Judy Greig

A systematic review/meta-analysis of primary research investigating swine, pork or pork products as a source of zoonotic hepatitis E virus

The objectives of our study were to identify and categorize primary research investigating swine/pork as a source of zoonotic hepatitis E virus (HEV) using the relatively new technique of scoping study, and to investigate the potential association between human exposure to swine/pork and HEV infection quantitatively using systematic review/meta-analysis methodology. From 1890 initially identified abstracts, 327 were considered for the review. Five study design types (cross-sectional, prevalence, genotyping, case-report and experimental transmission studies) were identified. A significant association between occupational exposure to swine and human HEV IgG seropositivity was reported in 10/13 cross-sectional studies. The association reported between pork consumption and HEV IgG seropositivity was inconsistent. The quantification of viral load in swine and retail pork, viral load required for infection in primates, cohort and case-control studies in humans, and formal risk assessment are recommended before specific public-health policy actions are taken.

A review of nosocomial norovirus outbreaks: infection control interventions found effective

The purpose of this study was to review documented outbreaks of enteric illness associated with nosocomial norovirus infections and to identify modes of transmission, morbidity and mortality patterns, and recommendations for control. Searches of electronic databases, public health publications, and federal, state/provincial public health websites were completed for 1 January 2000 to 31 December 2010. Computer-aided searches of literature databases and systematic searches of government websites identified 54 relevant outbreak reports. Transmission routes included person-to-person (18.5%), foodborne (3.7%) and in the majority (77.8%) the route was unknown. Actions taken during the outbreak to control infection included restricting the movements of patients and staff (22.5%), enhanced environmental cleaning (13.6%) and hand hygiene (10.3%). Rapid identification of norovirus outbreaks in hospitals is vital for the immediate implementation of infection control measures and isolation of infected individuals in this mainly immunocompromised population. Studies that statistically evaluate infection control measures are needed.

A Review of Gastrointestinal Outbreaks in Schools: Effective Infection Control Interventions

BACKGROUND The purpose of this study was to review documented outbreaks of gastrointestinal illness in schools, published in the last 10 years, to identify etiology, mode of transmission, the number of children affected, morbidity and mortality patterns, and interventions for control and prevention. METHODS Searches of electronic databases, public health publications, and federal, state, and provincial public health Web sites were completed. RESULTS Of the 121 outbreaks that met the inclusion criteria, 51% were bacterial, 40% viral, 7% were from Cryptosporidium, and 2% from multiple organisms. Transmission routes recorded in 101 reports included foodborne (45%), person-to-person (16%), waterborne (12%), and animal contact (11%). Actions to control outbreaks included alerting medical and public health authorities or the community to the outbreak (13%), treating cases (12%), enhancing hand washing (11%), and increased vigilance during food preparation (8%). Recommendations to prevent future outbreaks were compared with previously published studies that demonstrated effectiveness. CONCLUSIONS The risk of foodborne illness was reduced when food handlers practiced effective hand washing technique and received food safety training and certification. Student training programs on hand hygiene, enhanced cleaning and disinfection of the school, and hepatitis A vaccination were found effective. Children should be supervised on farm visits, hand washing strictly enforced, and food eaten in an area separated from the animals. Staff and students should have a positive, continuous communication with public health authorities including educational sessions and immediate reporting of possible outbreaks.

The Effect of Hazard Analysis Critical Control Point Programs on Microbial Contamination of Carcasses in Abattoirs: A Systematic Review of Published Data

Hazard analysis critical control point (HACCP) programs have been endorsed and implemented globally to enhance food safety. Our objective was to identify, assess, and summarize or synthesize the published research investigating the effect of HACCP programs on microbial prevalence and concentration on food animal carcasses in abattoirs through primary processing. The results of microbial testing pre- and post-HACCP implementation were reported in only 19 studies, mostly investigating beef (n=13 studies) and pork (n=8 studies) carcasses. In 12 of 13 studies measuring aerobic bacterial counts, reductions were reported on beef (7/8 studies), pork (3/3), poultry (1/1), and sheep (1/1). Significant (p<0.05) reductions in prevalence of Salmonella spp. were reported in studies on pork (2/3 studies) and poultry carcasses (3/3); no significant reductions were reported on beef carcasses (0/8 studies). These trends were confirmed through meta-analysis of these data; however, powerful meta-analysis was precluded because of an overall scarcity of individual studies and significant heterogeneity across studies. Australia reported extensive national data spanning the period from 4 years prior to HACCP implementation to 4 years post-HACCP, indicating reduction in microbial prevalence and concentration on beef carcasses in abattoirs slaughtering beef for export; however, the effect of abattoir changes initiated independent of HACCP could not be excluded. More primary research and access to relevant proprietary data are needed to properly evaluate HACCP program effectiveness using modeling techniques capable of differentiating the effects of HACCP from other concurrent factors.

Prevalence of Zoonotic or Potentially Zoonotic Bacteria, Antimicrobial Resistance, and Somatic Cell Counts in Organic Dairy Production: Current Knowledge and Research Gaps

The reviews objective was to identify, evaluate, and summarize the findings of all primary research published in English or French, investigating prevalence of zoonotic or potentially zoonotic bacteria, bacterial resistance to antimicrobials, and somatic cell count (SCC) in organic dairy production, or comparing organic and conventional dairy production, using a systematic review methodology. Among 47 studies included in the review, 32 comparison studies were suitable for quality assessment. Fifteen studies were not assessed for quality, due to their descriptive nature or a low sample size (n <or= 2 farms). Overall, bacterial outcomes were reported in 17 studies, and prevalence of antimicrobial resistance (AMR) and multidrug resistance (MDR) of zoonotic or potentially zoonotic bacteria in 12 and 7 studies, respectively. Campylobacter spp., Escherichia coli including Shiga toxin-producing strains, Salmonella spp., Staphylococcus aureus, and SCC were investigated in 2, 7, 4, 6, and 15 studies, respectively. Contradictory findings were reported for differences in bacterial outcomes and SCC between dairy production types (organic vs. conventional). Lower prevalence of AMR on organic dairy farms was reported more consistently in studies conducted in the United States, as opposed to those conducted in Europe. These conflicting findings may result from geographic differences in organic production regulations governing antimicrobial usage, use of antimicrobials in conventional dairy production, and baseline prevalence, as well as laboratory methods, study designs, or methods of analysis employed. The majority (four of seven) of MDR investigations reported no significant differences in prevalence. Overall, only 9 of 32 studies met all five methodological soundness criteria. More well designed, executed, and reported primary research is needed at the farm and post-farm levels.

Scoping Review of the Zika Virus Literature

The global primary literature on Zika virus (ZIKV) (n = 233 studies and reports, up to March 1, 2016) has been compiled using a scoping review methodology to systematically identify and characterise the literature underpinning this broad topic using methods that are documented, updateable and reproducible. Our results indicate that more than half the primary literature on ZIKV has been published since 2011. The articles mainly covered three topic categories: epidemiology of ZIKV (surveillance and outbreak investigations) 56.6% (132/233), pathogenesis of ZIKV (case symptoms/ outcomes and diagnosis) 38.2% (89/233) and ZIKV studies (molecular characterisation and in vitro evaluation of the virus) 18.5% (43/233). There has been little reported in the primary literature on ZIKV vectors (12/233), surveillance for ZIKV (13/233), diagnostic tests (12/233) and transmission (10/233). Three papers reported on ZIKV prevention/control strategies, one investigated knowledge and attitudes of health professionals and two vector mapping studies were reported. The majority of studies used observational study designs, 89.7% (209/233), of which 62/233 were case studies or case series, while fewer (24/233) used experimental study designs. Several knowledge gaps were identified by this review with respect to ZIKV epidemiology, the importance of potential non-human primates and other hosts in the transmission cycle, the burden of disease in humans, and complications related to human infection with ZIKV. Historically there has been little research on ZIKV; however, given its current spread through Australasia and the Americas, research resources are now being allocated to close many of the knowledge gaps identified in this scoping review. Future updates of this project will probably demonstrate enhanced evidence and understanding of ZIKV and its impact on public health.

A Scoping Review of the Role of Wildlife in the Transmission of Bacterial Pathogens and Antimicrobial Resistance to the Food Chain

Wildlife can contribute to environmental contamination with bacterial pathogens and their transfer to the human food chain. Global usage and frequent misuse of antimicrobials contribute to emergence of new antimicrobial resistant (AMR) strains of foodborne pathogens. We conducted a scoping review of published research to identify and characterize the evidence on wildlifes role in transmission of AMR and/or bacterial pathogens to the food chain. An advisory group (AG) of 13 North American experts from diverse disciplines was surveyed to solicit insight in the review scope, priority topics and research characteristics. A pre‐tested search strategy was implemented in seven bibliographic databases (1990 to January 2013). Citations were relevance screened, and key characteristics on priority topics extracted independently by two reviewers. Analysis identified topic areas with solid evidence and main knowledge gaps. North America reported 30% of 866 relevant articles. The prevalence of five targeted bacterial pathogens and/or AMR in any pathogen in wildlife was reported in 582 articles. Transmission risk factors for selected bacteria or AMR in any bacteria were reported in 300. Interventions to control transmission were discussed in 124 articles and formally evaluated in 50. The majority of primary research investigated birds, cervids, rodents, feral pigs, opossums, E. coli (n = 329), Salmonella (n = 293) and Campylobacter (n = 124). An association between wildlife and transmission of bacterial pathogens and/or AMR to the food chain was supported in 122 studies. The scoping review identified a significant body of research on the role of wild birds in the prevalence and transmission of E. coli, Salmonella and Campylobacter. There was little research employing molecular methods contributing to the evidence concerning the importance and direction of transmission of wildlife/pathogen combinations. Given the advancements of these methods, future research should focus in this area to help prioritize future intervention studies and risk mitigation strategies.

Prevalence of Zoonotic Bacteria in Wild and Farmed Aquatic Species and Seafood: A Scoping Study, Systematic Review, and Meta-analysis of Published Research

Increased reliance on seafood has brought to light concerns regarding food safety, but the information to inform risk assessment or surveillance needs is lacking. A scoping study (ScS) was conducted to characterize published research investigating selected zoonotic bacteria and public health topics in various wild and farmed aquatic species and seafood. This was followed by a systematic review (SR) on selected bacteria (Aeromonas spp., generic Escherichia coli, Salmonella spp., and Vibrio spp.) and aquatic species (clams, mussels, oysters, salmon, and shrimp [including prawn]); a meta-analysis (MA) was conducted only at the retail level due to considerable variability among various pathogen/seafood combinations. The ScS revealed the most frequently investigated themes were farm-level prevalence and intervention research for Vibrio spp. and Aeromonas spp. Antimicrobial use (AMU) and the association between AMU and antimicrobial resistance were rarely investigated. The SR indicated a consistent lack of reporting regarding study methodology and results, precluding the use of many studies in and full benefits of MA. MA of Aeromonas, E. coli, and Salmonella prevalence in retail salmon resulted in pooled estimates of 13% (6-27%), 2% (0.1-11%), and 1% (0-5%), respectively. When MA of pathogen/seafood combination resulted in statistically significant heterogeneity (p<0.1), median/range were reported at the region level. The results from our ScS, SR, and MA could be used for better design of future bacteriological surveys of seafood and as inputs for risk assessments or surveillance initiatives in this field.

A review of nosocomial Salmonella outbreaks: infection control interventions found effective

OBJECTIVE To review nosocomial salmonellosis outbreaks to identify: mode of transmission; morbidity and mortality patterns; and recommendations for control and prevention. DESIGN Documented nosocomial salmonellosis outbreaks in hospitals published from January 1995 to November 2011, written in the English language, were systematically reviewed. METHODS The study methodology incorporated steps from the PRISMA statement for a high quality review process. Computer-aided searches of Scopus, CAB Global Health and CINAHL(®), the Cumulative Index to Nursing and Allied Health Literature were completed to identify relevant outbreak reports written in English. To validate the electronic search methodology, bibliographies and reference lists of relevant review articles were hand-searched. Public health and government websites were searched for nosocomial salmonellosis. RESULTS Fifty-two relevant reports were identified. The most frequently reported routes of transmission were food 31/52 (59.6%) and person-to-person transmission 7/52 (13.5%). Actions taken during the outbreak to control transmission included improvements to: 1) infection control practices (41.8% of actions); isolation or cohorting patients, hand hygiene practices, and enhancing cleaning and disinfection in patient care areas; and 2) food handling practices (24.4% of actions); reviewing food preparation practices, enhancing cleaning and sanitation of the kitchen, and controlling food temperatures. Investigators made recommendations retrospectively in outbreak reports to provide direction to health centees but these recommendations were not statistically evaluated for effectiveness. CONCLUSIONS More emphasis should be placed on improving food handling practices, such as training food workers, monitoring food temperatures, and not using raw foods of animal origin, to prevent nosocomial salmonellosis outbreaks in hospitals because almost 60% of the outbreaks were foodborne.

The Accuracy of Diagnostic Tests for Lyme Disease in Humans, A Systematic Review and Meta-Analysis of North American Research.

There has been an increasing incidence of Lyme disease (LD) in Canada and the United States corresponding to the expanding range of the Ixodes tick vector and Lyme disease agent (Borrelia burgdorferi sensu stricto). There are many diagnostic tests for LD available in North America, all of which have some performance issues, and physicians are concerned about the appropriate use and interpretation of these tests. The objective of this systematic review is to summarize the North American evidence on the accuracy of diagnostic tests and test regimes at various stages of LD. Included in the review are 48 studies on diagnostic tests used in North America published since 1995. Thirteen studies examined a two-tier serological test protocol vs. clinical diagnosis, 24 studies examined single assays vs. clinical diagnosis, 9 studies examined single immunoblot vs. clinical diagnosis, 7 studies compared culture or PCR direct detection methods vs. clinical diagnosis, 22 studies compared two or more tests with each other and 8 studies compared a two-tiered serological test protocol to another test. Recent studies examining the sensitivity and specificity of various test protocols noted that the Immunetics® C6 B. burgdorferi ELISA™ and the two tier approach have superior specificity compared to proposed replacements, and the CDC recommended western blot algorithm has equivalent or superior specificity over other proposed test algorithms. There is a dramatic increase in test sensitivity with progression of B. burgdorferi infection from early to late LD. Direct detection methods, culture and PCR of tissue or blood samples were not as sensitive or timely compared to serological testing. It was also noted that there are a large number of both commercial (n = 42) and in-house developed tests used by private laboratories which have not been evaluated in the primary literature.