Diversity of Borrelia burgdorferi sensu lato in ticks and small mammals from different habitats

Abstract

Background Ixodid ticks are important vectors for zoonotic pathogens, with Ixodes ricinus being the most important in Europe. Rodents are hosts of immature life stages of I. ricinus ticks and are considered main reservoirs for tick-borne pathogens, e.g. Borrelia burgdorferi. The aim of this study was to analyse the prevalence as well as genospecies and sequence type (ST) diversity of Borrelia burgdorferi sensu lato in ticks and small mammals from central Germany and to elaborate on the influence of environmental and/or individual host and vector factors on Borrelia prevalence. Methods After species identification, 1167 small mammal skin samples and 1094 ticks from vegetation were screened by B. burgdorferi sensu lato real-time polymerase chain reaction, and positive samples were characterized by multilocus sequence typing. Generalized linear (mixed) models were used to estimate how seasonality, small mammal species/tick life stage and habitat affect individual infection status. Results In total, 10 small mammal species and three tick species, Ixodes ricinus, Ixodes inopinatus (both considered members of the I. ricinus complex) and Dermacentor reticulatus, were investigated. Borrelia DNA was detected in eight host species, i.e. the striped field mouse (Apodemus agrarius), the yellow-necked field mouse (Apodemus flavicollis), the wood mouse (Apodemus sylvaticus), the water vole (Arvicola amphibius), the bank vole (Clethrionomys glareolus), the field vole (Microtus agrestis), the common vole (Microtus arvalis), and the common shrew (Sorex araneus). Two species were Borrelia negative, the greater white-toothed shrew (Crocidura russula) and the pygmy shrew (Sorex minutus). The average prevalence was 6.2%, with two genospecies detected, Borrelia afzelii and Borrelia garinii, and at least three STs that had not been previously reported in small mammals. Borrelia prevalence in small mammals did not differ between seasons. Six genospecies of Borrelia—Borrelia afzelii, Borrelia valaisiana, Borrelia garinii, Borrelia lusitaniae, Borrelia spielmanii, and Borrelia burgdorferi sensu stricto—and 25 STs of Borrelia, of which 12 have not been previously described at all and five have not been previously reported in Germany, were detected in 13% of I. ricinus complex ticks. Prevalence was highest in adult females (25.3%) and lowest in nymphs (11.4%). Prevalence was significantly higher in ticks from grassland (16.8%) compared to forests (11.4%). Conclusions The high level of small mammal diversity in this region of Germany seems to be reflected in a wide variety of genospecies and STs of B. burgdorferi. Graphical abstract

Genetic analysis challenges the presence of Ixodes inopinatus in Central Europe: development of a multiplex PCR to distinguish I. inopinatus from I. ricinus

“…Sequencing of 16S rDNA is considered a gold standard for the identification of ticks and many other organisms, including bacteria. However, I. ricinus could not be differentiated from I. inopinatus by the commonly used 16S rDNA fragment [ 13 , 16 ] due to the high haplotype diversity of this gene [ 8 , 10 , 11 , 16 , 22 – 25 ]. The COI gene is another common marker used for species delineation within the animal kingdom (e.g., the BOLD [Barcode of Life Data System] database); however, similarly to 16S rDNA, its analyses do not have the power to detect potential hybridization between closely related species.…”

The Prevalence of Tick-Borne Encephalitis Virus in Wild Rodents Captured in Tick-Borne Encephalitis Foci in Highly Endemic Lithuania

“…Moreover, persistent TBEV infection for up to 100 dpi was reported in an experimentally infected M. arvalis in a study conducted by Achazi et al [ 15 ]. However, M. arvalis voles are not a common rodent species in TBEV studies mainly because their main type of habitat is grasslands and not forests and woodlands, as it is for I. ricinus ticks and most common rodents in TBEV studies— A. flavicollis and C. glareolus [ 60 ]. Knap et al [ 16 ] have suggested that A. flavicollis rodents might be less susceptible to TBEV infection compared to C. glareolus , although it has been implied that the rate of infection in a specific species might depend on the year.…”

Vector-Borne and Zoonotic Pathogens in Raccoon Dogs (Nyctereutes procyonoides) and Raccoons (Procyon lotor) from Schleswig-Holstein, Germany

“…with ct-values <34 and on Borreliella spp.-positive samples if the ct-values were <35. MLST was carried out as described by Schmidt et al [ 59 ] and Król et al [ 60 ].…”