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.

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.

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.

Identification and selection of food safety-related risk factors to be included in the Canadian Food Inspection Agency's Establishment-based Risk Assessment model for Hatcheries.

Towards the continuous improvement of its inspection system, the Canadian Food Inspection Agency (CFIA) is developing an Establishment-based Risk Assessment model for Hatcheries to allocate inspection resources based on the food safety risk associated with the Canadian hatcheries falling under its jurisdiction. The objectives of the current study were to identify and select critical food safety-related risk factors that would be included in this model, with a main focus on Salmonella. A literature review was used to develop a comprehensive list of risk factors that could potentially contribute to the food safety risk attributed to Canadian hatcheries operating in all production streams (breeders, layers, broilers, turkeys, waterfowl and game birds). The development of this list used a selection process that was conducted according to the availability of data sources, the clarity of definition and the measurability of the selected risk factors. A panel of experts reviewed and adjusted the identified risk factors. A final list of 29 risk factors was generated; 20 originated from the scientific literature and nine from the expert panel. Risk factors were grouped in three clusters according to whether they pertained to the inherent risk (nine factors identified), risk mitigation (nine factors identified) or compliance of a hatchery with its preventive control plan and regulatory requirements (11 factors identified). Criteria for assessing each risk factor were defined based on common practices used in the Canadian hatchery industry. This comprehensive list of risk factors and criteria represents useful information to support the design and implementation of a Canadian risk assessment model for hatcheries, but could also be used by like-minded food safety authorities.

Evaluating Virulence-Associated Genes and Antimicrobial Resistance of Avian Pathogenic Escherichia coli Isolates from Broiler and Broiler Breeder Chickens in Ontario, Canada.

Avian pathogenic Escherichia coli (APEC) is the causative agent of colibacillosis in poultry, an economically important disease worldwide. In Ontario, Canada, early and late systemic bacterial infections due to APEC were the most commonly reported diseases in broiler chickens. In 2016, Ontario poultry veterinarians submitted samples from 331 cases of broiler and broiler breeder chickens with a high suspicion of colibacillosis to the Animal Health Laboratory (Guelph, Ontario, Canada) for bacterial culture. Escherichia coli isolates from those samples were tested with multiplex PCR to detect the presence of 13 virulence-associated genes. The most common genes identified were sitA (detected in 93% of isolates), iss (88%), iroN (85%), iutA (79%), ompT (77%), and etsB (67%). In 94% of isolates, at least three virulence-associated genes were detected. Antimicrobial susceptibility testing of isolates by using the disk diffusion method revealed high frequencies of resistance to tetracycline (57% of isolates), gentamicin (50%), spectinomycin (46%), and ampicillin (44%). Relatively fewer isolates were resistant to trimethoprim-sulfamethoxazole (18%), ceftiofur (15%), kanamycin (11%), and apramycin (3%). A high proportion (46%) of the isolates were multidrug resistant (≥3 antimicrobial classes). On the basis of multivariable, mixed effects logistic regression models, statistically significant associations ( P ≤ 0.05) were identified between the following: ampicillin resistance and the presence of kpsII (odds ratio [OR] = 1.88), tsh (OR = 0.46), and ireA (OR = 0.32); ceftiofur resistance and etsB (OR = 2.98) and kpsII (OR = 2.61); gentamicin resistance and ompT (OR = 3.89) and sitA (OR = 3.54); kanamycin resistance and papC (OR = 50.10); spectinomycin resistance and ireA (OR = 2.50) and iutA (OR = 3.15); trimethoprim-sulfamethoxazole resistance and ompT (OR = 0.14) and tsh (OR = 0.31); and tetracycline resistance and cvaC (OR = 2.12), eitA (OR = 2.15), and papC (OR = 8.27). On the basis of a multivariable, mixed effects Poisson regression model, the number of antimicrobials to which an isolate was resistant increased with the presence of eitA (risk ratio [RR] = 1.37), iroN (RR = 1.24), papC (RR = 1.34), and sitA (RR = 1.77) and decreased with the presence of tsh (RR = 0.79). On the basis of bivariable logistic regression models, age group and time of sample collection were not significantly associated with resistance to individual antimicrobials, the presence of multidrug resistance, or the presence of virulence-associated genes. Our results provide information on antimicrobial resistance and virulence gene patterns currently present on Ontario broiler chicken and broiler breeder farms that can be used as a benchmark from which to measure changes.

White Chick Syndrome Associated with Chicken Astrovirus in Ontario, Canada.

Sixty-four cases of white chick syndrome (WCS) in broiler breeders producing affected progeny were reported from seven hatcheries in Ontario, Canada, between 2009 and 2016, with 43 of those originating from two hatcheries owned by a single company. WCS cases were identified by the presence of typical chicks in the hatchery that were generally weak with pale to white down, enlarged abdomens, and occasionally brown wiry fluff on the dorsum of the neck. Affected embryos and chicks had characteristic gross and histologic liver lesions, and livers were positive for chicken astrovirus (CAstV) RNA by real-time reverse transcriptase PCR. Affected broiler breeder flocks experienced egg production drops of 0% to 21% and hatchability drops of 0% to 68.4%. The amino acid sequence of the region encoding the capsid gene of WCS viruses demonstrated all Ontario CAstV to be in Group B, Subgroup Bii.

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).

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.

Arthritis and osteomyelitis associated with Enterococcus cecorum infection in broiler and broiler breeder chickens in Ontario, Canada.

In August 2008, an Ontario broiler chicken flock experienced an outbreak of lameness in 4-week-old birds, with morbidity reaching 7% by day 3. Necropsy examination and histopathology revealed arthritis of the hock, stifle, and coxofemoral joints, and femoral and vertebral osteomyelitis. Enterococcus cecorum was isolated from the lesions and identified by 16S ribosomal RNA sequencing. In October 2008, a second case of E. cecorum osteomyelitis involved a flock of 9-week-old broiler breeder chickens, with 2% of the male birds showing reluctance to walk. Necropsy examination revealed osteomyelitis and abscessation of the body of the caudal thoracic vertebra in affected birds, with impingement on the overlying spinal cord.