Expert Elicitation to Estimate the Relative Risk of Food Safety Criteria Included in the Establishment-Based Risk Assessment Model for Canadian Hatcheries.

The Canadian Food Inspection Agency is developing an Establishment-based Risk Assessment model for Hatcheries to allocate inspection resources according to the food safety risk associated with each hatchery falling under its jurisdiction. In a previous study, 29 factors contributing to the food safety risk of hatcheries were identified and grouped into three clusters (inherent risk, risk mitigation, and compliance) and assessment criteria were defined. The objective of the current study was to estimate the relative risk (RR) of these criteria. Two rounds of expert elicitations were conducted to allow 13 Canadian experts to estimate the RR of each criterion (n = 96) based on its potential impact on human health, with a specific focus on Salmonella spp. This process also aimed to estimate the maximum increase or decrease in the overall food safety risk of a hatchery when considering multiple criteria belonging to a specific cluster and to assess the risk attribution of Salmonella spp. at the hatchery and bird-type levels. Results showed that the respondent profile had no influence on the importance given to a majority of criteria. Uniformity of answers among experts improved from the first to the second round. Overall, 62.5%, 32.3%, and 5.2% of the criteria were attributed to an RR that was less than 2, between 2 and 3, and greater than 3, respectively. Mixing eggs from different supply flocks when placed into the same hatching unit, hatching multiple species, and importing eggs with unknown quality status were identified as having the highest contribution to a hatchery's inherent risk. Requiring information on the foodborne pathogen status of supplying flocks and the occurrence of regulatory enforcement actions were the most impactful risk mitigation and compliance factors, respectively. The median RR value assigned to each criterion and cluster will be used to build this new model.

Antimicrobial resistance in fecal Escherichia coli and Salmonella enterica isolates: a two-year prospective study of small poultry flocks in Ontario, Canada.

BACKGROUND: Although keeping small poultry flocks is increasingly popular in Ontario, information on the antimicrobial susceptibility of enteric bacteria of such flocks is lacking. The current study was conducted on small poultry flocks in Ontario between October 2015 and September 2017, and samples were submitted on a voluntary basis to Ontario's Animal Health Laboratory. From each submission, a pooled cecal sample was obtained from all the birds of the same species from the same flock and tested for the presence of two common enteric pathogens, E. coli and Salmonella. Three different isolates from each E. coli-positive sample and one isolate from each Salmonella-positive sample were selected and tested for susceptibility to 14 antimicrobials using a broth microdilution technique. RESULTS: A total of 433 fecal E. coli isolates (358 chicken, 27 turkey, 24 duck, and 24 game bird) and 5 Salmonella isolates (3 chicken, 1 turkey, and 1 duck) were recovered. One hundred and sixty-seven chicken, 5 turkey, 14 duck, and 15 game bird E. coli isolates were pan-susceptible. For E. coli, a moderate to high proportion of isolates were resistant to tetracycline (43% chicken, 81% turkey, 42% duck, and 38% game bird isolates), streptomycin (29% chicken, 37% turkey, and 33% game bird isolates), sulfonamides (17% chicken, 37% turkey, and 21% duck isolates), and ampicillin (16% chicken and 41% turkey isolates). Multidrug resistance was found in 37% of turkey, 20% of chicken, 13% of duck, and 8% of game bird E. coli isolates. Salmonella isolates were most frequently resistant to streptomycin, tetracycline, and sulfonamides. Resistance to cephalosporins, carbapenems, macrolides, and quinolones was infrequent in both E. coli and Salmonella isolates. Cluster and correlation analyses identified streptomycin-tetracycline-sulfisoxazole-trimethoprim-sulfamethoxazole as the most common resistance pattern in chicken E. coli isolates. Turkey E. coli isolates compared to all the other poultry species had higher odds of resistance to tetracycline and ampicillin, and a higher multidrug resistance rate. CONCLUSIONS: Escherichia coli isolates were frequently resistant to antimicrobials commonly used to treat poultry bacterial infections, which highlights the necessity of judicious antimicrobial use to limit the emergence of multidrug resistant bacteria.

Tissue residue depletion of fenbendazole after oral administration in turkeys.

The objectives of this study were to determine tissue depletion of fenbendazole in turkeys and estimate a withdrawal interval (WDI). Forty-eight 9-week-old turkeys were fed fenbendazole at 30 mg/kg of feed for 7 consecutive days. Three hens and 3 toms were sacrificed every 2 days from 2 to 16 days post-treatment, and tissues were collected to determine fenbendazole sulfone (FBZ-SO2) concentrations using mass spectrometry. At all timepoints, FBZ-SO2 concentrations in liver and skin-adherent fat were above the limit of quantification (1 ppb), with higher concentrations than those in kidney and muscle. Two turkeys had detectable FBZ-SO2 concentrations in kidney at 16 days. No detectable FBZ-SO2 concentrations were found in muscle at 14 and 16 days. Fenbendazole residues depleted very slowly from the liver and a WDI of at least 39 days should be observed under the conditions of this study, in order to comply with Canadian regulatory agencies.

Déplétion du fenbendazole pour les résidus tissulaires après l'administration orale chez les dindons. Les objectifs de cette étude consistaient à déterminer la déplétion du fenbendazole dans les tissus chez les dindons et d'estimer un délai d'attente (DA). Du fenbendazole a été administré à quarante-huit dindons âgés de 9 semaines, à raison de 30 mg/kg d'aliments pendant 7 jours consécutifs. Trois dindes et 3 dindons ont été sacrifiés tous les deux jours pendant les jours 2 à 16 après le traitement et les tissus ont été prélevés pour déterminer les concentrations de fenbendazole sulfone (FBZ-SO2) en utilisant la spectrométrie de masse. À tous les moments de prélèvement, les concentrations de FBZ-SO2 dans le foie et le gras adhérent à la peau étaient supérieures à la limite de quantification (1 ppm), avec des concentrations supérieures à celles présentes dans les reins et les muscles. Deux dindes avaient des concentrations de FBZ-SO2 détectables dans les reins à 16 jours. Aucune concentration détectable de FBZ-SO2 n'a été trouvées dans les muscles à 14 et à 16 jours. Les résidus de fenbendazole se résorbaient très lentement du foie et un DA d'au moins 39 jours devrait être observé conformément aux conditions de cette étude afin de satisfaire aux exigences des agences réglementaires canadiennes.(Traduit par Isabelle Vallières).

Flock-level prevalence, geographical distribution, and seasonal variation of avian reovirus among broiler flocks in Ontario.

Avian reovirus (ARV) is an economically significant pathogen of broiler chickens. Our objective was to determine the prevalence, geographical distribution, and seasonal variation of ARV infection among commercial broiler flocks in Ontario, Canada during grow-out. A cross-sectional study of 231 randomly selected flocks was conducted from July 2010 to January 2012. Fifteen blood samples, 15 whole intestines, and 15 cloacal swabs per flock were collected at slaughter; ELISA and PCR were used to determine a flock's ARV exposure status. Avian reovirus prevalence was 91% (95% CI: 87 to 94). District alone did not significantly explain the overall variation in the prevalence of ARV (univariable logistic regression; P = 0.073), although geographical differences were identified. The odds of ARV presence were significantly lower in the summer/autumn compared to the winter/spring (univariable exact logistic regression; P < 0.001). There was no association between flock mortality and flock ELISA mean titer or PCR status.

Prévalence au niveau du troupeau, distribution géographique et variations saisonnières du réovirus aviaire parmi les troupeaux de poulets à griller en Ontario. Le réovirus aviaire (RVA) est un agent pathogène important sur le plan économique pour les poulets à griller. Notre objectif consistait à déterminer la prévalence, la distribution géographique et les variations saisonnières de l'infection par le RVA parmi les troupeaux de poulets à griller commerciaux en Ontario, au Canada, durant la phase d'engraissement. Une étude transversale de 231 troupeaux choisis au hasard a été réalisée de juillet 2010 à janvier 2012. Quinze échantillons sanguins, 15 intestins complets et 15 écouvillons cloacaux ont été prélevés à l'abattage; des tests ELISA et ACP ont été utilisés pour déterminer l'état d'exposition du troupeau au RVA. La prévalence du réovirus aviaire était de 91 % (IC de 95 % : de 87 à 94). Le district à lui seul ne peut pas expliquer significativement la variation générale dans la prévalence du RVA (régression logistique univariable; P = 0,073), quoique des différences géographiques ont été identifiées. Les risques de la présence du RVA étaient significativement inférieurs à l'été/automne comparativement à l'hiver/printemps (régression logistique exacte univariable; P < 0,001). Il n'y avait aucune association entre la mortalité du troupeau et le titre moyen ELISA du troupeau ou de son état d'ACP.(Traduit par Isabelle Vallières).

Area-level global and local clustering of human Salmonella Enteritidis infection rates in the city of Toronto, Canada, 2007-2009.

BACKGROUND: Salmonella enterica serotype Enteritidis (S. Enteritidis) remains a major foodborne pathogen in North America yet studies examining the spatial epidemiology of salmonellosis in urban environments are lacking. Our ecological study combined a number of spatial statistical methods with a geographic information system to assess area-level heterogeneity of S. Enteritidis infection rates in the city of Toronto. METHODS: Data on S. Enteritidis infections between January 1, 2007 and December 31, 2009 were obtained from Ontario's surveillance system, and were grouped and analyzed at the forward sortation area (FSA)-level (an area signified by the first three characters of the postal code). Incidence rates were directly standardized using the FSA-level age- and sex-based standard population. A spatial empirical Bayes method was used to smooth the standardized incidence rates (SIRs). Global clustering of FSAs with high or low non-smoothed SIRs was evaluated using the Getis-Ord G method. Local clustering of FSAs with high, low, or dissimilar non-smoothed SIRs was assessed using the Getis-Ord Gi* and the Local Moran's I methods. RESULTS: Spatial heterogeneity of S. Enteritidis infection rates was detected across the city of Toronto. The non-smoothed FSA-level SIRs ranged from 0 to 16.9 infections per 100,000 person-years (mean = 6.6), whereas the smoothed SIRs ranged from 2.9 to 11.1 (mean = 6.3). The global Getis-Ord G method showed significant (p ≤ 0.05) maximum spatial clustering of FSAs with high SIRs at 3.3 km. The local Getis-Ord Gi* method identified eight FSAs with significantly high SIRs and one FSA with a significantly low SIR. The Local Moran's I method detected five FSAs with significantly high-high SIRs, one FSA with a significantly low-low SIR, and four significant outlier FSAs (one high-low, and three low-high). CONCLUSIONS: Salmonella Enteritidis infection rates clustered globally at a small distance band, suggesting clustering of high SIRs in small distinct areas. This finding was supported by the local cluster analyses, where distinct FSAs with high SIRs, mainly in downtown Toronto, were detected. These areas should be evaluated by future studies to identify risk factors of disease in order to implement targeted prevention and control programs. We demonstrated the usefulness of combining several spatial statistical techniques with a geographic information system to detect geographical areas of interest for further study, and to evaluate spatial processes that influenced S. Enteritidis infection rates. Our study methodology could be applied to other foodborne disease surveillance data.

Spatial-temporal epidemiology of human Salmonella Enteritidis infections with major phage types (PTs 1, 4, 5b, 8, 13, and 13a) in Ontario, Canada, 2008-2009.

BACKGROUND: In Ontario and Canada, the incidence of human Salmonella enterica serotype Enteritidis (S. Enteritidis) infections have increased steadily during the last decade. Our study evaluated the spatial and temporal epidemiology of the major phage types (PTs) of S. Enteritidis infections to aid public health practitioners design effective prevention and control programs. METHODS: Data on S. Enteritidis infections between January 1, 2008 and December 31, 2009 were obtained from Ontario's disease surveillance system. Salmonella Enteritidis infections with major phage types were classified by their annual health region-level incidence rates (IRs), monthly IRs, clinical symptoms, and exposure settings. A scan statistic was employed to detect retrospective phage type-specific spatial, temporal, and space-time clusters of S. Enteritidis infections. Space-time cluster cases' exposure settings were evaluated to identify common exposures. RESULTS: 1,336 cases were available for analysis. The six most frequently reported S. Enteritidis PTs were 8 (n = 398), 13a (n = 218), 13 (n = 198), 1 (n = 132), 5b (n = 83), and 4 (n = 76). Reported rates of S. Enteritidis infections with major phage types varied by health region and month. International travel and unknown exposure settings were the most frequently reported settings for PT 5b, 4, and 1 cases, whereas unknown exposure setting, private home, food premise, and international travel were the most frequently reported settings for PT 8, 13, and 13a cases. Diarrhea, abdominal pain, and fever were the most commonly reported clinical symptoms. A number of phage type-specific spatial, temporal, and space-time clusters were identified. Space-time clusters of PTs 1, 4, and 5b occurred mainly during the winter and spring months in the North West, North East, Eastern, Central East, and Central West regions. Space-time clusters of PTs 13 and 13a occurred at different times of the year in the Toronto region. Space-time clusters of PT 8 occurred at different times of the year in the North West and South West regions. CONCLUSIONS: Phage type-specific differences in exposure settings, and spatial-temporal clustering of S. Enteritidis infections were demonstrated that might guide public health surveillance of disease outbreaks. Our study methodology could be applied to other foodborne disease surveillance data to detect retrospective high disease rate clusters, which could aid public health authorities in developing effective prevention and control programs.

On-farm comparison of keel fracture prevalence and other welfare indicators in conventional cage and floor-housed laying hens in Ontario, Canada.

The objective of this study was to compare the flock-level prevalence of healed keel bone fractures and to benchmark other indicators of well-being in laying hens housed in conventional cages and single-tier floor housing systems at several points during the production period. Commercial farms in Ontario, Canada, that housed hens in cages (n=9) or floor barns (n=8) were included. Flocks were beak-trimmed brown hens of various strains. Each flock was visited at 20, 35, 50, and 65 wk of age. At each visit, 50 hens were weighed, palpated for healed keel fractures, and feather scored over 4 areas of the body. Data were collected from the farm records on cumulative mortality. Keel fracture prevalence was higher in floor-housed flocks compared to cage-housed flocks (48.3±0.04% vs. 24.8±0.03%; P<0.001). The majority of keel fractures occurred by 50 wk. Cumulative mortality tended to be higher in floor-housed flocks compared to cage-housed flocks (2.13±0.42% vs. 1.29±0.19%; P=0.078). Mean BW was lower (1,827±28.8 g vs. 1,888±26.8 g; P=0.02) yet more uniform (CV of BW 9.43±0.40% vs. 10.10±0.32%; P<0.001) in floor-housed flocks compared to cage-housed flocks. Feather condition was not affected by housing system type (P=0.618), although it declined with age (P<0.001). Individual hen factors assessed using Pearson partial correlations indicated that hens with fractures were heavier at 65 wk in both housing types (P<0.05) and that heavier hens housed on the floor had better feather scores (P<0.001) from 35 wk onward. Floor-housed hens with fractures had lower feather scores at 35 wk (P<0.05) but not at 50 or 65 wk. Housing hens in single-tier floor systems increased the flock-level prevalence of keel fractures and resulted in a lower, yet more uniform, BW compared to hens in conventional cages under commercial conditions in Ontario. Benchmarking welfare indicators from alternative housing systems for laying hens is important to ensure that progress is made in improving their well-being.

Genotyping of infectious bronchitis viruses identified in Canada between 2000 and 2013.

Infectious bronchitis virus (IBV) was detected in 185 samples originating from chicken flocks of various commodity groups in Canada. Flocks with clinical signs such as respiratory challenge, sudden death, egg production problems, or nephropathogenic conditions, and randomly selected flocks sampled at slaughter as part of an Ontario broiler surveillance project, were included. Most samples were from Ontario and Québec; however, a small number from British Columbia, Nova Scotia, and Newfoundland and Labrador were also analysed. The nucleotide sequence of the spike (S) protein gene was compared with sequences available in GenBank. Based on their S gene sequence similarities, Canadian IBVs could be divided into nine genotypes belonging to four groups: Canadian variant virus, strain Qu_mv; the classic, vaccine-like viruses, Connecticut and Massachusetts; US variant-like virus strains, California 1734/04, California 99, CU_82792, Pennsylvania 1220/98 and Pennsylvania Wolg/98; and non-Canadian, non-US virus, strain 4/91. Based on the field situation, the effectiveness of current vaccination practices mostly based on Massachusetts and Connecticut-type vaccines appeared generally satisfactory for minimizing the damage due to infection with Canadian variant and US variant-like viruses. However, the recent outbreaks of severe respiratory disease and production problems in Ontario chicken flocks related to the incursion of IBV strain 4/91 were not prevented by standard vaccination protocols. It appears that IBV strain 4/91 has now become endemic in Ontario and the need for 4/91-type vaccines must be evaluated.

Flock prevalence of exposure to avian adeno-associated virus, chicken anemia virus, fowl adenovirus, and infectious bursal disease virus among Ontario broiler chicken flocks.

Samples from 231 randomly selected commercial broiler chicken flocks in Ontario were tested at slaughter for exposure to chicken anemia virus (CAV), fowl adenovirus (FAdV), and infectious bursal disease virus (IBDV). Fifteen blood samples per flock were collected and analyzed for the presence of antibodies against CAV, FAdV, and IBDV by ELISA or agar gel immunodiffusion test. Fifteen cecal tonsils and cloacal swabs per flock were analyzed for the presence of CAV, FAdV, and IBDV by PCR. The prevalence of exposure to avian adeno-associated virus (AAAV) was estimated by a PCR test on a subset of FAdV-PCR-positive samples from 178 flocks. Genotypes of FAdV and IBDV were identified on a subset of isolates (n = 353 and 45, respectively). The flock-level period prevalence of exposure to AAAV, CAV, FAdV, and IBDV during grow-out were 88.76% (95% CI: 84.08-93.45%), 77.06% (95% CI: 71.59-82.52%), 96.54% (95% CI: 94.16-98.91%), and 48.92% (95% CI: 42.42-55.41%), respectively. Results of a multivariable logistic regression model showed a significant association of exposure to FAdV with exposure to AAAV (OR = 18.57, 95% CI: 3.67-93.86, P = 0.004) but not with exposure to CAV (P = 0.7752) or exposure to IBDV (P = 0.2274). Pathogenic FAdV genotypes (FAdV-02, FAdV-08, and FAdV-11) constituted 39.38% of the isolates. The most-common IBDV genotypes identified were IBDV NC171 (60%) and IBDV 05SA8 (28.89%). This is the first large-scale study to estimate the baseline flock prevalence of exposure to AAAV, CAV, FAdV, and IBDV in commercial broiler flocks in Canada. Potentially pathogenic genotypes of FAdV and IBDV that can guide vaccine development and disease control efforts in Ontario were identified.

Incidence, distribution, seasonality, and demographic risk factors of Salmonella Enteritidis human infections in Ontario, Canada, 2007-2009.

BACKGROUND: In Canada, surveillance systems have highlighted the increasing trend of Salmonella enterica serovar Enteritidis (S. Enteritidis) human infections. Our study objectives were to evaluate the epidemiology of S. Enteritidis infections in Ontario using surveillance data from January 1, 2007 through December 31, 2009. METHODS: Annual age-and-sex-adjusted incidence rates (IRs), annual and mean age-adjusted sex-specific IRs, and mean age-and-sex-adjusted IRs by public health unit (PHU), were calculated for laboratory-confirmed S. Enteritidis cases across Ontario using direct standardization. Multivariable Poisson regression with PHU as a random effect was used to estimate incidence rate ratios (IRRs) of S. Enteritidis infections among years, seasons, age groups, and sexes. RESULTS: The annual age-and-sex-adjusted IR per 100,000 person-years was 4.4 [95% CI 4.0-4.7] in 2007, and 5.2 [95% CI 4.8-5.6] in both 2008 and 2009. The annual age-adjusted sex-specific IRs per 100,000 person-years ranged from 4.5 to 5.5 for females and 4.2 to 5.2 for males. The mean age-adjusted sex-specific IR was 5.1 [95% CI 4.8-5.4] for females and 4.8 [95% CI 4.5-5.1] for males. High mean age-and-sex-adjusted IRs (6.001-8.10) were identified in three western PHUs, one northern PHU, and in the City of Toronto. Regression results showed a higher IRR of S. Enteritidis infections in 2009 [IRR = 1.18, 95% CI 1.06-1.32; P = 0.003] and 2008 [IRR = 1.17, 95% CI 1.05-1.31; P = 0.005] compared to 2007. Compared to the fall season, a higher IRR of S. Enteritidis infections was observed in the spring [IRR = 1.14, 95% CI 1.01-1.29; P = 0.040]. Children 0-4 years of age (reference category), followed by children 5-9 years of age [IRR = 0.64, 95% CI 0.52-0.78; P < 0.001] had the highest IRRs. Adults ≥ 60 years of age and 40-49 years of age [IRR = 0.31, 95% CI 0.26-0.37; P < 0.001] had the lowest IRRs. CONCLUSIONS: The study findings suggest that there was an increase in the incidence of S. Enteritidis infections in Ontario from 2007 to 2008-2009, and indicate seasonal, demographic, and regional differences, which warrant further public health attention.

Evaluating area-level spatial clustering of Salmonella Enteritidis infections and their socioeconomic determinants in the greater Toronto area, Ontario, Canada (2007 - 2009): a retrospective population-based ecological study.

BACKGROUND: There have been only a few region-level ecological studies conducted in Canada investigating enteric infections in humans. Our study objectives were to 1) assess the spatial clustering of Salmonella enterica serotype Enteritidis (S. Enteritidis) human infections in the Greater Toronto Area, and 2) identify underlying area-level associations between S. Enteritidis infection rates and socioeconomic status (SES) indicators that might explain the clustering of infections. METHODS: Retrospective data on S. Enteritidis infections from 2007 to 2009 were obtained from Ontario's reportable disease surveillance database and were grouped at the forward sortation area (FSA) - level. A spatial scan statistic was employed to identify FSA-level spatial clusters of high infection rates. Negative binomial regression was used to identify FSA-level associations between S. Enteritidis infection rates and SES indicators obtained from the 2006 Census of Canada. Global Moran's I statistic was used to evaluate the final model for residual spatial clustering. RESULTS: A spatial cluster that included nine neighbouring FSAs was identified in downtown Toronto. A significant positive curvilinear relationship was observed between S. Enteritidis infection rates and FSA-level average number of children at home per census family. Areas with high and areas with low average median family income had higher infection rates than FSAs with medium average median family income. Areas with a high proportion of visible minority population had lower infection rates than FSAs with a medium proportion of visible minority population. The Moran's I statistic was not significant, indicating that no residual spatial autocorrelation was present after accounting for the SES variables in the final model. CONCLUSIONS: Our study demonstrated that FSAs with high and low average median family income, medium proportion of visible minority population, and high average number of children at home per census family had the highest S. Enteritidis infection rates. These areas should be targeted when designing disease control and prevention programs. Future studies are needed in areas with high S. Enteritidis infection rates to identify sources of environmental contamination of the local food supply, to assess food safety practices at local food markets, retail stores, and restaurants, and to identify novel individual-level risk factors.

Temporal Study of Salmonella enterica Serovars Isolated from Environmental Samples from Ontario Poultry Breeder Flocks between 2009 and 2018.

This study's goal was to determine the prevalence, temporal trends, seasonal patterns, and temporal clustering of Salmonella enterica isolated from environmental samples from Ontario's poultry breeding flocks between 2009 and 2018. Clusters of common serovars and those of human health concern were identified using a scan statistic. The period prevalence of S. enterica was 25.3% in broiler breeders, 6.4% in layer breeders, and 28.6% in turkey breeders. An overall decreasing trend in S. enterica prevalence was identified in broiler breeders (from 27.8% in 2009 to 22.1% in 2018) and layer breeders (from 15.4% to 4.9%), while an increasing trend was identified in turkey breeders (from 12.0% to 24.5%). The most common serovars varied by commodity. Among broiler breeders, S. enterica serovars Kentucky (42.4% of 682 submissions), Heidelberg (19.2%), and Typhimurium (5.4%) were the most common. Salmonella enterica serovars Thompson (20.0% of 195 submissions) and Infantis (16.4%) were most common among layer breeders, and S. enterica serovars Schwarzengrund (23.6% of 1368 submissions), Senftenberg (12.9%), and Heidelberg and Uganda (9.6% each) were most common among turkey breeders. Salmonella enterica ser. Enteritidis prevalence was highest in submissions from broiler breeders (3.7% of 682 broiler breeder submissions). Temporal clusters of S. enterica serovars were identified for all poultry commodities. Seasonal effects varied by commodity, with most peaks occurring in the fall. Our study provides information on the prevalence and temporality of S. enterica serovars within Ontario's poultry breeder flocks that might guide prevention and control programs at the breeder level.

Using microsphere or fluorescein tracers and total oocyst output to measure ingestion of material following live-coccidiosis vaccinations.

One method of prevention of coccidiosis in broiler chickens raised without antibiotics relies on coccidiosis vaccination. Live-coccidiosis vaccines carry the risk for pathogenic effects if the Eimeria species overcycle. However, all chicks must receive an appropriate dose of Eimeria oocysts to induce immunity and reduce the risk of adverse effects. At the hatchery, coccidiosis vaccines are administered topically to boxes of chicks by spray or gel-droplet application. Determining the volume of vaccine ingested by individual chicks could provide a means of evaluating the success of different application methods. For each of 2 mass application methods (spray, gel-droplet), we used 3 quantification methodologies to determine the amount of vaccine material ingested by chicks: total oocyst counts from feces collected 5- to 8-days postvaccination; and counts of either microsphere or fluorescein tracers recovered from the gastrointestinal tract 30-min postvaccination. For each quantification methodology, chicks vaccinated via spray or gel-droplet application were compared to chicks vaccinated via oral gavage using the same concentration of oocysts per mL for all groups. Chicks vaccinated via gel-droplet application shed 10-fold more oocysts than those vaccinated by spray application. Individual chick consumption of vaccine material using tracers also revealed that chicks ingested more material following gel-droplet application than spray application, although the magnitude of the difference varied based on quantification methodology. The results of this study suggest that all 3 quantification methodologies can be used to help validate and improve mass vaccine application methods to ensure optimal ingestion, and therefore, coccidiosis vaccination success.

Development of interactive dashboards for monitoring endemic animal pathogens in Ontario, Canada: Ontario interactive animal pathogen dashboards.

The advancement of web-based technologies makes it possible to build user interfaces or web pages that present and summarize complex data in easy-to-read graphical formats that emphasize key information. Taking advantage of this technologic progress, we addressed the need for real-time visualizations of trends for major pathogens in the largest livestock industries in Ontario: poultry, swine, and cattle. These visualizations were built using test data from the laboratory information management system of the Animal Health Laboratory at the University of Guelph, a large veterinary diagnostic laboratory in Ontario. The data were processed using R software and used to construct interactive and dynamic visualizations using Tableau Desktop v.2021.4 (Tableau Software). We designed 12 dashboards: in chickens-influenza A virus, fowl adenovirus, infectious bronchitis virus, and infectious laryngotracheitis virus; in turkeys-influenza A virus; in swine, influenza A virus, rotavirus, and porcine reproductive and respiratory syndrome virus; in cattle-bovine viral diarrhea virus, Mycoplasma bovis, Salmonella Dublin in individual samples, and Salmonella Dublin in bulk tank milk samples. Data for each pathogen are presented in 2 dashboards. One shows the data of the last 10 y (general view) and the other the data of the last 3 y, but in more detail (comprehensive view). Information on gaining access to all dashboards is available at https://iapd.lsd.uoguelph.ca/. The visualizations provide near-real-time access to aggregated assay results for selected pathogens for veterinarians, animal health regulatory agencies, researchers, and other users who are interested in livestock pathogen surveillance.

In pursuit of a better broiler: tibial morphology, breaking strength, and ash content in conventional and slower-growing strains of broiler chickens.

This study was conducted to determine the differences in bone traits in 14 strains of broiler chickens differing in growth rate. The strains encompassed 2 conventional (CONV; ADG0-48 >60 g/d) and 12 slower-growing (SG) strains classified as FAST (ADG0-62 = 53-55 g/d), MOD (ADG0-62 = 50-51 g/d), and SLOW (ADG0-62 <50 g/d), with 4 strains represented in each SG category. A total of 7,216 mixed-sex birds were equally allocated into 164 pens (44 birds/pen; 30 kg/m2) in a randomized incomplete block design, with each strain represented in 8 to 12 pens over 2-3 trials. From each pen, 4 birds (2 males and 2 females) were individually weighed and euthanized at 2 target weights (TWs) according to their time to reach approximately 2.1 kg (TW1: 34 d for CONV and 48 d for SG strains) and 3.2 kg (TW2: 48 d for CONV and 62 d for SG strains). Tibiae samples were dissected, and length and diameter were recorded. Left tibiae were used for tibial breaking strength (TBS) at both TWs and tibial ash at TW2. At TW1, CONV birds' tibiae were narrowest and shortest (P < 0.001), yet had similar TBS compared to the other categories (P > 0.69). At TW2, category (P > 0.50) had no effect on tibial diameter, yet CONV birds had the shortest tibiae (P < 0.001). The CONV birds had greater TBS:BW ratio than FAST and MOD birds at both TWs 1 and 2 (P < 0.039) and similar ash content as the other categories at TW2 (P > 0.220). At 48 d of age, CONV birds had the greatest absolute TBS (P < 0.003), yet lower TBS:BW ratio than SLOW birds (P < 0.001). Tibiae from CONV birds were longer than MOD and SLOW birds, and thicker in diameter than the other categories, yet CONV birds had the lowest dimensions relative to BW (P < 0.001) at 48 d, indicating a negative association between accelerated growth and tibial dimensions. These results indicate that differences in functional abilities among categories may be due to differences in morphometric traits rather than differences in bone strength and mineralization.

In pursuit of a better broiler: walking ability and incidence of contact dermatitis in conventional and slower growing strains of broiler chickens.

In this study, the mobility, incidence, and severity of contact dermatitis and litter moisture content were assessed in 14 strains of broiler chickens differing in growth rate. The strains encompassed 2 conventional (CONV; ADG0-48 > 60 g/d) and 12 slower growing (SG) strains categorized as FAST (ADG0-62 = 53-55 g/d), MOD (ADG0-62 = 50-51 g/d), and SLOW (ADG0-62 < 50 g/d), with 4 strains in each category. A total of 7,216 mixed-sex birds were equally allocated into 164 pens (44 birds/pen; 30 kg/m2) in a randomized incomplete block design, with each strain represented in 8 to 12 pens over 2-3 trials. From each pen, 4 to 6 birds were tested in the latency-to-lie (LTL) and group obstacle tests 1 wk prior to the birds reaching 2 target weights (TWs) of approximately 2.1 kg (TW1: 34 d for CONV and 48 d for SG strains) and 3.2 kg (TW2: 48 d for CONV and 62 d for SG strains). The incidence of footpad dermatitis (FPD) and hock burns (HB) were evaluated a day prior to each TW. Litter moisture content was determined biweekly from d 14 to d 56. At TW1, CONV and SLOW had longer LTL than FAST birds. At TW2, CONV, MOD, and FAST birds had similar LTL. At both TWs, CONV birds were lighter than FAST birds in the group obstacle test, yet their number of obstacle crossings was similar. At TW1, CONV birds had greater incidence of FPD than FAST and MOD, while at TW2, CONV birds had greater incidence than the other categories. The incidence of HB in CONV and MOD was greater than SLOW birds at TW1, while at TW2, the incidence of HB was greater in CONV and FAST birds vs. MOD and SLOW birds. Litter moisture content was high in all categories from d 28 onward. Our results indicate that both BW and growth rate influence leg strength and walking ability, whereas the overall high litter moisture content and to a lesser extent growth rate influenced the incidence of contact dermatitis.

Temporal Study of Salmonella enterica Serovars Isolated from Fluff Samples from Ontario Poultry Hatcheries between 2009 and 2018.

The objectives of this study were to determine the prevalence, temporal trends, seasonal patterns, and temporal clustering of Salmonella enterica isolated from fluff samples from poultry hatcheries in Ontario between 2009 and 2018. A scan statistic was used to identify clusters of common serovars and those of human health concern. A multi-level logistic regression model was used to identify factors (poultry commodity, year, season) associated with S. enterica presence. The period prevalence of S. enterica was 7.5% in broiler hatcheries, 1.6% in layer hatcheries, 7.6% in turkey hatcheries, 29.7% in waterfowl hatcheries, and 13.8% in game-bird hatcheries. An overall increasing trend in S. enterica prevalence was identified in waterfowl and game-bird hatcheries, while a decreasing trend was identified in broiler and turkey hatcheries. Overall, the most common S. enterica serovars were Kentucky, Enteritidis, Heidelberg, and Senftenberg. Salmonella enterica ser. Enteritidis was the most common serovar in waterfowl hatcheries. Temporal clusters were identified for all poultry commodities. Seasonal effects varied by commodity, with the highest odds of S. enterica occurring in the summer and fall. Our study offers information on the prevalence and temporality of S. enterica serovars that might guide prevention and control programs at the hatchery level.

Factors associated with Salmonella enterica and Escherichia coli during downtime in commercial broiler chicken barns in Ontario.

Salmonella enterica and Escherichia coli are bacteria of concern to veterinary public health and poultry health. Our research aimed to determine the factors associated with S. enterica and E. coli in commercial broiler chicken barns during the rest period between flocks to identify the best methods of sanitation for bacterial load reduction. This involved collecting samples from September 2015 to July 2016 from the floors of 36 barns before sanitation (baseline) and at 2 time intervals after sanitation, followed by microbiological and molecular analysis. A priori variables of interest included sanitation procedure (dry cleaning, wet cleaning, disinfection), sampling point (baseline, 2 d after sanitation, 6 d after sanitation), and flooring type (concrete, wood). The odds of detecting S. enterica were higher on wooden floors that were wet-cleaned than on concrete floors that were dry-cleaned, lower in the winter and spring than in the fall, and lower when samples were collected 2 d and 6 d after sanitation than at baseline. For E. coli, the concentration was higher on wooden floors than on concrete floors and in the summer than in the fall, and it was lower in postsanitation samples from disinfected barns than in presanitation samples from dry-cleaned barns and in the winter than in the fall. Among E. coli isolates, factors associated with the presence of qacEΔ1, a gene associated with resistance to quaternary ammonium compounds, included sanitation procedure, flooring type, cycle length, and the number of times per yr the barn is disinfected. Our findings highlight the importance of cleaning after litter removal, although the sanitation procedure chosen might differ depending on which pathogen is present and causing disease issues; dry cleaning appears to be preferable for S. enterica control, especially in barns with wooden floors, whereas disinfection appears to be preferable for E. coli reduction.

Demographic, Husbandry, and Biosecurity Factors Associated with the Presence of Campylobacter spp. in Small Poultry Flocks in Ontario, Canada.

This study is part of a 2 year disease surveillance project conducted to establish the prevalence of poultry and zoonotic pathogens, including Campylobacter spp., among small poultry flocks in Ontario, Canada. For each post-mortem submission to the Animal Health Laboratory, a pooled sample of cecal tissue was cultured for Campylobacter spp., and a husbandry and biosecurity questionnaire was completed by the flock owner (n = 153). Using both laboratory and questionnaire data, our objective was to investigate demographic, husbandry, and biosecurity factors associated with the presence of Campylobacter spp. in small flocks. Two multivariable logistic regression models were built. In the farm model, the odds of Campylobacter spp. were higher in turkeys, and when birds were housed in a mixed group with different species and/or types of birds. The odds were lower when antibiotics were used within the last 12 months, and when birds had at least some free-range access. The effect of pest control depended on the number of birds at risk. In the coop model, the odds of Campylobacter spp. were lower when owners wore dedicated clothing when entering the coop. These results can be used to limit the transmission of Campylobacter spp. from small poultry flocks to humans.

Demographic Characteristics and Husbandry and Biosecurity Practices of Small Poultry Flocks in Ontario, Canada.

As part of a 2 yr disease surveillance project of small poultry flocks, owners of birds submitted for postmortem examination to the Animal Health Laboratory were asked to complete a questionnaire designed to gather information on the characteristics of the flock and its environment, how the flock was managed, and biosecurity measures used. A total of 153 unique questionnaires were received. Personal consumption of meat or eggs was the most common reason for owning a small flock (69.3%). Almost all owners (97.4%) reported having chickens on their property, while 21.6% had waterfowl, 15.7% had turkeys, and 15.7% had game birds. Nearly 70% (69.9%) of the flocks had some degree of outdoor access. For those with indoor access, the most common bedding material provided was soft wood shavings (70.2%). Kitchen waste or leftovers were offered to 65.3% of flocks, and well water was the most common source of drinking water (80.6%). For flocks with indoor access, dedicated shoes and clothes were used when entering or cleaning the coop by fewer than half of owners, and shoes were rarely disinfected before or after contact with the flock. Most owners (93.8%) reported washing their hands after contact with their birds, although only 48.3% reported washing their hands before contact. Among owners who sourced birds from a hatchery, only 36.8% indicated that the birds had been vaccinated, and 21.1% were unsure if vaccines had been administered. Among owners using medication (60.5%), the use of antibiotics was common (60.9%). Overall, questionnaire responses describe a wide range of husbandry and biosecurity practices, often suboptimal, and point out the need for educational material for Ontario small flock owners.

Artículo Regular­Características demográficas y prácticas de cría y bioseguridad de pequeñas parvadas de aves de corral en Ontario, Canadá. Como parte de un proyecto de vigilancia de enfermedades de dos años de pequeñas parvadas avícolas, se solicitó a los propietarios de aves remitidaspara exámenes post mortem en el Laboratorio de Sanidad Animal que completaran un cuestionario diseñado para recopilar información sobre las características de la parvada y su entorno, cómo se manejó la parva y se que medidas de bioseguridad fueron usadas. Se recibieron un total de 153 cuestionarios únicos. El consumo personal de carne o huevo fue la razón más común para tener una parvada pequeña (69.3%). Casi todos los propietarios (97.4%) informaron tener pollos en su propiedad, mientras que el 21.6% tenía aves acuáticas, el 15.7% tenía pavos y el 15.7% tenía aves para caza. Casi el 70% (69.9%) de las parvadas tenían algún grado de acceso al aire libre. Para aquellos con acceso interior, el material de cama más común proporcionado fue viruta de madera blanda (70.2%). Al 65.3% de las parvadas se le ofrecieron desperdicios de cocina o sobras y el agua de pozo fue la fuente más común de agua potable (80.6%). En el caso de las parvadas con acceso al interior, menos de la mitad de los propietarios utilizaron zapatos y ropa especiales para entrar o limpiar los alojamientos y los zapatos rara vez se desinfectaban antes o después del contacto con la parvada. La mayoría de los propietarios (93.8%) informaron lavarse las manos después del contacto con sus aves, aunque solo el 48.3% informó lavarse las manos antes del contacto. Entre los propietarios que obtuvieron aves de una planta incubadora, solo el 36.8% indicó que las aves habían sido vacunadas y el 21.1% no estaba seguro de si se habían administrado vacunas. Entre los propietarios que usaban medicación (60.5%), el uso de antibióticos era común (60.9%). En general, las respuestas al cuestionario describen una amplia gama de prácticas de críanza y bioseguridad, a menudo subóptimas, y señalan la necesidad de material educativo para los propietarios de pequeñas parvadas en Ontario.