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Background In British Columbia, Canada, most adults 50–69 years old became eligible for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine in April 2021, with chimpanzee adenoviral vectored vaccine (ChAdOx1) restricted to ≥55-year-olds and second doses deferred ≥6 weeks to optimize single-dose coverage. Methods Among adults 50–69 years old, single-dose messenger RNA (mRNA) and ChAdOx1 vaccine effectiveness (VE) against SARS-CoV-2 infection and hospitalization, including variant-specific, was assessed by test-negative design between 4 April and 2 October 2021. Results Single-dose VE included 11 861 cases and 99 544 controls. Median of postvaccination follow-up was 32 days (interquartile range, 15–52 days). Alpha, Gamma, and Delta variants comprised 23%, 18%, and 56%, respectively, of genetically characterized viruses. At 21–55 days postvaccination, single-dose mRNA and ChAdOx1 VE (95% confidence interval [CI]) was 74% (71%–76%) and 59% (53%–65%) against any infection and 86% (80%–90%) and 94% (85%–97%) against hospitalization, respectively. VE (95% CI) was similar against Alpha and Gamma infections for mRNA (80% [76%–84%] and 80% [75%–84%], respectively) and ChAdOx1 (69% [60%–76%] and 66% [56%–73%], respectively). mRNA VE was lower at 63% (95% CI, 56%–69%) against Delta but 85% (95% CI, 71%–92%) against Delta-associated hospitalization (nonestimable for ChAdOx1). Conclusions A single mRNA or ChAdOx1 vaccine dose gave important protection against SARS-CoV-2, including early variants of concern. ChAdOx1 VE was lower against infection, but 1 dose of either vaccine reduced the hospitalization risk by >85% to at least 8 weeks postvaccination. Findings inform program options, including longer dosing intervals.

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 50% by week 8. P.1 accounted for

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 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.

Objectives International data on listeriosis during infancy from large populations are essential to guide evidence-based empiric antibiotic guidelines for sepsis in infancy. We aimed to determine the incidence, clinical manifestations, and outcome of listeriosis in infants Methods Prospective, active surveillance of listeriosis in infants Results In Canada, eight sporadic listeriosis cases were reported (incidence, 1.1/100,000 live births/year). In Switzerland, four cases were reported (incidence, 4.5/100,000 live births/year) of which three were part of a confirmed outbreak with an unclear source. In the two countries, eight of the 12 cases (66.6%) presented as early-onset disease (within the first 7 days of life) and none presented after 28 days life. Conclusions Neonatal listeriosis is rare. Infants presenting with sepsis, especially after 4 weeks of life, may not routinely require empiric antibiotic coverage for listeriosis. Outbreak-related cases still occur. Continued surveillance is important.

Contexte : En 2018, une éclosion d’Escherichia coli O121 produisant la toxine de Shiga avec sept cas a été associée à la production de fromage au lait cru de type Gouda en Colombie-Britannique, au Canada. Objectifs : Décrire l’enquête sur l’éclosion d’E. coli O121 et recommander des mesures de contrôle plus strictes pour les fromages au lait cru de type Gouda. Méthodes : Les cas d’E. coli O121 ont été identifiés grâce aux résultats d’analyses en laboratoire et aux données de surveillance épidémiologique. Ils ont ensuite été interrogés en fonction de l’exposition d’intérêt, puis analysés en fonction des valeurs du Rapport Foodbook pour la Colombie-Britannique. Une investigation a été effectuée dans l’usine laitière et des prélèvements ont été effectués dans les produits de fromage afin de déterminer la source de contamination. Le typage de séquence multilocus pour le génome entier a été effectué sur tous les isolats cliniques et alimentaires positifs pour E. coli O121 au laboratoire provincial. Résultats Quatre des sept cas avaient consommé le même fromage au lait cru de type Gouda entre août et octobre 2018. Ce fromage avait été affiné pendant une période supérieure au minimum requis de 60 jours, et aucun défaut n’a été constaté dans sa production. Un échantillon du fromage visé a cependant obtenu un résultat positif à l’analyse de dépistage de la bactérie E. coli O121. Sept isolats cliniques et un isolat de fromage ont été jugés identiques par typage de séquence multilocus pour le génome entier avec une différence de 0 à 6,5 allèles. Conclusion Le Gouda au lait cru et les fromages de type Gouda au lait cru avaient déjà été impliqués dans trois éclosions antérieures d’E. coli producteur de toxines Shiga en Amérique du Nord. Il a donc été recommandé d’étiqueter les produits afin de sensibiliser les consommateurs au risque et de thermiser le lait afin de réduire le risque de maladie associé au Gouda au lait cru et au fromage de type Gouda au lait cru.

Background: In 2018, a Shiga toxin–producing Escherichia coli O121 outbreak that affected seven individuals was associated with raw milk Gouda-like cheese produced in British Columbia, Canada. Objectives: To describe the E. coli O121 outbreak investigation and recommend greater control measures for raw milk Gouda-like cheese. Methods: Cases of E. coli O121 were identified through laboratory testing results and epidemiologic surveillance data. The cases were interviewed on exposures of interest, which were analyzed against Foodbook Report values for British Columbia. Environmental inspection of the dairy plant and the cheese products was conducted to ascertain a source of contamination. Whole genome multi-locus sequence typing (wgMLST) was performed on all positive E. coli O121 clinical and food isolates at the provincial laboratory. Results: Four out of the seven cases consumed the same raw milk Gouda-like cheese between August and October 2018. The implicated cheese was aged longer than the required minimum of 60 days, and no production deficiencies were noted. One sample of the implicated cheese tested positive for E. coli O121. The seven clinical isolates and one cheese isolate matched by wgMLST within 6.5 alleles. Conclusion: Raw milk Gouda and Gouda-like cheese has been implicated in three previous Shiga toxin–producing E. coli outbreaks in North America. It was recommended product labelling to increase consumer awareness and thermization of milk to decrease the risk of illness associated with raw milk Gouda and Gouda-like cheese.

Background The Canadian coronavirus disease 2019 (COVID-19) immunization strategy deferred second doses and allowed mixed schedules. We compared 2-dose vaccine effectiveness (VE) by vaccine type (mRNA and/or ChAdOx1), interval between doses, and time since second dose in 2 of Canada’s larger provinces. Methods Two-dose VE against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection or hospitalization among adults ≥18 years, including due to Alpha, Gamma, and Delta variants of concern (VOCs), was assessed ≥14 days postvaccination by test-negative design studies separately conducted in British Columbia and Quebec, Canada, between 30 May and 27 November (epi-weeks 22–47) 2021. Results In both provinces, all homologous or heterologous mRNA and/or ChAdOx1 2-dose schedules were associated with ≥90% reduction in SARS-CoV-2 hospitalization risk for ≥7 months. With slight decline from a peak of >90%, VE against infection was ≥80% for ≥6 months following homologous mRNA vaccination, lower by ∼10% when both doses were ChAdOx1 but comparably high following heterologous ChAdOx1 + mRNA receipt. Findings were similar by age group, sex, and VOC. VE was significantly higher with longer 7–8-week versus manufacturer-specified 3–4-week intervals between mRNA doses. Conclusions Two doses of any mRNA and/or ChAdOx1 combination gave substantial and sustained protection against SARS-CoV-2 hospitalization, spanning Delta-dominant circulation. ChAdOx1 VE against infection was improved by heterologous mRNA series completion. A 7–8-week interval between first and second doses improved mRNA VE and may be the optimal schedule outside periods of intense epidemic surge. Findings support interchangeability and extended intervals between SARS-CoV-2 vaccine doses, with potential global implications for low-coverage areas and, going forward, for children.

This study identified factors associated with hospital admission among people with laboratory-diagnosed COVID-19 cases in British Columbia. The study used data from the BC COVID-19 Cohort, which integrates data on all COVID-19 cases with data on hospitalizations, medical visits, emergency room visits, prescription drugs, chronic conditions and deaths. The analysis included all laboratory-diagnosed COVID-19 cases in British Columbia to 15 January 2021. We evaluated factors associated with hospital admission using multivariable Poisson regression analysis with robust error variance. Of the 56,874 COVID-19 cases included in the analysis, 2298 were hospitalized. Factors associated with increased hospitalization risk were as follows: male sex (adjusted risk ratio (aRR) = 1.27, 95%CI = 1.17–1.37), older age (p-trend &lt, 0.0001 across age groups increasing hospitalization risk with increasing age [aRR 30–39 years = 3.06, 95%CI = 2.32–4.03, to aRR 80+ years = 43.68, 95%CI = 33.41–57.10 compared to 20–29 years-old]), asthma (aRR = 1.15, 95%CI = 1.04–1.26), cancer (aRR = 1.19, 95%CI = 1.09–1.29), chronic kidney disease (aRR = 1.32, 95%CI = 1.19–1.47), diabetes (treated without insulin aRR = 1.13, 95%CI = 1.03–1.25, requiring insulin aRR = 5.05, 95%CI = 4.43–5.76), hypertension (aRR = 1.19, 95%CI = 1.08–1.31), injection drug use (aRR = 2.51, 95%CI = 2.14–2.95), intellectual and developmental disabilities (aRR = 1.67, 95%CI = 1.05–2.66), problematic alcohol use (aRR = 1.63, 95%CI = 1.43–1.85), immunosuppression (aRR = 1.29, 95%CI = 1.09–1.53), and schizophrenia and psychotic disorders (aRR = 1.49, 95%CI = 1.23–1.82). In an analysis restricted to women of reproductive age, pregnancy (aRR = 2.69, 95%CI = 1.42–5.07) was associated with increased risk of hospital admission. Older age, male sex, substance use, intellectual and developmental disability, chronic comorbidities, and pregnancy increase the risk of COVID-19-related hospitalization.

BackgroundThe Canadian COVID-19 immunization strategy deferred second doses and allowed mixed schedules. We compared two-dose vaccine effectiveness (VE) by vaccine type (mRNA and/or ChAdOx1), interval between doses, and time since second dose in two of Canada’s larger provinces.MethodsTwo-dose VE against infections and hospitalizations due to SARS-CoV-2, including variants of concern, was assessed between May 30 and October 2, 2021 using test-negative designs separately conducted among community-dwelling adults ≥18-years-old in British Columbia (BC) and Quebec, Canada.FindingsIn both provinces, two doses of homologous or heterologous SARS-CoV-2 vaccines were associated with ∼95% reduction in the risk of hospitalization. VE exceeded 90% against SARS-CoV-2 infection when at least one dose was an mRNA vaccine, but was lower at ∼70% when both doses were ChAdOx1. Estimates were similar by age group (including adults ≥70-years-old) and for Delta-variant outcomes. VE was significantly higher against both infection and hospitalization with longer 7-8-week vs. manufacturer-specified 3-4-week interval between doses. Two-dose mRNA VE was maintained against hospitalization for the 5-7-month monitoring period and while showing some decline against infection, remained ≥80%.InterpretationTwo doses of mRNA and/or ChAdOx1 vaccines gave excellent protection against hospitalization, with no sign of decline by 5-7 months post-vaccination. A 7-8-week interval between doses improved VE and may be optimal in most circumstances. Findings indicate prolonged two-dose protection and support the use of mixed schedules and longer intervals between doses, with global health, equity and access implications in the context of recent third-dose proposals.

IntroductionIn randomized controlled trials, single-dose efficacy against SARS-CoV-2 illness exceeded 90% for mRNA vaccines (BNT162b2 and mRNA-1273), and 75% for ChAdOx1. In British Columbia (BC), Canada second doses were deferred up to 16 weeks and ChAdOx1 was only initially recommended for adults 55 years of age and older. We compared single-dose vaccine effectiveness (VE) during the spring 2021 wave in BC when Alpha and Gamma variants of concern (VOC) predominated.MethodsVE was estimated against infection and hospitalization by test-negative design: cases were RT-PCR test-positive for SARS-CoV-2 and controls were test-negative. Adults 50-69 years old with specimen collection between April 4 and May 22 (weeks 14-20) were included. Variant-specific VE was estimated between weeks 17-20 when genetic characterization of all case viruses was performed, primarily through whole genome sequencing.ResultsVE analyses included 7,116 (10%) cases and 60,958 controls. Three-quarters of vaccinated participants received mRNA vaccine (60% BNT162b2, 15% mRNA-1273) and 25% received ChAdOx1. Half of genetically characterized viruses were Alpha, with 38% Gamma, 4% Delta and 8% non-VOCs. Single-dose VE against any infection was 75% (95%CI: 72-78) for BNT162b2, 82% (95%CI: 76-87) for mRNA-1273 and 61% (95%CI: 54-66) for ChAdOx1. VE against hospitalization was 83% (95%CI: 76-89), 85% (95%CI: 63-94) and 96% (95%CI: 86-99), respectively. VE against Alpha vs. Gamma infections did not differ among mRNA (78%;95%CI: 73-82 and 80%;95%CI: 74-85) or ChAdOx1 (66%;95%CI: 57-74 and 60%;95%CI: 48-69) recipients.ConclusionsA single dose of mRNA vaccine reduced the SARS-CoV-2 infection risk by at least 75%, including infections due to early VOC. Although effectiveness of a single dose of ChAdOx1 was lower at 60% against infection, just one dose of any vaccine reduced the hospitalization risk by more than 80%. In the context of constrained vaccine supplies, these findings have implications for global vaccine deployment to reduce the overall burden of infections and hospitalizations due to SARS-CoV-2.

BackgroundThis study identified factors associated with hospital admission among people with laboratory-diagnosed COVID-19 cases in British Columbia.MethodsThis study was performed using the BC COVID-19 Cohort, which integrates data on all COVID-19 cases, hospitalizations, medical visits, emergency room visits, prescription drugs, chronic conditions and deaths. The analysis included all laboratory-diagnosed COVID-19 cases in British Columbia as of January 15th, 2021. We evaluated factors associated with hospital admission using multivariable Poisson regression analysis with robust error variance.FindingsFrom 56,874 COVID-19 cases included in the analyses, 2,298 were hospitalized. Models showed significant association of the following factors with increased hospitalization risk: male sex (adjusted risk ratio (aRR)=1.27; 95%CI=1.17-1.37), older age (p-trend InterpretationOlder age, male sex, substance use, intellectual and developmental disability, chronic comorbidities, and pregnancy increase the risk of COVID-19-related hospitalization.FundingBC Centre for Disease Control, Canadian Institutes of Health Research.Research in contextEvidence before this studyFactors such as older age, social inequities and chronic health conditions have been associated to severe COVID-19 illness. Most of the evidence comes from studies that don’t include all COVID-19 diagnoses in a jurisdiction), focusing on in-hospital mortality. In addition, mental illness and substance use were not evaluated in these studies. This study assessed factors associated with hospital admission among people with laboratory-diagnosed COVID-19 cases in British Columbia.Added value of this studyIn this population-based cohort study that included 56,874 laboratory-confirmed COVID-19 cases, older age, male sex, injection drug use, problematic alcohol use, intellectual and developmental disability, schizophrenia and psychotic disorders, chronic comorbidities and pregnancy were associated with the risk of hospitalization. Insulin-dependent diabetes was associated with higher risk of hospitalization, especially in the subpopulation younger than 40 years. To the best of our knowledge this is the first study reporting this finding, (insulin use and increased risk of COVID-19-related death has been described previously).Implications of all the available evidencePrioritization of vaccination in population groups with the above mentioned risk factors could reduce COVID-19 serious outcomes. The findings indicate the presence of the syndemic of substance use, mental illness and COVID-19, which deserve special public health considerations.

Contaminated beef is a known vehicle of Escherichia coli O157:H7 infection, although more attention is given to the control of E. coli O157:H7 in ground, rather than whole-cut, beef products. In September 2012, an investigation was initiated at an Alberta, Canada, beef plant after the detection of E. coli O157:H7 in two samples of trim cut from beef originating from this plant. Later in September 2012, Alberta Health Services identified five laboratory-confirmed infections of E. coli O157:H7, and case patients reported eating needle-tenderized beef steaks purchased at a store in Edmonton, Alberta, produced with beef from the Alberta plant. In total, 18 laboratory-confirmed illnesses in Canada in September and October 2012 were linked to beef from the Alberta plant, including the five individuals who ate needle-tenderized steaks purchased at the Edmonton store. A unique strain of E. coli O157:H7, defined by molecular subtyping and whole genome sequencing, was detected in clinical isolates, four samples of leftover beef from case patient homes, and eight samples of Alberta plant beef tested by industry and food safety partners. Investigators identified several deficiencies in the control of E. coli O157:H7 at the plant; in particular, the evaluation of, and response to, the detection of E. coli O157 in beef samples during routine testing were inadequate. To control the outbreak, 4,000 tons of beef products were recalled, making it the largest beef recall in Canadian history. This outbreak, in combination with similar outbreaks in the United States and research demonstrating that mechanical tenderization can transfer foodborne pathogens present on the surface into the interior of beef cuts, prompted amendments to Canada's Food and Drug Regulations requiring mechanically tenderized beef to be labeled as such and to provide safe cooking instructions to consumers. A detailed review of this event also led to recommendations and action to improve the safety of Canada's beef supply.

We compared 2 climate classification systems describing georeferenced environmental Cryptococcus gattii sensu lato isolations occurring during 1989-2016. Each system suggests the fungus was isolated in temperate climates before the 1999 outbreak on Vancouver Island, British Columbia, Canada. However, the Köppen-Geiger system is more precise and should be used to define climates where pathogens are detected.

IntroductionRandomized-controlled trials of mRNA vaccine protection against SARS-CoV-2 included relatively few elderly participants. We assess singe-dose mRNA vaccine effectiveness (VE) in adults ≥70-years-old in British Columbia (BC), Canada where the second dose was deferred by up to 16 weeks and where a spring 2021 wave uniquely included co-dominant circulation of B.1.1.7 and P.1 variants of concern (VOC).MethodsAnalyses included community-dwelling adults ≥70-years-old with specimen collection between April 4 (epidemiological week 14) and May 1 (week 17). Adjusted VE was estimated by test-negative design through provincial laboratory and immunization data linkage. Cases were RT-PCR test-positive for SARS-CoV-2 and controls were test-negative. Vaccine status was defined by receipt of a single-dose ≥21 days before specimen collection, but a range of intervals was assessed. In variant-specific analyses, test-positive cases were restricted to those genetically-characterized as B.1.1.7, P.1 or non-VOC.ResultsVE analyses included 16,993 specimens: 1,226 (7.2%) test-positive cases and 15,767 test-negative controls. Of 1,131 (92%) viruses genetically categorized, 509 (45%), 314 (28%) and 276 (24%) were B.1.1.7, P.1 and non-VOC lineages, respectively. VE was negligible at 14% (95% CI 0-26) during the period 0-13 days post-vaccination but increased from 43% (95% CI 30-53) at 14-20 days to 75% (95% CI 63-83) at 35-41 days post-vaccination. VE at ≥21 days was 65% (95% CI 58-71) overall: 72% (95% CI 58-81), 67% (95% CI 57-75) and 61% (95% CI 45-72) for non-VOC, B.1.1.7 and P.1, respectively.ConclusionsA single dose of mRNA vaccine reduced the risk of SARS-CoV-2 in adults ≥70-years-old by about two-thirds, with protection only minimally reduced against B.1.1.7 and P.1 variants. Substantial single-dose protection in older adults reinforces the option to defer the second dose when vaccine supply is scarce and broader first-dose coverage is needed.

Background Randomized-controlled trials of messenger RNA (mRNA) vaccine protection against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) included relatively few elderly participants. We assess single-dose mRNA vaccine effectiveness (VE) in adults ≥ 70 years old in British Columbia, Canada, where second doses were deferred by up to 16 weeks and where a spring 2021 wave uniquely included codominant circulation of Alpha (B.1.1.7) and Gamma (P.1) variants of concern (VOC). Methods Analyses included community-dwelling adults ≥ 70 years old with specimen collection between 4 April (epidemiological week 14) and 1 May (week 17) 2021. Adjusted VE was estimated by test-negative design. Cases were reverse-transcription polymerase chain reaction (RT-PCR) test-positive for SARS-CoV-2, and controls were test-negative. Vaccine status was defined by receipt of a single-dose ≥ 21 days before specimen collection, but a range of intervals was assessed. Variant-specific VE was estimated against viruses genetically characterized as Alpha, Gamma or non-VOC lineages. Results VE analyses included 16 993 specimens: 1226 (7%) test-positive cases and 15 767 test-negative controls. Of 1131 (92%) genetically characterized viruses, 509 (45%), 314 (28%), and 276 (24%) were Alpha, Gamma, and non-VOC lineages, respectively. At 0–13 days postvaccination, VE was negligible at 14% (95% confidence interval [CI], 0–26) but increased from 43% (95% CI, 30–53) at 14–20 days to 75% (95% CI, 63–83) at 35–41 days postvaccination. VE at ≥ 21 days postvaccination was 65% (95% CI, 58–71) overall: 72% (95% CI, 58–81), 67% (95% CI, 57–75), and 61% (95% CI, 45–72) for non-VOC, Alpha, and Gamma variants, respectively. Conclusions A single dose of mRNA vaccine reduced the risk of SARS-CoV-2 by about two-thirds in adults ≥ 70 years old, with protection only minimally reduced against Alpha and Gamma variants., Vaccine effectiveness estimated by test-negative design in British Columbia, Canada, shows one dose of mRNA vaccine reduced the risk of SARS-CoV-2 infection in adults ≥70-years-old by about two-thirds, with protection only minimally reduced against Alpha (B.1.1.7) and Gamma (P.1) variants.

Lyme disease, caused by

Background Cryptococcosis due to Cryptococcus neoformans and Cryptococcus gattii varies with geographic region, populations affected, disease manifestations, and severity of infection, which impact treatment. Methods We developed a retrospective cohort of patients diagnosed with culture-proven cryptococcosis during 1995–2013 from 5 centers in North America and Australia. We compared underlying diseases, clinical manifestations, treatment, and outcomes in patients with C. gattii or C. neoformans infection. Results A total of 709 patients (452 C. neoformans; 257 C. gattii) were identified. Mean age was 50.2 years; 61.4% were male; and 52.3% were white. Time to diagnosis was prolonged in C. gattii patients compared with C. neoformans (mean, 52.2 vs 36.0 days; P Conclusions This study emphasizes differences in species-specific epidemiology and outcomes of patients with cryptococcosis, including underlying diseases, site of infection, and mortality. Species identification in patients with cryptococcosis is necessary to discern epidemiologic patterns, guide treatment regimens, and predict clinical progression and outcomes.

BackgroundThe province of British Columbia (BC) has been recognized for successful SARS-CoV-2 control, with surveillance data showing amongst the lowest case and death rates in Canada. We estimate sero-prevalence for two periods flanking the start (March) and end (May) of first-wave mitigation measures in BC.MethodsSerial cross-sectional sampling was conducted using anonymized residual sera obtained from an outpatient laboratory network, including children and adults in the Greater Vancouver Area (population ∼3 million) where community attack rates were expected to be highest. Screening used two chemiluminescent immuno-assays for spike (S1) and nucleocapsid antibodies. Samples sero-positive on either screening assay were assessed by a third assay targeting the S1 receptor binding domain plus a neutralization assay. Age-standardized sero-prevalence estimates were based on dual-assay positivity. The May sero-prevalence estimate was extrapolated to the source population to assess surveillance under-ascertainment, quantified as the ratio of estimated infections versus reported cases.ResultsSerum collection dates spanned March 5-13 and May 15-27, 2020. In March, two of 869 specimens were dual-assay positive, with age-standardized sero-prevalence of 0.28% (95%CI=0.03-0.95). Neither specimen had detectable neutralizing antibodies. In May, four of 885 specimens were dual-assay positive, with age-standardized sero-prevalence of 0.55% (95%CI=0.15-1.37%). All four specimens had detectable neutralizing antibodies. We estimate ∼8 times more infections than reported cases.ConclusionsLess than 1% of British Columbians had been infected with SARS-CoV-2 when first-wave mitigation measures were relaxed in May 2020. Our findings indicate successful suppression of community transmission in BC, but also substantial residual susceptibility. Further sero-survey snapshots are planned as the pandemic unfolds.Key pointsCross-sectional sampling of anonymized residual sera at the start and end of first-wave mitigation measures in British Columbia, Canada shows SARS-CoV-2 sero-prevalence below 1% throughout the winter-spring 2020. Findings indicate successful suppression of community transmission but also substantial residual susceptibility.

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 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.

A Canadian outbreak investigation into a cluster of Escherichia coli O121 was initiated in late 2016. When initial interviews using a closed-ended hypothesis-generating questionnaire did not point to a common source, cases were centrally re-interviewed using an open-ended approach. The open-ended interviews led cases to describe exposures with greater specificity, as well as food preparation activities. Data collected supported hypothesis generation, particularly with respect to flour exposures. In March 2017, an open sample of Brand X flour from a case home, and a closed sample collected at retail of the same brand and production date, tested positive for the outbreak strain of E. coli O121. In total, 76% (16/21) of cases reported that they used or probably used Brand X flour or that it was used or probably was used in the home during their exposure period. Crucial hypothesis-generating techniques used during the course of the investigation included a centralised open-ended interviewing approach and product sampling from case homes. This was the first outbreak investigation in Canada to identify flour as the source of infection.

Background Climate change is increasing the number and intensity of extreme weather events in many parts of the world. Precipitation extremes have been linked to both outbreaks and sporadic cases of waterborne illness. We have previously shown a link between heavy rain and turbidity to population-level risk of sporadic cryptosporidiosis and giardiasis in a major Canadian urban population. The risk increased with 30 or more dry days in the 60 days preceding the week of extreme rain. The goal of this study was to investigate the change in cryptosporidiosis and giardiasis risk due to climate change, primarily change in extreme precipitation. Methods Cases of cryptosporidiosis and giardiasis were extracted from a reportable disease system (1997–2009). We used distributed lag non-linear Poisson regression models and projections of the exposure-outcome relationship to estimate future illness (2020–2099). The climate projections are derived from twelve statistically downscaled regional climate models. Relative Concentration Pathway 8.5 was used to project precipitation derived from daily gridded weather observation data (~ 6 × 10 km resolution) covering the central of three adjacent watersheds serving metropolitan Vancouver for the 2020s, 2040s, 2060s and 2080s. Results Precipitation is predicted to steadily increase in these watersheds during the wet season (Oct. -Mar.) and decrease in other parts of the year up through the 2080s. More weeks with extreme rain (>90th percentile) are expected. These weeks are predicted to increase the annual rates of cryptosporidiosis and giardiasis by approximately 16% by the 2080s corresponding to an increase of 55–136 additional cases per year depending upon the climate model used. The predicted increase in the number of waterborne illness cases are during the wet months. The range in future projections compared to historical monthly case counts typically differed by 10–20% across climate models but the direction of change was consistent for all models. Discussion If new water filtration measures had not been implemented in our study area in 2010–2015, the risk of cryptosporidiosis and giardiasis would have been expected to increase with climate change, particularly precipitation changes. In addition to the predicted increase in the frequency and intensity of extreme precipitation events, the frequency and length of wet and dry spells could also affect the risk of waterborne diseases as we observed in the historical period. These findings add to the growing evidence regarding the need to prepare water systems to manage and become resilient to climate change-related health risks.

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.

Between 12 July and 29 September 2013, 29 individuals in five Canadian provinces became ill following infection with the same strain of Escherichia coli O157:H7 as defined by molecular typing results. Five case patients were hospitalized, and one died. Twenty-six case patients (90%) reported eating Gouda cheese originating from a dairy plant in British Columbia. All of the 22 case patients with sufficient product details available reported consuming Gouda cheese made with raw milk; this cheese had been produced between March and July 2013 and was aged for a minimum of 60 days. The outbreak strain was isolated from the implicated Gouda cheese, including one core sample obtained from an intact cheese wheel 83 days after production. The findings indicate that raw milk was the primary source of the E. coli O157:H7, which persisted through production and the minimum 60-day aging period. This outbreak is the third caused by E. coli O157:H7 traced to Gouda cheese made with raw milk in North America. These findings provide further evidence that a 60-day ripening period cannot ensure die-off of pathogens that might be present in raw milk Gouda cheese after production and have triggered an evaluation of processing conditions, physicochemical parameters, and options to mitigate the risk of E. coli O157:H7 infection associated with raw milk Gouda cheese produced in Canada.

Cryptococcus gattii emerged on Vancouver Island in 1999 for unknown reasons, causing human and animal fatalities and illness. The apparent emergence of this fungus in another temperate area, this time in the Pacific Northwest, suggests the fungus may have expanded its ecological niche. Yet studies that directly examine the potential roles of climatic and land use changes on C. gattii are still lacking. We aim to summarize the existing global literature on the ecology of C. gattii, with particular focus on the gap in knowledge surrounding the potential effects of climatic and land use changes. We systematically reviewed English peer-reviewed literature on the ecological determinants of C. gattii. We included studies published from January 1970 through June 2016 and identified 56 relevant studies for our review. We identified environmental isolations of C. gattii from 18 countries, spanning 72 separate regions across six continents. Fifty-three tree species were associated with C. gattii, spanning 10 climate classifications and 36 terrestrial ecoregions. No studies directly tested the potential effects of climatic changes (including climatic oscillations and global climate change) on C. gattii, while only one study directly assessed those of land use change. To improve model predictions of current and future distributions of C. gattii, more focus is needed on the potential effects of climatic and land use changes to help decrease the public health risk. The apparent emergence of C. gattii in British Columbia is also an opportunity to explore the factors behind emerging infectious diseases in Canada and elsewhere.