Wastewater-based surveillance as a tool for public health action: SARS-CoV-2 and beyond.

Wastewater-based surveillance (WBS) has undergone dramatic advancement in the context of the coronavirus disease 2019 (COVID-19) pandemic. The power and potential of this platform technology were rapidly realized when it became evident that not only did WBS-measured SARS-CoV-2 RNA correlate strongly with COVID-19 clinical disease within monitored populations but also, in fact, it functioned as a leading indicator. Teams from across the globe rapidly innovated novel approaches by which wastewater could be collected from diverse sewersheds ranging from wastewater treatment plants (enabling community-level surveillance) to more granular locations including individual neighborhoods and high-risk buildings such as long-term care facilities (LTCF). Efficient processes enabled SARS-CoV-2 RNA extraction and concentration from the highly dilute wastewater matrix. Molecular and genomic tools to identify, quantify, and characterize SARS-CoV-2 and its various variants were adapted from clinical programs and applied to these mixed environmental systems. Novel data-sharing tools allowed this information to be mobilized and made immediately available to public health and government decision-makers and even the public, enabling evidence-informed decision-making based on local disease dynamics. WBS has since been recognized as a tool of transformative potential, providing near-real-time cost-effective, objective, comprehensive, and inclusive data on the changing prevalence of measured analytes across space and time in populations. However, as a consequence of rapid innovation from hundreds of teams simultaneously, tremendous heterogeneity currently exists in the SARS-CoV-2 WBS literature. This manuscript provides a state-of-the-art review of WBS as established with SARS-CoV-2 and details the current work underway expanding its scope to other infectious disease targets.

Household Transmission Dynamics of Asymptomatic SARS-CoV-2-Infected Children: A Multinational, Controlled Case-Ascertained Prospective Study.

BACKGROUND: Asymptomatic SARS-CoV-2 infection in children is highly prevalent but its acute and chronic implications have been minimally described. METHODS: In this controlled case-ascertained household transmission study, we recruited asymptomatic children <18 years with SARS-CoV-2 nucleic acid testing performed at 12 tertiary care pediatric institutions in Canada and the United States. We attempted to recruit all test-positive children and 1 to 3 test-negative, site-matched controls. After 14 days' follow-up we assessed the clinical (ie, symptomatic) and combined (ie, test-positive, or symptomatic) secondary attack rates (SARs) among household contacts. Additionally, post-COVID-19 condition (PCC) was assessed in SARS-CoV-2-positive participating children after 90 days' follow-up. RESULTS: A total of 111 test-positive and 256 SARS-CoV-2 test-negative asymptomatic children were enrolled between January 2021 and April 2022. After 14 days, excluding households with co-primary cases, the clinical SAR among household contacts of SARS-CoV-2-positive and -negative index children was 10.6% (19/179; 95% CI: 6.5%-16.1%) and 2.0% (13/663; 95% CI: 1.0%-3.3%), respectively (relative risk = 5.4; 95% CI: 2.7-10.7). In households with a SARS-CoV-2-positive index child, age <5 years, being pre-symptomatic (ie, developed symptoms after test), and testing positive during Omicron and Delta circulation periods (vs earlier) were associated with increased clinical and combined SARs among household contacts. Among 77 asymptomatic SARS-CoV-2-infected children with 90-day follow-up, 6 (7.8%; 95% CI: 2.9%-16.2%) reported PCC. CONCLUSIONS: Asymptomatic SARS-CoV-2-infected children, especially those <5 years, are important contributors to household transmission, with 1 in 10 exposed household contacts developing symptomatic illness within 14 days. Asymptomatic SARS-CoV-2-infected children may develop PCC.

Characterizing the Pain Experience of Children With Acute Gastroenteritis Based on Identified Pathogens.

OBJECTIVES: Pain is common with acute gastroenteritis (AGE) yet little is known about the severity associated with specific enteropathogens. We sought to explore the correlation of pain severity with specific enteropathogens in children with AGE. METHODS: Participants were prospectively recruited by the Alberta Provincial Pediatric EnTeric Infection TEam at 2 pediatric emergency departments (EDs) (December 2014-August 2018). Pain was measured (by child and/or caregiver) using the 11-point Verbal Numerical Rating Scale. RESULTS: We recruited 2686 participants; 46.8% (n = 1256) females, with median age 20.1 months (interquartile range 10.3, 45.3). The mean highest pain scores were 5.5 [standard deviation (SD) 3.0] and 4.2 (SD 2.9) in the 24 hours preceding the ED visit, and in the ED, respectively. Prior to ED visit, the mean highest pain scores with bacterial detection were 6.6 (SD 2.5), compared to 5.5 (SD 2.9) for single virus and 5.5 (SD 3.1) for negative stool tests. In the ED, the mean highest pain scores with bacterial detection were 5.5 (SD 2.7), compared to 4.1 (SD 2.9) for single virus and 4.2 (SD 3.0) for negative stool tests. Using multivariable modeling, factors associated with greater pain severity prior to ED visit included older age, fever, illness duration, number of diarrheal or vomiting episodes in the preceding 24 hours, and respiratory symptoms, but not enteropathogen type. CONCLUSION: Children with AGE experience significant pain, particularly when the episode is associated with the presence of a bacterial enteric pathogen. However, older age and fever appear to influence children's pain experiences more than etiologic pathogens.

Clinical Profiles of Childhood Astrovirus-, Sapovirus-, and Norovirus-Associated Acute Gastroenteritis in Pediatric Emergency Departments in Alberta, 2014-2018.

BACKGROUND: Infections by previously underdiagnosed viruses astrovirus and sapovirus are poorly characterized compared with norovirus, the most common cause of acute gastroenteritis. METHODS: Children <18 years old with acute gastroenteritis were recruited from pediatric emergency departments in Alberta, Canada between 2014 and 2018. We described and compared the clinical course of acute gastroenteritis in children with astrovirus, sapovirus, and norovirus. RESULTS: Astrovirus was detected in 56 of 2688 (2.1%) children, sapovirus was detected in 146 of 2688 (5.4%) children, and norovirus was detected in 486 of 2688 (18.1%) children. At illness onset, ~60% of astrovirus cases experienced both diarrhea and vomiting. Among sapovirus and norovirus cases, 35% experienced diarrhea at onset and 80% of 91% (sapovirus/norovirus) vomited; however, diarrhea became more prevalent than vomiting at approximately day 4 of illness. Over the full course of illness, diarrhea was 18% (95% confidence interval [CI], 8%- 29%) more prevalent among children with astrovirus than norovirus infections and had longer duration with greater maximal events; there were a median of 4.0 fewer maximal vomiting events (95% CI, 2.0-5.0). Vomiting continued for a median of 24.8 hours longer (95% CI, 9.6-31.7) among children with sapovirus versus norovirus. Differences between these viruses were otherwise minimal. CONCLUSIONS: Sapovirus infections attended in the emergency department are more similar to norovirus than previously reported, whereas astrovirus infections have several distinguishable characteristics.

Pathogen-Specific Effects of Probiotics in Children With Acute Gastroenteritis Seeking Emergency Care: A Randomized Trial.

BACKGROUND: It is unknown if probiotics exert pathogen-specific effects in children with diarrhea secondary to acute gastroenteritis. METHODS: Analysis of patient-level data from 2 multicenter randomized, placebo controlled trials conducted in pediatric emergency departments in Canada and the United States. Participants were 3-48 months with >3 diarrheal episodes in the preceding 24 hours and were symptomatic for <72 hours and <7 days in the Canadian and US studies, respectively. Participants received either placebo or a probiotic preparation (Canada-Lactobacillus rhamnosus R0011/Lactobacillus helveticus R0052; US-L. rhamnosus GG). The primary outcome was post-intervention moderate-to-severe disease (ie, ≥9 on the Modified Vesikari Scale [MVS] score). RESULTS: Pathogens were identified in specimens from 59.3% of children (928/1565). No pathogen groups were less likely to experience an MVS score ≥9 based on treatment allocation (test for interaction = 0.35). No differences between groups were identified for adenovirus (adjusted relative risk [aRR]: 1.42; 95% confidence interval [CI]: .62, 3.23), norovirus (aRR: 0.98; 95% CI: .56, 1.74), rotavirus (aRR: 0.86; 95% CI: .43, 1.71) or bacteria (aRR: 1.19; 95% CI: .41, 3.43). At pathogen-group and among individual pathogens there were no differences in diarrhea duration or the total number of diarrheal stools between treatment groups, regardless of intervention allocation or among probiotic sub-groups. Among adenovirus-infected children, those administered the L. rhamnosus R0011/L. helveticus R0052 product experienced fewer diarrheal episodes (aRR: 0.65; 95% CI: .47, .90). CONCLUSIONS: Neither probiotic product resulted in less severe disease compared to placebo across a range of the most common etiologic pathogens. The preponderance of evidence does not support the notion that there are pathogen specific benefits associated with probiotic use in children with acute gastroenteritis. CLINICAL TRIALS REGISTRATION: NCT01773967 and NCT01853124.

Attribution of Pediatric Acute Gastroenteritis Episodes and Emergency Department Visits to Norovirus Genogroups I and II.

BACKGROUND: Norovirus is a leading cause of acute gastroenteritis. With vaccines in development, population-based estimates of norovirus burden are needed to identify target populations, quantify potential benefits, and understand disease dynamics. METHODS: We estimated the attributable fraction (AF) for norovirus infections in children, defined as the proportion of children testing positive for norovirus whose gastroenteritis was attributable to norovirus. We calculated the standardized incidence and emergency department (ED) visit rates attributable to norovirus using provincial gastroenteritis visit administrative data. RESULTS: From 3731 gastroenteritis case patients and 2135 controls we determined that the AFs were 67.0% (95% confidence interval [CI], 31.5%-100%) and 91.6% (88.8%-94.4%) for norovirus genogroups I (GI) and II (GII), respectively. Norovirus GII AF varied by season but not age. We attributed 116 episodes (95% CI, 103-129) and 59 (51-67) ED visits per 10 000 child-years to norovirus GII across all ages, accounting for 20% and 18% of all medically attended gastroenteritis episodes and ED visits, respectively. CONCLUSIONS: In children, a large proportion of norovirus GII detections reflect causation, demonstrating significant potential for norovirus GII vaccines. Seasonal variation in the norovirus GII AF may have implications for understanding the role asymptomatic carriage plays in disease dynamics.

Microbial Etiologies and Clinical Characteristics of Children Seeking Emergency Department Care Due to Vomiting in the Absence of Diarrhea.

BACKGROUND: As children with isolated vomiting are rarely able to provide a specimen suitable for routine pathogen testing, we have limited knowledge about their infecting pathogens. METHODS: Between December 2014 and August 2018, children <18 years old with presumed acute gastroenteritis who presented to 2 emergency departments (EDs) in Alberta, Canada, were recruited. Eligible participants had ≥3 episodes of vomiting and/or diarrhea in a 24-hour period, <7 days of symptoms, and provided a rectal swab or stool specimen. We quantified the proportion of children with isolated vomiting in whom an enteropathogen was identified, and analyzed clinical characteristics, types of enteropathogens, resources used, and alternative diagnoses. RESULTS: Of the 2695 participants, at the ED visit, 295 (10.9%), 1321 (49.0%), and 1079 (40.0%) reported having isolated diarrhea, vomiting and diarrhea, or isolated vomiting, respectively. An enteropathogen was detected most commonly in those with vomiting and diarrhea (1067/1321; 80.8%); detection did not differ between those with isolated diarrhea (170/295; 57.6%) and isolated vomiting (589/1079; 54.6%) (95% confidence interval of the difference: -3.4%, 9.3%). Children with isolated vomiting most often had a virus (557/1077; 51.7%), most commonly norovirus (321/1077; 29.8%); 5.7% (62/1079) had a bacterial pathogen. X-rays, ultrasounds, and urine tests were most commonly performed in children with isolated vomiting. Alternate etiologies were most common in those with isolated vomiting (5.7%; 61/1079). CONCLUSIONS: The rate of enteropathogen identification in children with isolated vomiting using molecular diagnostic tests and rectal swabs is substantial. Molecular diagnostics offer an emerging diagnostic strategy in children with isolated vomiting.

Global Trends in Norovirus Genotype Distribution among Children with Acute Gastroenteritis.

Noroviruses are a leading cause of acute gastroenteritis (AGE) among adults and children worldwide. NoroSurv is a global network for norovirus strain surveillance among children <5 years of age with AGE. Participants in 16 countries across 6 continents used standardized protocols for dual typing (genotype and polymerase type) and uploaded 1,325 dual-typed sequences to the NoroSurv web portal during 2016-2020. More than 50% of submitted sequences were GII.4 Sydney[P16] or GII.4 Sydney[P31] strains. Other common strains included GII.2[P16], GII.3[P12], GII.6[P7], and GI.3[P3] viruses. In total, 22 genotypes and 36 dual types, including GII.3 and GII.20 viruses with rarely reported polymerase types, were detected, reflecting high strain diversity. Surveillance data captured in NoroSurv enables the monitoring of trends in norovirus strains associated childhood AGE throughout the world on a near real-time basis.

Multicenter Trial of a Combination Probiotic for Children with Gastroenteritis.

BACKGROUND: Gastroenteritis accounts for approximately 1.7 million visits to the emergency department (ED) by children in the United States every year. Data to determine whether the use of probiotics improves outcomes in these children are lacking. METHODS: We conducted a randomized, double-blind trial involving 886 children 3 to 48 months of age with gastroenteritis who presented to six pediatric EDs in Canada. Participants received a 5-day course of a combination probiotic product containing Lactobacillus rhamnosus R0011 and L. helveticus R0052, at a dose of 4.0×109 colony-forming units twice daily or placebo. The primary outcome was moderate-to-severe gastroenteritis, which was defined according to a post-enrollment modified Vesikari scale symptom score of 9 or higher (scores range from 0 to 20, with higher scores indicating more severe disease). Secondary outcomes included the duration of diarrhea and vomiting, the percentage of children who had unscheduled physician visits, and the presence or absence of adverse events. RESULTS: Moderate-to-severe gastroenteritis within 14 days after enrollment occurred in 108 of 414 participants (26.1%) who were assigned to probiotics and 102 of 413 participants (24.7%) who were assigned to placebo (odds ratio, 1.06; 95% confidence interval [CI], 0.77 to 1.46; P=0.72). After adjustment for trial site, age, detection of rotavirus in stool, and frequency of diarrhea and vomiting before enrollment, trial-group assignment did not predict moderate-to-severe gastroenteritis (odds ratio, 1.06; 95% CI, 0.76 to 1.49; P=0.74). There were no significant differences between the probiotic group and the placebo group in the median duration of diarrhea (52.5 hours [interquartile range, 18.3 to 95.8] and 55.5 hours [interquartile range, 20.2 to 102.3], respectively; P=0.31) or vomiting (17.7 hours [interquartile range, 0 to 58.6] and 18.7 hours [interquartile range, 0 to 51.6], P=0.18), the percentages of participants with unscheduled visits to a health care provider (30.2% and 26.6%; odds ratio, 1.19; 95% CI, 0.87 to 1.62; P=0.27), and the percentage of participants who reported an adverse event (34.8% and 38.7%; odds ratio, 0.83; 95% CI, 0.62 to 1.11; P=0.21). CONCLUSIONS: In children who presented to the emergency department with gastroenteritis, twice-daily administration of a combined L. rhamnosus-L. helveticus probiotic did not prevent the development of moderate-to-severe gastroenteritis within 14 days after enrollment. (Funded by the Canadian Institutes of Health Research and others; PROGUT ClinicalTrials.gov number, NCT01853124 .).

Comparison of approaches to quantify SARS-CoV-2 in wastewater using RT-qPCR: Results and implications from a collaborative inter-laboratory study in Canada.

Detection of SARS-CoV-2 RNA in wastewater is a promising tool for informing public health decisions during the COVID-19 pandemic. However, approaches for its analysis by use of reverse transcription quantitative polymerase chain reaction (RT-qPCR) are still far from standardized globally. To characterize inter- and intra-laboratory variability among results when using various methods deployed across Canada, aliquots from a real wastewater sample were spiked with surrogates of SARS-CoV-2 (gamma-radiation inactivated SARS-CoV-2 and human coronavirus strain 229E [HCoV-229E]) at low and high levels then provided "blind" to eight laboratories. Concentration estimates reported by individual laboratories were consistently within a 1.0-log10 range for aliquots of the same spiked condition. All laboratories distinguished between low- and high-spikes for both surrogates. As expected, greater variability was observed in the results amongst laboratories than within individual laboratories, but SARS-CoV-2 RNA concentration estimates for each spiked condition remained mostly within 1.0-log10 ranges. The no-spike wastewater aliquots provided yielded non-detects or trace levels (<20 gene copies/mL) of SARS-CoV-2 RNA. Detections appear linked to methods that included or focused on the solids fraction of the wastewater matrix and might represent in-situ SARS-CoV-2 to the wastewater sample. HCoV-229E RNA was not detected in the no-spike aliquots. Overall, all methods yielded comparable results at the conditions tested. Partitioning behavior of SARS-CoV-2 and spiked surrogates in wastewater should be considered to evaluate method effectiveness. A consistent method and laboratory to explore wastewater SARS-CoV-2 temporal trends for a given system, with appropriate quality control protocols and documented in adequate detail should succeed.

A Clinical Epidemiology and Molecular Attribution Evaluation of Adenoviruses in Pediatric Acute Gastroenteritis: a Case-Control Study.

The objective of this study was to characterize the etiological role of human adenovirus (HAdV) serotypes in pediatric gastroenteritis. Using a case-control design, we compared the frequencies of HAdV serotypes between children with ≥3 episodes of vomiting or diarrhea within 24 h and <7 days of symptoms (i.e., cases) and those with no infectious symptoms (i.e., controls). Stool samples and/or rectal swabs underwent molecular serotyping with cycle threshold (Ct) values provided by multiplex real-time reverse transcription-PCR testing. Cases without respiratory symptoms were analyzed to calculate the proportion of disease attributed to individual HAdV serotypes (i.e., attributable fraction). Between December 2014 and August 2018, adenoviruses were detected in 18.8% (629/3,347) of cases and 7.2% (97/1,355) of controls, a difference of 11.6% (95% confidence interval [CI], 9.6%, 13.5%). In 96% (95% CI, 92 to 98%) of HAdV F40/41 detections, the symptoms could be attributed to the identified serotype; when serotypes C1, C2, C5, and C6 were detected, they were responsible for symptoms in 52% (95% CI, 12 to 73%). Ct values were lower among cases than among controls (P < 0.001). HAdV F40/41, C2, and C1 accounted for 59.7% (279/467), 17.6% (82/467), and 12.0% (56/467) of all typed cases, respectively. Among cases, Ct values were lower for F40/41 serotypes than for non-F40/41 serotypes (P < 0.001). HAdV F40/41 serotypes account for the majority of HAdV-positive gastroenteritis cases, and when detected, disease is almost always attributed to infection with these pathogens. Non-F40/41 HAdV species have a higher frequency of asymptomatic infection and may not necessarily explain gastroenteritis symptoms. Real-time quantitative PCR may be useful in differentiating asymptomatic shedding from active infection.

Performance of Stool-testing Recommendations for Acute Gastroenteritis When Used to Identify Children With 9 Potential Bacterial Enteropathogens.

BACKGROUND: The ability to identify bacterial pathogens that necessitate specific clinical management or public health action in children with acute gastroenteritis is crucial to patient care and public health. However, existing stool-testing guidelines offer inconsistent recommendations, and their performance characteristics are unknown. We evaluated 6 leading gastroenteritis guidelines (eg, those of the Centers for Disease Control and Prevention and Infectious Disease Society of America) that recommend when to test children's stool for bacterial enteropathogens. METHODS: Via 2 emergency departments in Alberta, Canada, we enrolled 2447 children <18 years old who presented with ≥3 episodes of diarrhea and/or vomiting in a 24-hour period. All participants were tested for 9 bacterial enteropathogens: Aeromonas, Campylobacter, Escherichia coli O157, other Shiga toxin-producing E. coli, enterotoxigenic E. coli, Salmonella, Shigella, Vibrio, and Yersinia. Patient data gathered at the index visit were used to determine whether guidelines would recommend testing. Sensitivity and specificity to recommend testing for children with bacterial enteropathogens were calculated for each guideline. RESULTS: Outcome data were available for 2391 (97.7%) participants, and 6% (144/2391) of participants tested positive for a bacterial enteropathogen. Guideline sensitivity ranged from 25.8% (95% confidence interval [CI] 18.7-33.0%) to 66.9% (95% CI 59.3-74.6%), and varied for individual pathogens. Guideline specificity for all bacterial enteropathogens ranged from 63.6% (95% CI 61.6-65.6%) to 96.5% (95% CI 95.7-97.2%). CONCLUSIONS: No guideline provided optimally balanced performance. The most sensitive guidelines missed one-third of cases and would drastically increase testing volumes. The most specific guidelines missed almost 75% of cases.

Emergence of a Novel Recombinant Norovirus GII.P16-GII.12 Strain Causing Gastroenteritis, Alberta, Canada.

We identified a novel recombinant GII.P16-GII.12 norovirus associated with epidemic and endemic gastroenteritis during March 1, 2018-February 12, 2019, in Alberta, Canada. GII.12 viruses have not been detected in Alberta since 2000. Comparing the full genome of this strain to previously published sequences revealed this virus to be a novel recombinant strain.

Comparative Evaluation of Enteric Bacterial Culture and a Molecular Multiplex Syndromic Panel in Children with Acute Gastroenteritis.

Although enteric multianalyte syndromic panels are increasingly employed, direct comparisons with traditional methods and the inclusion of host phenotype correlations are limited. Luminex xTAG gastrointestinal pathogen panel (GPP) and culture results are highly concordant. However, phenotypic and microbiological confirmatory testing raises concerns regarding the accuracy of the GPP, especially for Salmonella spp. A total of 3,089 children with gastroenteritis submitted stool specimens, rectal swab specimens, and clinical data. The primary outcome was bacterial pathogen detection agreement for shared targets between culture and the Luminex xTAG GPP. Secondary analyses included phenotype assessment, additional testing of GPP-negative/culture-positive isolate suspensions with the GPP, and in-house and commercial confirmatory nucleic acid testing of GPP-positive/culture-negative extracts. The overall percent agreement between technologies was >99% for each pathogen. Salmonella spp. were detected in specimens from 64 participants: 12 (19%) by culture only, 9 (14%) by GPP only, and 43 (67%) by both techniques. Positive percent agreement for Salmonella spp. was 78.2% (95% confidence interval [CI], 64.6%, 87.8%). Isolate suspensions from the 12 participants with specimens GPP negative/culture positive for Salmonella tested positive by GPP. Specimens GPP positive/culture negative for Salmonella originated in younger children with less diarrhea and more vomiting. GPP-positive/culture-negative specimen extracts tested positive using additional assays for 0/2 Campylobacter-positive specimens, 0/4 Escherichia coli O157-positive specimens, 0/9 Salmonella-positive specimens, and 2/3 Shigella-positive specimens. For both rectal swab and stool samples, the median cycle threshold (CT ) values, determined using quantitative PCR, were higher for GPP-negative/culture-positive samples than for GPP-positive/culture-positive samples (for rectal swabs, 36.9 [interquartile range {IQR}, 33.7, 37.1] versus 30.0 [IQR, 26.2, 33.2], respectively [P = 0.002]; for stool samples, 36.9 [IQR, 33.7, 37.1] versus 29.0 [IQR, 24.8, 30.8], respectively [P = 0.001]). GPP and culture have excellent overall agreement; however, for specific pathogens, GPP is less sensitive than culture and, notably, identifies samples false positive for Salmonella spp.

Pigment Visibility on Rectal Swabs Used To Detect Enteropathogens: a Prospective Cohort Study.

Data are lacking regarding the impact of visible pigment on rectal swab diagnostic accuracy. We describe the test characteristics of rectal swabs with and without pigment in children with gastroenteritis. Between December 2014 and September 2017, children (age, <18 years) with ≥3 episodes of vomiting and/or diarrhea in a 24-h period and symptoms for <7 days were enrolled through two pediatric emergency departments and from a province-wide nursing telephone advice line in Alberta, Canada. Specimens were analyzed by employing nucleic acid amplification panels. The primary outcomes were the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for the rectal swabs, with stool specimen results being used as the reference standard. An enteropathogen was detected in 76.0% (1,399/1,841) of the paired specimens. A total of 54.4% (1,001/1841) of the swabs had visible pigment. The respective enteropathogen detection characteristics of swabs with and without visible pigment were as follows: 92.2% (95% confidence interval [CI], 90.0%, 94.0%) versus 83.7% (95% CI, 80.5%, 86.4%) for sensitivity, 94.3% (95% CI, 90.5%, 96.6%) versus 91.2% (95% CI, 86.3%, 94.5%) for specificity, 97.9% (95% CI, 96.4%, 98.8%) versus 96.5% (95% CI, 94.5%, 97.8%) for PPV, and 80.9% (95% CI, 76.0%, 85.1%) versus 65.8% (95% CI, 60.0%, 71.1%) for NPV. Processing of swabs without visible pigment would increase the rate of identification of positive swabs from 50.0% (682/1,365) to 88.3% (1,205/1,365). There is a modest decrease in the reliability of a negative test on swabs without evidence of pigment, but the overall yield is significantly greater when they are not excluded from testing. Hence, rectal swabs without visible feces should not be routinely rejected from testing.

A prospective comparative study of children with gastroenteritis: emergency department compared with symptomatic care at home.

Little is known about the epidemiology and severity of gastroenteritis among children treated at home. We sought to compare illness severity and etiology between children brought for emergency department (ED) care to those managed at home (i.e., community). Prospective cohort study of children enrolled between December 2014 and December 2016 in two pediatric EDs in Alberta, Canada along with children treated at home after telephone triage (i.e., community). Primary outcomes were maximal frequency of vomiting and diarrhea in the 24-h pre-enrollment period; secondary outcomes included etiologic pathogens, dehydration severity, future healthcare visits, and treatments provided. A total of 1613 patients (1317 ED, 296 community) were enrolled. Median maximal frequency of vomiting was higher in the ED cohort (5 (3, 10) vs. 5 (2, 8); P < 0.001). Proportion of children with diarrhea and its 24-h median frequency were lower in the ED cohort (61.3 vs. 82.8% and 2 (0, 6) vs. 4 (1, 7); P < 0.001, respectively). In regression analysis, the ED cohort had a higher maximum number of vomiting episodes pre-enrollment (incident rate ratio (IRR) 1.25; 95% CI 1.12, 1.40) while the community cohort had higher maximal 24-h period diarrheal episodes (IRR 1.20; 95% CI 1.01, 1.43). Norovirus was identified more frequently in the community cohort (36.8% vs. 23.6%; P < 0.001). Children treated in the ED have a greater number of vomiting episodes; those treated at home have more diarrheal episodes. Norovirus is more common among children treated symptomatically at home and thus may represent a greater burden of disease than previously thought.

Diagnostic Interpretation Guidance for Pediatric Enteric Pathogens: A Modified Delphi Consensus Process.

BACKGROUND: We sought to develop diagnostic test guidance definitions for pediatric enteric infections to facilitate the interpretation of positive test results in the era of multianalyte molecular diagnostic test platforms. METHODS: We employed a systematic, two-phase, modified Delphi consensus process consisting of three web-based surveys and an expert panel face-to-face meeting. In phase 1, we surveyed an advisory panel of North American experts to select pathogens requiring diagnostic test guidance definition development. In phase 2, we convened a 14-member expert panel to develop, refine, and select the final definitions through two web-based questionnaires interspersed with a face-to-face meeting. Both questionnaires asked panelists to rate the degree to which they agreed that if the definition is met the pathogen is likely to be causative of clinical illness. RESULTS: The advisory panel survey identified 19 pathogens requiring definitions. In the expert panel premeeting survey, 13 of the 19 definitions evaluated were rated as being highly likely ("agree" or "strongly agree") to be responsible for acute gastroenteritis symptoms by ≥67% of respondent panel members. The definitions for the remaining six pathogens (Aeromonas, Clostridium difficile, Edwardsiella, nonenteric adenovirus, astrovirus, and Entamoeba histolytica) were indeterminate. After the expert panel meeting, only two of the modified definitions, C. difficile and E. histolytica/dispar, failed to achieve the a priori specified threshold of ≥67% agreement. CONCLUSIONS: We developed diagnostic test guidance definitions to assist healthcare providers for 17 enteric pathogens. We identified two pathogens that require further research and definition development.

Physician perspectives on vaccination and diagnostic testing in children with gastroenteritis: A primary care physician survey.

OBJECTIVES: Gastroenteritis remains a common paediatric illness. Little is known about physician knowledge of enteric pathogen diagnostic tests. At the time of study conduct, Alberta lacked a publicly funded rotavirus vaccination program and knowledge of primary care physician perspectives was lacking. We sought to ascertain diagnostic testing methods and to understand knowledge and perceptions regarding enteric pathogen vaccination. METHODS: A 30-item electronic survey was distributed across Alberta's five health care zones. The survey was developed by virology, microbiology, paediatrics, family medicine and public health experts. Participants were members of Alberta's Primary Care Networks, the TARRANT network and The Society of General Pediatricians of Greater Edmonton. Study outcomes included: (1) physician knowledge of available diagnostic tests, (2) perspectives regarding stool sample collection and (3) support for an enteric vaccine program. RESULTS: Stool culture was reported as the test to identify parasites (47%), viruses (74%) and Clostridium difficile (67%). Although electron microscopy and enzyme immunoassay were used to identify viruses in Alberta during the study period, only 20% and 48% of respondents respectively identified them as tests employed for such purposes. Stool testing was viewed as being inconvenient (62%; 55/89), whereas rectal swabs were thought to have the potential to significantly improve specimen collection rates (82%; 72/88). Seventy-three per cent (66/90) of the respondent physicians support the adoption of future enteric pathogen vaccines. CONCLUSIONS: Simplification of diagnostic testing and stool sample collection could contribute to improved pathogen identification rates. Implementation of an enteric vaccine into the routine paediatric vaccination schedule is supported by the majority of respondents.

Shiga Toxin-Producing Escherichia coli Infection, Antibiotics, and Risk of Developing Hemolytic Uremic Syndrome: A Meta-analysis.

BACKGROUND: Antibiotic administration to individuals with Shiga toxin-producing Escherichia coli (STEC) infection remains controversial. We assessed if antibiotic administration to individuals with STEC infection is associated with development of hemolytic uremic syndrome (HUS). METHODS: The analysis included studies published up to 29 April 2015, that provided data from patients (1) with STEC infection, (2) who received antibiotics, (3) who developed HUS, and (4) for whom data reported timing of antibiotic administration in relation to HUS. Risk of bias was assessed; strength of evidence was adjudicated. HUS was the primary outcome. Secondary outcomes restricted the analysis to low-risk-of-bias studies employing commonly used HUS criteria. Pooled estimates of the odds ratio (OR) were obtained using random-effects models. RESULTS: Seventeen reports and 1896 patients met eligibility; 8 (47%) studies were retrospective, 5 (29%) were prospective cohort, 3 (18%) were case-control, and 1 was a trial. The pooled OR, including all studies, associating antibiotic administration and development of HUS was 1.33 (95% confidence interval [CI], .89-1.99; I(2) = 42%). The repeat analysis including only studies with a low risk of bias and those employing an appropriate definition of HUS yielded an OR of 2.24 (95% CI, 1.45-3.46; I(2) = 0%). CONCLUSIONS: Overall, use of antibiotics was not associated with an increased risk of developing HUS; however, after excluding studies at high risk of bias and those that did not employ an acceptable definition of HUS, there was a significant association. Consequently, the use of antibiotics in individuals with STEC infections is not recommended.

Alberta Provincial Pediatric EnTeric Infection TEam (APPETITE): epidemiology, emerging organisms, and economics.

BACKGROUND: Each year in Canada there are 5 million episodes of acute gastroenteritis (AGE) with up to 70% attributed to an unidentified pathogen. Moreover, 90% of individuals with AGE do not seek care when ill, thus, burden of disease estimates are limited by under-diagnosing and under-reporting. Further, little is known about the pathogens causing AGE as the majority of episodes are attributed to an "unidentified" etiology. Our team has two main objectives: 1) to improve health through enhanced enteric pathogen identification; 2) to develop economic models incorporating pathogen burden and societal preferences to inform enteric vaccine decision making. METHODS/DESIGN: This project involves multiple stages: 1) Molecular microbiology experts will participate in a modified Delphi process designed to define criteria to aid in interpreting positive molecular enteric pathogen test results. 2) Clinical data and specimens will be collected from children aged 0-18 years, with vomiting and/or diarrhea who seek medical care in emergency departments, primary care clinics and from those who contact a provincial medical advice line but who do not seek care. Samples to be collected will include stool, rectal swabs (N = 2), and an oral swab. Specimens will be tested employing 1) stool culture; 2) in-house multiplex (N = 5) viral polymerase chain reaction (PCR) panel; and 3) multi-target (N = 15) PCR commercially available array. All participants will have follow-up data collected 14 days later to enable calculation of a Modified Vesikari Scale score and a Burden of Disease Index. Specimens will also be collected from asymptomatic children during their well child vaccination visits to a provincial public health clinic. Following the completion of the initial phases, discrete choice experiments will be conducted to enable a better understanding of societal preferences for diagnostic testing and vaccine policy. All of the results obtained will be integrated into economic models. DISCUSSION: This study is collecting novel samples (e.g., oral swabs) from previously untested groups of children (e.g., those not seeking medical care) which are then undergoing extensive molecular testing to shed a new perspective on the epidemiology of AGE. The knowledge gained will provide the broadest understanding of the epidemiology of vomiting and diarrhea of children to date.