Seroprevalence of Cache Valley virus and related viruses in sheep and other livestock from Saskatchewan, Canada.

Cache Valley virus, an orthobunyavirus, is an important cause of ovine neonatal malformations. Information on the seroprevalence of this virus in Saskatchewan livestock populations is lacking. The objectives of this study were to determine the seroprevalence of Cache Valley virus and closely related viruses in sheep, cattle, goats, horses, and mule deer in Saskatchewan by performing a plaque-reduction neutralization test using Cache Valley virus. In total, sera from 130 sheep from 50 flocks were tested. Seroprevalence in sheep was 64.6% (84/130) and 94.0% (47/50) of flocks had 1 or more seropositive sheep. Antibodies to Cache Valley virus or closely related viruses were also detected in serum samples collected from cattle, goats, horses, and mule deer with seroprevalences of 20.0% (5/25), 33.3% (8/24), 69.0% (40/58), and 50.8% (33/65), respectively. These results suggest widespread exposure to Cache Valley virus or closely related viruses in domestic animals and mule deer in Saskatchewan.

Séroprevalence du virus de la Vallée Cache ou de virus connexes chez les moutons et d'autres animaux de cheptel en Saskatchewan, Canada. Le virus de la Vallée Cache, un orthobunyavirus, est une cause importante de malformations néonatales ovines. Il manque des renseignements sur la séroprévalence de ce virus dans les populations des cheptels de la Saskatchewan. Les objectifs de cette étude consistaient à déterminer la séroprévalence du virus de la Vallée Cache et des virus étroitement apparentés chez les moutons, les bovins, les chèvres, les chevaux et les cerfs mulets en Saskatchewan en réalisant un test de séro-neutralisation par réduction des plages en utilisant le virus de la Vallée Cache. Au total, le sérum provenant de 130 moutons dans 50 troupeaux a été testé. Chez les moutons, la séroprévalence était de 64,6 % (84/130) et 94,0 % (47/50) des troupeaux avaient un mouton ou plusieurs moutons séropositifs. Les anticorps pour le virus de la Vallée Cache ou les virus étroitement apparentés ont aussi été détectés dans les échantillons de sérum prélevés auprès des bovins, des chèvres, des chevaux et des cerfs mulets avec une séroprévalence de 20,0 % (5/25), de 33,3 % (8/24), de 69,0 % (40/58) et de 50,8 % (33/65), respectivement. Ces résultats suggèrent une vaste exposition au virus de la Vallée Cache ou à des virus étroitement apparentés chez les animaux domestiques et les cerfs mulets en Saskatchewan.(Traduit par Isabelle Vallières).

Prevalence of Maedi-visna in Saskatchewan sheep.

A study was conducted to estimate flock and individual seroprevalence of Maedi-visna in Saskatchewan and evaluate risk factors for seropositive flocks. Thirty-five percent (24/68) of flocks and 4.6% (93/2010) of individual samples were positive. Within-flock prevalence ranged from 3.3% to 96.7%. Significant flock-level predictors of flock prevalence included large flock size, purchasing > 50 sheep and respiratory problems in the previous 5 years.

Prévalence de maedi-visna chez des moutons de la Saskatchewan. Une étude a été réalisée pour estimer la séroprévalence individuelle et dans le troupeau de maedi-visna en Saskatchewan et évaluer les facteurs de risque des troupeaux séropositifs. Trente-cinq pour cent (24/68) des échantillons des troupeaux et 4,6 % (93/2010) des échantillons individuels étaient positifs. La prévalence dans le troupeau variait de 3,3 % à 96,7 %. Les prédicteurs importants au niveau du troupeau incluaient une taille importante du troupeau, l'achat de > 50 moutons et des problèmes respiratoires au cours des cinq années antérieures.(Traduit par Isabelle Vallières).

Disease risks associated with free-ranging wild boar in Saskatchewan.

This study investigated the disease status of Saskatchewan's feral wild boar population. Whole carcasses, tissue samples, and/or serum from 81 hunter-killed boars from Saskatchewan were submitted to the Canadian Wildlife Health Cooperative (CWHC) between 2009 and 2014. Serological tests were negative for PRRS, H1N1, and H3N2 swine influenza, PCV-2, and TGE/PRCV in 22/22 boars and for Toxoplasma gondii and Mycoplasma hyopneumoniae in 20/20 boars. Of 20 boars whose sera were tested 20 were positive for Actinobacillus pleuropneumoniae, with 7 positive for, among other strains, serotype 14; 16 were positive for Lawsonia intracellularis, 1 was positive and 6 were suspicious for Salmonella spp. Polymerase chain reaction tests were negative for PRRS and PCV2 in 58/58 boars and positive for Torque teno virus in 1/8 boars. Digestion assays were negative for Trichinella spp. in 22/22 boars. The high seroprevalence of A. pleuropneumoniae serotype 14 is noteworthy as this serotype has not been previously reported in North America.

Risques de maladie associés au sanglier en liberté en Saskatchewan. Cette étude a examiné l'état des maladies de la population de sangliers féraux de la Saskatchewan. Des carcasses entières, des échantillons de tissus et/ou du sérum provenant de 81 sangliers tués par des chasseurs de la Saskatchewan ont été soumis à la Canadian Wildlife Health Cooperative (CWHC) entre 2009 et 2014. Les tests sérologiques étaient négatifs pour SRRP, l'influenza porcine H1N1 et H3N2, CVP-2 et GET/CVRP chez 22/22 sangliers et pour Toxoplasma gondii et Mycoplasma hyopneumoniae chez 20/20 sangliers. Parmi les 20 sangliers dont le sérum a été analysé, 20 présentaient des résultats positifs pour Actinobacillus pleuropneumoniae, et sept étaient positifs pour le sérotype 14, entre autres souches; 16 étaient positifs pour Lawsonia intracellularis, un était positif et six étaient suspectés pour Salmonella spp. Des tests d'amplification en chaîne par la polymérase ont été négatifs pour SRRP et CVP2 chez 58/58 sangliers et positifs pour le virus torque teno chez 1/8 des sangliers. Des épreuves de digestion ont été négatives pour Trichinella spp. chez 22/22 sangliers. La séroprévalence élevée du sérotype A. pleuropneumoniae 14 mérite d'être signalée car ce sérotype n'a pas été signalé antérieurement en Amérique du Nord.(Traduit par Isabelle Vallières).

A survey to detect Toxocara vitulorum and other gastrointestinal parasites in bison (Bison bison) herds from Manitoba and Saskatchewan.

An egg count survey using environmental fecal samples obtained in spring or early summer was conducted to estimate the apparent prevalence of Toxocara vitulorum in unweaned bison calves and of other intestinal parasites in adult bison on 98 farms in Manitoba and Saskatchewan. Calf samples were pooled (maximum 5 samples per pool) by farm and positive pools were examined to determine individual T. vitulorum counts. Toxocara vitulorum eggs were found on 4 farms in Manitoba and none in Saskatchewan. Apparent herd-level prevalence estimates were 12% [95% confidence interval (95% CI): 3.4% to 28.2%] and 0% (95% CI: 0% to 5.7%) respectively. Samples from adult bison contained eggs/oocysts from trichostrongyle species, Eimeria sp., Monieza sp., Capillaria sp., Nematodirus sp. and Trichuris sp. in 100%, 95%, 72%, 13%, 13%, and 5% of herds, respectively. Strongyloides sp. were not found in any herd. Further studies are needed to assess parasite distribution patterns in bison and to evaluate the risk that T. vitulorum may pose to bison, cattle, and wildlife.

Une enquête pour détecterToxocara vitulorumet d'autres parasites gastro-intestinaux dans des troupeaux de bisons(Bison bison)du Manitoba et de la Saskatchewan. Une enquête sur la numération des œufs à l'aide d'échantillons fécaux environnementaux obtenus au printemps ou au début de l'été a été réalisée afin d'estimer la prévalence apparente de Toxocara vitulorum chez des veaux de bisons non sevrés et d'autres parasites intestinaux chez les bisons adultes dans 98 fermes du Manitoba et de la Saskatchewan. Les échantillons des veaux ont été regroupés (maximum de 5 échantillons par groupe) par ferme et les groupes positifs ont été examinés afin de déterminer les numérations individuelles de T. vitulorum. Des œufs de Toxocara vitulorum ont été trouvés dans 4 fermes au Manitoba et dans aucune ferme en Saskatchewan. Les estimations de prévalence apparentes au niveau du troupeau étaient de 12 % (intervalle de confiance de 95 % [IC de 95 %] : de 3,4 % à 28,2 %) et 0 % (IC de 95 % : de 0 % à 5,7 %) respectivement. Les échantillons des bisons adultes contenaient des œufs/ookystes d'espèces de trichostrongyles, Eimeria sp., Monieza sp., Capillaria sp., Nematodirus sp. et Trichuris sp. dans 100 %, 95 %, 72 %, 13 %, 13 % et 5 % des troupeaux, respectivement. Strongyloides sp. n'a pas été trouvé dans aucun troupeau. De nouvelles études sont requises pour évaluer les tendances de distribution des parasites chez les bisons et le risque que T. vitulorum puisse poser pour les bisons, le bétail et la faune.(Traduit par Isabelle Vallières).

A systematic review-meta-analysis and meta-regression on the effect of selected competitive exclusion products on Salmonella spp. prevalence and concentration in broiler chickens.

The effectiveness of various competitive exclusion (CE) products for reducing Salmonella colonization in broiler chickens was evaluated using systematic review-meta-analysis-meta-regression (SR-MA-MR). Relevance screening identified 201 relevant studies that were subjected to methodological assessment. Of these studies, 159 were suitable for data extraction, 66 were presented in a number of MAs and 130 were examined in a meta-regression (MR). Fourteen different CE products were identified, 9 of them commercial products, and the most common route of administration was oral gavage (63.7% of trials). Meta-analyses indicated that a number of CE products reduce Salmonella colonization in broilers, the most effective one being Preempt™ which was formerly known as CF-3. Five study characteristics (publication year, CE type, CE route, sample origin, and Salmonella serovar administered/recovered) and three methodological soundness characteristics (treatment assignment, intervention and laboratory methods description) were retained as statistically significant (p<0.05) in the final MR model. The MR analysis indicated that, undefined CE products outperformed all commercial products, except for: Preempt™ and Broilact(®). Both were considered comparable to the undefined chicken source CE culture products in effectiveness. The administration of CE through spraying the chicks at the hatchery was determined to be just as effective as the oral gavage treatment, and more practical for farmers to administer. The results of this study could be useful in decision-making concerning the on-farm use of CE products in broiler chickens, and as inputs for risk assessments as the industry pushes for more antibiotic-free alternatives. Out of the various interventions to reduce Salmonella colonization in broilers on-farm, CE was the most studied; its inability to be licenced in certain countries and proof of consistent efficacy remains a barrier.

The effectiveness of selected feed and water additives for reducing Salmonella spp. of public health importance in broiler chickens: a systematic review, meta-analysis, and meta-regression approach.

Eating inappropriately prepared poultry meat is a major cause of foodborne salmonellosis. Our objectives were to determine the efficacy of feed and water additives (other than competitive exclusion and antimicrobials) on reducing Salmonella prevalence or concentration in broiler chickens using systematic review-meta-analysis and to explore sources of heterogeneity found in the meta-analysis through meta-regression. Six electronic databases were searched (Current Contents (1999-2009), Agricola (1924-2009), MEDLINE (1860-2009), Scopus (1960-2009), Centre for Agricultural Bioscience (CAB) (1913-2009), and CAB Global Health (1971-2009)), five topic experts were contacted, and the bibliographies of review articles and a topic-relevant textbook were manually searched to identify all relevant research. Study inclusion criteria comprised: English-language primary research investigating the effects of feed and water additives on the Salmonella prevalence or concentration in broiler chickens. Data extraction and study methodological assessment were conducted by two reviewers independently using pretested forms. Seventy challenge studies (n=910 unique treatment-control comparisons), seven controlled studies (n=154), and one quasi-experiment (n=1) met the inclusion criteria. Compared to an assumed control group prevalence of 44 of 1000 broilers, random-effects meta-analysis indicated that the Salmonella cecal colonization in groups with prebiotics (fructooligosaccharide, lactose, whey, dried milk, lactulose, lactosucrose, sucrose, maltose, mannanoligosaccharide) added to feed or water was 15 out of 1000 broilers; with lactose added to feed or water it was 10 out of 1000 broilers; with experimental chlorate product (ECP) added to feed or water it was 21 out of 1000. For ECP the concentration of Salmonella in the ceca was decreased by 0.61 log(10)cfu/g in the treated group compared to the control group. Significant heterogeneity (Cochran's Q-statistic p≤0.10) was observed among studies examining all organic acids (controlled or challenge experiments), butyric acid, formic acid, a formic/propionic acid mixture, fermented liquid feed, and D-mannose. Meta-regressions were conducted to examine the source of heterogeneity among studies. For prevalence outcomes, 36% and 60% of the total variance was within and between studies, respectively. For concentration outcomes, 39% and 33% of the total variance was within and between studies, respectively. Inadequate blinding and randomization was common, and no studies undergoing meta-analysis or meta-regression were conducted on a commercial farm. The strength of evidence of the effect of these additives was very low. Studies conducted under commercial conditions are needed to understand the potential benefit of these interventions for the poultry industry and to improve the strength of evidence of the effectiveness of these additives.

Assessment of the efficacy and quality of evidence for five on-farm interventions for Salmonella reduction in grow-finish swine: a systematic review and meta-analysis.

Five on-farm practices for reduction of Salmonella shedding or sero-prevalence in grow-finish swine were selected through scoping study and expert consultation. Specific examples were selected based on supporting evidence from at least one controlled trial (CT), and availability to Canadian swine producers. Efficacy was evaluated using systematic review and meta-analysis (SR-MA) methodology. A modified Grading of Recommendations, Assessment, and Evaluation (GRADE) approach was applied to assess the quality of evidence for each intervention, and a 'summary of findings' table was developed to present findings 'at-a-glance'. MA of the small dataset of CTs investigating feeding meal, and measuring serology, yielded a significant summary estimate of efficacy (odds ratio (OR)=0.21; 95% confidence intervals (CI): 0.14, 0.31) with non-significant heterogeneity (P>0.10). MA of the dataset investigating inclusion of organic acids in the ration, measuring serology, yielded a significant summary estimate with significant heterogeneity across studies (P<0.001, I(2)=91%) precluding presentation of a single summary estimate; a range of results were reported (OR Range: 28 (1.6, 498); 0.07 (CI: 0.042, 0.33)). Pen disinfection between batches of finishers was studied in one large CT measuring both fecal culture (OR 0.84 (0.68, 1.1)) and serology (OR 0.48 (0.40, 0.58)) outcomes. The dataset investigating Salmonella spp. vaccination contained inconsistent findings (OR Range: 4.5 (1.3, 15); 0.07 (0.008, 0.68)), with significant heterogeneity across studies (P=0.005, I(2)=82), assessed measuring fecal culture. MA of the dataset investigating inclusion of in-feed tetracyclines yielded a significant OR indicating a potential harmful effect, measuring fecal culture, (OR Range: 14 (1.9, 108); 1.0 (0.43, 2.5)) with significant heterogeneity (P=0.003, I(2)=82%) across studies, suggesting some potential for withdrawal of in-feed tetracyclines to reduce Salmonella shedding. Therefore our ranking of intervention efficacy is: feeding meal>inclusion of acids in ration, feeder pen disinfection or Salmonella spp. vaccination>in-feed tetrayclines. Study design characteristics increasing risk of bias, including failure to justify sample size (19 of 31 studies) and failure to report random or systematic sampling (13 of 31 studies), resulted in modified GRADE evidence rankings of 'low' for these interventions. This suggests that further research is likely to affect our findings. Field CTs investigating herd-level interventions with measurements at the herd- and individual-levels are recommended. Overall, SR-MA was a useful approach for ranking efficacy, and GRADE offered a transparent method for ranking quality of evidence, although both were limited by the small number of comparable studies available.

Prevalence of zoonotic bacteria in wild and farmed aquatic species and seafood: a scoping study, systematic review, and meta-analysis of published research.

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

A systematic review-meta-analysis of chilling interventions and a meta-regression of various processing interventions for Salmonella contamination of chicken.

CONTEXT: The results of individual studies investigating the efficacy of chilling and other processing interventions on Salmonella prevalence or concentration in broiler chicken carcasses are inconsistent or contradictory. OBJECTIVE: Determine efficacy of chilling on reducing Salmonella prevalence or concentration on broiler carcasses using systematic review-meta-analysis, and explore sources of heterogeneity among studies investigating various processing interventions through meta-regression. DATA SOURCES: A comprehensive search included electronic search in six databases, manual search of reference lists of topic-related articles, and consultation with five topic experts to assure that all relevant intervention research was identified. STUDY INCLUSION: Primary intervention research, published in English, encompassing control, challenge, cohort, or before-and-after study designs investigating the efficacy of any chilling or other processing interventions on Salmonella prevalence or concentration in broiler chicken carcasses. RISK OF BIAS ASSESSMENT AND DATA EXTRACTION: Data pertaining to study methodology and reported results, chilling or other processing intervention parameters, populations sampled and outcomes measured were assessed for methodological soundness and extracted by two independent reviewers using pretested checklists. RESULTS: Random-effects meta-analyses of immersion chilling with chlorine (n=9 trials), acetic acid (n=16) and potable water (n=13) trended towards reductions in the odds or log(10)CFU/ml of Salmonella. Significant heterogeneity (P-value≤0.1 and I(2)>25%) precluded the reporting of pooled summary effect estimates. Meta-regression of all processing interventions indicated that serotype, disinfectant type and treatment time and pH were significantly associated with studies reporting reductions in concentration while study design, population sampled, study setting, publication date, intervention and disinfectant type, and treatment pH were significantly associated with studies reporting reductions in prevalence. Methodological and reporting flaws were consistently observed in relevant intervention research as well as a lack of studies conducted under commercial conditions and using Salmonella concentration outcomes. CONCLUSIONS: Chilling may be effective at reducing Salmonella concentration and prevalence, but significant heterogeneity precluded reporting of pooled summary effect estimates for many chilling interventions. Investigations into potential sources of heterogeneity among all processing interventions found that the use of other chemical disinfectants, such as organic acids and surfactants might result in larger reductions in Salmonella contamination than more commonly utilized oxidizing agents like chlorine.

Comparison of bacterial culture, polymerase chain reaction, and a mix-enzyme-linked immunosorbent assay for the detection of Salmonella status in grow-to-finish pigs in western Canada with a Bayesian approach.

Among grow-to-finish pigs from 10 herds in Alberta and Saskatchewan, 23 (16%) of 144 fecal samples were culture-positive and 40 (28%) of 144 pigs were seropositive for Salmonella. With a Bayesian model specifying dependence between the 2 tests, the sensitivity (Se) of culture and real-time polymerase chain reaction (RT-PCR) was 79% to 86%, depending on the cut-off value for the enzyme-linked immunosorbent assay (ELISA). Culture specificity (Sp) was assumed to be 100%; RT-PCR Sp was found to be 94%. The ELISA Se was 76% and 51% at optical density cut-off values ≥ 20% and ≥ 40%, respectively; the Sp was 94% at each cut-off value. The model showed some sensitivity to ELISA prior information, the ELISA Se being approximately 8% lower when informative prior information was specified in the model. When there was no adjustment for dependence between culture and RT-PCR, the posterior estimates for both culture and RT-PCR Se were 11% higher than with the conditional-dependence model and had considerably narrower probability intervals, which suggests that correlation between culture and PCR is important and should be adjusted for in future studies.

Distribution of Salmonella serovars in breeding, nursery, and grow-to-finish pigs, and risk factors for shedding in ten farrow-to-finish swine farms in Alberta and Saskatchewan.

The study objectives were to investigate Salmonella prevalence, serovar distribution, and risk factors for shedding in 10 purposively selected farrow-to-finish farms in Saskatchewan and Alberta. Pooled fecal samples from the breeding and grow-finish phases and individual fecal samples from breeding, nursery, and grow-finish pigs were cultured for Salmonella; serotyping of isolates was performed. Pig and pen characteristics were recorded for each pig and pen sampled.Overall, 407/1143 (36%) of samples were Salmonella positive; within-farm prevalence ranged from 1% to 79%. Sows, nursery, and grow-finish pigs accounted for 43%, 29%, and 28% of positive samples, respectively. More Salmonella were detected in pooled pen than individual pig samples (P < 0.001). Among 418 Salmonella isolates, there were 19 distinct serovars; the most common were S. Derby (28.5%), S. Typhimurium, var. Copenhagen (19.1%), S. Putten (11.8%), S. Infantis (6.8%), and S. Mbandaka (6.1%). Sows were more likely to shed Salmonella than nursery or grow-finisher (OR 2.9, P < 0.001) pigs. Pelleted feed (OR 8.2, P < 0.001) and nose-to-nose pig contact through pens (OR 2.2, P = 0.005) were associated with increased Salmonella prevalence. Significant differences in serovar distribution were detected among production phases. The use of pooled pen samples is recommended as a more efficient means for accurate evaluation of Salmonella status in different phases of pig production. The breeding herd might be an important source of Salmonella persistence within farrow-to-finish farms and should be targeted in control efforts. The latter might also apply to the use of pelleted feed, which remains the most consistently reported significant risk factor for Salmonella shedding in pigs.

Antimicrobial use through feed, water, and injection in 20 swine farms in Alberta and Saskatchewan.

Antimicrobial resistance (AMR) is an emerging animal welfare and public health issue linked to antimicrobial use (AMU) in livestock. This study was conducted in 2004 on 20 swine farms in Alberta and Saskatchewan. On-farm records and questionnaires were used to retrospectively describe the antimicrobial exposures of pigs through feed, water, and injection. Antimicrobial use in all production categories was described over 12 months. On-farm records and questionnaires provided sufficient data to describe antimicrobial exposure rates through feed and water. In contrast, on-farm records did not supply sufficient data to describe parenteral antimicrobial exposure rates. Records lacked data on the number of exposures per treatment, therefore parenteral AMU was described as an exposure incidence. Parenteral exposure records were often unavailable for pigs less than 22 kg, in which case questionnaires were used. The incidence of parenteral AMU was significantly higher in herds reporting exposure by questionnaire compared with existing records, suggesting that on-farm records did not reliably describe parenteral AMU. However, because antimicrobial exposures in feed and water were markedly more common than through injection, it was concluded that existing on-farm data would be a valuable resource for investigating AMU and AMR in pigs.