Borrelia duttonii-like spirochetes parasitize Meriones persicus in East Azerbaijan Province of Iran.

In Iran, Borrelia persica and Borrelia microti/microti-like borreliae have been established as causative agents of tickborne relapsing fever (TBRF). However, the epidemiology of two previously described species, Borrelia balthazardi and Borrelia latyschewii (latychevi), has remained elusive for many years. We investigated Borrelia infection in various rodents and small mammals in the TBRF endemic East Azerbaijan Province, northwestern Iran, where B. perisca and B. balthazardi might coexist. Among trapped animals (n=210), a 16S real-time PCR detected Borrelia DNA in 11 Meriones persicus. Multilocus sequence analysis (MLSA) using six different loci, including four coding regions (flaB, glpQ, groEL, p66) and two non-coding (rrs, IGS) followed by phylogeny revealed considerable sequence identity between the borreliae detected, B. microti, and East African Borrelia duttonii, and Borrelia recurrentis. Our results indicate that B. microti and microti-like borreliae, including the specimens previously characterized in the south of Iran and the present study, are different ecotypes of B. duttonii, i.e., exhibiting a single species/entity or descendants of a recent common ancestor. Our findings also suggest that the species we had long coined as B. balthazardi and the microti-like borreliae detected herein might be the same.