversity of Borrelia species in several bat species from Mexico. A total of 69 bats belonging to 11 species were collected and molecular detection of Borrelia was performed by amplifying three genes using specific primers. Only five individuals of four bat species (Saccopteryxbilineata, Choeroniscus godmani, Sturnira parvidens and Lasiurus cinereus) tested positive for Borrelia DNA. We now show the first Borrelia record in Mexican bats from two different ecosystems, where previously several potential vector species of the genus Ixodes and Ornithodoros had been reported. The Borrelia sequences obtained from the bats revealed two new putative lineages, one from the relapsing fever group and the second one belonging to the Borrelia burgdorferi s.l. complex, both of which are related to zoonotic species. These results highlight the importance of bats as potential hosts of Borrelia, and the imperative need of active surveillance in flying mammals in order to understand their potential role in the life cycle of this bacteria genus.