A descriptive study on spatial and temporal distributions of genetic clusters of porcine reproductive and respiratory syndrome virus infecting pig sites in Quebec, Canada, between 2010 and 2019.

BACKGROUND: The wide diversity of porcine reproductive and respiratory syndrome virus (PRRSV) strains combined with incomplete heterologous cross-protection complicates the management of the disease at both the herd and the regional levels. The objectives of this study were to describe the spatial and temporal distribution of various PRRSV genetic clusters infecting pig sites in Quebec, Canada, and to compare PRRSV regional diversity of wild-type sequences over the years. MATERIALS AND METHODS: A retrospective surveillance-based study was conducted on all pig sites which had PRRSV ORF5 sequences from field submissions transferred into the Laboratoire d'épidémiologie et de médecine porcine database from January 1, 2010 to December 31, 2019. A maximum likelihood phylogenetic tree inferred from multiple sequence alignment was used to identify genetic clusters. For each wild-type cluster gathering ≥ 15 sequences, the number of pig sites in which the cluster was detected per administrative region and per year were displayed on bubble charts and the spatiotemporal distribution of pig sites was illustrated using pie chart maps. A molecular analysis of variance was performed to compare PRRSV wild-type sequence diversity according to the administrative region for each year. RESULTS: A total of 32 wild-type clusters gathering 1653 PRRSV2 sequences from 693 pig sites were described. Each cluster was detected on up to 132 pig sites and 7 administrative regions over the 10-year period. Annually, the mean (min-max) number of wild-type clusters detected in at least one pig site reached 24 (17-29). Some clusters remained localized on a few sites over time whereas others were widespread over the territory during a few or many years. For each year, regional differences were also observed in PRRSV diversity of wild-type sequences. CONCLUSIONS: The differences observed in both the spatiotemporal distributions of PRRSV clusters and in the regional diversity of wild-type sequences highlight the importance of ongoing provincial surveillance to improve collective PRRS management strategies.

Prospective validation of an equation based on plasma cystatin C for monitoring the glomerular filtration rate in children treated with cisplatin or ifosfamide for cancer.

We recently proposed an equation to estimate the glomerular filtration rate (GFR) in children with cancer based on plasma cystatin C and serum creatinine levels together with body weight (the "CysPed equation"). The current clinical study reports a prospective evaluation of this equation in 18 children treated by nephrotoxic chemotherapy. The CysPed equation resulted in less bias and greater precision compared to two equations previously proposed equations by Schwartz, with or without plasma cystatin C. Moreover, the decrease in GFR due to chemotherapy was clearly identified by the CysPed equation. This equation may be used to monitor the renal function in childhood cancer units.

Draft genome sequences of four Staphylococcus hyicus strains, SC302, SC304, SC306, and SC310, isolated from swine from Eastern Canada.

The bacterium Staphylococcus hyicus causes porcine exudative epidermitis in piglets, which represents both health and welfare concerns. Few genome sequences of this pathogen are published. We provide four additional ones to help future genomic analysis of S. hyicus. These are genomes of strains isolated from Canadian swine.

[Pelvic exam in gynecology and obstetrics: Guidelines for clinical practice]. / Examen pelvien en gynécologie et obstétrique : recommandations pour la pratique clinique.

OBJECTIVE: To provide guidelines for the pelvic clinical exam in gynecology and obstetrics. MATERIAL AND METHODS: A multidisciplinary experts consensus committee of 45 experts was formed, including representatives of patients' associations and users of the health system. The entire guidelines process was conducted independently of any funding. The authors were advised to follow the rules of the Grading of Recommendations Assessment, Development and Evaluation (GRADE®) system to guide assessment of quality of evidence. The potential drawbacks of making strong recommendations in the presence of low-quality evidence were emphasized. METHODS: The committee studied 40 questions within 4 fields for symptomatic or asymptomatic women (emergency conditions, gynecological consultation, gynecological diseases, obstetrics, and pregnancy). Each question was formulated in a PICO (Patients, Intervention, Comparison, Outcome) format and the evidence profiles were produced. The literature review and recommendations were made according to the GRADE® methodology. RESULTS: The experts' synthesis work and the application of the GRADE method resulted in 27 recommendations. Among the formalized recommendations, 17 present a strong agreement, 7 a weak agreement and 3 an expert consensus agreement. Thirteen questions resulted in an absence of recommendation due to lack of evidence in the literature. CONCLUSIONS: The need to perform clinical examination in gynecological and obstetrics patients was specified in 27 pre-defined situations based on scientific evidence. More research is required to investigate the benefit in other cases.

Population pharmacokinetic analysis reveals no impact of aprepitant on the pharmacokinetics of ifosfamide, 2-dechloroifosfamide, and 3-dechloroifosfamide.

PURPOSE: Several case reports and retrospective series have clearly pointed to the role of aprepitant, an antiemetic drug, in the development of encephalopathy when used with ifosfamide. Described as an inhibitor of several CYP metabolic pathways, aprepitant is suspected of drug-drug-interaction on ifosfamide pharmacokinetics. The pharmacokinetics of ifosfamide and two of its metabolites (2-dechloroifosfamide and 3-dechloroifosfamide) was studied in patients with soft tissue sarcomas to evaluate the impact of aprepitant administration. METHODS: A population pharmacokinetic approach was applied to analyze data obtained in 42 patients at cycle 1 (without aprepitant) and cycle 2 (with aprepitant for 34 of them). RESULTS: A previously published pharmacokinetic model including a time-dependency process well fit the data. Aprepitant had no impact on ifosfamide or its two metabolite pharmacokinetic parameters. CONCLUSION: This study suggests that aprepitant does not lead to a significant modification of ifosfamide metabolization, even though other metabolites such as 4 hydroxyifosfamide and chloroacetaldehyde were not monitored in this study.

Systemic exposure to cisplatin and paclitaxel after intraperitoneal chemotherapy in ovarian cancer.

PURPOSE: To determine the systemic exposure to cisplatin and paclitaxel after adjuvant intraperitoneal administration in patients with advanced ovarian cancer who underwent primary debulking surgery. This could provide an explanation for the high incidence of systemic adverse events associated with this treatment regimen. METHODS: This is a prospective pharmacokinetic study in patients with newly diagnosed advanced ovarian cancer who were treated with intraperitoneal administered cisplatin and paclitaxel. Plasma and peritoneal fluid samples were obtained during the first treatment cycle. The systemic exposure to cisplatin and paclitaxel was determined and compared to previously published exposure data after intravenous administration. An exploratory analysis was performed to investigate the relation between systemic exposure to cisplatin and the occurrence of adverse events. RESULTS: Pharmacokinetics of ultrafiltered cisplatin were studied in eleven evaluable patients. The geometric mean [range] peak plasma concentration (Cmax) and area under the plasma-concentration time curve (AUC0-24 h) for cisplatin was 2.2 [1.8-2.7] mg/L and 10.1 [9.0-12.6] mg h/L, with a coefficient of variation (CV%) of 14 and 13.0%, respectively. The geometric mean [range] observed plasma concentration of paclitaxel was 0.06 [0.04-0.08] mg/L. No correlation was found between systemic exposure to ultrafiltered cisplatin and adverse events. CONCLUSION: Systemic exposure to ultrafiltered cisplatin after intraperitoneal administration is high. In addition to a local effect, this provides a pharmacological explanation for high incidence of adverse events seen after intraperitoneal administration of high-dose cisplatin. The study was registered at ClinicalTrials.gov under registration number NCT02861872.

The Impact of Salt Accumulation on the Growth of Duckweed in a Continuous System for Pig Manure Treatment.

Duckweed (Lemna) is a possible solution for the treatment of aqueous waste streams and the simultaneous provision of protein-rich biomass. Nitrification-Denitrification effluent (NDNE) from pig manure treatment has been previously used as a growing medium for duckweed. This study investigated the use of a continuous duckweed cultivation system to treat NDNE as a stand-alone technology. For this purpose, a system with a continuous supply of waste streams from the pig manure treatment, continuous biomass production, and continuous discharge that meets the legal standards in Flanders (Belgium) was simulated for a 175-day growing season. In this simulation, salt accumulation was taken into account. To prevent accumulating salts from reaching a toxic concentration and consequently inhibiting growth, the cultivation system must be buffered, which can be achieved by altering the depth of the system. To determine the minimum depth of such a system, a tray experiment was set up. For that, salt accumulation data obtained from previous research were used for simulating systems with different pond depths. It was found that a depth of at least 1 m is needed to prevent a significant relative growth inhibition at the end of the growing season compared to the start. This implies a high water consumption (5-10 times more than maize). As a response, a second cultivation system was investigated for the use of more concentrated NDNE. For this purpose, salt tolerance experiments were conducted on synthetic and biological media. Surprisingly, it was observed that duckweed grows better on diluted NDNE (to 75% NDNE, or EC of 8 mS/cm) than on a synthetic medium (EC of 1.5 mS/cm), indicating the potential of such a system.

The Creative Process and Emotions of Pupils in a Training Context with a Design Project.

For many years, researchers have been investigating how the creative process occurs and what factors influence it. The scope of these studies is essential in the school context to enable pupils to develop their creativity and thus address the needs of the 21st century society. Although very rich, these studies are generally not situated in a real teaching and learning context. The output of the present research will make it possible to model, to better understand, and to identify the creative process in pupils as they design and produce utility objects in an educational and training context with ecological validity (real context of training). In the context of teaching Creative and Manual Activities in education, in the French part of Switzerland, we are focusing on observations of the creative process in line with psychology, didactics, and pedagogy. During their class, 22 pupils were invited to create a water fountain and, in parallel, to complete a Creative process Report Diary about the stages they do and the multivariate factors (cognitive, conative, emotional, and environmental factors) they mobilize at each lesson. Results presented the main frequent stages and factors at each lesson and we proposed a model describing the transitions between the stages and how the multivariate factors are involved in each stage. They illustrate what pupils actually do in a creative learning context.

Gram-negative central line-associated bloodstream infection incidence peak during the summer: a national seasonality cohort study.

Central line-associated bloodstream infections (CLABSI) cause increased morbidity, mortality, and hospital costs that are partially preventable. The phenomenon of seasonality among CLABSI rates has not been fully elucidated, but has implications for accurate surveillance and infection prevention trials. Longitudinal dynamic cohort of hospitals participating in hospital-wide and intensive care unit bloodstream infection surveillance for at least one full year over 2000 to 2014. Mixed-effects negative binomial regression analysis calculated the peak-to-low ratio between months as an adjusted CLABSI incidence rate ratio (IRR) with 95% confidence intervals (CI). Multivariate regression models examined the associations between CLABSI pathogens and ambient temperature and relative humidity. The study population included 104 hospital sites comprising 11,239 CLABSI. Regression analysis identified a hospital-wide increase in total CLABSI during July-August, with a higher gram-negative peak-to-low incidence rate ratio (IRR 2.52 [95% CI 1.92-3.30], p < 0.001) compared to gram-positive bacteria (IRR 1.29 [95% CI 1.11-1.48], p < 0.001). Subgroup analysis replicated this trend for CLABSI diagnosed in the intensive care unit. Only gram-negative CLABSI rates were associated with increased temperature (IRR + 30.3% per 5 °C increase [95% CI 17.3-43.6], p < 0.001) and humidity (IRR + 22.9% per 10% increase [95% CI 7.7-38.3), p < 0.001). The incidence and proportion of gram-negative CLABSI approximately doubled during the summer periods. Ambient temperature and humidity were associated with increases of hospital-acquired gram-negative infections. CLABSI surveillance, preventive intervention trials and epidemiological studies should consider seasonal variation and climatological factors when preparing study designs or interpreting their results.

Comparison of Two Types of Amino Acid Solutions on 177Lu-Dotatate Pharmacokinetics and Pharmacodynamics in Patients with Metastatic Gastroenteropancreatic Neuroendocrine Tumors.

BACKGROUND: 177Lu-Dotatate is used in the treatment of somatostatin-receptor-positive inoperable progressive gastroenteropancreatic neuroendocrine tumors. A co-infusion of amino acids (AAs) is administered to prevent renal toxicity. OBJECTIVE: This study aimed to quantify the impact of two types of AA cocktails on the pharmacokinetics and toxicity of 177Lu-Dotatate. METHODS: Four injections of 7400 MBq 177Lu-Dotatate were given per patient with administration of either Primene® 10% (containing a cocktail of 20 AAs with 22g of Lysine and 16.8 g of Arginine) or Lysakare® (containing 25 g of Lysine and 25 g of Arginine). Nine blood samples were collected at each cycle. Radioactivity-time data were analyzed according to a population-based model using NONMEM (version 7.4.1). Renal and hematological toxicity was evaluated after each cycle. RESULTS: 1,678 177Lu-Dotatate plasma concentrations versus time were analyzed from 83 consecutive patients with Primene® (n= 45 pts) or Lysakare® (n= 36 pts). Population pharmacokinetic analysis showed that Primene® significantly increased the elimination rate constant of 177Lu-Dotatate as opposed to Lysakare®. Primene® also significantly lowered Lutathera® plasma exposure (AUC) by 34%, whereas Lysakare® increased AUC by 7%. There was no renal toxicity in either case. Lymphopenia significantly correlated with AUC (p=0.021) with a trend towards higher toxicity with Lysakare®. CONCLUSION: Unlike Primene®, Lysakare® does not increase 177Lu-Dotatate elimination. This difference is associated with a significant impact on AUC. The latter parameter has a high interpatient variability but a low intrapatient variability, which could have important clinical implications for treatment tailoring.

Seasonal variation of hospital-acquired bloodstream infections: A national cohort study.

BACKGROUND: Hospital-acquired bloodstream infections (HABSIs) cause increased morbidity, mortality, and hospital costs that are partially preventable. HABSI seasonality has been described for gram-negative bacteria but has not been stratified per infection origin. OBJECTIVE: To assess seasonality among all types of HABSIs and their associations with climate. METHODS: Hospitals performing surveillance for at least 1 full calendar year between 2000 and 2014 were included. Mixed-effects negative binomial regression analysis calculated the peak-to-low monthly ratio as an adjusted HABSI incidence rate ratio (IRR) with 95% confidence intervals (CIs). Another regression model examined associations between HABSI rates and climate variables. These analyses were stratified by microorganism and infectious origin. RESULTS: The study population included 104 hospitals comprising 44,111 HABSIs. Regression analysis identified an incidence rate ratio (IRR) peak in August for gram-negative HABSIs (IRR, 1.59; 95% CI, 1.49-1.71), CLABSIs (IRR, 1.49; 95% CI, 1.30-1.70), and urinary tract HABSI (IRR, 1.52; 95% CI, 1.34-1.74). The gram-negative incidence increased by 13.1% (95% CI, 9.9%-16.4%) for every 5°C increase in temperature. Seasonality was most present among E. coli, K. pneumoniae, E. cloacae, and the nonfermenters. Gram-positive and pulmonary HABSIs did not demonstrate seasonal variation. CONCLUSIONS: Seasonality with summer spikes occurred among gram-negative bacteria, CLABSIs, and urinary tract HABSIs. Higher ambient temperature was associated with gram-negative HABSI rates. The preventable causative factors for seasonality, such as the nurse-to-patient ratio, indoor room temperature or device-utilization, need to be examined to assess areas for improving patient safety.

Human muscle stem cells are refractory to aging.

Age-related loss of muscle mass and strength is widely attributed to limitation in the capacity of muscle resident satellite cells to perform their myogenic function. This idea contains two notions that have not been comprehensively evaluated by experiment. First, it entails the idea that we damage and lose substantial amounts of muscle in the course of our normal daily activities. Second, it suggests that mechanisms of muscle repair are in some way exhausted, thus limiting muscle regeneration. A third potential option is that the aged environment becomes inimical to the conduct of muscle regeneration. In the present study, we used our established model of human muscle xenografting to test whether muscle samples taken from cadavers, of a range of ages, maintained their myogenic potential after being transplanted into immunodeficient mice. We find no measurable difference in regeneration across the range of ages investigated up to 78 years of age. Moreover, we report that satellite cells maintained their myogenic capacity even when muscles were grafted 11 days postmortem in our model. We conclude that the loss of muscle mass with increasing age is not attributable to any intrinsic loss of myogenicity and is most likely a reflection of progressive and detrimental changes in the muscle microenvironment such as to disfavor the myogenic function of these cells.

Selective screening for lysosomal storage disorders in a large cohort of minorities of African descent shows high prevalence rates and novel variants.

Population studies point to regional and ethnicity-specific differences in genetic predisposition for some lysosomal storage disorders (LSDs). The aim of the study was to determine the prevalence of the three treatable forms of lysosomal storage disorders (Gaucher disease [GD], Pompe disease [PD], and Fabry disease [FD]) in a cohort of mostly urban-dwelling individuals of African ancestry, a previously unknown genetic landscape for LSDs. Large-scale selective multistep biochemical and genetic screening was performed in patients seeking healthcare for various health concerns. Fluorimetric enzyme assays for GD, PD, and FD were performed on dried blood spots. Targeted gene sequencing was performed on samples that showed significantly lower enzyme activities (<10% of control mean) after two tiers of enzymatic screening. A total of 5287 unique samples representing a cross section of patients who visited Howard University Hospital and College of Medicine from 2015 to 2017 were included in the study. Study samples were obtained from a population where ~90% reported as African-American, ~5% Hispanic, and <5% Caucasian or other. Regarding GD, three subjects had either homozygous or heterozygous mutations in the GBA gene. As to PD, eight subjects were either homozygous or compound heterozygous for GAA mutations, including three novel mutations: (a) c.472 A > G; p.T158A, (b) c.503G > T; p.R168L, (c) c.1985del. Regarding FD, two subjects had pathogenic GLA mutations, and four had single nucleotide polymorphisms in the 5'UTR, previously implicated in modulating gene expression. The findings highlight a higher incidence of abnormal enzyme levels and pathogenic mutations in the target population reflecting ancestry-based specific genotype and phenotype variations.

Plasma cystatin C is a marker of renal glomerular injury in children treated with cisplatin or ifosfamide.

BACKGROUND: Plasma cystatin C is a potential marker of the glomerular filtration rate (GFR), and urinary cystatin C has been proposed as a marker of tubular dysfunction. PROCEDURE: A prospective study (NCT02822404) was conducted to assess the benefit of considering cystatin C plasma and urinary levels to better evaluate cisplatin and/or ifosfamide renal toxicity in children with cancer. Plasma 51 Cr-EDTA clearance as a marker of GFR and urinary markers of tubular toxicity were monitored in 40 children treated by cisplatin and/or ifosfamide. Several equations previously proposed to estimate GFR, with or without inclusion of plasma cystatin C level, were compared. A population pharmacokinetic approach was also used to analyze plasma 51 Cr-EDTA data, and evaluate the relationship between patient covariates (including plasma cystatin C level) and GFR during the course of chemotherapy treatment. RESULTS: Equations including plasma cystatin C described GFR changes during chemotherapy better than those without this variable. An equation based on plasma cystatin C, serum creatinine, and body weight enabled us to accurately describe the evolution of GFR during chemotherapy. The urinary cystatin C/creatinine ratio was compared between children with or without tubular toxicity, according to a standard assessment of tubular dysfunction. However, although the urinary cystatin C/creatinine ratio was increased in children with tubular toxicity, this marker does not provide additional information to the well-known markers of tubulopathy. CONCLUSIONS: Monitoring of plasma cystatin C may be substituted to radionucleide glomerular exploration in children treated by cisplatin and/or ifosfamide.

Homozygous hypomorphic BRCA2 variant in primary ovarian insufficiency without cancer or Fanconi anaemia trait.

BACKGROUND: Primary ovarian insufficiency (POI) affects 1% of women under 40 years and is a public health problem. The genetic causes of POI are highly heterogeneous with isolated or syndromic forms. Recently, variants in genes involved in DNA repair have been shown to cause POI. Notably, syndromic POI with Fanconi anaemia (FA) traits related to biallelic BRCA2 truncated variants has been reported. Here, we report a novel phenotype of isolated POI with a BRCA2 variant in a consanguineous Turkish family. METHODS: Exome sequencing (ES) was performed in the patient. We also performed functional studies, including a homologous recombination (HR) test, cell proliferation, radiation-induced RAD51 foci formation assays and chromosome breakage studies in primary and lymphoblastoid immortalised cells. The expression of BRCA2 in human foetal ovaries was studied. RESULTS: ES identified a homozygous missense c.8524C>T/p.R2842C-BRCA2 variant. BRCA2 defects induce cancer predisposition and FA. Remarkably, neither the patient nor her family exhibited somatic pathologies. The patient's cells showed intermediate levels of chromosomal breaks, cell proliferation and radiation-induced RAD51 foci formation compared with controls and FA cells. R2842C-BRCA2 only partially complemented HR efficiency compared with wild type-BRCA2. BRCA2 is expressed in human foetal ovaries in pachytene stage oocytes, when meiotic HR occurs. CONCLUSION: We describe the functional assessment of a homozygous hypomorphic BRCA2 variant in a patient with POI without cancer or FA trait. Our findings extend the phenotype of BRCA2 biallelic alterations to fully isolated POI. This study has a major impact on the management and genetic counselling of patients with POI.

Wide variation in tissue, systemic, and drain fluid exposure after oxaliplatin-based HIPEC: results of the GUTOX study.

PURPOSE: In this exploratory study, the effect of postprocedural flushing with crystalloids after oxaliplatin-based hyperthermic intraperitoneal chemotherapy (HIPEC) on platinum concentrations in peritoneal tissue, blood, and drain fluid was studied. Interpatient variability in oxaliplatin pharmacokinetics and the relation between platinum concentration in peritoneal fluid and platinum exposure in tissue and blood was explored. METHODS: Ten patients with peritoneal carcinomatosis of colorectal origin were treated with HIPEC including postprocedural flushing, followed by ten patients without flushing afterwards. Tissue, peritoneal fluid, blood, and drain fluid samples were collected for measurement of total and ultrafiltered platinum concentrations. RESULTS: Peritoneal tissue concentration and systemic ultrafiltered platinum exposure showed large inter individual variability, ranging from 65 to 1640 µg/g dry weight and 10.5 to 28.0 µg*h/ml, respectively. No effect of flushing was found on geometric mean platinum concentration in peritoneal tissue (348 vs. 356 µg/g dry weight), blood (14.8 vs. 18.1 µg*h/ml), or drain fluid (day 1: 7.6 vs. 7.7 µg/ml; day 2: 1.7 vs. 1.9 µg/ml). The platinum concentration in peritoneal fluid at the start of HIPEC differed twofold between patients and was positively correlated with systemic exposure (p = .04) and peak plasma concentration (p = .04). CONCLUSION: In this exploratory study, no effect was found for postprocedural flushing on platinum concentrations in peritoneal tissue, blood, or drain fluid. BSA-based HIPEC procedure leads to large interpatient variability in platinum exposure in all compartments. The study was registered at ClinicalTrials.gov on 7 December 2017 under registration number NCT03364907.

Real-life effectiveness of omalizumab in difficult-to-treat versus severe asthma: a national cohort study in Belgium.

BACKGROUND: Guidelines recommend omalizumab in patients with uncontrolled severe allergic asthma. We investigated real-life use of omalizumab, the proportion of patients fulfilling eligibility criteria, its costs and its effectiveness. METHOD: In a cohort of asthma patients initiating treatment with omalizumab in Belgium between 2010 and 2016, we investigated fulfilment of eligibility criteria (chronic use of high-dose inhaled corticosteroids (ICSs) plus long-acting ß2-agonists (LABAs) and ≥2 severe asthma exacerbations in previous year), and compared hospitalisations and systemic corticosteroid consumption in the year before and after omalizumab initiation. We computed healthcare costs in the respective time periods and compared the cost per prevented hospitalisation in patients fulfilling eligibility criteria versus those who did not. RESULTS: Between 2010 and 2016, omalizumab treatment was initiated in 2068 patients with asthma; only 24% fulfilled the eligibility criteria, mainly due to nonadherence to high-dose ICSs + LABAs. The proportion of patients hospitalised for asthma decreased from 41% to 21% in eligible patients (absolute risk reduction, 20%), whereas the absolute risk reduction was 5% (from 19% to 14%) in noneligible patients. The cost per prevented hospitalisation was €44 238 versus €139 495, respectively. Chronic use of systemic corticosteroids was discontinued in 35% of eligible patients versus 15% of noneligible patients. CONCLUSION: In Belgium, omalizumab is mostly initiated in uncontrolled asthma patients who are nonadherent to ICSs + LABAs. Omalizumab decreases hospitalisations and the use of systemic corticosteroids, but at a high cost. Careful management of patients with difficult-to-treat asthma should be a priority before prescribing omalizumab.

Positioning Quebec ORF5 sequences of porcine reproductive and respiratory syndrome virus (PRRSV) within Canada and worldwide diversity.

Sequencing of ORF5 gene is widely used and considered essential for diagnostics and control of porcine reproductive and respiratory syndrome (PRRS) in Canada. The objective of this study was to position Quebec ORF5 sequences of PRRS virus within Canada and worldwide diversity. Overall, 76.8% of the 5204 sequences gathered from Quebec (n = 5031), Ontario (n = 151) and Manitoba (n = 18) were classified into one of 34 genetic clusters defined as groupings including ≥15 sequences and having ≥70% rapid bootstrap support value from a maximum likelihood (ML)-phylogeny. Following the addition of PRRSV 2 international reference dataset from Shi et al. (2010), the most predominant lineages in our dataset were wild-type 1 and vaccine-like 5.1 (MLV) and 8.9 (ATP). No strains or only a very few (1 or 2) were assigned to lineages 1.3-1.5, 3, 4, 5.2, 6, 7 or 9. Most wild-type clusters (97%) detected in a dataset from Canada did not include any sequence from the international reference dataset. It might reflect recent subpopulations that were absent at the time of Shi's publication. As an example, cluster #25 first appeared in 2007, but since then had expanded considerably and is now the most prevalent wild-type cluster found in Quebec. A total of 117 RFLP patterns were identified and those were poorly correlated with genetic clusters based on phylogeny. Factors modulating PRRSV diversity such as pig movement that occurred within and between provinces should be further investigated in a perspective of disease control.