Bouchra Serhir

Institut National de Santé Publique du Québec (INSPQ) | INSPQ · Laboratoire de Santé Publique du Québec

Objectives: We evaluated the field diagnostic accuracy of a syphilis rapid test (RDT), using serum and whole blood by non-laboratorians in two Canadian Arctic communities. Methods: We implemented a multisite prospective field evaluation wherein patients were screened by an RDT containing treponemal and non-treponemal components (Chembio DPP® Syp...

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 tr...

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...

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 serolog...

As the 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, SARS-CoV-2 immunoassays with high specificity and positive predictive values are needed to obtain an accurate epidemiological picture. As more data accumulate about the immu...

The SARS-CoV-2 virus is responsible for the current worldwide coronavirus disease 2019 (COVID-19) pandemic, infecting millions of people and causing hundreds of thousands of deaths. The Spike glycoprotein of SARS-CoV-2 mediates viral entry and is the main target for neutralizing antibodies. Understanding the antibody response directed against SARS-...

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 vacc...

Background: Molecular phylogenetics are generally used to confirm hepatitis C virus (HCV) transmission events. In addition, the Laboratoire de santé publique du Québec (LSPQ) has been using molecular phylogenetics for surveillance of HCV genotyping since November 2001. Objectives: To describe the emergence of a specific lineage of HCV genotype 4...

Background: Molecular phylogenetics are generally used to confirm hepatitis C virus (HCV) transmission events. In addition, the Laboratoire de santé publique du Québec (LSPQ) has been using molecular phylogenetics for surveillance of HCV genotyping since November 2001. Objectives: To describe the emergence of a specific lineage of HCV genotype 4d (...

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 sam...

Objective: 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. Design: Retrospective case series. Participants and methods: A total of 169 eyes of 11...

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...

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 eq...

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% as compared to 86% and 39% using WB assay, respec...

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 EI...

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 200...

Background To determine the prevalence of Hepatitis C virus (HCV) and identify related risk factors among inmates in Quebec provincial prisons. Methods 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. Results The global prevalenc...

Objectives The 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 wor...

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 ge...

Sequence-based diversity measures expressed as the median/IQR and calculated from NGS of 7 segments representing 4 selected HIV-1 env GP120 conserved subdomains. (PDF)

Viral sequences data qualifiers. (XLSX)

Sequence based diversity measures calculation methods. (PDF)

Sequence-based diversity measures expressed as the median/IQR and calculated from NGS of 5 segments representing 5 selected HIV-1 env GP120 variable loops and 1 segment for a part of the gp41ectodomain. (PDF)

Sequence-based diversity measures expressed as the mean with student t-test results comparing recent versus chronic HIV infected sequences by 13 env segments. (PDF)

Syphilis is a sexually transmitted infection caused by the bacterium Treponema pallidum, with serious health consequences if left untreated, including transmission to unborn children. In parts of the Arctic, syphilis is either endemic or emerging. Identifying cases is critical to preventing transmission. The remoteness of most villages makes timely...

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 vi...

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...

Background: Accurate and practical biologic tools to estimate HIV incidence is crucial to better monitor the epidemic and evaluate the effectiveness of HIV prevention and treatment programs. Methods: We evaluated two avidity assays to measure recent HIV infection: the Sedia HIV-1 LAg-Avidity EIA (Sedia Biosciences, Portland) and the Centers for...

Spreadsheet with Sedia-LAg-Avidity and CDC-modified Bio-Rad-Avidity data for False Recent Rate (FRR) classification. (420 specimens for known long-term infections; 90 from the Quebec Primary HIV-1 Infection Cohort (>14 months post-seroconversion) and 330 from the LSPQ serobank: 2 years post-seroconversion. (XLSX)

Spreadsheet with Sedia-LAg-Avidity and CDC-modified Bio-Rad-Avidity data (Quebec Primary HIV-1 Infection Cohort) for MDRI estimation. N = 123 treatment-naive and 27 treatment-experienced patients for a total of 577 specimens. (XLSX)

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 b...

This article has no abstract.

Syphilis, caused by the bacterium Treponema pallidum subsp. 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...

Neurosyphilis (NS) is a diagnostic challenge, especially in HIV-infected patients, and criteria to decide 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 un...

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 in...

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 lo...

Background Previous analyses of SurvUDI data have shown an emerging positive association between sex work and HIV incidence among injection drug users (IDUs). Objective To characterise the association between sex work and HIV seroconversion among IDUs in the SurvUDI network between 2004 and 2010. Methods Participants who had injected in the past 6...

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 territo...

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...

In Nunavik, common practices and food habits such as consumption of raw meat and untreated water place the Inuit at risk for contracting zoonotic diseases. The aim of this study was to determine the seroprevalence of seven zoonotic infections among the permanent residents of Nunavik. The study was conducted in the fall 2004 as part of the Nunavik H...

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....

As a result of their intimate contact with the land and their nutritional habits, the Inuit of Nunavik are considered to be at risk from zoonotic infections. To better understand the risk factors for Toxoplasma gondii infection, a serosurvey was conducted in Nunavik, Québec, in September 2004. A representative sample of the Inuit adult population o...

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...

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...

Plaque reduction neutralization (PRN) is the "gold-standard" for the measurement of measles-specific neutralizing antibodies. However, it is a complicated assay and tends to be operator-dependent. It has been suggested that the simpler syncytium inhibition assay (SIA) can give results comparable to the PRN test. We compared these two assays using 5...

A gene (dexS) coding for a Streptococcus suis capsular type 2 dextranase (DexS) was detected in a recombinant gene library constructed in phage lambda ZapII, and its nucleotide sequence was determined. Sequence comparison showed that the dexS gene product had significant similarities with enzymes which hydrolyze glucose polymers. Moreover, conserve...

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 t...

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...

A double-antibody sandwich enzyme-linked immunosorbent assay (ELISA) was developed for the detection and the identification of Streptococcus suis capsular types 1, 2, 1/2, 3 and 22. The specificity of this test was first evaluated using reference strains of S. suis capsular types 1 to 28 and 1/2 as well as 15 different bacterial species susceptible...