BackgroundBlacklegged ticks, Ixodes scapularis are vectors of the tick-borne pathogens Borrelia burgdorferi, Anaplasma phagocytophilum and Babesia microti. Recently, the I. scapularis-borne bacterium Borrelia miyamotoi has been linked to human illness in North America. The range of this tick is expanding in Canada which may increase the potential for human exposure to these agents.MethodsIn this study, 4938 I. scapularis ticks collected in 2012 were tested following a newly developed PCR-based testing protocol to determine the prevalence of infection with B. miyamotoi and other pathogens in I. scapularis in Canada.ResultsBorrelia miyamotoi was detected in blacklegged ticks from all provinces except Newfoundland, although the infection prevalence was low (<1%). There was significant variation among provinces in the prevalence of infection of ticks with B. burgdorferi and A. phagocytophilum, but not with B. miyamotoi.ConclusionsGiven the widespread distribution of B. miyamotoi, infection due to this agent should be considered in patients who have been exposed to blacklegged ticks in Canada.

A 2-year capture-mark-recapture study was conducted in southern Manitoba, Canada, to test for an association between the duration of Sin Nombre virus (SNV) infection in deer mice (Peromyscus maniculatus) and virus shedding. Hantavirus-specific IgG antibodies were detected in 22.2% of captured deer mice, and recently infected deer mice were identified based on the detection of low-avidity IgG antibodies. SNV RNA was detected in blood samples from the majority of seropositive deer mice with no significant difference in the association of SNV RNA between the low- and high-avidity groups (57.8% and 52.1%, respectively). A small subset of seropositive mice (11.6%) had detectable SNV RNA in oropharyngeal fluids (OPF) or urine. A greater proportion of deer mice with low-avidity antibodies had SNV RNA in OPF or urine compared with rodents with high-avidity antibodies (21% versus 6.8%, respectively). This is the first study of naturally infected deer mice to provide evidence that recently infected mice are more likely to shed SNV and thus might represent a greater risk of human infection.

Multilocus sequence typing of 31 stx-carrying Escherichia coli O26:H11 strains isolated in Canada between 1999 and 2003 revealed a high degree of genetic relatedness at 10 loci, suggesting either that this is a clonal serotype (similar to O157:H7) or that additional genetic loci need to be examined.Shiga toxin-producing Escherichia coli (STEC) serotype O26:H11 is the second most common serotype of STEC identified in Canada, behind O157:H7 (12). STEC O26:H11 naturally occurs in cattle, diarrheic calves, and feedlots and has been reported globally in countries including, but not limited to, Japan, England, Argentina, and Canada (2,5,7,9,11). In humans, STEC O26:H11 causes sporadic cases and outbreaks of diarrhea, hemorrhagic colitis, and hemolytic-uremic syndrome; and the incidence of disease resulting from this serotype may outnumber that resulting from O157:H7 in particular regions (3, 10). The discrepancy between incidence and clinical reporting is partly due to a lack of accessible and standardized methods for differentiation of this pathogen. Nucleotide sequence data for this serotype are limited in comparison to those for O157:H7; however, the virulence determinants which have been consistently observed in O26:H11 isolates include the prophage-encoded stx 1 and stx 2 Shiga toxin genes, the hlyAencoded hemolysin, high-molecular-weight plasmids, and the locus for enterocyte effacement pathogenicity island, which encodes a type III secretion system and the eae-␤1 intimin gene (3,14). Multilocus sequencing typing (MLST) has previously been performed with strains of the O157:H7 and O78 serotypes (1, 8), and it was our objective to develop a MLST scheme to determine the genetic relatedness of stx 1 -carrying E. coli O26:H11 and potentially reveal epidemiological relationships.The National Microbiology Laboratory (NML) in Winnipeg, Manitoba, Canada, received isolates of E. coli O26:H11 from provincial public health laboratories in Alberta, British Columbia, Saskatchewan, Manitoba, and Nova Scotia, a collection that represents a latitudinal cross-section of Canadian regions (Table 1). We sought to develop an alternative to pulsed-field gel electrophoresis (PFGE) in order to reveal epidemiological relationships, and MLST was a candidate methodology because of the ease of standardization and its potentially robust discriminatory power. Sequence analysis of the mdh, gnd, gcl, ppk, metA, fliC, ftsZ, relA, recN, and metG genes from strains isolated from 1999 to 2003 in the different Canadian provinces was completed. Included in this study were two non-H11 O26 isolates to identify serotype-specific genetic relatedness. Additionally, the sole stx 1 -and stx 2 -carrying O26:H11 isolate reported to NML was used to identify the genetic relatedness to stx 1 -carrying strains at the loci examined. The PFGE patterns obtained with XbaI digestion were also determined for each strain.The oligonucleotide primers used to amplify mdh (580 bp), gnd (590 bp), gcl (758 bp), ppk (758 bp), and metA (601 bp) were described previously (1, 8)...