Influenza A virus vaccine research conducted in swine from 1990 to May 2018: A scoping review

BACKGROUND

Influenza A viruses of swine (IAV-S) are a global zoonotic and economic concern. Primary control is through vaccination yet a formal evidence map summarizing vaccine research conducted in pigs is not available.

OBJECTIVE

Ten characteristics of English language primary IAV-S vaccine research, conducted at the level of the pig or higher, were charted to identify research gaps, topics for systematic review, and coverage across different publication types.

DESIGN

Six online databases and grey literature were searched, without geographic, population, or study type restrictions, and abstracts screened independently and in duplicate for relevant research published between 1990 and May 2018. Full text data was charted by a single reviewer.

RESULTS

Over 11,000 unique citations were screened, identifying 376 for charting, including 175 proceedings from 60 conferences, and 170 journal articles from 51 journals. Reported outcomes were heterogeneous with measures of immunity (86%, n = 323) and virus detection (65%, n = 246) reported far more than production metrics (9%, n = 32). Study of transmissibility under conditions of natural exposure (n = 7), use of mathematical modelling (n = 11), and autogenous vaccine research reported in journals (n = 7), was limited.

CONCLUSIONS

Most research used challenge trials (n = 219) and may have poor field relevance or suitability for systematic review if the purpose is to inform clinical decisions. Literature on vaccinated breeding herds (n = 89) and weaned pigs (n = 136) is potentially sufficient for systematic review. Research under field conditions is limited, disproportionately reported in conference proceedings versus journal articles, and may be insufficient to support systematic review.

How to Conduct a Bayesian Network Meta-Analysis

Network meta-analysis is a general approach to integrate the results of multiple studies in which multiple treatments are compared, often in a pairwise manner. In this tutorial, we illustrate the procedures for conducting a network meta-analysis for binary outcomes data in the Bayesian framework using example data. Our goal is to describe the workflow of such an analysis and to explain how to generate informative results such as ranking plots and treatment risk posterior distribution plots. The R code used to conduct a network meta-analysis in the Bayesian setting is provided at GitHub.

Ouch! A cross-sectional study investigating self-reported human exposure to dog bites in rural and urban households in southern Ontario, Canada

This study investigated self-reported dog bites in humans in rural and urban households in southern Ontario, Canada. Our objectives were to determine, and compare, the incidence of dog bites in rural and urban households, and to describe the profile of bite victims, biting dogs, and the proportion of biting dogs that respondents self-reported as being not up to date on rabies vaccination. We conducted a cross-sectional observational study using an online questionnaire. The 2,006 respondents, each representing one household, included 1,002 rural and 1,004 urban residences. The incidence risk of at least one person in the household being bitten over the previous year in rural households (6.09% per year) was less than in urban households (10.76% per year). In 53.20% of households from which at least one person had been bitten within the past year, only a single person had been bitten. Mostly, victims were 25 to 34 years old (21.67%), male (54.19%), and playing with or interacting with the biting dog at the time of the incident (59.11%). Most biting dogs were 3 to 5 years old (32.02%), males (53.69%), and unleashed (76.85%). Based on self-reporting by respondents, 83.33% of respondent-owned biting dogs were vaccinated against rabies at the time of the biting incident. Irrespective of dog ownership, the odds of an individual in a rural household being bitten by a dog were 0.53 (95% CI: 0.38-0.73) the odds for an individual in an urban household. Dog bites constitute a serious, yet preventable, public health concern that requires targeted, community-specific efforts. Public health organizations could consider findings in developing messaging, particularly as we highlight biting dogs reported by their owners as not up to date on rabies vaccination.

Identifying the environmental drivers of Campylobacter infection risk in southern Ontario, Canada using a One Health approachs

BACKGROUND

Campylobacter bacteria infect both humans and animals. Sources of human exposure include contaminated food and water, contact with animals and/or their faeces, and contact with infected individuals. The objectives of this study were to: (a) identify environmental conditions associated with the occurrence of Campylobacter in humans in four regions of Ontario, and (b) identify pooled measures of effect across all four regions and potential sources of heterogeneity.

METHODS

To address objective 1, human Campylobacter cases from four health regions of Ontario, Canada were analysed using negative binomial regression and case cross-over analysis to identify relationships between environmental factors (temperature, precipitation and hydrology of the local watershed) and the risk of human infection. To address objective 2, meta-analytic models were used to explore pooled measures of effect and when appropriate, meta-regression models were used to explore potential sources of heterogeneity.

RESULTS

Human incidence exhibited strong seasonality with cases peaking in the late spring and summer. There was a decreasing yearly effect in three of the four health regions. A significant pooled effect was found for mean temperature after a 1-week lag (OR = 1.03, 95% CI 1.02, 1.04). No significant pooled effects were found for precipitation or water flow. However, increased precipitation was associated with lower odds of campylobacteriosis in Wellington and York regions at 2- and 3-week lags, respectively, from the case cross-over analysis.

CONCLUSION

These results demonstrate that a climatic factor (specifically, mean temperature in the week prior) was associated with human case occurrence after a biologically plausible time period, but hydrologic factors are not.

Examining the Effect of Host Recruitment Rates on the Transmission of Streptococcus suis in Nursery Swine Populations

Streptococcus suis is a swine pathogen that is capable of causing severe outbreaks of disease in the nursery. Demographic parameters such as host recruitment rates can have profound effects on the transmission dynamics of infectious diseases and, thus, are critically important in high-turnover populations such as farmed swine. However, knowledge concerning the implications that such parameters have on S. suis disease control remains unknown. A stochastic mathematical model incorporating sub-clinically infected pigs was developed to capture the effects of changes in host recruitment rate on disease incidence. Compared to our base model scenario, our results show that monthly introduction of pigs into the nursery (instead of weekly introduction) reduced cumulative cases of S. suis by up to 59%, while increasing disease-removal rates alone averted up to 64% of cases. Sensitivity analysis demonstrated that the course of infection in sub-clinically infected pigs was highly influential and generated significant variability in the model outcomes. Our model findings suggest that modifications to host recruitment rates could be leveraged as a tool for S. suis disease control, however improving our understanding of additional factors that influence the risk of transmission would improve the precision of the model estimates.

Cryptosporidium and Giardia in locally harvested clams in Iqaluit, Nunavut

High prevalences of Cryptosporidium and Giardia were recently found in enteric illness patients in the Qikiqtaaluk region of Nunavut, Canada, with a foodborne, waterborne or animal source of parasites suspected. Clams (Mya truncata) are a commonly consumed, culturally important and nutritious country food in Iqaluit; however, shellfish may concentrate protozoan pathogens from contaminated waters. The goal of this work was to investigate clams as a potential source of Cryptosporidium and Giardia infections in residents in Iqaluit, Nunavut. The objectives were to estimate the prevalence and genetically characterize Cryptosporidium and Giardia in locally harvested clams. Clams (n = 404) were collected from Iqaluit harvesters in September 2016. Haemolymph (n = 328) and digestive gland (n = 390) samples were screened for Cryptosporidium and Giardia via PCR, and amplified products were further processed for sequence analyses for definitive confirmation. Giardia DNA was found in haemolymph from 2 clams, while Cryptosporidium was not detected. The two Giardia sequences were identified as zoonotic Giardia enterica assemblage B. The overall prevalence of Giardia in clams near Iqaluit was low (0.6%) compared with other studies in southern Canada and elsewhere. The presence of Giardia DNA in clams suggests human or animal faecal contamination of coastal habitat around Iqaluit in shellfish harvesting waters. Results from this study are intended to inform public health practice and planning in Inuit Nunangat.

Scoping Reviews, Systematic Reviews, and Meta-Analysis: Applications in Veterinary Medicine

Evidence-based decision making is a hallmark of effective veterinary clinical practice. Scoping reviews, systematic reviews, and meta-analyses all are methods intended to provide transparent and replicable ways of summarizing a body of research to address an important clinical or public health issue. As these methods increasingly are being used by researchers and read by practitioners, it is important to understand the distinction between these techniques and to understand what research questions they can, and cannot, address. This review provides an overview of scoping reviews, systematic reviews, and meta-analysis, including a discussion of the method and uses. A sample dataset and coding to conduct a simple meta-analysis in the statistical program R also are provided. Scoping reviews are a descriptive approach, designed to chart the literature around a particular topic. The approach involves an extensive literature search, following by a structured mapping, or charting, of the literature. The results of scoping reviews can help to inform future research by identifying gaps in the existing literature and also can be used to identify areas where there may be a sufficient depth of literature to warrant a systematic review. Systematic reviews are intended to address a specific question by identifying and summarizing all of the available research that has addressed the review question. Questions types that can be addressed by a systematic review include prevalence/incidence questions, and questions related to etiology, intervention efficacy, and diagnostic test accuracy. The systematic review process follows structured steps with multiple reviewers working in parallel to reduce the potential for bias. An extensive literature search is undertaken and, for each relevant study identified by the search, a formal extraction of data, including the effect size, and assessment of the risk of bias is performed. The results from multiple studies can be combined using meta-analysis. Meta-analysis provides a summary effect size, and allows heterogeneity of effect among studies to be quantified and explored. These evidence synthesis approaches can provide scientific input to evidence-based clinical decision-making for veterinarians and regulatory bodies, and also can be useful for identifying gaps in the literature to enhance the efficiency of future research in a topic area.

Prevalence and genetic characterization of Giardia spp. and Cryptosporidium spp. in dogs in Iqaluit, Nunavut, Canada

There are few epidemiologic studies on the role of dogs in zoonotic parasitic transmission in the Circumpolar North. The objectives of this study were to: (a) estimate the faecal prevalence of Giardia spp. and Cryptosporidium spp. in dogs; (b) investigate potential associations between the type of dog population and the faecal presence of Giardia spp. and Cryptosporidium spp.; and (c) describe the molecular characteristics of Giardia spp. and Cryptosporidium spp. in dogs in Iqaluit, Nunavut. We conducted two cross-sectional studies in July and September 2016. In July, the team collected daily faecal samples for 3 days from each of 20 sled dogs. In September, the team collected three faecal samples from each of 59 sled dogs, 111 samples from shelter dogs and 104 from community dogs. We analysed faecal samples for the presence of Giardia spp. and Cryptosporidium spp. using rapid immunoassay and flotation techniques. Polymerase chain reaction (PCR) and sequencing of target genes were performed on positive faecal samples. Overall, the faecal prevalence of at least one of the target parasites, when one faecal sample was chosen at random for all dogs, was 8.16% (CI: 5.52-11.92), and for Giardia spp. and Cryptosporidium spp., prevalence was 4.42% (CI: 2.58-7.49) and 6.12% (CI: 3.88-9.53), respectively. The odds of faecal Giardia spp. in sled dogs were significantly higher than those in shelter and community dogs (OR 10.19 [CI: 1.16-89.35]). Sequence analysis revealed that 6 faecal samples were Giardia intestinalis, zoonotic assemblage B (n = 2) and species-specific assemblages D (n = 3) and E (n = 1), and five faecal samples were Cryptosporidium canis. Giardia intestinalis is zoonotic; however, Cryptosporidium canis is rare in humans and, when present, usually occurs in immunosuppressed individuals. Dogs may be a potential source of zoonotic Giardia intestinalis assemblage B infections in residents in Iqaluit, Nunavut, Canada; however, the direction of transmission is unclear.

A survey of veterinary student attitudes concerning whether marijuana could have therapeutic value for animals

Marijuana is increasingly recognized for its therapeutic value in human medicine. Although most veterinary research to date has been concerned with marijuana toxicity, there is some interest in the potential therapeutic value of marijuana in veterinary medicine. With the recent legalization of marijuana for recreational use in Canada in October 2018, there is a need for veterinarians and veterinary students to be in a position to address client questions and concerns on this topic. We distributed a questionnaire to current veterinary students at the Ontario Veterinary College in Guelph, Ontario, to determine their attitude(s) towards marijuana as a potential therapeutic agent in animals. The overall response rate for the questionnaire was 43.5% (207/476). Most students felt that marijuana has potential therapeutic value in animals (53.6%; 111/207), fewer were unsure (38.6%; 80/207), and a small number of students felt that marijuana does not have potential therapeutic value in animals (7.7%; 16/207). Data generated by this questionnaire identified an important distinction between two major active compounds found in marijuana: cannabidiol (CBD) and tetrahydrocannabinol (THC). Potential barriers to use in veterinary practice were also identified, including stigma and toxicity. Finally, many respondents showed an awareness of the limited scientific research regarding the safety and efficacy of marijuana in animals. Until a body of scientific literature on marijuana in animals becomes available, veterinarians may benefit from having an awareness of the different physiological and pharmacokinetic effects produced by different strains (including any adverse effects, and half-life), and a general understanding of current therapeutic applications of marijuana in humans.

Invited review: Completeness of reporting of experiments: REFLECTing on a year of animal trials in the Journal of Dairy Science

Reproducibility is an essential element of the scientific process, and it requires clear and complete reporting of study design, conduct, and analysis. In the human and animal health literature, incomplete reporting is associated with biased effect estimates. Moreover, incomplete reporting precludes knowledge synthesis and undervalues the resources allocated to the primary research. The Reporting Guidelines for Randomized Controlled Trials for Livestock and Food Safety (REFLECT) statement, published in 2010, is a checklist developed by expert consensus to provide guidance on what study elements should be reported in any intervention trial (designed experiment) involving livestock. The Journal of Dairy Science (JDS) has recently endorsed the use of reporting guidelines. To assess the status of reporting of controlled experiments in JDS and to provide a baseline for future comparison, we evaluated the reporting of 18 items from the REFLECT statement checklist in a sample of 137 controlled trials published in JDS in 2017. Two reviewers independently screened titles and abstracts for relevance and then evaluated a sample of 120 papers reporting controlled trials (experimental studies involving at least one intervention and one comparison or control group), using yes or no questions. Although some items, such as treatment details and statistical analysis, were well reported, other areas, including sample size justification, allocation concealment, blinding, study flow, baseline data, and ancillary analyses, were often not reported or were incompletely described. This work highlights the need for authors and reviewers to take advantage of guidelines and checklists for reporting. Adherence to reporting guidelines can help improve the completeness of reporting of research, expedite and better inform the peer-review process, increase clarity for the reader, and allow for knowledge synthesis, such as meta-analysis, all of which serve to increase the value of the work conducted.

The Influence of Climate and Livestock Reservoirs on Human Cases of Giardiasis

Giardia duodenalis is an intestinal parasite which causes diarrhoeal illness in people. Zoonotic subtypes found in livestock may contribute to human disease occurrence through runoff of manure into multi-use surface water. This study investigated temporal associations among selected environmental variables and G. duodenalis occurrence in livestock reservoirs on human giardiasis incidence using data collected in the Waterloo Health Region, Ontario, Canada. The study objectives were to: (1) evaluate associations between human cases and environmental variables between 1 June 2006 and 31 December 2013, and (2) evaluate associations between human cases, environmental variables and livestock reservoirs using a subset of this time series, with both analyses controlling for seasonal and long-term trends. Human disease incidence exhibited a seasonal trend but no annual trend. A Poisson multivariable regression model identified an inverse association with water level lagged by 1 month (IRR = 0.10, 95% CI 0.01, 0.85, P < 0.05). Case crossover analysis found varying associations between lagged variables including livestock reservoirs (1 week), mean air temperature (3 weeks), river water level (1 week) and flow rate (1 week), and precipitation (4 weeks). This study contributes to our understanding of epidemiologic relationships influencing human giardiasis cases in Ontario, Canada.

Modelling the transmission dynamics of Campylobacter in Ontario, Canada, assuming house flies, Musca domestica, are a mechanical vector of disease transmission

Campylobacter's complicated dynamics and multiple transmission routes have made it difficult to describe using a mathematical framework. Vector-borne disease transmission has been proposed as a potential transmission route of Campylobacter with house flies acting as a mechanical vector. This study aimed to (i) determine if a basic SIR compartment model that included flies as a mechanical vector and incorporated a seasonally forced environment compartment could be used to capture the observed disease dynamics in Ontario, Canada, and (ii) use this model to determine potential changes to campylobacteriosis incidence using predicted changes to fly population size and fly activity under multiple climate change scenarios. The model was fit to 1 year of data and validated against 8 and 12 years of data. It accurately captured the observed incidence. We then explored changes in human disease incidence under multiple climate change scenarios. When fly activity levels were at a 25% increase, our model predicted a 28.15% increase in incidence by 2050 using the medium-low emissions scenario and 30.20% increase using the high emissions scenario. This model demonstrates that the dynamics of Campylobacter transmission can be captured by a model that assumes that the primary transmission of the pathogen occurs via insect vectors.

Prevalence of Listeria monocytogenes in Select Ready-to-Eat Foods-Deli Meat, Soft Cheese, and Packaged Salad: A Systematic Review and Meta-Analysis

Listeria monocytogenes is the cause of listeriosis, an important foodborne disease. Contaminated ready-to-eat foods are common sources of L. monocytogenes, yet no global estimates exist for prevalence and levels in high-risk ready-to-eat foods. Our objective was to estimate the prevalence and levels of L. monocytogenes in deli meat, soft cheese, and packaged salad. We searched Medline, Web of Science, Agricola, Conference Proceedings Citation Index-Science, Science.gov, ScienceResearch.com , and OpenGREY for studies on L. monocytogenes prevalence and/or levels, with no restriction on publication date. We used a priori study selection, data extraction, and risk of biases processes. Results were synthesized with random-effects meta-analyses and meta-regressions to evaluate heterogeneity between studies. We included in the review 100 studies with a sample size restriction of ≥100, and we estimated L. monocytogenes prevalence in deli meat at 2.9% (95% confidence interval [CI], 2.3 to 3.6%), in soft cheese at 2.4% (95% CI, 1.6 to 3.6%), and in packaged salad at 2.0% (95% CI, 1.2 to 3.1%). High heterogeneity was present in all food groups, and meta-regressions did not reveal consistent explanations for heterogeneity. Pathogen level was not reported consistently or in the format required for synthesis, so meta-analyses of this variable were not performed. The high heterogeneity between studies indicates that use of global summary prevalence estimates for risk assessments are not advisable, but awareness of risk and the heterogeneity of the risk is relevant for education and further risk assessment.

Weather, environmental conditions, and waterborne Giardia and Cryptosporidium in Iqaluit, Nunavut

Indigenous communities in the Arctic often face unique drinking water quality challenges related to inadequate infrastructure and environmental contamination; however, limited research exists on waterborne parasites in these communities. This study examined Giardia and Cryptosporidium in untreated surface water used for drinking in Iqaluit, Canada. Water samples (n = 55) were collected weekly from June to September 2016 and tested for the presence of Giardia and Cryptosporidium using microscopy and polymerase chain reaction (PCR). Exact logistic regressions were used to examine associations between parasite presence and environmental exposure variables. Using microscopy, 20.0% of samples tested positive for Giardia (n = 11) and 1.8% of samples tested positive for Cryptosporidium (n = 1). Low water temperatures (1.1 to 6.7 °C) and low air temperatures (-0.1 to 4.5 °C) were significantly associated with an increased odds of parasite presence (p = 0.047, p = 0.041, respectively). These results suggest that surface water contamination with Giardia and Cryptosporidium may be lower in Iqaluit than in other Canadian regions; however, further research should examine the molecular characterization of waterborne parasites to evaluate the potential human health implications in Northern Canada.

Efficacy of Borrelia burgdorferi vaccine in dogs in North America: A systematic review and meta-analysis

BACKGROUND

Lyme borreliosis, a tick-borne disease, is endemic to some parts of North America and is an emerging disease in other parts of the world. Vaccination is an increasingly common, although controversial, method used in the prevention of Lyme disease in dogs; the reported efficacies of Borrelia burgdorferi vaccines in dogs are highly variable, ranging from 50% to 100%.

OBJECTIVES

To determine the efficacy of vaccines for prevention of Lyme disease in dogs in North America.

METHODS

Experimental and observational study designs were eligible for inclusion. The outcome of interest was the reduction of incidence of clinical illness after exposure to B. burgdorferi. Electronic databases searched were MEDLINE, Web of Science, and Centre for Agricultural Biosciences Abstracts. Clinical signs were extracted as dichotomous outcomes: lameness, anorexia, pyrexia, depression, and lymphadenopathy. Study quality was assessed using tools from the Cochrane collaboration.

RESULTS

In total, 3 observational studies and 13 challenge trials were included. None of the challenge trials assessed lymphadenopathy, but for each of the remaining 4 clinical signs, a meta-analysis was performed. Compared to unvaccinated dogs, vaccinated dogs had a reduced odds of developing lameness, depression, pyrexia, and anorexia (odds ratio: 0.15-0.23).

CONCLUSIONS AND CLINICAL IMPORTANCE

Based on the quantitative synthesis of results from challenge studies, vaccinated dogs are less likely to develop clinical signs after exposure to B. burgdorferi compared to unvaccinated dogs. These results should be interpreted with caution, however, as several shortcomings related to quality and study design were identified. Future studies should focus on larger sample sizes in field conditions.

Water quality and health in northern Canada: stored drinking water and acute gastrointestinal illness in Labrador Inuit

One of the highest self-reported incidence rates of acute gastrointestinal illness (AGI) in the global peer-reviewed literature occurs in Inuit communities in the Canadian Arctic. This high incidence of illness could be due, in part, to the consumption of contaminated water, as many northern communities face challenges related to the quality of municipal drinking water. Furthermore, many Inuit store drinking water in containers in the home, which could increase the risk of contamination between source and point-of-use (i.e., water recontamination during storage). To examine this risk, this research characterized drinking water collection and storage practices, identified potential risk factors for water contamination between source and point-of-use, and examined possible associations between drinking water contamination and self-reported AGI in the Inuit community of Rigolet, Canada. The study included a cross-sectional census survey that captured data on types of drinking water used, household practices related to drinking water (e.g., how it was collected and stored), physical characteristics of water storage containers, and self-reported AGI. Additionally, water samples were collected from all identified drinking water containers in homes and analyzed for presence of Escherichia coli and total coliforms. Despite municipally treated tap water being available in all homes, 77.6% of households had alternative sources of drinking water stored in containers, and of these containers, 25.2% tested positive for total coliforms. The use of transfer devices and water dippers (i.e., smaller bowls or measuring cups) for the collection and retrieval of water from containers were both significantly associated with increased odds of total coliform presence in stored water (OR_{transfer device} = 3.4, 95% CI 1.2-11.7; OR_dipper = 13.4, 95% CI 3.8-47.1). Twenty-eight-day period prevalence of self-reported AGI during the month before the survey was 17.2% (95% CI 13.0-22.5), which yielded an annual incidence rate of 2.4 cases per person per year (95% CI 1.8-3.1); no water-related risk factors were significantly associated with AGI. Considering the high prevalence of, and risk factors associated with, indicator bacteria in drinking water stored in containers, potential exposure to waterborne pathogens may be minimized through interventions at the household level.

Observational Study Design in Veterinary Pathology, Part 2: Methodology

Observational studies are a basis for much of our knowledge of veterinary pathology, yet considerations for conducting pathology-based observational studies are not readily available. In part 1 of this series, we offered advice on planning and carrying out an observational study. Part 2 of the series focuses on methodology. Our general recommendations are to consider using already-validated methods, published guidelines, data from primary sources, and quantitative analyses. We discuss 3 common methods in pathology research—histopathologic scoring, immunohistochemistry, and polymerase chain reaction—to illustrate principles of method validation. Some aspects of quality control include use of clear objective grading criteria, validation of key reagents, assessing sample quality, determining specificity and sensitivity, use of technical and biologic negative and positive controls, blinding of investigators, approaches to minimizing operator-dependent variation, measuring technical variation, and consistency in analysis of the different study groups. We close by discussing approaches to increasing the rigor of observational studies by corroborating results with complementary methods, using sufficiently large numbers of study subjects, consideration of the data in light of similar published studies, replicating the results in a second study population, and critical analysis of the study findings.

Observational Study Design in Veterinary Pathology, Part 1: Study Design

Observational studies are the basis for much of our knowledge of veterinary pathology and are highly relevant to the daily practice of pathology. However, recommendations for conducting pathology-based observational studies are not readily available. In part 1 of this series, we offer advice on planning and conducting an observational study with examples from the veterinary pathology literature. Investigators should recognize the importance of creativity, insight, and innovation in devising studies that solve problems and fill important gaps in knowledge. Studies should focus on specific and testable hypotheses, questions, or objectives. The methodology is developed to support these goals. We consider the merits and limitations of different types of analytic and descriptive studies, as well as of prospective vs retrospective enrollment. Investigators should define clear inclusion and exclusion criteria and select adequate numbers of study subjects, including careful selection of the most appropriate controls. Studies of causality must consider the temporal relationships between variables and the advantages of measuring incident cases rather than prevalent cases. Investigators must consider unique aspects of studies based on archived laboratory case material and take particular care to consider and mitigate the potential for selection bias and information bias. We close by discussing approaches to adding value and impact to observational studies. Part 2 of the series focuses on methodology and validation of methods.

Effects of milk replacer acidification and free-access feeding on early life feeding, oral, and lying behavior of dairy calves

Acidification is a practical way of preserving the bacteriological quality of milk so that it can be fed to calves under free-access conditions. The objectives of this study were to evaluate how milk replacer acidification and free-access feeding affect dairy calf behavior during the first week of life. Sixteen Holstein male calves were purchased at birth and transported to the University of Guelph Kemptville Campus Dairy Education and Research Centre. Calves were randomly assigned to 1 of 4 milk feeding programs: (1) free-access (ad libitum) feeding of acidified milk replacer (22% crude protein and 17% fat, 150 g/L; FA); (2) restricted (6 L/d, 150 g/L) feeding of acidified milk replacer (RA); (3) free-access feeding of nonacidified milk replacer (FN); and (4) restricted feeding of nonacidified milk replacer (RN). Formic acid was used to acidify milk replacer to a target pH between 4.0 and 4.5. Video recordings of each calf at 1, 2, and 6 d were analyzed continuously over 24 h for all occurrences of each behavior in the ethogram. Feeding behavior observations were organized into sucking bouts, from which feeding behavior outcome variables were calculated. Calves consuming acidified milk replacer demonstrated more fragmented feeding patterns, characterized by more pauses within a sucking bout (FA, FN, RA, and RN calves = 12.4, 4.4, 13.7, and 11.9 pauses/bout, respectively) and longer sucking bout duration (FA, FN, RA, and RN calves = 8.8, 5.2, 9.3, and 8.1 min/bout, respectively), than calves fed nonacidified milk replacer. Restricted-fed calves tended to have longer sucking bouts and performed more within-bout sucks (FA, FN, RA, and RN calves = 10.7, 5.8, 13.5, and 14.1, respectively) and pauses than free-access calves. Acidification and free-access feeding did not affect lying duration. Calves assigned to the acidified feeding treatments tended to perform more grooming behavior than those fed nonacidified milk replacer (FA, FN, RA, and RN calves = 0.9, 0.5, 0.8, and 0.6 h/d, respectively). Free-access feeding did not affect grooming duration. The observed differences in feeding and grooming behavior suggest that acidification to a pH between 4.0 and 4.5 may have altered the palatability of milk replacer. Calves assigned to the acidified milk replacer feeding treatments did not, however, show avoidance toward this feedstuff during the first week of life.

Modeling the effect of surgical sterilization on owned dog population size in Villa de Tezontepec, Hidalgo, Mexico, using an individual-based computer simulation model

Surgical sterilization programs for dogs have been proposed as interventions to control dog population size. Models can be used to help identify the long-term impact of reproduction control interventions for dogs. The objective of this study was to determine the projected impact of surgical sterilization interventions on the owned dog population size in Villa de Tezontepec, Hidalgo, Mexico. A stochastic, individual-based simulation model was constructed and parameterized using a combination of empirical data collected on the demographics of owned dogs in Villa de Tezontepec and data available from the peer-reviewed literature. Model outcomes were assessed using a 20-year time horizon. The model was used to examine: the effect of surgical sterilization strategies focused on: 1) dogs of any age and sex, 2) female dogs of any age, 3) young dogs (i.e., not yet reached sexual maturity) of any sex, and 4) young, female dogs. Model outcomes suggested that as surgical capacity increases from 21 to 84 surgeries/month, (8.6% to 34.5% annual sterilization) for dogs of any age, the mean dog population size after 20 years was reduced between 14% and 79% compared to the base case scenario (i.e. in the absence of intervention). Surgical sterilization interventions focused only on young dogs of any sex yielded greater reductions (81% - 90%) in the mean population size, depending on the level of surgical capacity. More focused sterilization targeted at female dogs of any age, resulted in reductions that were similar to focusing on mixed sex sterilization of only young dogs (82% - 92%). The greatest mean reduction in population size (90% - 91%) was associated with sterilization of only young, female dogs. Our model suggests that targeting sterilization to young females could enhance the efficacy of existing surgical dog population control interventions in this location, without investing extra resources.

Assessing the impact of environmental exposures and Cryptosporidium infection in cattle on human incidence of cryptosporidiosis in Southwestern Ontario, Canada

Cryptosporidium is a waterborne parasite that causes diarrheal disease in humans and in cattle. Risk factors for human illness include contact with surface water such as lakes and rivers, exposure to contaminated municipal drinking water, as well as zoonotic transmission from livestock and agriculture. The objectives of this study are twofold: 1) to describe the temporal distribution of cryptosporidiosis in Southwestern Ontario; and 2) to determine the distribution of human cryptosporidiosis, in relation to exposures such as cryptosporidium positive cattle farms, weather events, and hydrological factors. Seasonal trends in 214 bovine and 87 human cases were assessed using regression models that predicted monthly case counts in relation to observed monthly case counts. A case-crossover approach was used to evaluate acute associations between daily environmental exposures, such as weather, hydrology, the presence of Cryptosporidium positive cattle farms within the region, and the risk of human Cryptosporidium infection. Annual seasonality was found for both human cases and bovine cases with human cases peaking in mid-summer and bovine cases peaking in late winter to early spring. Bovine cases that occurred 21 days prior to human cases were associated with a three-fold increase in the odds of human case occurrence. At both 9 and 14 days prior to human case onset, the odds of a human case increased twofold per 10-degree Celsius increase in air temperature. These results provide a preliminary hypothesis for the zoonotic transmission of cryptosporidiosis from cattle to humans via the environment and suggest that the timing of environmental conditions in relation to case occurrence is biologically plausible.

How are perceptions associated with water consumption in Canadian Inuit? A cross-sectional survey in Rigolet, Labrador

Concerns regarding the safety and aesthetic qualities of one's municipal drinking water supply are important factors influencing drinking water perceptions and consumption patterns (i.e. sources used and daily volume of consumption). In northern Canada, Inuit communities face challenges with drinking water quality, and many Inuit have reported concerns regarding the safety of their drinking water. The objectives of this research were to describe perceptions of municipal tap water, examine use of water sources and changes following the installation of a potable water dispensing unit (PWDU) in 2014, and identify factors associated with water consumption in the Inuit community of Rigolet. This study used data from three cross-sectional census surveys conducted between 2012 and 2014. Principal component analysis (PCA) was used to aggregate data from multiple variables related to perceptions of water, and logistic regressions were used to identify variables associated with water consumption patterns. Three quarters of residents reported using the PWDU after its installation, with concomitant declines reported in consumption of bottled, tap, and brook water. Negative perceptions of tap water were associated with lower odds of consuming tap water (OR_{PCAcomponent1}=0.73, 95% CI 0.56-0.94; OR_{PCAcomponent2}=0.67, 95% CI 0.49-0.93); women had higher odds of drinking purchased water compared to men (OR=1.90, 95% CI 1.11-3.26). The median amount of water consumed per day was 1L. Using brook water (OR=2.60, 95% CI 1.22-5.56) and living in a household where no one had full-time employment (OR=2.94, 95% CI 1.35-6.39) were associated with consuming >2L of water per day. Results of this study may inform drinking water interventions, risk assessments, and public health messaging in Rigolet and other Indigenous communities.

Effects of local anesthetic or systemic analgesia on pain associated with cautery disbudding in calves: A systematic review and meta-analysis

Disbudding is a common management procedure performed on dairy farms and, when done without pain mitigation, is viewed as a key welfare issue. Use of pain control has increased in recent years, but full adoption of anesthesia and analgesia by veterinarians or dairy producers has not been achieved. This may in part be due to the lack of a consistent recommendations of treatment protocols between studies examining pain control methods for disbudding. The objective of this systematic review was to examine the effects of these pain control practices for the most common method of disbudding, cautery, on outcomes associated with disbudding pain in calves. The outcomes were plasma cortisol concentrations, pressure sensitivity of the horn bud area, and validated pain behaviors (ear flick, head shake, head rub, foot stamp, and vocalization). Intervention studies describing cautery disbudding in calves 12 wk of age or younger were eligible, provided they compared local anesthesia, nonsteroidal anti-inflammatory drug (NSAID), or local anesthesia and NSAID to 1 or more of local anesthesia, NSAID, or no pain control. The search strategy used the Agricola, Medline (via OvidSP), and Web of Science databases, as well as the Searchable Proceedings of Animal Conferences (S-PAC), ProQuest Dissertations and Theses Database, and Open Access Theses and Dissertations. Meta-analysis was performed for all outcomes measured at similar time points with more than 2 studies. Local anesthetic was associated with reduced plasma cortisol until 2 h postdisbudding; however, a rise in cortisol was observed in the meta-analysis of studies reporting at 4 h postdisbudding. Heterogeneity was present in several of the analyses for this comparison. The addition of NSAID to local anesthetic showed reduction in plasma cortisol at 4 h, and a reduction in pressure sensitivity and pain behaviors in some analyses between 3 and 6 h postdisbudding. Heterogeneity was present in some meta-analyses, including several using pain behavior outcomes. This may reflect the variation in measurement time periods for behavioral measures between studies, as well as differences among NSAID treatments. Overall, a protective effect of local anesthetic was seen for the acute pain of cautery disbudding, and the delayed rise in cortisol was mitigated by the addition of an NSAID, which also reduced other signs of pain, including pressure sensitivity and pain behaviors. Based on these findings, we recommend use of local anesthetic and an NSAID as best practices for pain mitigation for cautery disbudding of calves 12 wk of age or less. The magnitude and duration of the effect of NSAID treatment was not possible to deduce from the literature because wide variation existed between studies. We recommend consideration of more standardized outcome measurements, especially for pain behaviors. Adherence to reporting guidelines by authors would help ensure more transparent and complete information is available to end users.

Systematic Review: Impact of point sources on antibiotic-resistant bacteria in the natural environment

Point sources such as wastewater treatment plants and agricultural facilities may have a role in the dissemination of antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARG). To analyse the evidence for increases in ARB in the natural environment associated with these point sources of ARB and ARG, we conducted a systematic review. We evaluated 5,247 records retrieved through database searches, including both studies that ascertained ARG and ARB outcomes. All studies were subjected to a screening process to assess relevance to the question and methodology to address our review question. A risk of bias assessment was conducted upon the final pool of studies included in the review. This article summarizes the evidence only for those studies with ARB outcomes (n = 47). Thirty-five studies were at high (n = 11) or at unclear (n = 24) risk of bias in the estimation of source effects due to lack of information and/or failure to control for confounders. Statistical analysis was used in ten studies, of which one assessed the effect of multiple sources using modelling approaches; none reported effect measures. Most studies reported higher ARB prevalence or concentration downstream/near the source. However, this evidence was primarily descriptive and it could not be concluded that there is a clear impact of point sources on increases in ARB in the environment. To quantify increases in ARB in the environment due to specific point sources, there is a need for studies that stress study design, control of biases and analytical tools to provide effect measure estimates.

The reporting characteristics of bovine respiratory disease clinical intervention trials published prior to and following publication of the REFLECT statement

The goal of the REFLECT Statement (Reporting guidElines For randomized controLled trials in livEstoCk and food safeTy) (published in 2010) was to provide the veterinary research community with reporting guidelines tailored for randomized controlled trials for livestock and food safety. Our objective was to determine the prevalence of REFLECT Statement reporting of items 1-19 in controlled trials published in journals between 1970 and 2017 examining the comparative efficacy of FDA-registered antimicrobials against naturally acquired BRD (bovine respiratory disease) in weaned beef calves in Canada or the USA, and to compare the prevalence of reporting before and after 2010, when REFLECT was published. We divided REFLECT Statement, items 3, 5, 10, and 11 into subitems, because each dealt with multiple elements requiring separate assessment. As a result, 28 different items or subitems were evaluated independently. We searched MEDLINE^® and CABI (CAB Abstracts^® and Global Health^®) (Web of Science™) in April 2017 and screened 2327 references. Two reviewers independently assessed the reporting of each item and subitem. Ninety-five references were eligible for the study. The reporting of the REFLECT items showed a point estimate for the prevalence ratio >1 (i.e. a higher proportion of studies published post-2010 reported this item compared to studies published pre-2010), apart from items 10.3, i.e., item 10, subitem 3 (who assigned study units to the interventions), 13 (the flow of study units through the study), 16 (number of study units in analysis), 18 (multiplicity), and 19 (adverse effects). Fifty-three (79%) of 67 studies published before 2010 and all 28 (100%) papers published after 2010 reported using a random allocation method in either the title, abstract, or methods (Prevalence ratio = 1.25; 95% CI (1.09,1.43)). However, 8 studies published prior to 2010 and 7 studies published post-2010 reported the term "systematic randomization" or variations of this term (which is not true randomization) to describe the allocation procedure. Fifty-five percent (37/67) of studies published pre-2010 reported blinding status (blinded/not blinded) of outcome assessors, compared to 24/28 (86%) of studies published post-2010 (Prevalence ratio = 1.5, 95% CI (1.19, 2.02)). The reporting of recommended items in journal articles in this body of work is generally improving; however, there is also evidence of confusion about what constitutes a random allocation procedure, and this suggests an educational need. As this study is observational, this precludes concluding that the publication of the REFLECT Statement was the cause of this trend.