Everything but the kitchen sink: The use of multiple hypothesis generation methods to investigate an outbreak of Salmonella Enteritidis associated with frozen profiteroles and eclairs.

In December 2018, an outbreak of Salmonella Enteritidis infections was identified in Canada by whole-genome sequencing (WGS). An investigation was initiated to identify the source of the illnesses, which proved challenging and complex. Microbiological hypothesis generation methods included comparisons of Salmonella isolate sequence data to historical domestic outbreaks and international repositories. Epidemiological hypothesis generation methods included routine case interviews, open-ended centralized re-interviewing, thematic analysis of open-ended interview data, collection of purchase records, a grocery store site visit, analytic comparison to healthy control groups, and case-case analyses. Food safety hypothesis testing methods included food sample collection and analysis, and traceback investigations. Overall, 83 cases were identified across seven provinces, with onset dates from 6 November 2018 to 7 May 2019. Case ages ranged from 1 to 88 years; 60% (50/83) were female; 39% (22/56) were hospitalized; and three deaths were reported. Brand X profiteroles and eclairs imported from Thailand were identified as the source of the outbreak, and eggs from an unregistered facility were hypothesized as the likely cause of contamination. This study aims to describe the outbreak investigation and highlight the multiple hypothesis generation methods that were employed to identify the source.

A multi-provincial outbreak of Salmonella Newport infections associated with red onions: A report of the largest Salmonella outbreak in Canada in over 20 years.

An investigation into an outbreak of Salmonella Newport infections in Canada was initiated in July 2020. Cases were identified across several provinces through whole-genome sequencing (WGS). Exposure data were gathered through case interviews. Traceback investigations were conducted using receipts, invoices, import documentation, and menus. A total of 515 cases were identified in seven provinces, related by 0-6 whole-genome multi-locus sequence typing (wgMLST) allele differences. The median age of cases was 40 (range 1-100), 54% were female, 19% were hospitalized, and three deaths were reported. Forty-eight location-specific case sub-clusters were identified in restaurants, grocery stores, and congregate living facilities. Of the 414 cases with exposure information available, 71% (295) had reported eating onions the week prior to becoming ill, and 80% of those cases who reported eating onions, reported red onion specifically. The traceback investigation identified red onions from Grower A in California, USA, as the likely source of the outbreak, and the first of many food recall warnings was issued on 30 July 2020. Salmonella was not detected in any tested food or environmental samples. This paper summarizes the collaborative efforts undertaken to investigate and control the largest Salmonella outbreak in Canada in over 20 years.

Clinical Severity of Severe Acute Respiratory Syndrome Coronavirus 2 Omicron Variant Relative to Delta in British Columbia, Canada: A Retrospective Analysis of Whole-Genome Sequenced Cases.

BACKGROUND: In late 2021, the Omicron severe acute respiratory syndrome coronavirus 2 variant emerged and rapidly replaced Delta as the dominant variant. The increased transmissibility of Omicron led to surges in case rates and hospitalizations; however, the true severity of the variant remained unclear. We aimed to provide robust estimates of Omicron severity relative to Delta. METHODS: This retrospective cohort study was conducted with data from the British Columbia COVID-19 Cohort, a large provincial surveillance platform with linkage to administrative datasets. To capture the time of cocirculation with Omicron and Delta, December 2021 was chosen as the study period. Whole-genome sequencing was used to determine Omicron and Delta variants. To assess the severity (hospitalization, intensive care unit [ICU] admission, length of stay), we conducted adjusted Cox proportional hazard models, weighted by inverse probability of treatment weights (IPTW). RESULTS: The cohort was composed of 13 128 individuals (7729 Omicron and 5399 Delta). There were 419 coronavirus disease 2019 hospitalizations, with 118 (22%) among people diagnosed with Omicron (crude rate = 1.5% Omicron, 5.6% Delta). In multivariable IPTW analysis, Omicron was associated with a 50% lower risk of hospitalization compared with Delta (adjusted hazard ratio [aHR] = 0.50, 95% confidence interval [CI] = 0.43 to 0.59), a 73% lower risk of ICU admission (aHR = 0.27, 95% CI = 0.19 to 0.38), and a 5-day shorter hospital stay (aß = -5.03, 95% CI = -8.01 to -2.05). CONCLUSIONS: Our analysis supports findings from other studies that have demonstrated lower risk of severe outcomes in Omicron-infected individuals relative to Delta.

Emergence of SARS-CoV-2 Delta Variant and Effect of Nonpharmaceutical Interventions, British Columbia, Canada.

In British Columbia, Canada, initial growth of the SARS-CoV-2 Delta variant was slower than that reported in other jurisdictions. Delta became the dominant variant (>50% prevalence) within ≈7-13 weeks of first detection in regions within the United Kingdom and United States. In British Columbia, it remained at <10% of weekly incident COVID-19 cases for 13 weeks after first detection on March 21, 2021, eventually reaching dominance after 17 weeks. We describe the growth of Delta variant cases in British Columbia during March 1-June 30, 2021, and apply retrospective counterfactual modeling to examine factors for the initially low COVID-19 case rate after Delta introduction, such as vaccination coverage and nonpharmaceutical interventions. Growth of COVID-19 cases in the first 3 months after Delta emergence was likely limited in British Columbia because additional nonpharmaceutical interventions were implemented to reduce levels of contact at the end of March 2021, soon after variant emergence.

Clinical severity of Omicron subvariants BA.1, BA.2, and BA.5 in a population-based cohort study in British Columbia, Canada.

The SARS-CoV-2 variant Omicron emerged in late 2021. In British Columbia (BC), Canada, and globally, three genetically distinct subvariants of Omicron, BA.1, BA.2, and BA.5, emerged and became dominant successively within an 8-month period. SARS-CoV-2 subvariants continue to circulate in the population, acquiring new mutations that have the potential to alter infectivity, immunity, and disease severity. Here, we report a propensity-matched severity analysis from residents of BC over the course of the Omicron wave, including 39,237 individuals infected with BA.1, BA.2, or BA.5 based on paired high-quality sequence data and linked to comprehensive clinical outcomes data between December 23, 2021 and August 31, 2022. Relative to BA.1, BA.2 cases were associated with a 15% and 28% lower risk of hospitalization and intensive care unit (ICU) admission (aHRhospital = 1.17; 95% confidence interval [CI] = 1.096-1.252; aHRICU = 1.368; 95% CI = 1.152-1.624), whereas BA.5 infections were associated with an 18% higher risk of hospitalization (aHRhospital = 1.18; 95% CI = 1.133-1.224) after accounting for age, sex, comorbidities, vaccination status, geography, and social determinants of health. Phylogenetic analysis revealed no specific subclades associated with more severe clinical outcomes for any Omicron subvariant. In summary, BA.1, BA.2, and BA.5 subvariants were associated with differences in clinical severity, emphasizing how variant-specific monitoring programs remain critical components of patient and population-level public health responses as the pandemic continues.

Patterns of enteric infections in a population-wide cohort study of sequelae, British Columbia, Canada.

We assessed patterns of enteric infections caused by 14 pathogens, in a longitudinal cohort study of sequelae in British Columbia (BC) Canada, 2005-2014. Our population cohort of 5.8 million individuals was followed for an average of 7.5 years/person; during this time, 40 523 individuals experienced 42 308 incident laboratory-confirmed, provincially reported enteric infections (96.4 incident infections per 100 000 person-years). Most individuals (38 882/40 523; 96%) had only one, but 4% had multiple concurrent infections or more than one infection across the study. Among individuals with more than one infection, the pathogens and combinations occurring most frequently per individual matched the pathogens occurring most frequently in the BC population. An additional 298 557 new fee-for-service physician visits and hospitalisations for enteric infections, that did not coincide with a reported enteric infection, also occurred, and some may be potentially unreported enteric infections. Our findings demonstrate that sequelae risk analyses should explore the possible impacts of multiple infections, and that estimating risk for individuals who may have had a potentially unreported enteric infection is warranted.

Rapid Increase in SARS-CoV-2 P.1 Lineage Leading to Codominance with B.1.1.7 Lineage, British Columbia, Canada, January-April 2021.

Several severe acute respiratory syndrome coronavirus 2 variants of concern (VOCs) emerged in late 2020; lineage B.1.1.7 initially dominated globally. However, lineages B.1.351 and P.1 represent potentially greater risk for transmission and immune escape. In British Columbia, Canada, B.1.1.7 and B.1.351 were first identified in December 2020 and P.1 in February 2021. We combined quantitative PCR and whole-genome sequencing to assess relative contribution of VOCs in nearly 67,000 infections during the first 16 weeks of 2021 in British Columbia. B.1.1.7 accounted for <10% of screened or sequenced specimens early on, increasing to >50% by week 8. P.1 accounted for <10% until week 10, increased rapidly to peak at week 12, and by week 13 codominated within 10% of rates of B.1.1.7. B.1.351 was a minority throughout. This rapid expansion of P.1 but suppression of B.1.351 expands our understanding of population-level VOC patterns and might provide clues to fitness determinants for emerging VOCs.

Measuring the impact of sea surface temperature on the human incidence of Vibrio sp. infection in British Columbia, Canada, 1992-2017.

BACKGROUND: Vibrio growth in the environment is related to sea surface temperature (SST). The incidence of human Vibrio illness increased sharply in British Columbia (BC) between 2008 and 2015 for unknown reasons, culminating in the largest outbreak of shellfish-associated Vibrio parahaemolyticus (Vp) in Canadian history in 2015. Our objective was to assess the relationship between SST and Vibrio illness in BC, Canada during 1992-2017 and assess the role of SST and other environmental factors in the 2015 Vp outbreak. METHODS: Cases of Vibrio infection reported to the BC Centre for Disease Control during 1992-2017 were used. SST data were obtained from NOAA and NASA. We assessed changes in incidence trend of annual Vibrio cases during 1992-2017 using a Poisson regression. We assessed the correlation between annual Vibrio cases and the average annual maximum SST using a Spearman rank-order correlation. We modeled the association between weekly Vp case counts, SST and other environmental factors during 2007-2017 using a Poisson regression. RESULTS: There was a significant increase in Vibrio cases between 2008 and 2015 (annual slope = 0.163, P < 0.001). Increased Vibrio incidence was observed in most El Niño years. There was a significant correlation between annual Vibrio cases and maximum SST from 1992 to 2017 (r = 0.46, P = 0.018). Our model captured observed seasonal variation in shellfish-associated Vp in most years, but underestimated the 2015 Vp outbreak. CONCLUSIONS: Vibrio incidence has been increasing concurrently with increasing SST in BC during 2008-2015. The 2015 Vp outbreak was not fully explained by climatic factors and may in part have been associated with other factors. Vp subtyping would be useful in the future to understand the combined effects of SST changes and strain emergence.

Outbreak of Salmonella Chailey Infections Linked To Precut Coconut Pieces - United States and Canada, 2017.

Foodborne salmonellosis causes an estimated 1 million illnesses and 400 deaths annually in the United States (1). In recent years, salmonellosis outbreaks have been caused by foods not typically associated with Salmonella. On May 2, 2017, PulseNet, CDC's national molecular subtyping network for foodborne disease surveillance, identified a cluster of 14 Salmonella Chailey isolates with a rare pulsed-field gel electrophoresis (PFGE) pattern. On May 29, Canadian health officials informed CDC that they were also investigating a cluster of five Salmonella Chailey infections in British Columbia with the same PFGE pattern. Nineteen cases were identified and investigated by CDC, U.S. state health departments, the Public Health Agency of Canada, and the British Columbia Centre for Disease Control. Isolates from all cases were highly related by whole genome sequencing (WGS). Illness onset dates ranged from March 10 to May 7, 2017. Initial interviews revealed that infected persons consumed various fresh foods and shopped at grocery chain A; focused questionnaires identified precut coconut pieces from grocery chain A as a common vehicle. The Canadian Food Inspection Agency (CFIA) and the U.S. Food and Drug Administration (FDA) conducted a traceback investigation that implicated a single lot of frozen, precut coconut as the outbreak source. Grocery chain A voluntarily removed precut coconut pieces from their stores. This action likely limited the size and scope of this outbreak.

Evaluation of Agricultural Interventions on Human and Poultry-Related Salmonella Enteritidis in British Columbia.

A collaborative investigation between public health and animal health led to numerous interventions along the food chain in response to an outbreak of human salmonellosis and increased incidence of Salmonella Enteritidis (SE) among poultry. Incidence of both human and chicken SE decreased substantially in 2012 and 2013 following these interventions. We used time series analysis to assess the impact of three interventions: vaccination of broiler breeder flocks, separation in the hatchery of breeder eggs, and an industry order to stop farm-gate sales of ungraded broiler hatching eggs. Results show a Granger causal association between human SE incidence and SE incidence in chickens 8 months earlier. Among the interventions, separation of breeder flocks showed a consistent and statistically significant association with declining SE incidence in chickens. Our results did not show consistent declines in chicken SE following breeder flock vaccination (live or inactivated vaccine). None of the interventions had statistically significant impacts on human SE incidence. Our results are consistent with a positive effect of certain interventions and also reveal where additional data are needed for a more comprehensive evaluation. Multiple interventions throughout the food chain are best practices when dealing with enteric pathogens; collecting data on the timing and intensity of these interventions allow proper evaluation of their independent and combined effects. Finally, we identify considerations for others interested in undertaking similar evaluations. Ongoing collaborative work between public health and animal health is required to refine strategies for SE control in British Columbia.

Outbreak of Vibrio parahaemolyticus Associated with Consumption of Raw Oysters in Canada, 2015.

There has been a steady increase in illness incidence of Vibrio parahaemolyticus (Vp). The majority of illnesses are associated with consumption of raw oysters. In the summer of 2015, Canada experienced the largest outbreak associated with the consumption of raw oysters harvested from British Columbia (BC) coastal waters. Case investigation of laboratory-confirmed cases was conducted to collect information on exposures and to assist traceback. Investigations at processors and oyster sampling were conducted. Eighty-two laboratory-confirmed cases of Vp infection were reported between January 1 and October 26, 2015. The majority of the cases were reported in BC, associated with consumption of raw BC oysters in restaurants. Sea surface temperatures were above the historical levels in 2015. This outbreak identified the need to improve surveillance and response to increases in human cases of Vp. This is of particular importance due to the potential for increasing water temperatures and the likelihood of additional outbreaks of Vibrio.

Evaluating the Timeliness of Enteric Disease Surveillance in British Columbia, Canada, 2012-13.

Timely surveillance of enteric diseases is necessary to identify and control cases and outbreaks. Our objective was to evaluate the timeliness of enteric disease surveillance in British Columbia, Canada, compare these results to other settings, and recommend improvements. In 2012 and 2013, information was collected from case report forms and laboratory information systems on 2615 Salmonella, shigatoxin-producing E. coli, Shigella, and Listeria infections. Twelve date variables representing the surveillance process from onset of symptoms to case interview and final laboratory results were collected, and intervals were measured. The median time from onset of symptoms to reporting subtyping results to BC epidemiologists was 26-36 days and from onset of symptoms to case interview was 12-14 days. Our findings were comparable to the international literature except for a longer time (up to 29 day difference) to reporting of PFGE results to epidemiologists in BC. Such a delay may impact our ability to identify and solve outbreaks. Several process and system changes were implemented which should improve the timeliness of enteric disease surveillance.

Cohort profile: the British Columbia COVID-19 Cohort (BCC19C)-a dynamic, linked population-based cohort.

Purpose: The British Columbia COVID-19 Cohort (BCC19C) was developed from an innovative, dynamic surveillance platform and is accessed/analyzed through a cloud-based environment. The platform integrates recently developed provincial COVID-19 datasets (refreshed daily) with existing administrative holdings and provincial registries (refreshed weekly/monthly). The platform/cohort were established to inform the COVID-19 response in near "real-time" and to answer more in-depth epidemiologic questions. Participants: The surveillance platform facilitates the creation of large, up-to-date analytic cohorts of people accessing COVID-19 related services and their linked medical histories. The program of work focused on creating/analyzing these cohorts is referred to as the BCC19C. The administrative/registry datasets integrated within the platform are not specific to COVID-19 and allow for selection of "control" individuals who have not accessed COVID-19 services. Findings to date: The platform has vastly broadened the range of COVID-19 analyses possible, and outputs from BCC19C analyses have been used to create dashboards, support routine reporting and contribute to the peer-reviewed literature. Published manuscripts (total of 15 as of July, 2023) have appeared in high-profile publications, generated significant media attention and informed policy and programming. In this paper, we conducted an analysis to identify sociodemographic and health characteristics associated with receiving SARS-CoV-2 laboratory testing, testing positive, and being fully vaccinated. Other published analyses have compared the relative clinical severity of different variants of concern; quantified the high "real-world" effectiveness of vaccines in addition to the higher risk of myocarditis among younger males following a 2nd dose of an mRNA vaccine; developed and validated an algorithm for identifying long-COVID patients in administrative data; identified a higher rate of diabetes and healthcare utilization among people with long-COVID; and measured the impact of the pandemic on mental health, among other analyses. Future plans: While the global COVID-19 health emergency has ended, our program of work remains robust. We plan to integrate additional datasets into the surveillance platform to further improve and expand covariate measurement and scope of analyses. Our analyses continue to focus on retrospective studies of various aspects of the COVID-19 pandemic, as well as prospective assessment of post-acute COVID-19 conditions and other impacts of the pandemic.

Outbreak of Diarrhetic Shellfish Poisoning associated with mussels, British Columbia, Canada.

In 2011, a Diarrhetic Shellfish Poisoning (DSP) outbreak occurred in British Columbia (BC), Canada that was associated with cooked mussel consumption. This is the first reported DSP outbreak in BC. Investigation of ill individuals, traceback of product and laboratory testing for toxins were used in this investigation. Sixty-two illnesses were reported. Public health and food safety investigation identified a common food source and harvest area. Public health and regulatory agencies took actions to recall product and notify the public. Shellfish monitoring program changes were implemented after the outbreak. Improved response and understanding of toxin production will improve management of future DSP outbreaks.

Comparison of clinical and epidemiological features of Shiga toxin-producing Escherichia coli O157 and non-O157 infections in British Columbia, 2009 to 2011.

INTRODUCTION: Shiga toxin-producing Escherichia coli (STEC) are major foodborne agents that have the potential to cause severe enteric illnesses and large outbreaks worldwide. Several studies found non-O157 infections to be clinically milder than O157 STEC infections. OBJECTIVE: To compare the clinical and epidemiological profiles of O157 and non-O157 STEC human infections in British Columbia (BC). METHODS: All STEC cases reported in BC from 2009 to 2011 by four local health authorities were included in the study. Cases were classified according to STEC serotype based on laboratory information. Information was gathered via case interview forms. Data analysis included the χ(2) test and Mann-Whitney test; P<0.05 was considered to be statistically significant. RESULTS: A total of 260 STEC cases were reported, including 154 (59.2%) O157 cases, 63 (24.2%) non-O157 cases and 43 (16.5%) STEC cases with no serotype identified. Hospitalization rate was higher and duration of hospitalization was significantly longer for O157 cases compared with non-O157 cases, but other clinical features were not significantly different. Patients with non-O157 infections were significantly more likely to have travelled outside Canada, less likely to report food exposure at social gatherings and more likely to consume bagged greens and cheese. DISCUSSION: O157 is the predominant O serotype in BC and appeared to be more clinically severe than non-O157 STEC infections. However, the true incidence and severity of non-O157 remain unknown due to our current inability to detect all non-O157 cases. The present study and the literature suggest the need to identify more predictive virulence factors because serotype does not consistently predict disease severity.

INTRODUCTION: Les Escherichia coli producteurs de Shigatoxine (ECST) sont d'importants agents de toxi-infection alimentaire qui ont le potentiel de provoquer de graves maladies entériques et de vastes éclosions dans le monde. Selon plusieurs études, les infections à ECST non O157 sont plus modérées sur le plan clinique que celles à ECST O157. OBJECTIF: Comparer les profils cliniques et épidémiologiques des infections humaines à ECST O157 et non O157 en Colombie-Britannique (CB). MÉTHODOLOGIE: Les chercheurs ont inclus dans l'étude tous les cas d'ECST déclarés en CB entre 2009 et 2011 par quatre régies de la santé locales. Ils ont classé les cas selon le sérotype d'ECST tiré de données de laboratoire et ont obtenu de l'information au moyen de formulaires d'entrevue des cas. L'analyse des données incluait le test χ2 et le test de Mann-Whitney, et le P<0,05 était considéré comme statistiquement significatif. RÉSULTATS: Au total, 260 cas d'ECST ont été signalés, dont 154 cas O157 (59,2 %), 63 cas non O157 (24,2%) et 43 cas sans sérotype défini (16,5 %). Le taux d'hospitalisation était plus élevé et la durée d'hospitalisation considérablement plus longue dans les cas O157 que dans les cas non O157, mais d'autres caractéristiques cliniques n'étaient pas très différentes. Les patients atteints d'une infection non O157 étaient beaucoup plus susceptibles d'avoir voyagé à l'extérieur du Canada, moins susceptibles de déclarer avoir été exposés à des aliments lors de rencontres sociales et plus susceptibles d'avoir consommé des légumes verts emballés et du fromage. EXPOSÉ: Le sérotype O157 est le sérotype O prédominant en CB et semblait être plus grave sur le plan clinique que les infections à ECST non O157. Cependant, on ne connaît toujours pas la véritable incidence et la véritable gravité des infections non O157 en raison de notre incapacité à déceler tous les cas non O157. D'après la présente étude et les publications, il faudra déterminer des facteurs de virulence plus prédictifs, parce que le sérotype ne permet pas de prédire systématiquement la gravité de la maladie.

Estimates of influenza vaccine effectiveness for 2007-2008 from Canada's sentinel surveillance system: cross-protection against major and minor variants.

OBJECTIVES: To estimate influenza vaccine effectiveness (VE) for the 2007-2008 season and assess the sentinel surveillance system in Canada for monitoring virus evolution and impact on VE. METHODS: Nasal/nasopharyngeal swabs and epidemiologic details were collected from patients presenting to a sentinel physician within 7 days of influenza-like illness onset. Cases tested positive for influenza A/B virus by real-time polymerase chain reaction; controls tested negative. Hemagglutination inhibition (HI) and gene sequencing explored virus relatedness to vaccine. VE was calculated as 1 minus the odds ratio for influenza in vaccinated versus nonvaccinated participants, with adjustment for confounders. RESULTS: Of 1425 participants, 21% were vaccinated. Influenza virus was detected in 689 (48%), of which isolates from 663 were typed/subtyped: 189 (29%) were A/H1, 210 (32%) were A/H3, and 264 (40%) were B. Of A/H1N1 isolates, 6% showed minor HI antigenic mismatch to vaccine, with greater variation based on genetic identity. All A/H3N2 isolates showed moderate antigenic mismatch, and 98% of influenza B virus isolates showed major lineage-level mismatch to vaccine. Adjusted VE for A/H1N1, A/H3N2, and B components was 69% (95% confidence interval [CI], 44%-83%), 57% (95% CI, 32%-73%), and 55% (95% CI, 32%-70%), respectively, with an overall VE of 60% (95% CI, 45%-71%). CONCLUSIONS: Detailed antigenic and genotypic analysis of influenza viruses was consistent with epidemiologic estimates of VE showing cross-protection. A routine sentinel surveillance system that combines detailed virus and VE monitoring annually, as modeled in Canada, may guide improved vaccine selection and protection.

Developing International Classification of Disease code definitions for the study of enteric infection sequelae in Canada.

Background: Enteric infections and their chronic sequelae are a major cause of disability and death. Despite the increasing use of administrative health data in measuring the burden of chronic diseases in the population, there is a lack of validated International Classification of Disease (ICD) code-based case definitions, particularly in the Canadian context. Our objective was to validate ICD code definitions for sequelae of enteric infections in Canada: acute kidney injury (AKI); hemolytic uremic syndrome (HUS); thrombotic thrombocytopenic purpura (TTP); Guillain-Barré syndrome/Miller-Fisher syndrome (GBS/MFS); chronic inflammatory demyelinating polyneuropathy (CIDP); ankylosing spondylitis (AS); reactive arthritis; anterior uveitis; Crohn's disease, ulcerative colitis, celiac disease, erythema nodosum (EN); neonatal listeriosis (NL); and Graves' disease (GD). Methods: We used a multi-step approach by conducting a literature review to identify existing validated definitions, a clinician assessment of the validated definitions, a chart review to verify proposed definitions and a final clinician review. We measured the sensitivity and positive predictive value (PPV) of proposed definitions. Results: Forty studies met inclusion criteria. We identified validated definitions for 12 sequelae; clinicians developed three (EN, NL, GD). We reviewed 181 charts for 6 sequelae (AKI, HUS, TTP, GBS/MFS, CIDP, AS). Sensitivity (42.8%-100%) and PPV (63.6%-100%) of ICD code definitions varied. Six definitions were modified by clinicians following the chart review (AKI, TTP, GBS/MFS, CIDP, AS, reactive arthritis) to reflect coding practices, increase specificity or sensitivity, and address logistical constraints. Conclusion: The multi-step design to derive ICD code definitions provided flexibility to identify existing definitions, to improve their sensitivity and PPV and adapt them to the Canadian context.

A decade of experience: Cryptococcus gattii in British Columbia.

It has been over a decade since Cryptococcus gattii was first recognized as the causative organism of an outbreak of cryptococcosis on Vancouver Island, British Columbia. A number of novel observations have been associated with the study of this emergent pathogen. A novel genotype of C. gattii, VGIIa was described as the major genotype associated with clinical disease. Minor genotypes, VGIIb and VGI, are also responsible for disease in British Columbians, in both human and animal populations. The clinical major genotype VGIIa and minor genotype VGIIb are identical to C. gattii isolated from the environment of Vancouver Island. There is more heterogeneity in VGI, and a clear association with the environment is not apparent. Between 1999 and 2010, there have been 281 cases of C. gattii cryptococcosis. Risk factors for infection are reported to be age greater than 50 years, history of smoking, corticosteroid use, HIV infection, and history of cancer or chronic lung disease. The major C. gattii genotype VGIIa is as virulent in mice as the model Cryptococcus, H99 C. neoformans, although the outbreak strain produces a less protective inflammatory response in C57BL/6 mice. The minor genotype VGIIb is significantly less virulent in mouse models. Cryptococcus gattii is found associated with native trees and soil on Vancouver Island. Transiently positive isolations have been made from air and water. An ecological niche for this organism is associated within a limited biogeoclimatic zone characterized by daily average winter temperatures above freezing.

Pregnant women's knowledge, practices, and needs related to food safety and listeriosis: a study in British Columbia.

OBJECTIVE: To understand the knowledge, attitudes, practices, and needs of pregnant women regarding food safety, including the risk of listeriosis, in order to develop targeted messages and educational resources in British Columbia (BC). DESIGN: Qualitative study using focus groups and quantitative study using a standardized questionnaire. SETTING: Seven family practice clinics in BC. Focus groups were conducted in 3 program groups for new mothers. PARTICIPANTS: Pregnant women and women who had recently delivered babies. METHODS: Three focus groups were conducted with women who had recently delivered. Qualitative analysis to identify common themes was conducted. A questionnaire was completed by pregnant women at their health care providers' (HCPs') offices. Statistical analysis was done to assess associations between demographic features, knowledge, and practices. Results from both study methods were compared and common findings were presented. MAIN FINDINGS: Participants reported that food safety and the risk of listeriosis were important to them during pregnancy; however, their knowledge of high-risk foods and safe food practices was limited. Although they identified their HCPs as a valuable source of information, they explained there were barriers to getting information from them. Participants reported doing their own research using books, websites, and social networks. They made recommendations to improve food safety messages, as well as the availability and format of resources. CONCLUSION: Women in BC identified a gap between the information on food safety and listeriosis that they needed during pregnancy and the resources that were available. Using the information collected from this study, resources that are targeted at women of childbearing years, as well as their HCPs, are under development in BC.

Mathematical modeling of COVID-19 in British Columbia: An age-structured model with time-dependent contact rates.

Following the emergence of COVID-19 at the end of 2019, several mathematical models have been developed to study the transmission dynamics of this disease. Many of these models assume homogeneous mixing in the underlying population. However, contact rates and mixing patterns can vary dramatically among individuals depending on their age and activity level. Variation in contact rates among age groups and over time can significantly impact how well a model captures observed trends. To properly model the age-dependent dynamics of COVID-19 and understand the impacts of interventions, it is essential to consider heterogeneity arising from contact rates and mixing patterns. We developed an age-structured model that incorporates time-varying contact rates and population mixing computed from the ongoing BC Mix COVID-19 survey to study transmission dynamics of COVID-19 in British Columbia (BC), Canada. Using a Bayesian inference framework, we fit four versions of our model to weekly reported cases of COVID-19 in BC, with each version allowing different assumptions of contact rates. We show that in addition to incorporating age-specific contact rates and mixing patterns, time-dependent (weekly) contact rates are needed to adequately capture the observed transmission dynamics of COVID-19. Our approach provides a framework for explicitly including empirical contact rates in a transmission model, which removes the need to otherwise model the impact of many non-pharmaceutical interventions. Further, this approach allows projection of future cases based on clear assumptions of age-specific contact rates, as opposed to less tractable assumptions regarding transmission rates.