PT - JOURNAL ARTICLE AU - Kamran Kadkhoda AU - Cecilia Dumouchel AU - Janna Brancato AU - Ainsley Gretchen AU - Peter J. Krause TI - Human seroprevalence of <em>Borrelia miyamotoi</em> in Manitoba, Canada, in 2011-2014: a cross-sectional study AID - 10.9778/cmajo.20170070 DP - 2017 Sep 06 TA - CMAJ Open PG - E690--E693 VI - 5 IP - 3 4099 - http://www.cmajopen.ca/content/5/3/E690.short 4100 - http://www.cmajopen.ca/content/5/3/E690.full AB - Background: Hard tick-borne relapsing fever caused by Borrelia miyamotoi has been reported in Russia, the Netherlands, Germany, Japan and the northeastern and upper midwestern United States. We sought to investigate the presence of B. miyamotoi infection in humans in Manitoba, Canada.Methods: Two hundred fifty sera collected from residents of Manitoba with suspected Lyme disease between 2011 and 2014 were tested for Borrelia burgdorferi antibody using a C6 peptide enzyme-linked immunosorbent assay (ELISA) followed by Western blot. Residual sera were then anonymized, stored at -80°C and subsequently thawed and tested for B. miyamotoi antibody using a 2-step glycerosphosphodiester phosphodiesterase-based ELISA and Western blot assay.Results: Twenty-four of the 250 (9.6%) sera tested positive for B. miyamotoi immunoglobulin G. Participants who were B. miyamotoi seropositive were predominantly male (54%) and younger on average than those who were seronegative (32 and 44 yr of age, respectively). Participants who were seropositive for B. burgdorferi were significantly more likely to be B. miyamotoi seropositive than those who were B. burgdorferi seronegative (20.3% v. 6.6%, respectively, odds ratio 3.6, 95% confidence interval 1.5-8.5). Interpretation: This initial report of human B. miyamotoi infection in Canada should raise awareness of hard tick-borne relapsing fever among clinicians and residents of areas in Canada and western North America where Lyme disease is endemic.