Risk factors for canine infectious respiratory disease complex and the pathogens associated with the disease.

Background: Canine infectious respiratory disease complex (CIRDC) is a common respiratory condition typically associated with high-density populations. Objectives: The objectives of this study were to determine the most common pathogens involved in CIRDC and to identify risk factors (pathogens, environmental exposures) associated with the diagnosis. Animals and procedure: A prospective, multi-clinic, case-control study was conducted in Canada from April 2017 to May 2018. A total of 110 dogs (74 cases, 36 controls) were enrolled by participating veterinary clinics. Pathogens were detected using a respiratory PCR panel. Results: Canine parainfluenza virus (CPIV), Bordetella bronchiseptica, and canine respiratory coronavirus (CRCoV) were detected in cases only. According to 2 logistic regression models, detection of CPIV (OR: 14.42; 95% CI: 2.24 to ∞) and CRCoV (OR: 8.64; 95% CI: 1.26 to ∞) were associated with CIRDC disease status. In another model, exposures to multiple-dog gatherings also increased the odds (OR: 3.39; 95% CI: 1.26 to 9.81) of CIRDC diagnosis. Conclusions: Consistent with other studies, this study determined that CPIV, CRCoV, and B. bronchiseptica were important contributors to CIRDC cases. Detection of CPIV and CRCoV and exposure to areas of dog gatherings were identified as having a role in disease status when evaluated statistically, under the conditions of this study.

Facteurs de risque du complexe de maladies respiratoires infectieuses canines et agents pathogènes associés à la maladie. Contexte: Le complexe de maladies respiratoires infectieuses canines (CIRDC) est une affection respiratoire courante généralement associée aux populations à forte densité. Objectifs: Les objectifs de cette étude étaient de déterminer les agents pathogènes les plus courants impliqués dans le CIRDC et d'identifier les facteurs de risque (agents pathogènes, expositions environnementales) associés au diagnostic. Animaux et procédure: Une étude prospective multi-clinique cas-témoins a été menée au Canada d'avril 2017 à mai 2018. Au total, 110 chiens (74 cas, 36 témoins) ont été recrutés par les cliniques vétérinaires participantes. Les agents pathogènes ont été détectés à l'aide d'un panel de PCR respiratoire. Résultats: Le virus parainfluenza canin (CPIV), Bordetella bronchiseptica et le coronavirus respiratoire canin (CRCoV) n'ont été détectés que dans les cas. Selon 2 modèles de régression logistique, la détection de CPIV (OR: 14,42; IC à 95 %: 2,24 à ∞) et de CRCoV (OR: 8,64; IC à 95 %: 1,26 à ∞) était associée au statut de la maladie CIRDC. Dans un autre modèle, l'exposition à des rassemblements de plusieurs chiens augmentait également les chances (OR: 3,39; IC à 95 %: 1,26 à 9,81) de diagnostic de CIRDC. Conclusions: Conformément à d'autres études, cette étude a déterminé que CPIV, CRCoV et B. bronchiseptica étaient des contributeurs importants aux cas de CIRDC. La détection de CPIV et de CRCoV et l'exposition à des zones de rassemblement de chiens ont été identifiées comme ayant un rôle dans le statut de la maladie lorsqu'elles ont été évaluées statistiquement, dans les conditions de cette étude.(Traduit par Dr Serge Messier).

Occurrence of porcine reproductive and respiratory syndrome clinical outbreaks in Ontario sow herds, 2017 to 2019.

Background: Porcine reproductive and respiratory syndrome (PRRS) is one of the important endemic diseases in swine populations. Monitoring PRRS frequency in commercial herd populations has often been based on laboratory submissions. However, a limitation of this approach is that new clinical outbreaks of PRRS are challenging to identify if epidemiological information is not provided. This hinders the estimation of basic measures such as incidence. Objectives: The objectives of this study were to describe a system to monitor new clinical outbreaks in Ontario sow herds and to report the incidence of clinical PRRS outbreaks in a subset of Ontario sow herds. Procedure: We compared herd-level outbreak data from January 1, 2017 to December 31, 2019. Cases were confirmed as positive based on observation of sow herds with typical clinical signs suggestive of PRRS, followed by laboratory confirmation of the PRRS virus. Results and conclusion: The incidences from year to year were similar (P = 0.058) and were lower compared to estimates in the United States. Descriptively, the highest cumulative incidence was during 2018 (annual incidence risk = 0.067 cases per 100 sow herds, 95% CI = 0.050 to 0.090). This was characterized by an unusually high number of cases reported in the summer.

Occurrence d'éclosions cliniques de syndrome reproducteur et respiratoire porcin dans les troupeaux de truies de l'Ontario, 2017 à 2019. Contexte: Le syndrome reproducteur et respiratoire porcin (SRRP) est l'une des maladies endémiques les plus importantes dans les populations porcines. La surveillance de la fréquence du SRRP dans les troupeaux commerciaux s'est souvent basée sur les soumissions au laboratoire. Cependant, une limitation de cette approche est que les nouvelles éclosions cliniques de SRRP sont difficiles à identifier si les informations épidémiologiques ne sont pas fournies. Cela limite l'estimation de mesures de base telles que l'incidence. Objectifs: Les objectifs de cette étude étaient de décrire un système de surveillance des nouvelles éclosions cliniques dans les troupeaux de truies de l'Ontario et de signaler l'incidence des éclosions cliniques de SRRP dans un sous-ensemble de troupeaux de truies de l'Ontario. Procédure: Nous avons comparé les données épidémiques au niveau du troupeau du 1er janvier 2017 au 31 décembre 2019. Les cas ont été confirmés comme positifs sur la base de l'observation de troupeaux de truies présentant des signes cliniques typiques suggérant le SRRP, suivis d'une confirmation en laboratoire du virus du SRRP. Résultats et conclusion: Les incidences d'une année à l'autre étaient similaires (P = 0,058) et étaient inférieures aux estimations aux États-Unis. De manière descriptive, l'incidence cumulative la plus élevée a eu lieu en 2018 (risque d'incidence annuel = 0,067 cas pour 100 troupeaux de truies, IC à 95 % = 0,050 à 0,090). Cette situation était caractérisée par un nombre inhabituellement élevé de cas signalés en été.(Traduit par Dr Serge Messier).

Isolation of Elizabethkingia spp. from Diagnostic Specimens from Dogs and Cats, United States, 2019-2021.

We retrospectively reviewed Elizabethkingia spp. culture and susceptibility results from 86 veterinary diagnostic laboratory results from US dogs and cats. We noted 26 E. menigoseptica, 1 E. miricola, and 59 unspeciated Elizabethkingia isolates from 9 US states (2-22 isolates per state). Elizabethkingia infections in animals might increase risks to humans.

Serum concentrations of brain-derived neurotrophic factor as a potential biomarker of swine welfare.

Objective: Describe concentrations of brain-derived neurotrophic factor (BDNF) detectable in piglet sera before and after road transport, and evaluate the correlation of serum BDNF with other physiological parameters used to assess swine welfare. Animals: Commercial crosses of piglets that underwent weaning and transport at approximately 3 wk of age. Procedure: Sixteen piglets were randomly selected from a larger study for complete blood counts, serum biochemistry testing, cortisol assays, and BDNF assays. Samples were collected 1 d before transport and immediately after transport (> 30 h) under commercial conditions. We assessed the change in serum BDNF concentration; and the correlations between serum BDNF and serum cortisol, neutrophil to lymphocyte ratios (N:L), glucose, and hematological indicators of muscle fatigue. Results: Serum BDNF concentrations increased after transport (P < 0.05) and changed inversely compared to cortisol and N:L. Consistent correlations between BDNF and other physiological parameters were not observed. High inter-pig variation in serum BDNF was present at both sample times. Conclusions: Serum BDNF may be used as an additional indicator of swine welfare. Further research characterizing piglet BDNF concentrations in response to conditions promoting positive or negative affective states would be valuable. Clinical relevance: This communication discusses common hematological parameters used to quantify changes in pig welfare and introduces BDNF, which is a parameter of interest in human cognitive functioning research that may be useful for evaluating the effect of exposure to beneficial or aversive stimuli in animals. The implications of variation in sample collection, handling, and storage procedures for BDNF detection are highlighted.

Concentrations sériques du facteur neurotrophique dérivé du cerveau en tant que biomarqueur potentiel du bien-être des porcs. Objectif: Décrire les concentrations de facteur neurotrophique dérivé du cerveau (BDNF) détectables dans les sérums de porcelets avant et après le transport routier, et évaluer la corrélation du BDNF sérique avec d'autres paramètres physiologiques utilisés pour évaluer le bien-être des porcs. Animaux: Croisements commerciaux de porcelets qui ont été sevrés et transportés à l'âge d'environ 3 semaines. Procédure: Seize porcelets ont été sélectionnés au hasard dans une étude plus vaste pour une numération globulaire complète, des tests de biochimie sérique, des dosages de cortisol et des dosages de BDNF. Les échantillons ont été prélevés 1 jour avant le transport et immédiatement après le transport (> 30 h) dans des conditions commerciales. Nous avons évalué la variation de la concentration sérique de BDNF; et les corrélations entre le BDNF sérique et le cortisol sérique, les rapports neutrophiles/lymphocytes (N:L), le glucose et les indicateurs hématologiques de la fatigue musculaire. Résultats: Les concentrations sériques de BDNF ont augmenté après le transport (P < 0,05) et ont changé inversement par rapport au cortisol et à N:L. Des corrélations cohérentes entre le BDNF et d'autres paramètres physiologiques n'ont pas été observées. Une forte variation inter-porcs du BDNF sérique était présente aux deux moments d'échantillonnage. Conclusions: Le BDNF sérique peut être utilisé comme indicateur supplémentaire du bien-être des porcs. Des recherches supplémentaires caractérisant les concentrations de BDNF chez les porcelets en réponse à des conditions favorisant des états affectifs positifs ou négatifs seraient utiles. Pertinence clinique: Cette communication traite des paramètres hématologiques courants utilisés pour quantifier les changements dans le bien-être des porcs et présente le BDNF, qui est un paramètre d'intérêt dans la recherche sur le fonctionnement cognitif humain qui peut être utile pour évaluer l'effet de l'exposition à des stimuli bénéfiques ou aversifs chez les animaux. Les implications pour la détection par le BDNF des variations dans les procédures de collecte, de manipulation et de stockage des échantillons sont mises en évidence.(Traduit par Dr Serge Messier).

Assessment of exposure to influenza A viruses in pigs between weaning and market age.

Influenza A viruses (IAVs) are common causes of respiratory infection in pigs. The objective of this study was to characterize the circulation of IAVs between weaning and market age on the basis of development of antibody response and molecular epidemiology of detected viruses. Two batches of weaned pigs were followed in the nursery and finisher barns with a sample of 81 and 75 pigs. Nasal swabs and blood samples were collected from individual pigs for virological and serological analyses. A H3N2 subtype virus, of cluster IV, was detected in Study 1, with a maximum of 97.9% identity to HA gene of viruses previously isolated in Ontario. In Study 2, a H1N1 subtype virus, of 2009 H1N1 pandemic lineage, was detected, with a maximum of 97.8% identity to HA gene of viruses previously isolated in Ontario. On the basis of HA gene, it was observed that pigs were being detected with the same virus over time. The existence of antibody titers for IAV other than the isolated one confirmed that more than one subtype can circulate in the same population. In Study 1, pigs with higher numbers of IAV detection had lower serological titers for the same virus that was confirmed to circulate in the nursery (P < 0.01). Thorough knowledge of all endemic viral strains is fundamental for development of infection and disease control, particularly in complex production systems. This may include consideration of sampling and testing strategies which could detect circulation of all IAV variants, even if they have low prevalence.

Quantifying contact patterns in response to COVID-19 public health measures in Canada.

BACKGROUND: A variety of public health measures have been implemented during the COVID-19 pandemic in Canada to reduce contact between individuals. The objective of this study was to provide empirical contact pattern data to evaluate the impact of public health measures, the degree to which social contacts rebounded to normal levels, as well as direct public health efforts toward age- and location-specific settings. METHODS: Four population-based cross-sectional surveys were administered to members of a paid panel representative of Canadian adults by age, gender, official language, and region of residence during May (Survey 1), July (Survey 2), September (Survey 3), and December (Survey 4) 2020. A total of 4981 (Survey 1), 2493 (Survey 2), 2495 (Survey 3), and 2491 (Survey 4) respondents provided information about the age and setting for each direct contact made in a 24-h period. Contact matrices were constructed and contacts for those under the age of 18 years imputed. The next generation matrix approach was used to estimate the reproduction number (Rt) for each survey. Respondents with children under 18 years estimated the number of contacts their children made in school and extracurricular settings. RESULTS: Estimated Rt values were 0.49 (95% CI: 0.29-0.69) for May, 0.48 (95% CI: 0.29-0.68) for July, 1.06 (95% CI: 0.63-1.52) for September, and 0.81 (0.47-1.17) for December. The highest proportion of reported contacts occurred within the home (51.3% in May), in 'other' locations (49.2% in July) and at work (66.3 and 65.4% in September and December). Respondents with children reported an average of 22.7 (95% CI: 21.1-24.3) (September) and 19.0 (95% CI 17.7-20.4) (December) contacts at school per day per child in attendance. CONCLUSION: The skewed distribution of reported contacts toward workplace settings in September and December combined with the number of reported school-related contacts suggest that these settings represent important opportunities for transmission emphasizing the need to support and ensure infection control procedures in both workplaces and schools.

Choosing which metrics to use when reporting antimicrobial use information to veterinarians in the Canadian swine industry.

The objective of this study was to evaluate preferences for various metrics and denominators among Canadian swine veterinarians, in order to improve reporting of antimicrobial use (AMU) information to these stakeholders and to facilitate enhanced stewardship decisions. An online survey was made available to swine veterinarians across Canada; 12 responses (estimated response rate 17.6%) were submitted and analyzed. Responses represented veterinarians from every major pig-producing province and from a range of year of graduation from veterinary college. Participants self-evaluated their understanding of dose-based metrics as higher than weight- and frequency-based metrics and interpreted most results of AMU analyses correctly. Participants preferred dose-based metrics over others, and had various objectives for AMU information, including improving AMU on their clients' farms and enabling comparisons with other farms. The results are useful to those making decisions about which AMU metrics to use in reports targeted to swine veterinarians.

Choix des paramètres à utiliser lors de la communication d'informations sur l'utilisation des antimicrobiens aux vétérinaires de l'industrie porcine canadienne. L'objectif de la présente étude était d'évaluer les préférences pour divers paramètres et dénominateurs chez les vétérinaires porcins canadiens, afin d'améliorer la déclaration de l'information sur l'utilisation d'antimicrobiens (UMA) à ces intervenants et de faciliter des décisions de gérance améliorées. Un sondage en ligne a été mis à la disposition des vétérinaires porcins partout au Canada; 12 réponses (taux de réponse estimé à 17,6 %) ont été soumises et analysées. Les réponses représentaient des vétérinaires de toutes les grandes provinces productrices de porcs et d'une gamme d'années d'obtention du diplôme d'un collège vétérinaire. Les participants ont auto-évalué leur compréhension des mesures basées sur la dose comme étant supérieure aux mesures basées sur le poids et la fréquence et ont interprété correctement la plupart des résultats des analyses UMA. Les participants préféraient les mesures basées sur la dose aux autres, et avaient divers objectifs pour l'information sur l'UMA, notamment l'amélioration de l'UMA dans les fermes de leurs clients et la possibilité de comparer avec d'autres fermes. Les résultats sont utiles à ceux qui prennent des décisions sur les paramètres d'UMA à utiliser dans les rapports destinés aux vétérinaires porcins.(Traduit par Dr Serge Messier).

A within-host mathematical model of H9N2 avian influenza infection and type-I interferon response pathways in chickens.

Chickens infected with avian influenza virus (AIV) transmit the virus via respiratory and cloacal shedding. While previous mathematical models have shown that the innate immune response is necessary for the early suppression of virus production in infected respiratory cells, the different pathways by which the innate immune response can affect cloacal viral shedding have not been studied in chickens. The present study aims to evaluate the sensitivity of H9N2 low pathogenic AIV shedding in chicken gastrointestinal cells to different type-I interferon (IFN) response pathways, and to determine the impact of a cellular eclipse phase (latent period) on the time to peak virus shedding using a mathematical model describing within host viral kinetics. Our model results demonstrate that a mechanistic model that incorporates 1) the intracellular antiviral effects of type-I IFN on virus production, 2) destruction of infected cells by type-I IFN activated Natural Killer cells, and 3) an eclipse phase is most consistent with experimental cloacal virus shedding data. These results provide a potential mechanistic explanation for the delay to peak cloacal virus shedding observed in experimental studies conducted in chickens, as well as an improved understanding of the primary type-I IFN pathways involved in the control of cloacal virus shedding, which may lead to the development of more targeted vaccine candidates.

Veterinarian barriers to knowledge translation (KT) within the context of swine infectious disease research: an international survey of swine veterinarians.

BACKGROUND: Food animal veterinarians face commodity specific and urgent global challenges yet conditions preventing use of best available knowledge have been sparsely studied. The American Association of Swine Veterinarians (AASV) membership (N = 1289) was surveyed online to benchmark their information priorities and their motivations and sources for keeping current with infectious disease research, and to describe their reported time, skill, access, and process as barriers to knowledge translation (KT). RESULTS: Respondents (n = 80) were mostly from Canada (n = 40) and the U.S.A (n = 31) and demographics approximated the AASV's. Colleagues are the first choice for information on difficult cases (49%, 95%CI: 38-61). Half of respondents (53%, 95%CI: 41-64) spend an hour or less per week keeping up with infectious disease research. The majority reported moderate or less than moderate efficiency (62%, 95%CI: 51-72), and moderate or greater stress (59%, 95%CI: 48-70) with their process for keeping up. Journal article methods sections are commonly not read, almost a third (32%, 95% CI: 22-43) reported either they do not evaluate statistical methods or that they had poor confidence to do so, and half (52, 95%CI: 41-63) could not explain 'confounding bias'. Approximately half (55%, 95%CI: 41-69) with direct oversight of swine herds had full access to 2 or fewer academic journals. Approximately a third of respondents (34%, 95%CI: 24-46) selected only formats involving single research studies (either full text or summaries) as preferred reading materials for keeping current over expert summaries of the body of evidence. CONCLUSION: KT barriers are considerable and a source of stress for many swine veterinarians. Sub-optimal efficiency with keeping up and low confidence to appraise aspects of research are concerns. Results are consistent with previous literature and illustrate need for improved KT infrastructure and for additional training in statistical methods and interpretation of primary research. Further evaluation is warranted of why approximately a third of veterinarians in this study, for the purpose of keeping up, preferentially choose to review individual research studies over choices that would include an expert summary of the body of evidence. Consideration of reasons for this preference will be important in the planning of KT infrastructure improvements.

A case-crossover analysis of the impact of weather on primary cases of Middle East respiratory syndrome.

BACKGROUND: Middle East respiratory syndrome coronavirus (MERS-CoV) is endemic in dromedary camels in the Arabian Peninsula, and zoonotic transmission to people is a sporadic event. In the absence of epidemiological data on the reservoir species, patterns of zoonotic transmission have largely been approximated from primary human cases. This study aimed to identify meteorological factors that may increase the risk of primary MERS infections in humans. METHODS: A case-crossover design was used to identify associations between primary MERS cases and preceding weather conditions within the 2-week incubation period in Saudi Arabia using univariable conditional logistic regression. Cases with symptom onset between January 2015 - December 2017 were obtained from a publicly available line list of human MERS cases maintained by the World Health Organization. The complete case dataset (N = 1191) was reduced to approximate the cases most likely to represent spillover transmission from camels (N = 446). Data from meteorological stations closest to the largest city in each province were used to calculate the daily mean, minimum, and maximum temperature (οC), relative humidity (%), wind speed (m/s), and visibility (m). Weather variables were categorized according to strata; temperature and humidity into tertiles, and visibility and wind speed into halves. RESULTS: Lowest temperature (Odds Ratio = 1.27; 95% Confidence Interval = 1.04-1.56) and humidity (OR = 1.35; 95% CI = 1.10-1.65) were associated with increased cases 8-10 days later. High visibility was associated with an increased number of cases 7 days later (OR = 1.26; 95% CI = 1.01-1.57), while wind speed also showed statistically significant associations with cases 5-6 days later. CONCLUSIONS: Results suggest that primary MERS human cases in Saudi Arabia are more likely to occur when conditions are relatively cold and dry. This is similar to seasonal patterns that have been described for other respiratory diseases in temperate climates. It was hypothesized that low visibility would be positively associated with primary cases of MERS, however the opposite relationship was seen. This may reflect behavioural changes in different weather conditions. This analysis provides key initial evidence of an environmental component contributing to the development of primary MERS-CoV infections.

Impact of alignment algorithm on the estimation of pairwise genetic similarity of porcine reproductive and respiratory syndrome virus (PRRSV).

BACKGROUND: Porcine reproductive and respiratory syndrome (PRRS) is a major threat to the swine industry. It is caused by the PRRS virus (PRRSV). Determination and comparison of the nucleotide sequences of PRRSV strains provides useful information in support of control initiatives or epidemiological studies on transmission patterns. The alignment of sequences is the first step in analyzing sequence data, with multiple algorithms being available, but little is known on the impact of this methodological choice. Here, a study was conducted to evaluate the impact of different alignment algorithms on the resulting aligned sequence dataset and on practical issues when applied to a large field database of PRRSV open reading frame (ORF) 5 sequences collected in Quebec, Canada, from 2010 to 2014. Five multiple sequence alignment programs were compared: Clustal W, Clustal Omega, Muscle, T-Coffee and MAFFT. RESULTS: The resulting alignments showed very similar results in terms of average pairwise genetic similarity, proportion of pairwise comparisons having ≥97.5% genetic similarity and sum of pairs (SP) score, except for T-Coffee where increased length of aligned datasets as well as limitation to handle large datasets were observed. CONCLUSIONS: Based on efficiency at minimizing the number of gaps in different dataset sizes with default open gap values as well as the capability to handle a large number of sequences in a timely manner, the use of Clustal Omega might be recommended for the management of PRRSV extensive database for both research and surveillance purposes.

Field studies evaluating the direct, indirect, total, and overall efficacy of Streptococcus suis autogenous vaccine in nursery pigs.

Vaccine effectiveness (VE) was evaluated on a farrow-to-finish farm experiencing mortality due to Streptococcus suis. Direct, indirect, total, and overall vaccine effectiveness were analyzed by vaccinating only 75% of pigs in each litter. Cox's regression and logistic regression revealed total and overall VE to be 27% and 21%, respectively.

Études sur le terrain évaluant l'efficacité directe, indirecte, totale et globale du vaccin autogène pour Streptococcus suis chez les porcelets sevrés. L'efficacité vaccinale (EV) a été évaluée dans une ferme de naissage-engraissage aux prises avec des mortalités causées par Streptococcus suis. L'efficacité vaccinale directe, indirecte, totale et globale ont été analysées en vaccinant seulement 75 % des porcs dans chaque portée. La régression de Cox et la régression logistique ont révélé que l'EV totale et l'EV globale étaient de 27 % et 21 %, respectivement.(Traduit par Isabelle Vallières).

Modeling livestock population structure: a geospatial database for Ontario swine farms.

BACKGROUND: Infectious diseases in farmed animals have economic, social, and health consequences. Foreign animal diseases (FAD) of swine are of significant concern. Mathematical and simulation models are often used to simulate FAD outbreaks and best practices for control. However, simulation outcomes are sensitive to the population structure used. Within Canada, access to individual swine farm population data with which to parameterize models is a challenge because of privacy concerns. Our objective was to develop a methodology to model the farmed swine population in Ontario, Canada that could represent the existing population structure and improve the efficacy of simulation models. RESULTS: We developed a swine population model based on the factors such as facilities supporting farm infrastructure, land availability, zoning and local regulations, and natural geographic barriers that could affect swine farming in Ontario. Assigned farm locations were equal to the swine farm density described in the 2011 Canadian Census of Agriculture. Farms were then randomly assigned to farm types proportional to the existing swine herd types. We compared the swine population models with a known database of swine farm locations in Ontario and found that the modeled population was representative of farm locations with a high accuracy (AUC: 0.91, Standard deviation: 0.02) suggesting that our algorithm generated a reasonable approximation of farm locations in Ontario. CONCLUSION: In the absence of a readily accessible dataset providing details of the relative locations of swine farms in Ontario, development of a model livestock population that captures key characteristics of the true population structure while protecting privacy concerns is an important methodological advancement. This methodology will be useful for individuals interested in modeling the spread of pathogens between farms across a landscape and using these models to evaluate disease control strategies.

Factors contributing to mortality during a Streptoccocus suis outbreak in nursery pigs.

The objective of this study was to investigate the association between sow- and litter-level factors with mortality in a swine nursery barn experiencing a severe Streptococcus suis disease outbreak. All-cause mortality data from a 300-sow farrow-to-finish herd was analyzed using a Cox's regression model. The data were recorded over 6 months and included 24 cohorts, 297 sows, 295 litters, and 2779 piglets with an average of 14.4% post-weaning mortality. If the sows had 2 litters within the study period and pigs from their first litter experienced mortality, then pigs from their subsequent litter had a decreased risk of mortality [hazard ratio (HR) = 0.34, P < 0.05]. Pigs were more likely to experience mortality if at least 1 additional littermate experienced mortality (HR = 9.22, P = 0.001). Under conditions of this study, the results suggest mechanisms related to sow immunity and within-litter spread that could have contributed to the risk of mortality during the S. suis outbreak.

Facteurs contribuant à la mortalité durant une éclosion de Streptoccocus suis chez des porcelets en pouponnière. Cette étude avait pour objectif de faire enquête sur l'association entre les facteurs au niveau de la truie et de la portée en lien avec la mortalité dans une pouponnière de porcelets aux prises avec une grave éclosion de maladie causée par Streptococcus suis. Les données sur toutes les causes de mortalité provenant d'un troupeau de 300 truies de naissage-finition ont été analysées en utilisant un modèle de régression de Cox. Les données ont été enregistrées pendant 6 mois et incluaient 24 cohortes, 297 truies, 295 portées et 2779 porcelets avec une moyenne de mortalité après le sevrage de 14,4 %. Si les truies avaient 2 portées durant la période de l'étude et qu'il y avait de la mortalité chez les porcs de leur première portée, alors les porcs de leur portée subséquente présentaient un risque réduit de mortalité (taux de risque [TR] = 0,34, P < 0,05). Il était plus probable qu'il y ait de la mortalité chez les porcs si au moins 1 autre compagnon de portée était mort (TR = 9,22, P = 0,001). En vertu des conditions de cette étude, les résultats suggèrent des mécanismes associés à l'immunité des truies et à l'écart au sein de la portée qui ont pu contribuer au risque de mortalité durant l'éclosion de S. suis.(Traduit par Isabelle Vallières).

A longitudinal study describing horse demographics and movements during a competition season in Ontario, Canada.

The objective of this study was to describe the demographics and movement patterns of a sample of horses in Ontario, Canada. A convenience sample of 222 owners completed an initial questionnaire to provide demographic information for 570 horses. These horses were enrolled in a longitudinal study to document their movements from May to November 2015 using a monthly questionnaire. The median age of the participating horses was 11 years (IQR: 8 to 16 years). The primary discipline of participating horses included competitive disciplines (63.3%), leisure (33.3%), and racing (3.2%). During the 7-month period, there were 3001 unidirectional movements of horses between facilities. Reasons for travel on/off a facility included attending a competition (38.7%), leisure activities (18.8%), and training (7.5%). The demographic and movement data presented in this study provide insight into the characteristics of a subset of horses in Ontario, and may contribute to outbreak preparedness in the population.

Étude longitudinale décrivant les données démographiques des chevaux et leurs mouvements durant une saison compétitive en Ontario, au Canada. L'objectif de cette étude consistait à décrire les données démographiques et les mouvements d'un échantillon de chevaux en Ontario, au Canada. Un échantillon utile était composé de 222 propriétaires qui ont rempli un premier questionnaire afin de fournir des données démographiques pour 570 chevaux. Ces chevaux étaient inscrits dans une étude longitudinale afin de documenter leurs mouvements de mai à novembre 2015 à l'aide d'un questionnaire mensuel. L'âge médian des chevaux participants était de 11 ans (IQR : 8 à 16 ans). La discipline primaire des chevaux participants comprenait des disciplines de compétition (63,3 %), d'agrément (33,3 %) et de course (3,2 %). Durant la période de 7 mois, il y a eu 3001 déplacements unidirectionnels de chevaux entre les installations. Les raisons des déplacements à l'aller ou au départ d'une installation incluaient une compétition (38,7 %), des activités d'agrément (18,8 %) et l'entraînement (7,5 %). Les données sur la démographie et les mouvements dans cette étude ont fourni des renseignements sur les caractéristiques d'un sous-groupe de chevaux en Ontario et pourront contribuer à la préparation aux éclosions au sein de la population.(Traduit par Isabelle Vallières).

Description of risk factors associated with the detection of BVDV antibodies in Brazilian pig herds.

Bovine viral diarrhea virus (BVDV) infects ruminants as primary hosts. However, other animals like pigs are susceptible. This study was conducted to investigate seroprevalence and risk factors associated with the detection of BVDV antibodies in pig herds. A total of 1.705 serum samples of 33 finisher herds, from seven Brazilian states, were collected in slaughterhouses. The samples were tested by virus neutralization (VN) test. In total, 5.35% (91/1.705) were positive and 64% (21/33) of the herds had positive animals. A significant association with "trucks are not cleaned and disinfected" and "visitors do not respect 72-h interval between visits to farms" (P < 0.05) was found in association with detection of BVDV-2 antibodies. This study suggests that important biosecurity gaps are present in Brazilian pig farms, as the presence of BVDV antibodies in pigs suggests (direct or indirect) contact with population(s) of ruminant species. Closing biosecurity gaps prevents spread of BVDV and other pathogens such as foot-and-mouth disease virus (FMDV) between pig and ruminant farms. This data should be taken in account by CSF surveillance programs, once cross-reaction in serologic tests between classical swine fever virus (CSFV) and BVDV antibodies has been shown to occur.

Longitudinal study of influenza A virus circulation in a nursery swine barn.

Commercial production of swine often involves raising animals in large groups through the use of multi-stage production systems. In such systems, pigs can experience different degrees of contact with animals of the same or different ages. Population size and degree of contact can greatly influence transmission of endemic pathogens, including influenza A virus (IAV). IAV can display high genetic variability, which can further complicate population-level patterns. Yet, the IAV transmission in large multi-site swine production systems has not been well studied. The objectives of this study were to describe the IAV circulation in a multi-source nursery facility and identify factors associated with infection in nursery pigs. Pigs from five sow herds were mixed in one all-in/all-out nursery barn, with 81 and 75 pigs included in two longitudinal studies. Virus isolation was performed in Madin-Darby canine kidney cells and serology was performed using hemagglutination inhibition assays. Risk factor analysis for virological positivity was conducted using logistic regression and stratified Cox's regression for recurrent events. In Study 1, at ≈30 days post-weaning, 100% of pigs were positive, with 43.2% of pigs being positive recurrently over the entire study period. In study 2, 48% of pigs were positive at the peak of the outbreak, and 10.7% were positive recurrently over the entire study period. The results suggest that IAV can circulate during the nursery phase in an endemic pattern and that the likelihood of recurrent infections was associated in a non-linear way with the level of heterologous (within-subtype) maternal immunity (p < 0.05). High within-pen intracluster correlation coefficients (> 0.75) were also observed for the majority of sampling times suggesting that pen-level factors played a role in infection dynamics in this study.

Descriptive and network analyses of the equine contact network at an equestrian show in Ontario, Canada and implications for disease spread.

BACKGROUND: Identifying the contact structure within a population of horses attending a competition is an important element towards understanding the potential for the spread of equine pathogens as the horses subsequently travel from location to location. However, there is limited information in Ontario, Canada to quantify contact patterns of horses. The objective of this study was to describe the network of potential contacts associated with an equestrian show to determine how this network structure may influence potential disease transmission. RESULTS: This was a descriptive study of horses attending an equestrian show in southern Ontario, Canada on July 6 and 7, 2014. Horse show participants completed a questionnaire about their horse, travel patterns, and infection control practices. Questionnaire responses were received from horse owners of 79.7% (55/69) of the horses attending the show. Owners reported that horses attending the show were vaccinated for diseases such as rabies, equine influenza, and equine herpesvirus. Owners demonstrated high compliance with most infection control practices by reporting reduced opportunities for direct and indirect contact while away from home. The two-mode undirected network consisted of 820 nodes (41 locations and 779 horses). Eight percent of nodes in the network represented horses attending the show, 87% of nodes represented horses not attending the show, but boarded at individual home facilities, and 5% represented locations. The median degree of a horse in the network was 33 (range: 1-105). CONCLUSIONS: Developing disease management strategies without the explicit consideration of horses boarded at individual home facilities would underestimate the connectivity of horses in the population. The results of this study provides information that can be used by equestrian show organizers to configure event management in such a way that can limit the extent of potential disease spread.

Treatment rates for injectable tiamulin and lincomycin as an estimate of morbidity in a swine herd with endemic swine dysentery.

Treatment can be used as an indirect measure of morbidity, and treatment records can be used to describe disease patterns in a population. The aim of this study was to describe the rates of treatments with tiamulin and lincomycin by the intramuscular route in cohorts of pigs affected by swine dysentery. Data from treatment records from 19 cohorts of a 1500-head grower-finisher barn were analyzed using Poisson regression to determine factors associated with rates of treatment. Serial interval and reproductive numbers were extracted. Treatment rates displayed marked seasonality. The mean serial interval was estimated at 17 d with variability among batches. In the early period of most cohorts, the effective reproductive number did not exceed 1, and the highest estimate was 2.15 (95% CI: 1.46, 3.20). The average days-to-first treatment was 4.8 which suggests that pigs could have been infected at time of entry. The information about possible sources of infection and likely seasonality should be considered when developing disease and infection control measures in affected barns.

Taux de traitement pour la tiamuline et la lincomycine injectables en tant qu'estimation de la morbidité dans un troupeau porcin atteint de dysenterie porcine. Le traitement peut servir de mesure indirecte de la morbidité et les dossiers de traitement peuvent être utilisés pour décrire les profils pathologiques au sein d'une population. Le but de cette étude consistait à décrire les taux de traitement à l'aide de la tiamuline et de la lincomycine par voie intramusculaire dans des cohortes de porcs affectées par la dysenterie porcine. Les données des dossiers de traitement provenant de 19 cohortes d'une porcherie de 1500 porcs d'engraissement ont été analysées en utilisant la régression de Poisson pour déterminer les facteurs associés aux taux de traitement. Des données sur les intervalles sériels et la reproduction ont été extraites. Les taux de traitement ont affiché une saisonnalité marquée. L'intervalle sériel moyen était estimé à 17 jours avec de la variabilité entre les groupes. Au début de la période de la plupart des cohortes, le nombre effectif de reproductions n'a pas dépassé 1 et l'estimation la plus élevée était de 2,15 (IC de 95 % : 1,46, 3,20). Le nombre moyen avant le premier traitement était de 4,8 jours, ce qui suggère que les porcs auraient pu être infectés au moment de l'arrivée. Les renseignements sur les sources possibles d'infection et la saisonnalité probable devraient être considérés lors de l'élaboration de mesures de contrôle de la maladie et de l'infection dans les porcheries affectées.(Traduit par Isabelle Vallières).

Persistence of clinical signs associated with rotavirus following an outbreak of porcine epidemic diarrhea (PED) on a farrow-to-grow swine operation in southwestern Ontario.

Clinical signs attributed to porcine epidemic diarrhea (PED) persisted for several months in a southwestern Ontario farm following an outbreak of PED. Extensive testing revealed rotavirus infection and absence of PED in nursing and nursery pigs, highlighting the importance of repeated diagnostic testing following a disease outbreak.

Persistance des signes cliniques associés au rotavirus après une éclosion de diarrhée épidémique porcine (DEP) dans une exploitation porcine de type naisseur-finisseur dans le sud-ouest de l'Ontario. Les signes cliniques attribués à la diarrhée épidémique porcine (DEP) ont persisté pendant plusieurs mois dans une ferme du sud-ouest de l'Ontario après une éclosion de DEP. De nombreux tests ont révélé l'infection par le rotavirus et l'absence de DEP chez les porcs à l'allaitement et de la pouponnière, ce qui souligne l'importance de tests diagnostiques répétés après l'éclosion d'une maladie.(Traduit par Isabelle Vallières).