Humans infected with relapsing fever spirochete Borrelia miyamotoi, Russia

Abstract

Borrelia miyamotoi is distantly related to B. burgdorferi and transmitted by the same hard-body tick species. We report 46 cases of B. miyamotoi infection in humans and compare the frequency and clinical manifestations of this infection with those caused by B. garinii and B. burgdorferi infection. All 46 patients lived in Russia and had influenza-like illness with fever as high as 39.5°C; relapsing febrile illness occurred in 5 (11%) and erythema migrans in 4 (9%). In Russia, the rate of B. miyamotoi infection in Ixodes persulcatus ticks was 1%-16%, similar to rates in I. ricinus ticks in western Europe and I. scapularis ticks in the United States. B. miyamotoi infection may cause relapsing fever and Lyme disease-like symptoms throughout the Holarctic region of the world because of the widespread prevalence of this pathogen in its ixodid tick vectors.

Figure 1

Percentage of Ixodes persulcatus (I. p.) and I. ricinus (I. r.) ticks infected with Borrelia miyamotoi in Russia. The number of ticks that were tested is given in parenthesis. Star indicates study location of human B. miyamotoi infection.

Figure 2

Examples of relapsing fever episodes in 2 patients with Borrelia miyamotoi infection. Arrows indicate the timing of tick bite, hospital admission, PCR testing, anti-borreliae immunoglobulin (Ig) M testing, and initiation of antimicrobial drug therapy.

Figure 3

Phylogenetic tree of Borrelia spp. detected in persons and ticks, based on flagellin gene fragment (A) and16S rRNA gene fragment (B). Sequences were aligned and analyzed by using MEGA4.1 software (www.megasoftware.net). Genetic trees were constructed from the partial nucleotide sequences of the flagellin gene and the 16S rRNA gene by using the Kimura 2-parameter model and the unweighted pair group method with arithmetic mean. Arrow indicates the 16 Borrelia spp. from Yekaterinburg in 2009 that had the same nucleotide sequence. Circles indicate sequences that we listed in GenBank (accession nos. GU797331–GU797346 and JF951378–JF951392). Sequences for B. burgdorferi sensu lato and relapsing fever borreliae are shown for comparison. Scale bars indicate genetic distance.