Combining deep sequencing and conventional molecular approaches reveals broad diversity and distribution of fleas and Bartonella in rodents and shrews from Arctic and Subarctic ecosystems

• Published in: Parasites & Vectors
• Main Authors: Kayla J. Buhler, Champika Fernando, Janet E. Hill, Terry Galloway, Suzanne Carriere, Heather Fenton, Dominique Fauteux, Emily J. Jenkins
• Format: Article in Journal/Newspaper
• Language: English
• Published: BMC 2022
• Subjects: Zoonoses; Bartonella; Vector-borne disease; Fleas; Rodents; Arctic; Infectious and parasitic diseases; RC109-216; Canada; Climate change; Subarctic
• Online Access: https://doi.org/10.1186/s13071-022-05446-w; https://doaj.org/article/69d0a0e76a654e4f87837a37ee57fdc5

Abstract Background Bartonella are intracellular bacteria that are transmitted via animal scratches, bites and hematophagous arthropods. Rodents and their associated fleas play a key role in the maintenance of Bartonella worldwide, with > 22 species identified in rodent hosts. No studies have addressed the occurrence and diversity of Bartonella species and vectors for small mammals in Arctic and Subarctic ecosystems, which are increasingly impacted by invasive species and climate change. Methods In this study, we characterized the diversity of rodent fleas using conventional PCR targeting the mitochondrial cytochrome c oxidase II gene (COII) and Bartonella species in rodents and shrews (n = 505) from northern Canada using conventional PCR targeting the ITS (intergenic transcribed spacer) region and gltA (citrate synthase) gene. Metagenomic sequencing of a portion of the gltA gene was completed on a subset of 42 rodents and four rodent flea pools. Results Year, total summer precipitation the year prior to sampling, average minimum spring temperature and small mammal species were significant factors in predicting Bartonella positivity. Occurrence based on the ITS region was more than double that of the gltA gene and was 34% (n = 349) in northern red-backed voles, 35% (n = 20) in meadow voles, 37% (n = 68) in deer mice and 31% (n = 59) in shrews. Six species of Bartonella were identified with the ITS region, including B. grahamii, B. elizabethae, B. washoensis, Candidatus B. rudakovii, B. doshiae, B. vinsonii subsp. berkhoffii and subsp. arupensis. In addition, 47% (n = 49/105) of ITS amplicons had < 97% identity to sequences in GenBank, possibly due to a limited reference library or previously unreported species. An additional Bartonella species (B. heixiaziensis) was detected during metagenomic sequencing of the gltA gene in 6/11 rodents that had ITS sequences with < 97% identity in GenBank, highlighting that a limited reference library for the ITS marker likely accounted for low sequence similarity in ...