Ambikaipakan Senthilselvan

University of Alberta, Edmonton, Alberta, Canada

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Publications (174)498.21 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Abstract Background: Asthma is one of the most prevalent chronic diseases worldwide, affecting more than 200 million people. Vitamin D deficiency has been reported among individuals with asthma and might play a role in asthma exacerbations. In this cross-sectional study, we investigated the association of serum 25-hydroxy vitamin D [25(OH)D] levels and current asthma, ever asthma, and lung function. Methods: Data from 3,937 subjects aged 13-69 years who participated in the Canadian Health Measures Survey-Cycle 1 were considered in this study. Serum 25(OH)D levels were categorized into ≤49 nmol/L (low), 50-74 nmol/L (moderate) and ≥75 nmol/L (high). Results: The proportion of subjects with current and ever asthma was greater in the lower 25(OH)D category than in moderate and high categories. After adjusting for potential confounders, subjects in the low 25(OH)D levels were more likely to have current asthma than those in the moderate levels (OR:1.54, 95% CI:1.01-2.36). Low 25(OH)D levels were also associated with ever asthma (OR:2.12, 95% CI:1.40-3.21) among those with a family history of asthma and this association was stronger in those with asthma onset before 20 years of age. High 25(OH)D levels were associated with lower mean value of FEV1/FVC ratio. No significant association was observed between 25(OH)D levels and other lung function measurements. Conclusion: In this study, 25(OH)D levels below 50 nmol/L were associated with an increased risk of current and ever asthma. Further exploration of this relationship is needed to determine the optimal level of vitamin D in the management of asthma in adolescents and adults.
    The Journal of asthma : official journal of the Association for the Care of Asthma. 01/2015;
  • Ming Ye, Jeremy Beach, Jonathan W Martin, Ambikaipakan Senthilselvan
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    ABSTRACT: Although DDT [1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane] has been banned in many countries since the 1970s, it may still pose a risk to human respiratory health. In agriculture, DDT exposures have been associated with asthma and chronic bronchitis. However, little is known about the effect of DDT on lung function. We examined DDT/DDE concentrations in plasma and associations with lung function FVC (forced vital capacity), FEV1 (forced expiratory volume in one second), FEV1/FVC ratio, and FEF25%-75% (forced expiratory flow between 25% and 75% of FVC). We used data on 1,696 participants aged 20-79 years from the Canadian Health Measures Survey (CHMS) and conducted multiple regression analysis to estimate associations between plasma p,p'-DDT/DDE and lung function. Almost all participants (over 99.0%) had detectable concentrations plasma p,p'-DDE, while only 10.0% had detectable p,p'-DDT. Participants with detectable p,p'-DDT had significantly lower mean FVC (diff=311mL; 95% CI: -492, -130; p=0.003) and FEV1 (diff=232mL; 95% CI: -408, -55; p=0.015) than those without. A 100 μg/g lipid) increase in plasma p,p'-DDE was associated with an 18.8mL decrease in mean FVC (95% CI: -29, -9) and an 11.8mL decrease in mean FEV1 (95% CI: -21, -3). Neither exposure was associated with FEV1/FVC ratio or FEF25%-75%. DDT exposures, which may have occurred decades ago, were still detectable among Canadians. Plasma DDT and DDE were negatively associated with lung function parameters. Additional research on the potential effects of DDT use on lung function is warranted.
    Environmental Health Perspectives 12/2014; · 7.03 Impact Factor
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    ABSTRACT: Maternal depression is a risk factor for adolescent depression; however, the effect of childhood exposure to maternal depression on adolescent engagement in health risk behaviors (eg, substance use, delinquency) is unclear. We examined the relationship between maternal depressive symptoms (child's age 4-15) and engagement in health risk behaviors at age 16 to 17 by using data from 2910 mother-youth pairs in a nationally representative prospective Canadian cohort. Maternal depressive trajectories were estimated through finite mixture modeling, and multiple regression analyses examined the relationship between maternal depressive symptoms and engagement in various health risk behaviors (linear regression) and age of debut of various behaviors (Cox regression). Five trajectories of maternal depressive symptoms were found: recurrent maternal symptoms, midchildhood exposure to maternal symptoms, adolescent exposure to maternal symptoms, mild maternal symptoms, and low symptoms. Adolescents exposed to maternal depressive symptoms during middle childhood were more likely to use common substances (alcohol, cigarettes, marijuana), engage in violent and nonviolent delinquent behavior, and have an earlier debut ages of cigarette, alcohol, marijuana, and hallucinogen use. The results of this study suggest that exposure to maternal depressive symptoms, particularly in middle childhood, is associated with greater and earlier engagement in health risk behaviors. Copyright © 2015 by the American Academy of Pediatrics.
    Pediatrics 12/2014; · 5.30 Impact Factor
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    ABSTRACT: Children with non-renal solid organ transplants are surviving longer, but outcome is complicated by CKD. Accurate and frequent renal function monitoring is imperative to recognize and institute measures early to reverse, prevent, or arrest progression. This study of 59 children determined the accuracy (P30), bias, sensitivity and specificity between measured renal function by NM-GFR, and estimated GFR by three formulas: Filler (serum cystatin C), mSchwartz (serum creatinine), and CKiD (serum cystatin C, creatinine, urea, and height). Mean GFR by all formulas differed significantly from NM-GFR. Filler and mSchwartz formulas significantly increased the proportion of patients with GFR ≥ 90 mL/min/1.73 m2 (CKD stage 1) while decreasing those with GFR 60–89 mL/min/1.73 m2 (CKD stage 2). All formulas overestimated GFR. CKiD showed the highest P30 and lowest bias (79.7%; 6.9 mL/min/1.73 m2) followed by Filler (67.7%; 19.9 mL/min/1.73 m2) and Schwartz (57.6%; 26.8 mL/min/1.73 m2) for all GFR values. All formulas performed best with GFR ≥ 90 mL/min/1.73 m2, but CKiD was the only formula to achieve 91.1% accuracy. All formulas showed high sensitivities, but low specificities at NM-GFR cutoff at 90. Thus, GFR estimated by CKiD followed by Filler formula is an adequate method to monitor renal function closely and frequently in these children.
    Pediatric Transplantation 11/2014; · 1.63 Impact Factor
  • Y Lu, A Senthilselvan, A M Joffe, J Beach
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    ABSTRACT: Sharps injuries remain a common factor in occupational exposure of healthcare workers to blood-borne viruses. The extent to which the introduction of safety-engineered devices has been effective in reducing such injuries among healthcare workers is unclear.
    Occupational medicine (Oxford, England). 10/2014;
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    ABSTRACT: Background:Acute asthma is a common emergency department (ED) presentation. In a prospective multicenter cohort study we determined the frequency and factors associated with asthma relapse following discharge from the ED. Methods:Adults aged 18-55 years who were treated for acute asthma and discharged from 20 Canadian EDs underwent a structured ED interview and follow-up telephone interview four weeks later. Standardized anti-inflammatory treatment was offered at discharge. Multivariable analyses were performed. Results:Of 807 enrolled patients, 58% were female and the median age was 30 years. Relapse occurred in 144 patients (18%) within four weeks of ED discharge. Factors independently associated with relapse occurrence were: female sex (22% vs 12% males, adjusted odds ratio [aOR] = 1.9, 95% confidence interval [CI]: 1.2, 3.0), symptom duration of > 24 hours prior to ED visit (19% vs 13% short duration, aOR = 1.7, 95% CI: 1.3, 2.3), ever using oral corticosteroids (21% vs 12% for never use, aOR = 1.5, 95% CI: 1.1, 2.0), current use of an inhaled corticosteroids[ICS]/long-acting β-agonist combination product (25% vs 15% for ICS monotherapy, aOR = 1.9, 95% CI: 1.1, 3.2), and owning a spacer device (24% vs 15% not owning one aOR = 1.6, 95% CI: 1.3, 1.9). Conclusions:Despite receiving guideline-concordant anti-inflammatory treatments at ED discharge, almost one-in-five patients relapsed within four weeks. Female sex, prolonged symptoms, treatment-related factors and markers of prior asthma severity were significantly associated with relapse. These results may help clinicians target more aggressive interventions for patients at high risk of relapse.
    Chest 10/2014; · 7.13 Impact Factor
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    ABSTRACT: The study was designed to investigate whether beryllium exposure was related to illness diagnosed as sarcoidosis. Chronic beryllium disease (CBD) and sarcoidosis are clinically and pathologically indistinguishable, with only the presence of beryllium-specific T-lymphocytes identifying CBD. Testing for such cells is not feasible in community studies of sarcoidosis but a second characteristic of CBD, its much greater incidence in those with a glutamic acid residue at position 69 of the HLA-DPB1 gene (Glu69), provides an alternative approach to answering this question.
    Occupational and Environmental Medicine 10/2014; · 3.23 Impact Factor
  • S J Niruban, K Alagiakrishnan, J Beach, A Senthilselvan
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    ABSTRACT: Background/objectives:Vitamin D modifies airway inflammation and appears to be important in building immunity against respiratory infections, and so is potentially beneficial in asthma. However, to date results from studies investigating the relationship of vitamin D with respiratory outcomes are inconsistent. The objective of this study was to determine the association of vitamin D with current wheeze, ever asthma and lung function.Subjects/Methods:Data on 1213 children aged 6-12 years, from the Canadian Health Measures Survey, were considered for the study. Serum 25-hydroxy vitamin D (25(OH)D) levels were categorized into three categories: ⩽49 nmol/l (low); 50-74 nmol/l (moderate); and ⩾75 nmol/l (high).Results:Children in the low and high 25(OH)D categories were more likely to report current wheeze in comparison to those in the moderate category (odds ratio (OR): 3.26, 95% confidence interval (CI): 1.16-9.17 and OR: 2.14, 95% CI: 1.07-4.28, respectively). The results for the association between 25(OH)D levels and ever asthma were similar to those observed for current wheeze, except that a significant association was observed only in the lower category. The rate of increase in forced expiratory volume in one second and forced vital capacity with age was greater in the moderate category.Conclusions:Children in both low and high 25(OH)D categories had increased risk of current wheeze and reduced rate of change in lung function with age in comparison to the moderate category, raising the possibility of a U-shaped association between vitamin D levels and respiratory health. Clearer guidelines for optimal vitamin D levels are required to improve respiratory health in children.European Journal of Clinical Nutrition advance online publication, 2 July 2014; doi:10.1038/ejcn.2014.121.
    European Journal of Clinical Nutrition 07/2014; · 2.95 Impact Factor
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    ABSTRACT: The study objective was to evaluate the effects of sitagliptin in patients with type 2 diabetes (T2D) and heart failure (HF).
    JACC. Heart failure. 06/2014;
  • Journal of Allergy and Clinical Immunology 05/2014; · 11.25 Impact Factor
  • Yin Nwe Aung, Carina Majaesic, Ambikaipakan Senthilselvan, Piushkumar J Mandhane
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    ABSTRACT: Physician training influences patient care. To compare asthma management and change in the percentage predicted FEV1 among pediatric physician specialties. A retrospective cohort of children 6 years of age or older, seen in a multidisciplinary asthma clinic between 2009 and 2010, and followed to 2012, was completed to examine differences in asthma outcomes by specialty (2 pediatricians, 3 pediatric allergists, 5 pediatric respirologists). Univariate analyses compared investigation, including allergy testing (skin prick or RAST), comorbid conditions, and prescription by specialty. Multivariate regression, which controlled for random effect of the individual physician, examined specialty differences for prescribed inhaled corticosteroids (ICS) and changes in percentage predicted FEV1. More than 56% of the patients (309/548) were seen by pediatric respirologists, 26% by pediatric allergists, and 18% by pediatricians. Physician specialty influences investigation requested, comorbid diagnoses, treatment, and improvement in FEV1. Pediatric allergists' patients had more allergy tests, were more likely to be diagnosed with allergic rhinitis and, consequently, were more likely to be prescribed nasal steroids than pediatricians and pediatric respirologists. Pediatricians were less likely to prescribe ICS (odds ratio 0.39 [95% CI, 0.15-0.96]; P < .05) than pediatric allergists, with the greatest difference in ICS prescription among children with a percentage predicted FEV1 ≥ 80%. Improvement in FEV1 among children who received care with pediatric allergists was higher than those seen by pediatricians (13%; P < .001) and pediatric respirologists (8%; P = .005). Patient management domains with the greatest room for discretion (investigations, comorbid diagnoses, and treatment with ICS among children with normal lung function) are most heavily influenced by physician specialty. These results have implications for asthma management at the patient level and in future practice guidelines.
    The journal of allergy and clinical immunology. In practice. 05/2014; 2(3):306-312.e5.
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    ABSTRACT: This study sought to identify factors protective against the onset or recurrence of depression in early adulthood, and to describe their interactions with stressors during this transitional period. Methods 1137 members of Canada's National Population Health Survey were followed from ages 12-17 in 1994/95 and contacted every two years until 2008/09. Protective factors measured at age 16/17 included social support, physical activity, mastery, self-esteem, and education level. General linear mixed models were used to examine the relationship between the protective factors and five assessments of depression, including interactions between protective factors and four types of stress: stressful life events, and work, financial, and personal stress. High mastery in adolescence had a significant protective effect against depression in early adulthood. Participants with high social support in adolescence were significantly less likely to become depressed after experiencing work or financial stress, compared to those with low social support. Those who were physically active in adolescence were less likely to become depressed after experiencing work stress, and higher overall education level reduced depression risk following personal stress or major life events. Social support and physical activity may be ideal targets for school-based depression interventions during a potentially stressful transitional period.
    Preventive Medicine 04/2014; · 2.93 Impact Factor
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    Ming Ye, Jeremy Beach, Jonathan W Martin, Ambikaipakan Senthilselvan
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    ABSTRACT: Pesticides have been widely used to control pest and pest-related diseases in agriculture, fishery, forestry and the food industry. In this review, we identify a number of respiratory symptoms and diseases that have been associated with occupational pesticide exposures. Impaired lung function has also been observed among people occupationally exposed to pesticides. There was strong evidence for an association between occupational pesticide exposure and asthma, especially in agricultural occupations. In addition, we found suggestive evidence for a link between occupational pesticide exposure and chronic bronchitis or COPD. There was inconclusive evidence for the association between occupational pesticide exposure and lung cancer. Better control of pesticide uses and enforcement of safety behaviors, such as using personal protection equipment (PPE) in the workplace, are critical for reducing the risk of developing pesticide-related symptoms and diseases. Educational training programs focusing on basic safety precautions and proper uses of personal protection equipment (PPE) are possible interventions that could be used to control the respiratory diseases associated with pesticide exposure in occupational setting.
    International Journal of Environmental Research and Public Health 12/2013; 10(12):6442-71. · 1.99 Impact Factor
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    ABSTRACT: Background and Aim: White matter disease (WMD) of the brain is considered to be secondary to small vessel ischemia and can be a single unifying risk factor for the development of geriatric syndromes. The aim of our study was to investigate the association of the global and regional severity of WMD in the brain with geriatric syndromes burden. Methods: In our retrospective study, consecutive outpatient charts from patients seen between January 2010 and June 2011 at University of Alberta Hospital Seniors Clinic were reviewed. Subjects with brain computed tomography (CT) scans were included in the study. Subjects with incomplete information or with diseases that confounded WMD assessment on CT were excluded. White matter disease was quantified on CT using Wahlund scoring. A multiple linear regression analysis was conducted to determine the association of WMD severity with geriatric syndromes burden after controlling for confounding vascular risk factors. Results: Of the 505 subjects, 326 (64.6%) were women. Mean age of the study patients was 79.8 years (SD ± 7.04), prevalence of WMD disease was 79.4%, and mean WMD score was 5.1 (SD ± 4.4). In subjects aged < and > 80 years, the mean number of geriatric syndromes was 2.83 (standard error of the mean [SE] 0.08) and 3.22 (SE 0.08), respectively. In the adjusted regression analysis, there was a significant association between WMD severity, globally (regression coefficient (β) = 0.457, SE 0.155; P = 0.003), as well as WMD in specific regions: frontal (P < 0.001), parieto-occipital (P = 0.004), and infratentorial regions (P = 0.04) with geriatric syndromes burden. The association remains even after correcting for age, sex, and all vascular risk factors. Conclusion: In our study, there was a significant association between the severity of global and selected regional WMD of the brain with geriatric syndromes burden, thus raising the possibility of a shared biologic association through vascular pathology of the brain.
    Postgraduate Medicine 11/2013; 125(6):17-23. · 1.97 Impact Factor
  • Manoj Kumar, Sue Chandra, Zainab Ijaz, Ambikaipakan Senthilselvan
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    ABSTRACT: Epidural analgesia is the commonest mode for providing pain relief in labour, with a combination of bupivacaine and fentanyl most often used in practice. To test whether late-preterm and term neonates exposed to opioids in epidural analgesia in labour are more likely to develop respiratory distress in the immediate neonatal period. A case-control study was conducted of singleton infants born during January 2006 to December 2010. Cases were neonates ≥34 weeks gestation, who developed respiratory distress within 24 h of life requiring supplemental oxygen ≥2 h and/or positive pressure ventilation in the neonatal intensive care unit. Controls were gestation and site-matched neonates who did not develop any respiratory distress within the same period. The information on exposure to epidural analgesia and on potential confounding variables was obtained from the standardised delivery record, routinely filled out on all women admitted to the labour wards. In our study, 206 cases and 206 matched controls were enrolled. Exposure to epidural analgesia was present in 146 (70.9%) cases as compared with 131 (63.6%) of the controls. The association between exposure to epidural analgesia and respiratory distress in neonates was statistically significant upon adjustment for all potential confounders (adjusted OR: 1.75, 95% CI 1.03 to 2.99; p = 0.04). When data was separately analysed for term and late-preterm infants, the results were consistent across these subpopulations, showing no interaction effect. Late-preterm and term infants exposed to maternal epidural analgesia in labour are more likely to develop respiratory distress in the immediate neonatal period.
    Archives of Disease in Childhood - Fetal and Neonatal Edition 10/2013; · 3.86 Impact Factor
  • Canadian Journal of Diabetes 10/2013; 37S4:S45. · 0.46 Impact Factor
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    ABSTRACT: The effectiveness of recommended measures, such as "cover your mouth when coughing", in disrupting the chain of transmission of infectious respiratory diseases (IRD) has been questioned. The objective of the current study was to determine the effectiveness of simple primary respiratory hygiene/cough etiquette maneuvers in blocking droplets expelled as aerosol during coughing. In this study, 31 healthy non-smokers performed cough etiquette maneuvers in an effort to cover their voluntarily elicited best effort coughs in an open bench format. A laser diffraction system was used to obtain accurate, non-invasive, quantitative, real time measurements of the size and number of droplets emitted during the assessed cough etiquette maneuvers. Recommended cough etiquette maneuvers did not block the release and dispersion of a variety of different diameter droplets to the surrounding environment. Droplets smaller than one-micron size dominate the total number of droplets leaked when practicing assessed maneuvers. All the assessed cough etiquette maneuvers, performed as recommended, do not block droplets expelled as aerosol when coughing. This aerosol can penetrate profound levels of the respiratory system. Practicing these assessed primary respiratory hygiene/cough etiquette maneuvers would still permit direct, indirect, and/or airborne transmission and spread of IRD, such as influenza and Tuberculosis. All the assessed cough etiquette maneuvers, as recommended, do not fully interrupt the chain of transmission of IRD. This knowledge urges us all to critically review recommended CE and to search for new evidence-based procedures that effectively disrupt the transmission of respiratory pathogens. Interrupting the chain of transmission of IRD will optimize the protection of first responders, paramedics, nurses, and doctors working in triage sites, emergency rooms, intensive care units, and the general public against cough-droplet-spread diseases.
    BMC Public Health 09/2013; 13(1):811. · 2.32 Impact Factor
  • S Konrad, A Hossain, A Senthilselvan, J A Dosman, P Pahwa
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    ABSTRACT: Knowledge about chronic bronchitis (CB) among Aboriginal people in Canada is limited. The aim of this study was to determine the prevalence of CB and its associated factors among Aboriginal people aged 15 years plus. Logistic regression analysis was used on data from the cross-sectional 2006 Aboriginal Peoples Survey to determine risk factors associated with CB. CB prevalence was 6.6% among First Nations, 6.2% among Métis and 2.4% among Inuit. Prevalence was higher among females than males (7.2% versus 5.0%). Individuals with CB were more likely to be older, living at a lower income, with a lower educational attainment and residing in rural areas. Smoking status and body mass index were also significantly associated with CB, but their effect differed by sex. Obesity was particularly significantly associated with CB among females compared with males, and current smoking and non-smoking status was significantly associated with CB among females but not males. These findings identify factors associated with CB among Aboriginal people. As such, they may represent potentially preventable risk factors that can inform health promotion and disease prevention practices.
    Chronic Diseases and Injuries in Canada 09/2013; 33(4):218-25. · 1.22 Impact Factor
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    ABSTRACT: The public health impact of the emergence of new norovirus (NoV) strains is uncertain. A biennial pattern of alternating quiescent and epidemic levels of NoV outbreak activity associated with the emergence of new GII.4 variants was observed in Alberta, Canada between July 2000 and June 2008. In this study, NoV GI and GII strains isolated from 710 outbreak specimens in Alberta between July 2008 and January 2013 were characterized to update historical data. The seasonality and annual variation in NoV outbreak burden was analyzed over a 10 year period (July 2002 to June 2012). We found that GII.4-2006b had persisted as the predominant variant over three observation periods (July 2006 to June 2009) during which the biennial NoV outbreak pattern continued. The emergence of GII.4-2010 (winter 2009) was not associated with increased outbreak activity and outbreak activity between July 2009 and June 2012 when GII.4-2010 predominated (67.5-97.7%) did not follow a biennial pattern. GII.4-2012 first emerged in Alberta in September 2011 and became predominant in 2012/13. NoV GI, relatively rare in past years had a higher activity level (37.3%) as GI.6 and GI.7 in the winter of 2012-13. A higher proportion of GI outbreaks occurred in non-health-care-facility settings as compared to GII. Our study suggests that factors other than new variants emergence contribute to the levels of NoV outbreak activity in Alberta.
    Journal of clinical microbiology 05/2013; · 4.23 Impact Factor
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    ABSTRACT: Beijing strains are speculated to have a selective advantage over other Mycobacterium tuberculosis strains because of increased transmissibility and virulence. In Alberta, a province of Canada that receives a large number of immigrants, we conducted a population-based study to determine whether Beijing strains were associated with increased transmission leading to disease compared with non-Beijing strains. Beijing strains accounted for 258 (19%) of 1,379 pulmonary tuberculosis cases in 1991-2007; overall, 21% of Beijing cases and 37% of non-Beijing cases were associated with transmission clusters. Beijing index cases had significantly fewer secondary cases within 2 years than did non-Beijing cases, but this difference disappeared after adjustment for demographic characteristics, infectiousness, and M. tuberculosis lineage. In a province that has effective tuberculosis control, transmission of Beijing strains posed no more of a public health threat than did non-Beijing strains.
    Emerging Infectious Diseases 05/2013; 19(5):701-11. · 7.33 Impact Factor

Publication Stats

2k Citations
498.21 Total Impact Points

Institutions

  • 2002–2014
    • University of Alberta
      • • School of Public Health
      • • Department of Public Health Sciences
      • • Department of Medicine
      • • Division of Neurosurgery
      Edmonton, Alberta, Canada
  • 2012
    • University of Toronto
      Toronto, Ontario, Canada
  • 1992–2011
    • University of Saskatchewan
      • • Canadian Centre for Health and Safety in Agriculture
      • • Department of Community Health and Epidemiology
      • • Department of Medicine
      • • College of Medicine
      Saskatoon, Saskatchewan, Canada
  • 2009
    • Canadian Agency for Drugs and Technologies in Health
      Ottawa, Ontario, Canada
  • 1997
    • Royal University Hospital
      Saskatoon, Saskatchewan, Canada