Molecular survey of Leptospira spp. and Bartonella spp. in Alaskan voles

Abstract

Leptospira spp. and Bartonella spp. are two Gram-negative bacterial genera responsible for important zoonotic diseases worldwide, yet they remain poorly studied in northern ecosystems. Out objective was to assess Bartonella and Leptospira prevalence in vole populations in Interior Alaska and examine potential associations between prevalence and human activities (landscape and resource modification from sled dog kennels and reindeer farms). I surveyed for Bartonella and Leptospira in three vole species, Clethrionomys rutilis, Microtus pennsylvanicus, and Alexandronomys oeconomus, collected from three different areas in Interior Alaska in the summer of 2024. Using conventional PCR, I targeted the 16S rRNA gene for Leptospira spp. and the 16S-23S internal transcribed spacer (ITS) region for Bartonella spp. While no voles were found positive for Leptospira, Bartonella DNA was detected in 38 of 229 voles. Five species of Bartonella were identified: B. henselae, B. grahamii, B. doshiae, B. rochalimae, and B. heixiaziensis. This is the first study to identify B. grahamii, B. doshiae, B. rochalimae, B. henselae, and B. heixiaziensis in Alaska, and the third to identify Bartonella in Alaskan voles. Bartonella prevalence varied significantly across all three areas, with an areawide prevalence of 16.5%. While Bartonella prevalence varied significantly on a geographical scale, anthropogenic disturbance was not found to be correlated with prevalence. These findings suggest that ecological and population-level factors may play an influential role in the transmission dynamics of Bartonella in small mammal populations. This study contributes to the understanding of bacterial pathogens in northern small mammal populations.