At-a-glance - Traumatic brain injury management in Canada: changing patterns of care. / Aperçu - Prise en charge des traumatismes crâniens au Canada : évolution des tendances en matière de soins.

INTRODUCTION: With growing awareness about traumatic brain injuries (TBI), there is limited information about population level patterns of TBI care in Canada. METHODS: We examined data from the Canadian Community Health Survey (years 2004, 2009, and 2014) among all respondents ages 12 years and older. TBI management characteristics examined included access to care within 48 hours of injury, point of care, hospital admission, and follow-up. RESULTS: We observed that many Canadians sought care within 48 hours of their injury, with no changes over time. We found a significant decline in the proportion of Canadians opting to visit an emergency department (p = 0.03, all ages), and a significant increase in youth opting to visit a doctor's office (p < 0.01). CONCLUSION: TBIs are an important and growing health concern in Canada. Care for such injuries appears to have shifted towards the use of health care professionals outside the hospital environment, including primary care doctors.

INTRODUCTION: Malgré une plus grande sensibilisation aux traumatismes crâniens, nous disposons de peu de renseignements à l'échelle de la population sur les types de soins prodigués en lien avec les traumatismes crâniens au Canada. MÉTHODOLOGIE: Nous avons examiné les données de l'Enquête sur la santé dans les collectivités canadiennes (années 2005, 2009 et 2014) portant sur les répondants de 12 ans et plus. Les variables sélectionnées en lien avec la prise en charge des traumatismes crâniens ont été l'accès à des soins dans les 48 heures suivant la blessure, le point de service, l'admission à l'hôpital et les soins de suivi. RÉSULTATS: Nous avons constaté qu'un grand nombre de Canadiens avaient bénéficié de soins médicaux dans les 48 heures suivant leur blessure, sans changement dans cette proportion au fil du temps. Nous avons aussi observé un déclin significatif de la proportion de Canadiens ayant décidé de se rendre au service des urgences (p = 0,03, tous âges confondus) et une augmentation significative du nombre de jeunes ayant décidé de consulter un médecin (p < 0,01). CONCLUSION: Les traumatismes crâniens sont un problème de santé important et en augmentation au Canada. Ces blessures semblent de plus en plus être traitées par des professionnels de la santé en dehors des hôpitaux, en particulier par des médecins de première ligne.

Status report -- Childhood overweight and obesity in Canada: an integrative assessment. / Rapport d'étape -- Embonpoint et obésité chez les enfants au Canada : une évaluation globale.

INTRODUCTION: Obesity is a complex risk factor for chronic disease that is associated with a number of socioecological determinants. In this status report, we provide an overview of the socioecological framework that is now guiding our ongoing surveillance efforts in the area of childhood overweight and obesity. This framework considers individual risk and protective factors (sociodemographic, lifestyle, psychosocial and early-life) through the lens of the life stage, levels of influence and environments in which these factors play a role. METHODS: Using data from the Canadian Community Health Survey and the Canadian Health Measures Survey, univariate and bivariate analyses were used to report on behavioural, psychosocial, and early life factors associated with excess weight among Canadian children. RESULTS: Estimates of early-life (e.g. breastfeeding), behavioural (e.g. physical activity), and psychosocial factors (e.g. sense of community) are presented as they relate to age group, sex, income adequacy and weight status. CONCLUSION: Building upon our recent reporting on trends in and sociodemographic factors associated with childhood obesity in Canada, this work illustrates the remaining risk and protective factors shown in our surveillance framework. This analysis supports the shift towards a holistic appraisal of determinants related to healthy weights.

INTRODUCTION: L'obésité est un facteur de risque complexe des maladies chroniques associé à un certain nombre de déterminants socioécologiques. Ce rapport d'étape fournit un aperçu du cadre socioécologique qui guide actuellement nos efforts de suivi de l'embonpoint et de l'obésité chez les enfants. Ce cadre intègre différents facteurs de risque et de protection (facteurs sociodémographiques, liés au mode de vie, psychosociaux et en début de vie) et tient compte de l'étape de vie, des niveaux d'influence et de l'environnement au sein desquels ces facteurs jouent un rôle. MÉTHODOLOGIE: Nous avons effectué des analyses univariées et bivariées fondées sur les données de l'Enquête sur la santé dans les collectivités canadiennes et de l'Enquête canadienne sur les mesures de la santé pour rendre compte des facteurs comportementaux, des facteurs psychosociaux et des facteurs en début de vie associés à un surplus de poids chez les enfants canadiens. RÉSULTATS: Les estimations liées aux facteurs en début de vie (p. ex. l'allaitement), aux facteurs comportementaux (p. ex. l'activité physique) et aux facteurs psychosociaux (p. ex. le sentiment d'appartenance à la collectivité) sont présentées en fonction du groupe d'âge, du sexe, de la suffisance du revenu et du poids. CONCLUSION: Cette étude, qui s'appuie sur notre publication récente sur les tendances en matière d'obésité chez les enfants au Canada et les facteurs sociodémographiques qui y sont associés, présente les facteurs de risque et de protection intégrés à notre cadre de surveillance. D'après notre analyse, une évaluation plus globale des déterminants associés au maintien d'un poids santé est nécessaire.

Notes from the Field: Baseline Assessment of the Use of Ebola Rapid Diagnostic Tests--Forécariah, Guinea, October-November 2015.

The Ebola virus disease (Ebola) epidemic in West Africa began in Guinea in early 2014. The reemergence of Ebola and risk of ongoing, undetected transmission continues because of the potential for sexual transmission and other as yet unknown transmission pathways. On March 17, 2016, two new cases of Ebola in Guinea were confirmed by the World Health Organization. This reemergence of Ebola in Guinea is the first since the original outbreak in the country was declared over on December 29, 2015. The prefecture of Forécariah, in western Guinea, was considerably affected by Ebola in 2015, with an incidence rate of 159 cases per 100,000 persons. Guinea also has a high prevalence of malaria; in a nationwide 2012 survey, malaria prevalence was reported to be 44% among healthy children aged ≤5 years. Malaria is an important reason for seeking health care; during 2014, 34% of outpatient consultations were related to malaria.

Canadian Public Health Laboratory Network laboratory guidelines for the use of direct tests to detect syphilis in Canada.

Treponema pallidum subsp. pallidum and/or its nucleic acid can be detected by various methods such as microscopy, rabbit infectivity test or polymerase chain reaction (PCR) tests. The rabbit infectivity test for T. pallidum, although very sensitive, has been discontinued from most laboratories due to ethical issues related to the need for animal inoculation with live T. pallidum, the technically demanding procedure and long turnaround time for results, thus making it impractical for routine diagnostic use. Dark-field and phase-contrast microscopy are still useful at clinic- or hospital-based laboratories for near-bedside detection of T. pallidum in genital, skin or mucous lesions although their availability is decreasing. The lack of reliable and specific anti-T. pallidum antibodies and its inferior sensitivity to PCR may explain why the direct fluorescent antibody test for T. pallidum is not widely available for clinical use. Immunohistochemical staining for T. pallidum also depends on the availability of specific antibodies, and the method is only applicable for histopathological examination of biopsy and autopsy specimens necessitating an invasive specimen collection approach. With recent advances in molecular diagnostics, PCR is considered to be the most reliable, versatile and practical for laboratories to implement. In addition to being an objective and sensitive test for direct detection of Treponema pallidum subsp. pallidum DNA in skin and mucous membrane lesions, the resulting PCR amplicons from selected gene targets can be further characterized for antimicrobial (macrolide) susceptibility testing, strain typing and identification of T. pallidum subspecies.

Diverses méthodes, telles que la microscopie, le test d'infectivité du lapin et la réaction en chaîne de la polymérase (PCR), permettent de déceler le Treponema pallidum sous-espèce pallidum et/ou son acide nucléique. Même s'il est très sensible, le test d'infectivité du lapin n'est plus utilisé dans la plupart des laboratoires pour déceler le T. pallidum. En effet, des raisons éthiques liées à la nécessité d'inoculer le T. pallidum vivant à l'animal, l'intervention exigeante sur le plan technique et la longue attente avant d'obtenir les résultats le rendent peu pratique pour un usage diagnostique régulier. Dans les laboratoires des cliniques ou des hôpitaux, la microscopie à fond noir et la microscopie à contraste de phase contribuent toujours à déceler le T. pallidum dans les lésions génitales, cutanées ou muqueuses près du chevet du patient, mais elles sont de moins en moins offertes. Le test d'immunofluorescence directe est peu utilisé pour diagnostiquer le T. pallidum en milieu clinique, peut-être en raison de l'absence d'anticorps anti-T. pallidum fiables et spécifiques et de sa faible sensibilité par rapport au PCR. La coloration immunohistochimique du T. pallidum dépend également de la présence d'anticorps spécifiques, et la méthode est applicable seulement à l'examen histopathologique des prélèvements invasifs de biopsies et d'autopsies. Étant donné les progrès récents des diagnostics moléculaires, la PCR est considérée comme le test le plus fiable, le plus polyvalent et le plus pratique à utiliser en laboratoire. Le PCR est objectif et spécifique pour la détection directe de l'ADN du Treponema pallidum sous-espèce pallidum dans les lésions de la peau et des muqueuses ; ses amplicons provenant de cibles géniques précises peuvent être caractérisés en vue de tests de susceptibilité antimicrobienne (aux macrolides), du typage des souches et du dépistage des sousespèces de T. pallidum.

Canadian Public Health Laboratory Network laboratory guidelines for congenital syphilis and syphilis screening in pregnant women in Canada.

Despite universal access to screening for syphilis in all pregnant women in Canada, cases of congenital syphilis have been reported in recent years in areas experiencing a resurgence of infectious syphilis in heterosexual partnerships. Antenatal screening in the first trimester continues to be important and should be repeated at 28 to 32 weeks and again at delivery in women at high risk of acquiring syphilis. The diagnosis of congenital syphilis is complex and is based on a combination of maternal history and clinical and laboratory criteria in both mother and infant. Serologic tests for syphilis remain important in the diagnosis of congenital syphilis and are complicated by the passive transfer of maternal antibodies which can affect the interpretation of reactive serologic tests in the infant. All infants born to mothers with reactive syphilis tests should have nontreponemal tests (NTT) and treponemal tests (TT) performed in parallel with the mother's tests. A fourfold or higher titre in the NTT in the infant at delivery is strongly suggestive of congenital infection but the absence of a fourfold or greater NTT titre does not exclude congenital infection. IgM tests for syphilis are not currently available in Canada and are not recommended due to poor performance. Other evaluation in the newborn infant may include long bone radiographs and cerebrospinal fluid tests but all suspect cases should be managed in conjunction with sexually transmitted infection and/or pediatric experts.

Même si toutes les femmes du Canada ont accès au test de dépistage de la syphilis, des cas de syphilis congénitale ont été déclarés ces dernières années dans des régions où l'on constate une résurgence de la syphilis infectieuse chez des partenaires hétérosexuels. Il est toujours important de procéder à un dépistage anténatal pendant le premier trimestre, de le reprendre entre 28 et 32 semaines de grossesse, puis à l'accouchement chez les femmes très vulnérables à la syphilis. Le diagnostic de syphilis congénitale est complexe. Il repose sur l'histoire de la mère ainsi que sur des critères cliniques et des critères de laboratoire à la fois chez la mère et le nourrisson. Les tests sérologiques de la syphilis s'imposent toujours pour diagnostiquer la syphilis congénitale, mais ils sont compliqués par le transfert passif des anticorps maternels qui peut nuire à l'interprétation des résultats réactifs chez le nourrisson. Tous les nourrissons nés d'une mère dont les tests de syphilis sont réactifs devraient subir des tests non tréponomiques (TNT) et des tests tréponomiques (TT) conjointement aux tests de la mère. Un titrage du TNT au moins quatre fois plus élevé que la normale chez le nourrisson à l'accouchement est fortement évocateur d'une infection congénitale, mais l'absence d'un tel résultat n'en exclut pas la possibilité. Les tests d'IgM pour déceler la syphilis ne sont pas offerts au Canada. Ils ne sont pas recommandés en raison de leurs piètres résultats. Parmi les autres évaluations du nouveau-né, soulignons les radiographies des os longs et les tests du liquide céphalorachidien, mais il faut prendre en charge tous les cas présumés conjointement avec des pédiatres ou des spécialistes des infections transmises sexuellement.

Demographic changes and trends in risk behaviours, HIV and other sexually transmitted infections among female sex workers in Bangalore, India involved in a focused HIV preventive intervention.

The primary objectives of this study were to assess the changing demographic characteristics of female sex workers (FSWs) in the urban Bangalore district, India, and trends in programme coverage, HIV/sexually transmitted infection prevalence rates and condom use. Cross-sectional, integrated behavioural and biological assessments of FSWs were conducted in 2006, 2009 and 2011. Univariate and multivariate analyses were used to describe trends over time. The results indicate the mean age of initiation into sex work has increased (26.9 years in 2006 vs 27.6 years in 2011, p<0.01), a higher proportion of FSWs reported being in 'stable' relationships in 2011 (70.2% vs 43.2% in 2006, p<0.01) and having conducted sex work outside the district in the past 6 months (10.0% in 2011 vs 16.0% in 2006 p=0.01). There was an increase in the proportion of FSWs using cellphones to solicit clients (4.4% in 2006 vs 57.5% in 2011, p<0.01) and their homes for sex work (61.4% in 2006 vs 77.8% in 2011, p<0.01). Reactive syphilis prevalence declined (12.6% in 2006 to 4% in 2011, p=0.02), as did high-titre syphilis prevalence (9.5% in 2006 to 2.5% in 2011, p=0.01). HIV prevalence declined but not significantly (12.7% in 2006 and 9.3% in 2011, p=0.39). Condom use remained above 90% increasing significantly among repeat (paying) clients (66.6% in 2006 to 93.6% in 2011, p<0.01). However, condom use remained low with non-paying partners when compared with occasional paying partners (17.6% vs 97.2% in 2011, p<0.01). Given the changing dynamics in the FSW population at multiple levels, there is a need to develop and customise strategies to meet local needs.

Patterns and trends in Pakistan's heterogeneous HIV epidemic.

BACKGROUND: Considerable HIV transmission occurs among injection drug users (IDUs) in Pakistan and recently the HIV prevalence has been increasing among male (MSW), hijra (transgender; HSW) and female (FSW) sex workers. We describe past and estimate future patterns of HIV emergence among these populations in several cities in Pakistan. METHODS: The density of these key populations per 1000 adult men was calculated using 2011 mapping data from Karachi, Lahore, Faisalabad, Larkana, Peshawar and Quetta, and surveillance data were used to assess bridging between these key populations. We used the UNAIDS Estimation and Projection Package model to estimate and project HIV epidemics among these key populations in Karachi, Lahore, Faisalabad and Larkana. RESULTS: The density and bridging of key populations varied across cities. Lahore had the largest FSW population (11.5/1000 adult men) and the smallest IDU population (1.7/1000 adult men). Quetta had the most sexual and drug injection bridging between sex workers and IDUs (6.7%, 7.0% and 3.8% of FSW, MSW and HSW, respectively, reported injecting drugs). Model evidence suggests that by 2015 HIV prevalence is likely to reach 17-22% among MSWs/HSWs in Karachi, 44-49% among IDUs in Lahore and 46-66% among IDUs in Karachi. Projection suggests the prevalence may reach as high as 65-75% among IDUs in Faisalabad by 2025. HIV prevalence is also estimated to increase among FSWs, particularly in Karachi and Larkana. CONCLUSIONS: There is a need to closely monitor regional and subpopulation epidemic patterns and implement prevention programmes customised to local epidemics.

A Protocol for the secure linking of registries for HPV surveillance.

INTRODUCTION: In order to monitor the effectiveness of HPV vaccination in Canada the linkage of multiple data registries may be required. These registries may not always be managed by the same organization and, furthermore, privacy legislation or practices may restrict any data linkages of records that can actually be done among registries. The objective of this study was to develop a secure protocol for linking data from different registries and to allow on-going monitoring of HPV vaccine effectiveness. METHODS: A secure linking protocol, using commutative hash functions and secure multi-party computation techniques was developed. This protocol allows for the exact matching of records among registries and the computation of statistics on the linked data while meeting five practical requirements to ensure patient confidentiality and privacy. The statistics considered were: odds ratio and its confidence interval, chi-square test, and relative risk and its confidence interval. Additional statistics on contingency tables, such as other measures of association, can be added using the same principles presented. The computation time performance of this protocol was evaluated. RESULTS: The protocol has acceptable computation time and scales linearly with the size of the data set and the size of the contingency table. The worse case computation time for up to 100,000 patients returned by each query and a 16 cell contingency table is less than 4 hours for basic statistics, and the best case is under 3 hours. DISCUSSION: A computationally practical protocol for the secure linking of data from multiple registries has been demonstrated in the context of HPV vaccine initiative impact assessment. The basic protocol can be generalized to the surveillance of other conditions, diseases, or vaccination programs.

Acceptability of human papillomavirus vaccination and sexual experience prior to disclosure to health care providers among men who have sex with men in Vancouver, Canada: implications for targeted vaccination programs.

BACKGROUND: Men who have sex with men (MSM) may benefit from human papillomavirus (HPV) vaccine due to increased risk for HPV infection and related disease. We assessed HPV vaccine acceptability and sexual experience prior to disclosure to Health Care Providers (HCP) to understand implications of targeted vaccination strategies for MSM. METHODS: From July 2008 to February 2009, 1169 MSM aged ≥19 years were recruited at community venues in Vancouver. We assessed key variables from a self-administered questionnaire and independent predictors of HPV vaccine acceptability using multivariate logistic regression. RESULTS: Of 1041 respondents, 697 (67.0%) were willing to receive HPV vaccine and 71.3% had heard of HPV. Significant multivariate predictors of higher vaccine acceptability were (adjusted odds ratio [95% CI]): previous diagnosis of genital warts (1.7 [1.1, 2.6]), disclosure of sexual behavior to HCP (1.6 [1.1, 2.3]), annual income at least $20,000 (1.5 [1.1, 2.1]), previous hepatitis A or B vaccination (1.4 [1.0, 2.0]), and no recent recreational drug use (1.4 [1.0, 2.0]). Most MSM (78.7%) had disclosed sexual behavior to HCP and median time from first sexual contact with males to disclosure was 6.0 years (IQR 2-14 years); for men ≤26 years these were 72.0% and 3.0 years (IQR 1-8 years) respectively. CONCLUSIONS: Willingness to receive HPV vaccine was substantial among MSM in Vancouver; however, acceptability varied by demographics, risk, and health history. HPV vaccine programs delivered by HCP would offer limited benefit given the duration of time from sexual debut to disclosure to HCP.

Estimation of the burden of disease and costs of genital Chlamydia trachomatis infection in Canada.

BACKGROUND: Rates of Chlamydia trachomatis (CT) infection in Canada have been increasing since the mid-1990s. We sought to estimate the burden of CT in this population. METHODS: We developed an age- and sex-structured mathematical model parameterized to reproduce trends in CT prevalence between 1991 and 2009 in the Canadian population aged 10 to 39 years. Costs were identified, measured, and valued using a modified societal perspective and converted to year 2009 Canadian dollars. Cost-effectiveness of the implemented policy of enhanced screening for asymptomatic infections was estimated by comparison with model-projected trends in the absence of increased screening. Main outcome measures were current net cost and burden of illness attributable to CT infection, and incremental cost-effectiveness ratios. RESULTS: Under base case model assumptions, there was a trend of increasing detection of CT cases (due to increases in screening), despite an underlying stabilization of actual CT infections. Average estimated costs associated with CT infection over this period were $51.4 million per year. Costs of screening and treatment of asymptomatic infections as a proportion of total CT costs were estimated to have increased over time, whereas costs of long-term sequelae associated with untreated infections declined over the same period. Compared with no change in screening, enhanced screening was estimated to be highly cost-effective, with an incremental cost-effectiveness ratio of $2910 per quality-adjusted life year. CONCLUSIONS: Despite increases in screening, the economic burden of CT in Canada remains high. Further investigation of trends in chlamydia-associated complications is required to better understand the impact of screening on incidence.

Use of quantitative HIV RNA detection for early diagnosis of HIV infection in infants and acute HIV infections in Alberta, Canada.

Quantitative HIV RNA viral load (QVL) assays (Roche Diagnostics) were sensitive and specific when used to diagnose HIV infection in (i) HIV-exposed infants (sensitivity of 100% [63.1 to 100%] and specificity of 100% [97.9 to 100%]) and (ii) suspected acute HIV infection patients with a negative/indeterminate Western blot (sensitivity of 97.6% [91.6 to 99.7%] and specificity of 100% [96.1 to 100%]). No false-positive QVL results were identified.

Trends in age disparities between younger and middle-age adults among reported rates of chlamydia, gonorrhea, and infectious syphilis infections in Canada: findings from 1997 to 2007.

BACKGROUND: The objective was to determine trends in age disparities between reported rates of chlamydia, gonorrhea, and infectious syphilis among younger versus middle-age Canadians. METHODS: We examined age- and sex-specific reported rates of chlamydia, gonorrhea, and infectious syphilis between 1997 and 2007. Sexually transmitted infection (STI) rates in the younger age group (15-29 years) were compared to the middle-age group (40-59 years) over the 11-year period. We used Poisson regression to examine trends in age-specific (younger:middle-age) rate ratios. RESULTS: Between 1997 and 2007, both the number and rate of reported cases increased for all 3 nationally notifiable STIs. Although chlamydia and gonorrhea rates continued to be higher among younger adults, rates of all 3 STIs increased more dramatically among middle-age adults. Between 1997 and 2007, chlamydia rates increased by 86.8% among adults aged 15 to 29 (P <0.0001) and 165.9% among adults 40- to 59-years-old (P <0.0001). The corresponding increases for gonorrhea were 133.3% (P <0.0001) and 210.2% (P <0.0001) respectively. Infectious syphilis rates increased 5-fold among younger adults compared to an increase of 11-fold among middle-age adults (P <0.0001) since 1997. The reported rate ratios (younger:middle-age) decreased over time for chlamydia (P <0.0001), gonorrhea (P <0.0001), and syphilis (P = 0.005). Males were disproportionately represented among reported chlamydia, gonorrhea, and infectious syphilis cases, constituting 59.8%, 87.6%, and 93.0% of middle-age adult cases, respectively, in 2007. CONCLUSIONS: Middle-age adults may be increasingly affected by chlamydia, gonorrhea and infectious syphilis. There is a need for sexual health information targeting Canada's middle-age adults and their health care providers.

Maculopapular rash and tremor are associated with West Nile fever and neurological syndromes.

The clinical features associated with West Nile virus (WNV) infections are described based on data collected from history forms submitted with samples during a province-wide WNV testing programme. Age 40-59 years (OR 1.7, p<0.008), residence in the southeast of Alberta (OR 4.2, p<0.001), maculopapular rash (OR 8.6, p<0.001) or tremor (OR 3.6, p<0.001) were independently associated with WNV infection.

A population-based approach to determine the prevalence of transmitted drug-resistant HIV among recent versus established HIV infections: results from the Canadian HIV strain and drug resistance surveillance program.

OBJECTIVES: Published results on primary or transmitted HIV drug resistance may be biased because they have been largely derived from specific cohort studies or higher risk individuals who present symptomatically. Here, we present results from a representative population-based study of newly diagnosed cases of HIV in Canada and compare the prevalence of transmitted drug resistance between recent and established infections. METHODS: Available archived sera taken for the purpose of diagnostic HIV testing from all treatment-naive HIV-positive individuals who were newly diagnosed between 2000 and 2001 were tested for recency of infection, HIV-1 subtype, and mutations conferring reduced susceptibility to reverse transcriptase inhibitors and protease inhibitors (PIs). Recent infections were identified using the Organon Teknika Vironostika HIV-1-LS assay. After full-length sequencing of the pol gene, drug resistance mutations were identified using the 2004 International AIDS Society-USA mutations panel. Differences in drug resistance profiles between recent and prevalent infections were examined using the chi test and the Fisher exact test. The variables examined included gender, age at diagnosis, year of diagnosis, exposure category, ethnicity, and HIV-1 subtype. RESULTS: Among the study population, 8.1% had genotypic evidence of transmitted drug resistance: 4.1% against nucleoside reverse transcriptase inhibitors, 1.4% against nonnucleoside reverse transcriptase inhibitors, 1.5% against PIs, and 1% against > or =2 classes of drugs. A higher proportion of recent infections had genotypic evidence of transmitted drug resistance when compared with established infections (12.2% vs. 6.1%, respectively; P = 0.005). Transmitted drug resistance was identified mainly among recently infected Caucasian men who have sex with men but it was not limited to this group. Compared with the year 2000, a higher proportion of recently infected individuals with resistance-conferring mutations were diagnosed during the year 2001 (66.7% vs. 46.6%). CONCLUSIONS: In Canada, transmitted drug resistance is occurring within all 3 drug classes and across different population groups. The results suggest that the prevalence rates may be higher among recent versus established infections. Given the public health implications of transmitting drug-resistant HIV, it is important to continue population-based drug resistance surveillance to guide optimum prevention and treatment of HIV infection.

Nucleic acid testing for west nile virus RNA in plasma enhances rapid diagnosis of acute infection in symptomatic patients.

Although nucleic acid amplification testing (NAAT) for West Nile virus (WNV) is useful in screening blood donors, such methods have not been studied in symptomatic patients. For diagnosis of WNV infection, 1.0 mL of plasma was tested by NAAT, and WNV-specific immunoglobulin M was assayed. Of 276 WNV cases, 191 were tested by both serology and NAAT. Of these, 86 (45.0%), 111 (58.1%), and 180 (94.2%) were detected by NAAT, serology, and combined NAAT and serology, respectively. NAAT-based screening was most useful within 8 days of the onset of symptoms. Viremia is common in early symptomatic WNV infection, and NAAT enhances diagnostic yield.

Clinical utility of commercial enzyme immunoassays during the inaugural season of West Nile virus activity, Alberta, Canada.

West Nile virus (WNV) has spread rapidly across North America, creating a need for rapid and accurate laboratory diagnosis on a large scale. Immunoglobulin M (IgM) capture enzyme immunoassays (EIA) became commercially available in the summer of 2003, but limited data are available on their clinical performance. Consolidated human WNV diagnostic testing for the province of Alberta, Canada, at the public health laboratory permitted a large-scale evaluation of the assays, covering a wide clinical spectrum. Two thousand nine hundred sixty-nine sera were tested, from 2,553 Alberta residents, and 266 cases were identified. Sensitivities of the Focus assay and first-generation Panbio IgM capture EIA were 79 and 80%, respectively. During the first week of illness only 53 to 58% of cases were positive, but sensitivity was 96 to 97% after day 8. Sensitivity for neurological cases was 92% overall. Specificity was high for the Focus kit at 98.9%, but only 82.9% for the first Panbio kit. A positive Focus WNV IgG result with a twofold rise in IgG index was a reliable indicator of acute flavivirus infection (67/67 WNV). Agreement between the IgG test and hemagglutinin inhibition titers in paired sera was at least 82%. Commercial IgM and IgG EIA proved useful for WNV diagnosis, provided follow-up sera were collected after 8 days of illness.

Magnitude and determinants of first-time and repeat testing among individuals with newly diagnosed HIV infection between 2000 and 2001 in Alberta, Canada: results from population-based laboratory surveillance.

The purpose of the study was to determine the magnitude and predictors of first-time and repeat testing for HIV infection among newly diagnosed cases in Alberta, Canada, and to determine the extent of co-infection with hepatitis C (HCV) and hepatitis B (HBV). Using the Provincial Laboratory for Public Health (PLPH) database, all newly diagnosed HIV cases in Alberta between 2000 and 2001 were identified and the testing history for HIV, HCV, and HBV among these cases since 1992 was reviewed. Significant differences in the characteristics of first-time and repeat testers were identified using the chi test, and where appropriate, the Fisher exact test. The independent variables examined included age, gender, risk factors, area and population of residence, testing agency, and co-infection with HCV and HBV. Logistical regression analyses were conducted to further explore independent factors associated with first-time vs. repeat testing for HIV infection. Of the 398 cases, 278 (69.8%) were newly diagnosed at their first test for HIV infection, 73.1% during 2000 and 67.3% during 2001 (P = 0.81). Among repeat testers, the mean number of previous negative tests was 3.4 (range = 2-11 tests). The median interval between the last negative and first positive test was 648 days (range = 53-2678 days). Repeat testers were 1.9 times more likely to be injecting drug users and 1.8 times more likely to reside in Northern Alberta. Among those with a laboratory test result in the PLPH database, 53.7% were positive for HCV, 47.7 and 64.5% of first-time and repeat testers, respectively; and 19.1% were positive for HBV, 22 and 13.6% of first-time and repeat testers, respectively. A high proportion of HIV cases newly diagnosed between 2000 and 2001 in Alberta had no previous testing history for HIV infection. Even among repeat testers, HIV testing was sought infrequently. There are significant regional differences within Alberta in the characteristics of the HIV epidemic and associated test-seeking behaviors. These data reinforce the need to make the most of each test-seeking event with proper counseling and other relevant support services. Given the high prevalence of co-infection with HCV, these results clearly support the need for testing and counseling strategies to take into account additional risks associated with HCV infections.

Characteristics of individuals with male-to-male and heterosexually acquired infectious syphilis during an outbreak in Calgary, Alberta, Canada.

BACKGROUND: Eliminating syphilis is important not only to prevent the sequelae of infection but also to control the spread of HIV. Current prevention and control efforts in Canada have been ineffective in eliminating this disease. GOAL: The goal of the study was to determine the characteristics of individuals with infectious syphilis due to male-to-male and heterosexual contact, diagnosed during an outbreak in Calgary, Alberta, Canada. STUDY DESIGN: This was a prospective study of individuals with infectious syphilis diagnosed at the STD clinic in Calgary between January 2000 and April 2002. RESULTS: The outbreak reported here (September 2000 to April 2002) involves 32 cases of infectious syphilis, corresponding to rates of 0.9/100,000 population during 2000 and 1.8/100,000 population during 2001. Between September 2000 and June 2001, the cases diagnosed were among men who have sex with men (MSM); between May 2001 and April 2002, they were due to locally acquired infections among heterosexuals, including one case of congenital syphilis. Compared to the heterosexuals, MSM tended to be older, be coinfected with HIV, and report excessive alcohol use (versus injection drug use) and had infectious syphilis diagnosed earlier. MSM used the Internet and bars or bathhouses to initiate sexual contact, whereas heterosexually acquired infections were largely among sex workers and their clients. Contact tracing was more successful among the heterosexuals than among MSM. The public health staff at the STD clinic initiated a series of multifaceted interventions in response to the outbreak. These interventions were moderately successful, as measured by the increased numbers of individuals seeking counseling and testing services at the clinic. CONCLUSION: The results highlight key differences in the risk factor-specific characteristics of the outbreak that should be taken into account when designing prevention and control strategies.