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We aimed to determine population immunity to measles in Canada, and to assess the risk of future outbreaks. We tested 11,176 sera from Cycles 2 (2009-2011) and 3 (2011-2013) cohorts from the biobank of Statistics Canada's Canadian Health Measures Survey (CHMS) using the BioPlex 2220 MMRV IgG assay. We then tested all BioPlex negative and equivocal samples using a more sensitive Plaque Reduction Neutralization Test (PRNT). We determined the weighted proportion of positive, equivocal, and negative samples by age, sex, region and whether individuals were born in Canada. We found that 90.0% (95% confidence interval (CI): 88.2, 91.9) of samples were positive, 4.5% (95% CI: 3.4, 5.5) were equivocal and 5.5% (95% CI: 4.3, 6.7) were negative. Individuals in the 12-19 year age band had the lowest proportion positive at 78.7% (95% CI: 74.2, 83.2) and the highest proportion of positive samples was found in those 60-79 years (99.6%, 95% CI: 99.3, 99.9). Seropositivity was consistently90% across a broad range of pediatric and adult age bands (6-39 years). We found that a slightly higher proportion of females were positive (91.9%, 95% CI: 90.1, 93.6) compared to males (88.3%, 95% CI: 85.8, 90.7). When taking into account interaction between age and born in Canada status, we found individuals born in Canada aged 19 and under were less susceptible (OR = 0.6 (95% CI: 0.4, 0.95)) compared to those born outside Canada whereas, those aged 20 and over were more susceptible (OR = 1.7 (95% CI: 1.1, 2.8)). Our findings indicate that measles immunity in Canada is below the 95% immunity threshold required to sustain measles elimination, underscoring the importance of maintaining high vaccine coverage to prevent future measles outbreaks and sustain Canada's elimination status.

To describe the demographics, clinical presentation, proportion of co-infection with human immunodeficiency virus (HIV), and treatment of patients with ocular syphilis seen at the ophthalmology department of 2 tertiary centres in Montreal, Canada.Retrospective case series.A total of 169 eyes of 115 patients, seen between 2000 and 2015, with a positive syphilis treponemal serology and a likely syphilis-related ophthalmologic diagnosis. Subgroup analysis was performed between HIV-infected and HIV-uninfected patients.Mean age of onset was 55 years, and 79% were male. Mean presenting logMAR visual acuity was 0.7. HIV status was available for 66%, of whom 49% were HIV-infected. The anatomical ocular diagnoses included isolated anterior uveitis (18%) and posterior segment involvement (42%). Both eyes were affected in 47%. Lumbar puncture (LP) was performed in 55%, of whom 22% had a positive cerebrospinal fluid (CSF) Venereal Disease Research Laboratory (VDRL) test. Antibiotherapy, consisting of intravenous penicillin alone or in addition to intramuscular benzathine penicillin, was administered in 65 patients (69%). Treatment allowed a visual improvement of -0.23 logMAR. HIV-infected patients were younger men (p0.01) and had more abnormal CSF analysis (p = 0.02), but there were no statistically significant differences in the anatomical location of ocular inflammation or visual function improvement.Given its varied presentations, syphilis must always be part of the differential diagnosis of intraocular inflammation. HIV testing and an LP are required in the evaluation of ocular syphilis, which should be treated as neurosyphilis with the appropriate regimen.

Background Intense transmission of syphilis has emerged in some Canadian Arctic communities despite screening and prevention efforts. The remoteness of most communities and limited diagnostic infrastructure yield long delays (≥14 days) between screening and treatment of cases. These hamper syphilis control efforts and may contribute to sustained transmission. Syphilis rapid diagnostic tests (RDTs) have been developed to make screening more accessible and to inform clinical decision-making within the same clinical encounter. These RDTs have been successfully deployed in several countries, but not yet in Canada. Methods and design We describe the methodology of the “Stopping Syphilis Transmission in Arctic Communities Through Rapid Diagnostic Testing” (STAR) study, wherein the clinical and epidemiological impact of deploying a dual syphilis RDT in the context of ongoing transmission in Nunavut and Nunavik will be evaluated. In this prospective multisite field evaluation, sexually active individuals aged ≥14 years at risk for syphilis will be offered screening by an RDT at the point-of-care by non-laboratory trained registered nurses. Whole blood and serum specimens will be concurrently collected, when feasible, for rapid testing with an RDT containing both treponemal and non-treponemal components (Chembio DPP® Syphilis Screen & Confirm) and compared to laboratory-based reference testing according to a reverse sequence algorithm. The diagnostic accuracy of the RDT, using both whole blood and centrifuged serum specimens, will be validated under real-world conditions in remote Northern settings, outside of specialized laboratories. Additionally, screening-to-treatment time, case detection rates, and the number of infectious contacts averted by using the RDT relative to reference testing will be estimated. The impact of both diagnostic approaches on syphilis transmission dynamics will also be modeled. Discussion This study will provide much needed evidence for strengthening rapid responses to emerging syphilis outbreaks in remote Arctic regions, by supplementing traditional diagnostic strategies with an RDT to rapidly triage patients likely in need of treatment. These results will also inform the development and tailoring of future diagnostic strategies and public health responses to emerging outbreaks in the North.

The identification of transmission clusters (TCs) of HIV-1 using phylogenetic analyses can provide insights into viral transmission network and help improve prevention strategies. We compared the use of partial HIV-1 envelope fragment of 1,070 bp with its loop 3 (108 bp) to determine its utility in inferring HIV-1 transmission clustering. Serum samples of recently (n = 106) and chronically (n = 156) HIV-1-infected patients with status confirmed were sequenced. HIV-1 envelope nucleotide-based phylogenetic analyses were used to infer HIV-1 TCs. Those were constructed using ClusterPickerGUI_1.2.3 considering a pairwise genetic distance of ≤10% threshold. Logistic regression analyses were used to examine the relationship between the demographic factors that were likely associated with HIV-1 clustering. Ninety-eight distinct consensus envelope sequences were subjected to phylogenetic analyses. Using a partial envelope fragment sequence, 42 sequences were grouped into 15 distinct small TCs while the V3 loop reproduces 10 clusters. The agreement between the partial envelope and the V3 loop fragments was significantly moderate with a Cohen's kappa (κ) coefficient of 0.59, p

Canada eliminated measles in 1998. We conducted a sero-epidemiology study to estimate population immunity to measles in the province of Ontario, Canada and to identify groups at higher risk of outbreaks. We used a previously developed modified enzyme immunoassay to test 1,199 residual sera from patients aged 1–39 years. We re-tested negative and equivocal sera using a plaque reduction neutralization assay. We interpreted our results in the context of Ontario’s immunization program and vaccine coverage data. Of 1,199 sera, 1035 (86.3%, 95% confidence interval (CI) 84.4, 88.2) were above the measles threshold for protection, 70 (5.8%, 95% CI 4.5, 7.2) were equivocal and 94 (7.8%, 95% CI 6.3, 9.4) were negative. The proportion of positive sera was highest for those 1–5 years, with 180/199 (90.5%, 95% CI 86.4, 94.5) positive sera, and lowest for those age 12–19 years, at 158/199 (79.4%, 95% CI 73.8, 85.0). Adjusted for age, females were more likely than males to have antibody titers above the threshold of protection (odds ratio = 1.60, 95% CI 1.14, 2.24). Most of the study cohort were eligible for two measles vaccine doses, and vaccine uptake in Ontario is >90% for school-aged cohorts. We observed a higher than expected proportion of sera with antibody levels below the threshold of protection, suggesting that immunity in some Ontario age-groups may be waning, despite high vaccine coverage. Alternatively, the traditional measles correlates of protection may not be an appropriate measure of population protection in measles-eliminated settings.

As the coronavirus disease 2019 (COVID-19) pandemic second wave is emerging, it is of the upmost importance to screen the population immunity in order to keep track of infected individuals. Consequently, immunoassays for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) with high specificity and positive predictive values are needed to obtain an accurate epidemiological picture., As the coronavirus disease 2019 (COVID-19) pandemic second wave is emerging, it is of the upmost importance to screen the population immunity in order to keep track of infected individuals. Consequently, immunoassays for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) with high specificity and positive predictive values are needed to obtain an accurate epidemiological picture. As more data accumulate about the immune responses and the kinetics of neutralizing-antibody (nAb) production in SARS-CoV-2-infected individuals, new applications are forecast for serological assays such as nAb activity prediction in convalescent-phase plasma from recovered patients. This multicenter study, involving six hospital centers, determined the baseline clinical performances, reproducibility, and nAb level correlations of 10 commercially available immunoassays. In addition, three lateral-flow chromatography assays were evaluated, as these devices can be used in logistically challenged areas. All assays were evaluated using the same patient panels in duplicate, thus enabling accurate comparison of the tests. Seven immunoassays examined in this study were shown to have excellent specificity (98 to 100%) and good to excellent positive predictive values (82 to 100%) when used in a low (5%)-seroprevalence setting. We observed sensitivities as low as 74% and as high as 95% at ≥15 days after symptom onset. The determination of optimized cutoff values through receiver operating characteristic (ROC) curve analyses had a significant impact on the diagnostic resolution of several enzyme immunoassays by increasing the sensitivity significantly without a large trade-off in specificity. We found that spike-based immunoassays seem to be better correlates of nAb activity. Finally, the results reported here will add to the general knowledge of the interlaboratory reproducibility of clinical performance parameters of immunoassays and provide new evidence about nAb activity prediction.

The COVID-19 pandemic has led to the influx of immunoassays for the detection of antibodies towards severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) into the global market. The Canadian Public Health Laboratory Network Serology Task Force undertook a nationwide evaluation of twelve laboratory and 6 point-of-care based commercial serological assays for the detection of SARS-CoV-2 antibodies. We determined that there was considerable variability in the performance of individual tests and that an orthogonal testing algorithm should be prioritized to maximize the accuracy and comparability of results across the country. The manual enzyme immunoassays and point-of-care tests evaluated had lower specificity and increased coefficients of variation compared to automated enzyme immunoassays platforms putting into question their utility for large-scale sero-surveillance. Overall, the data presented here provide a comprehensive approach for applying accurate serological assays for longitudinal sero-surveillance and vaccine trials while informing Canadian public health policy.

The SARS-CoV-2 virus is responsible for the coronavirus disease 2019 (COVID-19) pandemic, infecting millions of people and causing hundreds of thousands of deaths. The Spike glycoproteins of SARS-CoV-2 mediates viral entry and is the main target for neutralizing antibodies. Understanding the antibody response directed against SARS-CoV-2 is crucial for the development of vaccine, therapeutic and public health interventions. Here we perform a cross-sectional study on 106 different SARS-CoV-2-infected individuals to evaluate humoral responses against SARS-CoV-2 Spike. The vast majority of infected individuals elicits anti-Spike antibodies within 2 weeks after the onset of symptoms. The levels of receptor-binding domain (RBD)-specific IgG persist overtime, while the levels of anti-RBD IgM decrease after symptoms resolution. While most of individuals develop neutralizing antibodies within two weeks of infection, the level of neutralizing activity is significantly decreased over time. Our results highlight the importance of studying the persistence of neutralizing activity upon natural SARS-CoV-2 infection., Graphical Abstract, Highlights • Antibodies against SARS-CoV-2 Spike correlate with COVID-19 disease severity • RBD-specific IgM and IgA decline more rapidly than IgG • SARS-CoV-2 neutralizing antibodies are elicited within two weeks of infection • Neutralizing antibodies decline significantly after resolution of the infection

OBJECTIVES: To compare the prevalence of HIV, hepatitis C virus (HCV) infections, and related risky behaviours among inmates in Quebec’s provincial prisons between 2003 and 2014–2015. METHODS: Cross-sectional data were anonymously collected from May 2014 to March 2015 for men (n = 1315) and women (n = 250) and combined with data collected in 2003 to evaluate trends in the last decade. Participants completed a questionnaire and provided saliva samples. The data from the 2003 and 2014–2015 surveys were merged for statistical analysis. RESULTS: HIV prevalence was stable between 2003 and 2014–2015 for men (2.4% vs. 1.8%, p = 0.4), whereas it decreased for women (8.8% vs. 0.8%, p

Background Laboratory diagnostic of syphilis is based on both treponemal and non-treponemal assays. While automated treponemal assays are available, non-treponemal antibody testing continue to require extensive hands on time. The BioPlex 2200 Syphilis Total & RPR assay by Bio-Rad Laboratories is a fully automated assay that detects both treponemal and non-treponemal antibodies with on board RPR titer capability. Methods We compared the BioPlex Total & RPR assay with the BiopPex IgG assay and with the Wampole Impact RPR card test for the treponemal and non-treponemal antibodies detection respectively. A total of 504 prospective sera sent to our laboratory for syphilis testing were tested with both BioPlex assays to establish agreement of treponemal results. Also, a panel of 52 sera with known titer values was provided by our reference laboratory. These sera were tested with the BioPlex Total & RPR assay and the manual Wampole RPR card to compare titer results, using essential agreement within 1 dilution range and correlation of log2 transformed titer values with Spearman coefficient. Results Of the 504 sera tested, 112 were positive for treponemal antibodies with BioPlex Total & RPR and 109 with BioPlex IgG. Positive, negative and overall agreements were 95% (104/109)(95% CI [89%, 98%]), 98% (387/395)(95% CI [96%, 99%]) and 97% (491/504)(95% CI [95%, 99%]) respectively for these sera. Essential agreement within 1 dilution of quantitative RPR titer results for the 52 sera panel was 90% and the Spearman correlation coefficient of titers obtained with the two assays was 0.926 with a p Conclusion The BioPlex 2200 Syphilis Total & RPR assay is a fully automated assay that compares favorably with the BioPlex 2200 Syphilis IgG assay and that yields non treponemal titers that correlates favorably with a traditional manual RPR card test. Reliable automated non treponemal assays are needed. Disclosure No significant relationships.

The rapid confirmatory Bio-Rad Geenius HIV 1/2 assay was evaluated as an alternative to the HIV-1 Western blot (WB) confirmatory assay. A total of 370 retrospective samples collected from 356 patients were tested., The rapid confirmatory Bio-Rad Geenius HIV 1/2 assay was evaluated as an alternative to the HIV-1 Western blot (WB) confirmatory assay. A total of 370 retrospective samples collected from 356 patients were tested. Sensitivity of the Geenius assay to detect HIV-1 and HIV-2 infections was 100% and 97%, respectively, and that of the WB assay was 86% and 39%, respectively. Geenius reduced the number of indeterminate results by 85% and exhibited a differentiation capacity for HIV-1 and HIV-2 of 100% and 89%, respectively. Three of 10 patients presenting with an early HIV infection (1 to 2 weeks before seroconversion by WB) were positive using Geenius. None of the HIV-negative samples were positive using Geenius or WB. However, 7% and 10% of them were indeterminate with Geenius and WB, respectively, leading to a specificity rate of 93% for Geenius and 90% for WB. Ninety cadaveric samples (54 negative, 23 HIV-1 positive, and 3 HIV-1 indeterminate) were tested with Geenius, leading to a sensitivity of 100%, a specificity of 96%, and an indeterminate rate of 4%. Our results indicate that the Bio-Rad Geenius HIV 1/2 rapid test exhibits better sensitivity to detect HIV-1 infections and better performance than WB to confirm and differentiate between HIV-1 and HIV-2 infections. The performance of this new confirmatory assay to detect early infections, to reduce the rate of indeterminate status, and to confirm HIV-1 infection in cadaveric blood samples makes Geenius a potent reliable alternative to the WB.

Background: HIV-1 transmitted/founder viruses (TF) are selected during the acute phase of infection from a multitude of virions present during transmission. They possess the capacity to establish infection and viral dissemination in a new host. Deciphering the discrete genetic determinant of infectivity in their envelope may provide clues for vaccine design. Methods: One hundred twenty-six clade B HIV-1 consensus envelope sequences from untreated acute and early infected individuals were compared to 105 sequences obtained from chronically infected individuals using next generation sequencing and molecular analyses. Results: We identified an envelope amino acid signature associated with TF viruses. They are more likely to have an isoleucine (I) in position 841 instead of an arginine (R). This mutation of R to I (R841I) in the gp41 cytoplasmic tail (gp41CT), specifically in lentivirus lytic peptides segment 1 (LLP-1), is significantly enriched compared to chronic viruses (OR = 0.2, 95% CI (0.09, 0.44), p = 0.00001). Conversely, a mutation of lysine (K) to isoleucine (I) located in position six (K6I) of the envelope signal peptide was selected by chronic viruses and compared to TF (OR = 3.26, 95% CI (1.76&ndash, 6.02), p = 0.0001). Conclusions: The highly conserved gp41 CT_ LLP-1 domain plays a major role in virus replication in mediating intracellular traffic and Env incorporation into virions in interacting with encoded matrix protein. The presence of an isoleucine in gp41 in the TF viruses&rsquo, envelope may sustain its role in the successful establishment of infection during the acute stage.

ObjectivesThe objectives of this study were: (1) to examine the correlates of HIV positivity among participants who injected drugs and engaged in sex work (PWID-SWs) in the SurvUDI network between 2004 and 2016, after stratification by sex, and (2) to compare these correlates with those of sexually active participants who did not engage in sex work (PWID non-SWs).Design and settingThis biobehavioural survey is an open cohort of services where participants who had injected in the past 6 months were recruited mainly through harm reduction programmes in Eastern Central Canada.ParticipantsData from 5476 participants (9223 visits in total; 785 not included in multivariate analyses due to missing values) were included.MethodsParticipants completed an interviewer-administered questionnaire and provided saliva samples for anti-HIV antibody testing. Generalised estimating equations taking into account multiple participations were used.ResultsBaseline HIV prevalence was higher among SWs compared with non-SWs (women: 13.0% vs 7.7%; PConclusionThese results suggest that sex work has an impact on the risk of HIV acquisition and that risk behaviours vary according to gender. Public health practitioners should take those specificities into account when designing HIV prevention interventions aimed at PWIDs.

Identifying recent HIV-1 infections is crucial for monitoring HIV-1 incidence and optimizing public health prevention efforts. To identify recent HIV-1 infections, we evaluated and compared the performance of 4 sequence-based diversity measures including percent diversity, percent complexity, Shannon entropy and number of haplotypes targeting 13 genetic segments within the env gene of HIV-1. A total of 597 diagnostic samples obtained in 2013 and 2015 from recently and chronically HIV-1 infected individuals were selected. From the selected samples, 249 (134 from recent versus 115 from chronic infections) env coding regions, including V1-C5 of gp120 and the gp41 ectodomain of HIV-1, were successfully amplified and sequenced by next generation sequencing (NGS) using the Illumina MiSeq platform. The ability of the four sequence-based diversity measures to correctly identify recent HIV infections was evaluated using the frequency distribution curves, median and interquartile range and area under the curve (AUC) of the receiver operating characteristic (ROC). Comparing the median and interquartile range and evaluating the frequency distribution curves associated with the 4 sequence-based diversity measures, we observed that the percent diversity, number of haplotypes and Shannon entropy demonstrated significant potential to discriminate recent from chronic infections (p

Background Although reverse sequence algorithms (RSA) for syphilis screening are performing well, they still have to rely on treponemal confirmatory tests at least for sera reactive by enzyme immunoassay/chemiluminescence immunoassay (EIA/CIA) and unreactive by rapid plasma reagin (RPR). Quebec’s laboratory network previously showed that 3.3% of EIA/CIA reactive and weakly-reactive RPR samples (RPR titer of 1 to 4) would have been misclassified as syphilis cases if a treponemal confirmatory test had not been performed. Objectives To correlate the magnitude of signal-to-cutoff (S/CO) ratios of the 4 most used commercial first-line EIA/CIA kits in Quebec with syphilis confirmation results and establish a S/CO value above which treponemal confirmation would not be required. Methods Serum samples from previously undiagnosed individuals (n = 7 404) obtained between January 2014 and February 2017 that were reactive by EIA/CIA and either negative by RPR or reactive with a low titer (1 to 4) were included in the study. All samples were tested with Treponema pallidum particle agglutination (TP-PA) and, if negative or inconclusive, with a line immunoassay (LIA). Syphilis infection confirmation was defined by a reactive TP-PA or LIA. Logistic regression analysis was used to determine S/CO values (95% CI lower bound = 0.98) above which confirmation would not be required. The four kits studied were Architect TP, BioPlex IgG, Syphilis EIA II, and Trep-Sure. Results Of 2609 reactive EIA/CIA specimens tested for the determination of S/CO values, 1730 (66%) were confirmed as true syphilis cases. Confirmation rate was significantly higher in samples with low-titer positive RPR (92%) than with negative RPR samples (54%); p

To determine the prevalence of hepatitis C virus (HCV) and identify related risk factors among inmates in Quebec provincial prisons.Anonymous cross-sectional data were collected between May 2014 and March 2015 for 1315 men and 250 women who completed a questionnaire and provided oral fluid samples.The global prevalence of HCV infection was 11.9% in male participants and 19.2% in female participants (P = .003). Among people who inject drugs (PWID), the prevalence was much higher compared to that in persons who does not: 51.0% versus 2.4% in men (P .001) and 61.4% versus 2.8% in women (P .001). In the multivariable analysis, lifetime history of injection drug use was the most important risk factor for HCV infection (adjusted odds ratio [AOR]: 14.2; 95% confidence interval [95% CI]: 9.5-21.4), with needle sharing significantly associated with HCV among PWID (AOR: 1.4; 95% CI: 1.1-1.7). Tattooing in prison was frequent, especially among men (37.2%), and independently associated with HCV infection among non-PWID (AOR: 2.8; 95% CI: 1.4-5.6).Inmates are at high risk for HCV infection especially because of a high proportion of active or past PWID among them. In addition, tattooing while in prison seems to contribute to HCV infection among non-PWID.

The Cree communities of James Bay are at risk for contracting infectious diseases transmitted by wildlife. Data from serological testing for a range of zoonotic infections performed in the general population (six communities), or trappers and their spouses (one community), were abstracted from four population-based studies conducted in Cree territory (Quebec) between 2005 and 2009. Evidence of exposure to Trichinella species, Toxoplasma gondii, Toxocara canis, Echinococcus granulosus, Leptospira species, Coxiella burnetii and Francisella tularensis was verified in all communities, whereas antibodies against Sin Nombre virus and California serogroup viruses (Jamestown Canyon and snowshoe hare viruses) were evaluated in three and six communities, respectively. Seroprevalence varied widely among communities: snowshoe hare virus (1% to 42%), F tularensis (14% to 37%), Leptospira species (10% to 27%), Jamestown Canyon virus (9% to 24%), C burnetii (0% to 18%), T gondii (4% to 12%), T canis (0% to 10%), E granulosus (0% to 4%) and Trichinella species (0% to 1%). No subject had serological evidence of Sin Nombre virus exposure. These data suggest that large proportions of the Cree population have been exposed to at least one of the targeted zoonotic agents. The Cree population, particularly those most heavily exposed to fauna, as well as the medical staff living in these regions, should be aware of these diseases. Greater awareness would not only help to decrease exposures but would also increase the chance of appropriate diagnostic testing.Les communautés cries de la Baie James sont vulnérables aux maladies infectieuses transmises par les animaux sauvages. Les données tirées des tests sérologiques sur une série de zoonoses effectués dans la population générale (six communautés) ou chez les trappeurs et leur conjointe (une communauté) ont été extraites de quatre études en population menées en territoire cri, au Québec, entre 2005 et 2009. Les manifestations d’exposition aux espèces de

International audience; BACKGROUND: Recent analyses have shown an emerging positive association between sex work and human immunodeficiency virus (HIV) incidence among people who inject drugs (PWIDs) in the SurvUDI network. METHODS: Participants who had injected in the past 6 months were recruited across the Province of Quebec and in the city of Ottawa, mainly in harm reduction programs. They completed a questionnaire and provided gingival exudate for HIV antibody testing. The associations with HIV seroconversion were tested with a Cox proportional hazard model using time-dependent covariables including the main variable of interest, sexual activity (sex work; no sex work; sexually inactive). The final model included significant variables and confounders of the associations with sexual activity. RESULTS: Seventy-two HIV seroconversions were observed during 5239.2 person-years (py) of follow-up (incidence rates: total = 1.4/100 py; 95% confidence interval [CI], 1.1-1.7; sex work = 2.5/100 py; 95% CI, 1.5-3.6; no sex work = 0.8/100 py; 95% CI, 0.5-1.2; sexually inactive = 1.8/100 py; 95% CI, 1.1-2.5). In the final multivariate model, HIV incidence was significantly associated with sexual activity (sex work: adjusted hazard ratio [AHR], 2.19; 95% CI, 1.13-4.25; sexually inactive: AHR, 1.62; 95% CI, 0.92-2.88), and injection with a needle/syringe used by someone else (AHR, 2.84; 95% CI, 1.73-4.66). CONCLUSIONS: Sex work is independently associated with HIV incidence among PWIDs. At the other end of the spectrum of sexual activity, sexually inactive PWIDs have a higher HIV incidence rate, likely due to more profound dependence leading to increased vulnerabilities, which may include mental illness, poverty, and social exclusion. Further studies are needed to understand whether the association between sex work and HIV is related to sexual transmission or other vulnerability factors

The Cree communities of James Bay might be at risk of contracting zoonoses from their contacts with wildlife. Evidence of exposure to seven zoonotic infections, namely Trichinella spp., Toxoplasma gondii, Toxocara canis, Echinococcus granulosus, Leptospira spp., Coxiella burnetii, and Francisella tularensis, was sought in sera from 267 residents of Chisasibi (166) and Waskaganish (101). Study participants responded to questionnaires documenting socio-demographic characteristics and hunting and trapping activities. Associations were assessed by univariable and multivariable logistic regression analysis. High seroprevalence rates were documented for Leptospira spp. (23%), Francisella tularensis (18%), and Toxoplasma gondii (9%). Seroprevalence rates of less than 5% were observed for Coxiella burnetii, Echinococcus granulosus, and Toxocara canis. No subject exhibited serological proof of Trichinella spp. exposure in either community. Serological evidence of exposure to Leptospira spp. and T. gondii was greater in Chisasibi than in Waskaganish, while the T. canis seroprevalence rate was higher in Waskaganish than in Chisasibi. Handling of rabbits was associated with seropositivity for Leptospira spp. Statistical trends were also detected between the handling of ducks and exposure to Toxoplasma gondii, and between both handling animals without gloves and springtime hunting activities and Leptospira spp. seropositivity in Chisasibi and Waskaganish, respectively. A review of the medical records revealed few clinical events potentially related to zoonotic exposures. However, public health authorities and health care workers in these communities should be alert to the risk of these zoonoses.

Neurosyphilis refers to infection of the central nervous system by Treponema pallidum, which may occur at any stage. Neurosyphilis has been categorized in many ways including early and late, asymptomatic versus symptomatic and infectious versus non-infectious. Late neurosyphilis primarily affects the central nervous system parenchyma, and occurs beyond early latent syphilis, years to decades after the initial infection. Associated clinical syndromes include general paresis, tabes dorsalis, vision loss, hearing loss and psychiatric manifestations. Unique algorithms are recommended for HIV-infected and HIV-uninfected patients, as immunocompromised patients may present with serologic and cerebrospinal fluid findings that are different from immunocompetent hosts. Antibody assays include a VDRL assay and the FTA-Abs, while polymerase chain reaction for T. pallidum can be used as direct detection assays for some specimens. This chapter reviews guidelines for specimen types and sample collection, and identifies two possible algorithms for use with immunocompromised and immunocompetent hosts using currently available tests in Canada, along with a review of treatment response and laboratory testing follow-up.La neurosyphilis désigne l’infection du système nerveux central par le

Syphilis, caused by the bacteriumTreponema pallidumsubsp.pallidum, is an infection recognized since antiquity. It was first reported at the end of the 15th century in Europe. Infections may be sexually transmitted as well as spread from an infected mother to her fetus or through blood transfusions. The laboratory diagnosis of syphilis infection is complex. Because this organism cannot be cultured, serology is used as the principal diagnostic method. Some of the issues related to serological diagnoses are that antibodies take time to appear after infection, and serology screening tests require several secondary confirmatory tests that can produce complex results needing interpretation by experts in the field. Traditionally, syphilis screening was performed using either rapid plasma reagin or Venereal Disease Research Laboratory tests, and confirmed by treponemal tests such as MHA-TP, TPPA or FTA-Abs. Currently, that trend is reversed, ie, most of the laboratories in Canada now screen for syphilis using treponemal enzyme immunoassays and confirm the status of infection using rapid plasma reagin or Venereal Disease Research Laboratory tests; this approach is often referred to as the reverse algorithm. This chapter reviews guidelines for specimen types and sample collection, treponemal and non-treponemal tests utilized in Canada, the current status of serological tests for syphilis in Canada, the complexity of serological diagnosis of syphilis infection and serological testing algorithms. Both traditional and reverse sequence algorithms are recommended and the algorithm used should be based on a combination of local disease epidemiology, test volumes, performance of the proposed assays and available resources.

Repeated outbreaks of trichinellosis caused by the consumption of Trichinella-infected walrus (Odobenus rosmarus) meat, which have sometimes led to serious morbidity, have stimulated Inuit communities in Nunavik (northern Quebec), Canada, to develop an innovative trichinellosis prevention program. The program involves preconsumption testing of meat samples from harvested walrus at a regional laboratory and the rapid dissemination of the results of such testing to communities. Local health authorities in Inukjuak conducted an epidemiological investigation after testing identified Trichinella-positive walrus meat in September 1997. This report describes the events that occurred before, during, and after the trichinellosis outbreak and also documents how the prevention program contributed to successful resolution of the outbreak.

Background In the past 15 years, a recrudescence of syphilis was observed in Canada, along with a surge in ocular syphilis cases. Without treatment, ocular syphilis can have serious consequences potentially leading to blindness. Our goal was to describe the demographics, clinical presentations, proportion of co-infection with HIV, treatments and visual outcomes of ocular syphilis cases. Methods Patients with a confirmed positive syphilis serology between 2000 and 2015 were identified through the reference laboratory database. A retrospective chart review was performed for those who visited the ophthalmology clinic of Hôpital Maisonneuve-Rosemont or Hôpital Notre-Dame to identify ocular syphilis cases. Results Among the 119 patients (174 eyes) identified (2.5% of the population screened), 80% were male; of which 63% were MSM. Mean presenting logMAR visual acuity was 0.70 (20/100 Snellen) and unilateral ocular involvement occurred in 54%. Ocular manifestations included interstitial keratitis (24 eyes), anterior uveitis (37 eyes), intermediate uveitis (17 eyes), posterior uveitis (31 eyes), panuveitis (27 eyes), isolated optic nerve involvement (25 eyes), and others (12 eyes) including VI nerve palsy, scleritis, and episcleritis. Cerebrospinal fluid (CSF) examination was done in 65 (55%) patients. Of those, VDRL was positive in 14 (22%) patients; white blood cells and proteins were elevated in, respectively, 28 (43%) and 39 (60%) of patients. HIV status was unknown in 39 (33%) patients; among those whose serology were performed (or previous status was known), 38 (48%) were HIV infected. Intravenous aqueous penicillin G was administered in 69 (58%), intramuscular benzathine penicillin in 25 (21%) and other antibiotics, mainly due to allergy, in three (3%) patients. Treatment allowed a visual improvement of –0.22 logMAR (gain of five lines on Snellen chart) after a mean follow-up period of 19 months. Conclusion Syphilis can manifest with a widely diversified array of ocular presentations, especially uveitis and optic nerve involvement. Therefore it is primordial to keep this diagnosis in mind when facing high-risk patients with ocular symptoms. It is of utmost importance that clinicians improve rates of lumbar puncture, HIV screening and intraveinous penicillin treatment when managing ocular syphilis. Disclosures All authors: No reported disclosures.

The diagnosis of neurosyphilis (NS) is a challenge, especially in HIV-infected patients, and the criteria for deciding when to perform a lumbar puncture (LP) in HIV-infected patients with syphilis are controversial. We retrospectively reviewed demographic, clinical, and laboratory data from 122 cases of HIV-infected patients with documented early syphilis who underwent an LP to rule out NS, and we evaluated 3 laboratory-developed validated real-time PCR assays, the Treponema pallidum particle agglutination (TPPA) assay, the fluorescent treponemal antibody absorption (FTA-ABS) assay, and the line immunoassay INNO-LIA Syphilis, for the diagnosis of NS from cerebrospinal fluid (CSF) samples of these patients. NS was defined by a reactive CSF-VDRL test result and/or a CSF white blood cell (WBC) count of >20 cells/μl. Thirty of the 122 patients (24.6%) had early NS. Headache, visual symptoms, a CD4 cell count of P = P = 0.575). For the diagnosis of NS, the PCR, FTA-ABS, TPPA, and INNO-LIA assays had sensitivities of 58%, 100%, 68%, and 100%, specificities of 67%, 12%, 49%, and 13%, and negative predictive values of 85%, 100%, 84%, and 100%, respectively. Visual disturbances, headache, uncontrolled HIV-1 viremia, and a CD4 cell count of

Background: The Cree communities of James Bay are at risk of contracting infectious diseases conveyed by wildlife. Aims: To present the seroprevalence of different zonotic diseases for the populati...

We previously reported that group D streptococci exhibited immunoglobulin G (IgG)-binding activity and that a 52-kDa IgG-binding protein was present in all Streptococcus suis strains examined (B. Serhir, R. Higgins, B. Foiry, and M. Jacques, J. Gen. Microbiol. 139:2953-2958, 1993). The objective of the present study was to purify and characterize this protein. Pig IgG were immobilized through their Fab fragments to ECH-Sepharose 4B, and the protein was purified by affinity chromatography. Electron microscopy observations of the purified material showed filamentous structures with a diameter of approximately 4 nm; these structures were not observed when the material was treated with either urea or ethanolamine. Electrophoretic and Western immunoblot analyses showed that the 52-kDa protein constituted the bulk of the recovered material. This protein was stained with either Coomassie brilliant blue or silver nitrate; it reacted with a large variety of mammalian IgG, human IgG (Fc) fragments, human IgA, and other human plasma proteins. The 52-kDa protein exhibited lower IgG-binding affinities than protein A and protein G. However, it was able to compete with protein A and protein G for binding to human IgG. In addition, it bound chicken IgG with high affinity. This last property differentiated the 52-kDa protein of S. suis from the six IgG-binding proteins described to date. The 52-kDa protein displayed similar affinities for untreated and deglycosylated pig IgG. The N-terminal amino acid sequence (SIITDVYAXEVLDSXGNPTLEV) revealed no homology with any bacterial proteins in the Swiss-Prot database. Its isoelectric point of approximately 4.6 and its amino acid composition, rich in aspartic and glutamic acids, showed that it had some similarities with other IgG-binding proteins. In this report, we have purified and characterized a 52-kDa IgG-binding protein from S. suis capsular type 2. Although this protein shares some similarities with other IgG- and/or IgA-binding proteins, it is unique in reacting with chicken IgG.

We evaluated the seroprevalence of 10 zoonotic agents among the general population (15 years old and over) of Eastmain and Wemindji, James Bay, Quebec, in 2007. Overall seroprevalence rates were similar between the 2 communities. Nearly half the individuals tested (n = 251; 146 women, 105 men) were seropositive (n = 115) for at least one zoonosis. The highest seroprevalence rates were for Leptospira sp. (23%), Francisella tularensis (17%), and the California serogroup viruses (JC and SSH viruses) (10%). The other zoonoses (Toxoplasma gondii, Coxiella burnetii, Echinococcus granulosus, Toxocara canis, and Trichinella sp.) had seroprevalence rates ≤5%; no exposures were identified to hantaviruses (Sin Nombre virus). Overall, seropositivity was related to age, gender, hunting, and owning a dog. There was no medical history suggestive of overt diseases. Nonetheless, physicians should consider these agents when confronted with difficult or confusing diagnoses. In particular, the bacterial zoonoses should be ruled out in individuals with high or prolonged fever.

In June 2000, bear meat infected with Trichinella nativa was consumed by 78 individuals in 2 northern Saskatchewan communities. Interviews and blood collections were performed on exposed individuals at the onset of the outbreak and 7 weeks later. All exposed individuals were treated with mebendazole or albendazole, and symptomatic patients received prednisone. Confirmed cases were more likely to have consumed dried meat, rather than boiled meat (P

Background Currently, 24 out of 39 laboratories in Quebec use the AxSYM HIV Ag/Ab Combo for HIV screening. This kit will be discontinued December 2013 and three novel 4th generation screening HIV assays (Architect, Roche Elecsys HIV Combi and ADVIA CENTAUR), approved by Health Canada, represent the alternative to AxSYM. Objective and Methods: To investigate the performance of these 3 novel screening HIV Combo assays, in 6 clinical sites from Quebec. A total of 150 samples from patients with documented acute infection, a panel of 25 Seracare HIV-1 specimens, 3 quality control specimens (HIV-1.2 Ab POS, p24Ag POS, HIV-1.2 NEG), and 5577 sera from routine diagnostic patients were tested. Results Sensitivity assessment- The 3 novel combos demonstrated comparable 100% sensitivity. Confirmed positive samples on the Architect and Roche Elecsys presented much greater S/CO values than AxSYM. Specificity assessment- Each novel combo was compared separately to the AxSYM. Discordant results were confirmed using supplemental confirmatory assays. The specificity of Architect was evaluated using 1099 specimens: 1095/1099 were non reactive, 3/1099 were reactive and 1/1099 was discordant. For Roche Combo, 3282 specimens were tested: 3222/3282 were non reactive, 41/3282 were reactive, and 19/3282 were discordant. The Advia Centaur was evaluated using 1196 specimens, 1177/1196 were non reactive, 12/1196 were reactive and 7 were discordant. Amongst the 66 specimens that were reactive with novel and AxSYM combos, 52 (79%) were confirmed positive. All discordant results were confirmed negative. The 5494 specimens that were negative with both kits (novel and AxSYM) demonstrated lower S/CO values on Architect and Roche than on AxSym. Conclusions The 3 novel HIV Ag/Ab Combo demonstrated good performance (sensitivity, specificity and concordance) with better segregation of positive and negative samples than AxSYM. All 3 kits represent a good alternative to the AxSYM.

Background Recent recommendations propose that serum samples reactive by both syphilis enzyme immunoassay (EIA) or chemoluminescent immonoassay (CLIA) and RPR may not need treponemal confirmatory testing. There is uncertainty regarding the confirmation rate of EIA/CLIA reactive and low titer RPR samples. Methods Reactive samples for EIA/CLIA and low titer RPR from five Quebec diagnostic laboratories between December 14 th 2011 and December 3 rd 2012 were prospectively tested with TPPA and, if negative or inconclusive, with a line immunoassay (LIA). Syphilis infection confirmation was defined by a reactive TPPA or LIA. Results Samples reactive for EIA/CLIA and RPR with titers ranging from 1:1 to 1:8 were submitted for confirmatory testing (N = 345). Of these, 335 (97.1%) were confirmed and 2.9% (95% CI 1.4–5.3%) were misclassified as syphilis cases. When stratifying by RPR titer, unconfirmed samples (misclassified cases) were found only in samples with RPR titer of 1:1 and 1:2. Samples with titers above 1:2 were classified as true syphilis cases. Proportion of confirmed cases increased with RPR titer (p = 0.01). Conclusions In our setting, only patients with serum RPR titers ranging from 1:1 to 1:2 would have been misclassified as syphilis cases had a confirmatory test not been conducted. A safe and cost-effective approach, for EIA/CLIA reactive and RPR reactive samples management in a reverse sequence algorithm may be to submit only samples with low RPR titers (≤ 1:2) instead of all EIA/CLIA and RPR reactive samples for confirmation.

SUMMARY: This study was undertaken to search for the presence of immunoglobulin G (IgG)-binding proteins in Streptococcus suis, an important swine pathogen. Whole bacterial cells were incubated with human or pig IgG conjugated to gold particles and examined by transmission electron microscopy. Cells of some S. suis strains were labelled as were cells of the positive control strain, Staphylococcus aureus Cowan I. Binding of pig and human IgG to five different bacterial species of group D streptococci, to reference strains representing the 29 capsular types of S. suis, and to 12 S. suis capsular type 2 strains was then examined using Western blotting. All strains interacted with pig and human IgG, although the binding profiles were slightly different. A 52 kDa protein was observed in all capsular types of S. suis. This protein, absent in other group D streptococcal species, was observed in all capsular type 2 isolates originating from diseased or clinically healthy pigs, and was shown to bind human IgG-Fc fragments. The IgG-binding activity was also observed in the culture supernatant and was sensitive to proteolysis.