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

Characteristics of People Who Do Not Complete a Public Health Interview: An Assessment of Colorado Enteric Disease Surveillance Data

OBJECTIVES

Although enteric disease case interviews are critical for control measures and education, not all case-patients are interviewed. We evaluated systematic differences between people with an enteric disease in Colorado who were and were not interviewed to identify ways to increase response rates and reduce biases in the surveillance data used to guide public health interventions.

METHODS

We obtained data from the Colorado Electronic Disease Reporting System from March 1, 2017, through December 31, 2019. Among case-patients not interviewed and interviewed, we used univariate analyses to describe sociodemographic characteristics, timing of contact attempts, and effect of additional funding.

RESULTS

As compared with case-patients who were interviewed, case-patients who were not interviewed were significantly more likely to be aged 18 to 39 years (35.7% vs 31.7%; P < .001); identify as male, Hispanic, or Black; be experiencing homelessness or hospitalization; reside in rural/frontier areas or an institution; or live in areas with lower levels of education, life expectancy, and income. Time to first contact attempt was longer for case-patients who were not interviewed than for those who were (mean days from specimen collection to first contact attempt, 9.8 vs 6.8; P < .001). Residing in a jurisdiction with additional funding for interviewing was associated with increased interview rates (87.7% vs 68.8%) and timeliness of public health report and first contact attempt (2.3 vs 4.4 days; P < .001).

CONCLUSION

Findings can guide efforts to improve response rates in groups least likely to be interviewed, resulting in reduced biases in surveillance data, better disease mitigation, and increased efficiency in case investigations. Timeliness of case interviews and additional funding to conduct case investigations were factors in increasing response rates.

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.

Determining the long-term health burden and risk of sequelae for 14 foodborne infections in British Columbia, Canada: protocol for a retrospective population-based cohort study

INTRODUCTION

Over one in eight Canadians is affected by a foodborne infection annually; however, the long-term consequences, including the risks and costs of sequelae, are unclear. We aim to estimate the health burden and direct costs of 14 infections commonly transmitted by food, considering the acute illness and subsequent sequelae and mortality, for the population of British Columbia, Canada (~4.7 million).

METHODS AND ANALYSIS

We will conduct a population-based retrospective cohort study of the British Columbia provincial population, over a 10-year study period (1 January 2005 to 31 December 2014). Exposure is defined as a provincially reported illness caused by Clostridium botulinum, Campylobacter, Cryptosporidium, Cyclospora, Giardia, hepatitis A virus, Listeria, non-typhoidal Salmonella spp, Salmonella Typhi, Salmonella Paratyphi, Shiga toxin-producing Escherichia coli, Shigella, Vibrio parahaemolyticus or Yersinia (excluding pestis). We will link individual-level longitudinal data from eight province-wide administrative health and reportable disease databases that include physician visits, hospitalisations and day surgeries, deaths, stillbirths, prescription medications (except those to treat HIV) and reportable foodborne diseases. Using these linked databases, we will investigate the likelihood of various sequelae and death. Hazard models will be used to estimate the risk of outcomes and their association with the type of foodborne infection. Epidemiological analyses will be conducted to determine the progression of illness and the fraction of sequelae attributable to specific foodborne infections. Economic analyses will assess the consequent direct healthcare costs.

ETHICS AND DISSEMINATION

This study has been approved by a University of Waterloo Research Ethics Committee (no 30645), the University of British Columbia Behavioral Research Ethics Board (no H16-00021) and McGill University's Institutional Review Board (no A03-M12-19A). Results will be disseminated via presentations to academics, public health practitioners and knowledge users, and publication in peer-reviewed journals. Where such publications are not open access, manuscripts will also be available via the University of Waterloo's Institutional Repository (https://uwspace.uwaterloo.ca).

Shiga toxin-producing Escherichia coli in British Columbia, 2011-2017: Analysis to inform exclusion guidelines

Background

Shiga toxin-producing Escherichia coli (STEC) can cause severe illness including bloody diarrhea and hemolytic-uremic syndrome (HUS) through the production of Shiga toxins 1 (Stx1) and 2 (Stx2). E. coli O157:H7 was the most common serotype detected in the 1980s to 1990s, but improvements in laboratory methods have led to increased detection of non-O157 STEC. Non-O157 STEC producing only Stx1 tend to cause milder clinical illness. Exclusion guidelines restrict return to high-risk work or settings for STEC cases, but most do not differentiate between STEC serogroups and Stx type.

Objective

To analyze British Columbia (BC) laboratory and surveillance data to inform the BC STEC exclusion guideline.

Methods

For all STEC cases reported in BC in 2011-2017, laboratory and epidemiological data were obtained through provincial laboratory and reportable disease electronic systems, respectively. Incidence was measured for all STEC combined as well as by serogroup. Associations were measured between serogroups, Stx types and clinical outcomes.

Results

Over the seven year period, 984 cases of STEC were reported. A decrease in O157 incidence was observed, while non-O157 rates increased. The O157 serogroup was significantly associated with Stx2. Significant associations were observed between Stx2 and bloody diarrhea, hospitalization and HUS.

Conclusion

The epidemiology of STEC has changed in BC as laboratories increasingly distinguish between O157 and non-O157 cases and identify Stx type. It appears that non-O157 cases with Stx1 are less severe than O157 cases with Stx2. The BC STEC exclusion guidelines were updated as a result of this analysis.

Foodborne Outbreak Investigation: Effect of Recall Inaccuracies on Food Histories

HIGHLIGHTS

Comparably low accuracy of dietary recall is present after 7 and 18 days. Experiencing gastrointestinal symptoms did not affect accuracy of dietary recall. Repeatedly recalling food exposures leads to a higher rate of false positives. Prevalence of exposure was associated with higher sensitivity and lower specificity. Recall inaccuracies can be quantified and accounted for in public health practice.