A Scoping Review on the Epidemiology of Orthobunyaviruses of Canadian Public and Animal Health Relevance in the Context of Vector Species.

Background: Mosquito-borne orthobunyaviruses are a growing priority for public and animal health in Canada. It is anticipated that disease incidence will increase due to a warming climate, given that habitats are expanding for reservoir hosts and vectors, particularly in Canada. Little is known about the ecology of primary vectors that perpetuate these orthobunyaviruses, including the viral transmission cycle and the impact of climatic and landscape factors. Methods: A scoping review was conducted to describe the current state of knowledge on the epidemiology of orthobunyaviruses relevant to Canada. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews guidelines was used to characterize studies focused on vector species. A literature search was conducted in six databases and gray literature. Eligible studies characterized orthobunyavirus epidemiology related to vector species, including viral competency, geospatial distributions, seasonal trends, and/or risk factors. Results: A total of 1734 unique citations were identified. Screening of these citations revealed 172 relevant studies, from which 87 studies presented primary data related to vectors. The orthobunyaviruses included Cache Valley virus (CVV), Jamestown Canyon virus (JCV), Snowshoe Hare virus (SHV), and La Crosse virus (LACV). Surveillance was the predominant study focus, with most citations representing the United States, specifically, LACV surveillance in Tennessee, followed by CVV and JCV in Connecticut. Orthobunyaviruses were detected in many mosquito species across multiple genera, with high vector specificity only being reported for LACV, which included Aedes triseriatus, Aedes albopictus, and Aedes japonicus. Peridomestic areas were positively associated with infected mosquitoes compared with dense forests. Orthobunyavirus infections, coinfections, and gut microbiota affected mosquito feeding and breeding behavior. Conclusion: Knowledge gaps included Canadian surveillance data, disease modeling, and risk projections. Further research in these areas, especially accounting for climate change, is needed to guide health policy for prevention of orthobunyaviral disease.

A Scoping Review on the Epidemiology of Orthobunyaviruses in Canada, in the Context of Human, Wildlife, and Domestic Animal Host Species.

Background: Mosquito-borne orthobunyaviruses in Canada are a growing public health concern. Orthobunyaviral diseases are commonly underdiagnosed and in Canada, likely underreported as surveillance is passive. No vaccines or specific treatments exist for these disease agents. Further, climate change is facilitating habitat expansion for relevant reservoirs and vectors, and it is likely that the majority of the Canadian population is susceptible to these viruses. Methods: A scoping review was conducted to describe the current state of knowledge on orthobunyavirus epidemiology in Canada. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews guideline was used. Literature searches were conducted in six databases and in gray literature. The epidemiology of orthobunyaviruses was characterized for studies focusing on host species, including spatiotemporal patterns, risk factors, and climate change impact. Results: A total of 172 relevant studies were identified from 1734 citations from which 95 addressed host species, including humans, wildlife, and domestic animals including livestock. The orthobunyaviruses-Cache Valley virus (CVV), Jamestown Canyon virus (JCV), Snowshoe Hare virus (SHV), and La Crosse virus (LACV)-were identified, and prevalence was widespread across vertebrate species. CVV, JCV, and SHV were detected across Canada and the United States. LACV was reported only in the United States, predominantly the Mid-Atlantic and Appalachian regions. Disease varied by orthobunyavirus and was associated with age, environment, preexisting compromised immune systems, or livestock breeding schedule. Conclusion: Knowledge gaps included seroprevalence data in Canada, risk factor analyses, particularly for livestock, and disease projections in the context of climate change. Additional surveillance and mitigation strategies, especially accounting for climate change, are needed to guide future public health efforts to prevent orthobunyavirus exposure and disease.

Cache a Killer: Cache Valley virus seropositivity and associated farm management risk factors in sheep in Ontario, Canada.

Cache Valley virus (CVV) disease is a mosquito-borne zoonosis endemic to North America. CVV disease is reported most often in sheep, causing lethal congenital deformities. There are limited data on CVV in Ontario, which is the largest sheep producing province in Canada. This study aimed to determine CVV seroprevalence in Ontario sheep flocks and investigate farm management factors associated with CVV exposure. A cross-sectional study was performed including 364 mature ewes across 18 farms selected from the five largest sheep districts in the province. A questionnaire was administered at each farm to determine farm management practices pertinent to the flock and ewes specifically sampled. Mixed multivariable logistic regression with a random effect for farm was conducted to assess associations between CVV seropositivity (outcome variable) and farm management risk factors (predictor variables). CVV seroprevalence was 33.2% in individual ewes (95% CI: 28.4%-38.1%) as determined by a virus neutralization assay with a titre > 4. Sixteen of the eighteen flocks (88.9%) had at least one CVV seropositive ewe. Increased age, smaller flock size, and sheep housing near wetlands, lakes, or ponds were found to be significantly associated with higher odds of CVV seropositivity. These findings are valuable in guiding breeding practices and housing during mosquito season to minimize infection and, ultimately, CVV disease in the flock.

Identifying hepatic genes regulating the ovine response to gastrointestinal nematodes using RNA-Sequencing.

Gastrointestinal nematode (GIN) infections are considered the most important disease of grazing sheep and due to increasing anthelmintic resistance, chemical control alone is inadequate. Resistance to Gastrointestinal nematode infection is a heritable trait, and through natural selection many sheep breeds have higher resistance. Studying the transcriptome from GIN-exposed and GIN-unexposed sheep using RNA-Sequencing technology can provide measurements of transcript levels associated with the host response to Gastrointestinal nematode infection, and these transcripts may harbor genetic markers that can be used in selective breeding programs to enhance disease resistance. The objective of this study was to compare liver transcriptomes of sheep naturally exposed to Gastrointestinal nematode s, with either high or low parasite burdens, to GIN-unexposed control sheep in order to identify key regulator genes and biological processes associated with Gastrointestinal nematode infection. Differential gene expression analysis revealed no significant differentially expressed genes (DEG) between sheep with a high or low parasite burden (p-value ≤0.01; False Discovery Rate (FDR) ≤ 0.05; and Fold-Change (FC) of > ±2). However, when compared to the control group, low parasite burden sheep showed 146 differentially expressed genes (64 upregulated and 82 downregulated in the low parasite burden group relative to the control), and high parasite burden sheep showed 159 differentially expressed genes (57 upregulated and 102 downregulated in the low parasite burden group relative to the control) (p-value ≤0.01; FDR ≤0.05; and FC of > ±2). Among these two lists of significant differentially expressed genes, 86 differentially expressed genes (34 upregulated, 52 downregulated in the parasited group relative to the control) were found in common between the two parasite burden groups compared to the control (GIN-unexposed sheep). Functional analysis of these significant 86 differentially expressed genes found upregulated genes involved in immune response and downregulated genes involved in lipid metabolism. Results of this study offer insight into the liver transcriptome during natural Gastrointestinal nematode exposure that helps provide a better understanding of the key regulator genes involved in Gastrointestinal nematode infection in sheep.

Udder Health for Dairy Goats.

Staphylococcus aureus is the most important cause of clinical mastitis in goats, and non-aureus staphylococci is the most common isolate from subclinical mastitis. Environmental streptococci are a severe problem. Somatic cell counts and California mastitis test are a screening test for mastitis and an indicator of poor udder health, but values should be interpreted differently than with dairy cattle. Somatic cell scores likely are a more useful way of viewing data. High bacterial counts in milk are common; mastitis may be involved as a cause. Proper udder preparation, milking procedure, and postmilking management are key factors in mastitis control.

Correlation of subclinical gastrointestinal nematode parasitism with growth and reproductive performance in ewe lambs in Ontario.

Infection with gastrointestinal nematode parasites (GINs) is an important cause of productivity loss on sheep farms in Ontario and worldwide. However, efforts to quantify the effect of GIN infection on growth have demonstrated mixed results. Furthermore, there has been limited investigation of their effect on reproductive performance. This study evaluated the effect of subclinical GIN parasitism on growth and reproductive performance of ewe lambs under Ontario grazing conditions. Rideau cross ewe lambs (n = 140) born in spring 2016 on a farm in central Ontario were followed for two years from before weaning through to November 2017, including their first lambing and lactation. These animals grazed from May to November of each year and were sampled every 6-8 weeks during both grazing seasons and once at mid-gestation in March 2017. At each sampling the ewe lambs were weighed, body condition scores assigned, fecal egg counts (FECs) performed, and pasture samples collected to assess number of infective GIN larvae. Study animals with a FEC of 500 eggs per gram or higher were selectively treated with anthelmintics to prevent morbidity and mortality. Fecal samples were cultured to determine infecting GIN species, and climate data were obtained from a weather station 26 km away from the farm. Precipitation levels and numbers of infective larvae on pasture were low during the first grazing season but were more typical of Ontario conditions in the second grazing season. The three most common GIN species were Haemonchus contortus, Teladorsagia circumcincta, and Trichostrongylus spp. General linear mixed models were generated for weight change over time, litter size at lambing, and weaning weights of offspring. Despite moderate peak GIN burdens in both grazing seasons, FEC was not significantly associated with weight change or litter size, apart from periparturient egg rise in study ewe lambs with larger litters (p = 0.05). Significant positive quadratic and negative linear associations were identified between late lactation FECs and offspring weaning weights; the association between FECs and weaning weights changed from negative to positive at a FEC of 361 eggs per gram. These results indicate that when GIN burdens are moderate as evidenced by fecal egg counts and infection is subclinical, there appears to be low to no impact on growth and reproductive performance in ewe lambs in the first 18 months of life. This suggests that when GIN parasitism is regularly monitored and controlled using targeted selective treatment, animal performance is minimally affected.

Correlation of salivary antibody to carbohydrate larval antigen (CarLA) with health and gastrointestinal nematode parasitism in sheep under Ontario grazing conditions.

Leveraging mucosal immunity is a promising method for controlling gastrointestinal nematode (GIN) parasitism in sheep. Salivary antibody to carbohydrate larval antigen (sCarLA), a heritable measure of immunity to third-stage GIN larvae (L3), has been successfully applied to genetic improvement programs in New Zealand. However, sCarLA levels wane in the absence of ongoing GIN exposure. New Zealand's temperate climate permits year-round exposure to L3, but cold winters in boreal regions such as Ontario, Canada interrupt exposure for five months or more. This study investigated associations between sCarLA levels, GIN parasitism, and indicators of overall health in sheep grazing under Ontario conditions. A commercial flock of 140 Rideau cross ewe lambs were followed from approximately 30 days of age in May 2016 until November 2017, including lambing and lactation in the spring of 2017. Every 6-8 weeks during the grazing season and at mid-gestation in March 2017, fecal egg counts were performed, blood collected to assess serum albumin, globulin, and hematocrit, and pasture samples obtained to confirm exposure to infective larvae. Measurements of sCarLA level were performed at the beginning, middle, and end of each grazing season, and at mid-gestation. Spearman's rank correlation coefficients were calculated to compare sCarLA levels over time, and general linear mixed models created to evaluate associations between sCarLA levels, GIN fecal egg count, hematocrit, serum albumin, and serum globulin. Levels of sCarLA followed a similar seasonal pattern to GIN fecal egg counts with a 6-8 week delay; much higher sCarLA levels were observed in the second grazing season. The proportion of the flock with detectable sCarLA (≥ 0.3 units/mL) was 68.3 % by the end of the first grazing season, declined over winter to 43.9 % at lambing, and approached 100 % after 3 months of grazing in the second grazing season. Correlations between sCarLA levels over time were consistently positive, of weak to moderate strength, and significant (p < 0.05). At all time points, sCarLA level was significantly (p < 0.001) and negatively associated with fecal egg counts. The flock displayed minimal variability in hematocrit, serum albumin, and serum globulin; none of which were significantly associated with sCarLA levels. These results suggest that sCarLA can be maintained over winter and is a useful measure of immunity to GINs in sheep under Ontario grazing conditions.

Management factors associated with perinatal lamb mortality in Prince Edward Island flocks.

The objective of this observational cohort study was to identify management factors associated with lamb mortality risk for sheep flocks in Prince Edward Island, Canada. Data were collected from 50 lambing groups from 36 sheep flocks during 3 farm visits before, during and after the lambing seasons in 2014-15. Variables of interest included flock management practices, ewe health indicators, ewe nutrition, litter size and lamb birth weight. Principal component analysis was performed and resulting component scores were used for further analysis using a mixed Poisson regression model with lamb mortality risk as the outcome. The median group-level lamb mortality in the first 8 weeks of life was 10.0 % (0 %-30.3 %), with 25 groups having lamb mortality greater than 10 %, which is considered higher than the standard productivity goal. Four principal component scores were retained in the final model identifying generalized factors associated with lamb mortality: 1) flock factors, 2) forage factors, 3) lamb health factors, and 4) general health factors. Specifically, the following management factors were indirectly through the 4 principal components associated with lower lamb mortality: using goal setting; having a strong working relationship with a veterinarian; seeking veterinary advice for animal treatment; using benzimidazole-class anthelmintics; feeding forage with high crude protein, digestible energy, and net energy for maintenance and low acid detergent fiber to late-gestation ewes; applying visual lamb identification methods; using anti-coccidial prophylactic medication to lambs; administering clostridial vaccines to lambs; avoiding separation of hypothermic lambs from their dams; and treatment/prevention of neurological and/or wasting disease. Although this study is exploratory, and confirmation is required, the results should help sheep farmers and researchers direct attention to management variables that could reduce lamb mortality in sheep flocks.

Comparison of ITS-2 rDNA nemabiome sequencing with morphological identification to quantify gastrointestinal nematode community species composition in small ruminant feces.

Mixed gastrointestinal nematode (GIN) infections are a common and significant cause of financial loss for small ruminant producers. Morphologic examination of third-stage larvae (L3) can be used to identify species composition in feces but has limitations due to the requirement for specialized expertise and the extensive time (8-15 d depending on method used) and labour involved. Moreover, differential development and survival of larvae during coproculture to the third stage often occurs. Deep amplicon sequencing of the ITS-2 rDNA locus of first-stage larvae (L1) allows for higher throughput with reduced specialist labour and reduces the risk of misidentification. Harvesting of L1 soon after hatching is also faster and further reduces labour as well as biases that can occur due to differential larval development and survival. This study compares the results of morphologic examination of L3 with those of ITS-2 rDNA deep amplicon sequencing of L1 from a set of pooled fecal samples. The proportions of eggs that were successfully recovered as larvae following culture to L3 and L1 were also compared. Larval recovery rate was significantly lower from L3 cultures than from L1 cultures (p < 0.001); eggs were 238.7 times less likely to develop to L3 than to L1 (95 % confidence interval for odds ratio 80.0-712.0). Significantly lower proportions of Teladorsagia circumcincta (odds ratio = 3.1, p = 0.008) and higher proportions of Trichostrongylus spp. (p = 0.009) were identified using morphologic examination of L3 compared with deep amplicon sequencing of L1 on the same samples. This is consistent with previous reports of differential survival of these species in L3 cultures. These results indicate that deep amplicon sequencing of L1 may reduce bias introduced by differential GIN survival to L3 in small ruminants.

Efficacy of fenbendazole and ivermectin in treating gastrointestinal nematode infections in an Ontario cow-calf herd.

The objective of this randomized clinical trial was to compare performance of cow-calf pairs in southern Ontario treated with fenbendazole or ivermectin, or not treated, for gastrointestinal nematode infections. Treatments were administered to 128 cow-calf pairs over 2 years. Weights, body condition score, and fecal egg counts (FEC) were collected at treatment and at 28-day intervals. Treating calves with an anthelmintic was significantly advantageous compared with not treating, and there was no significant difference between treatment with fenbendazole or ivermectin. Neither treatment nor calf FEC had a significant effect on calf weaning weight. This could be the result of time of treatment, low initial FEC, or lack of power. Treatment affected cow FEC (P = 0.003). Cows in the ivermectin groups had the lowest FEC (P < 0.05), but because FEC were all low, biological significance is questionable. Additional work is needed to provide recommendations on when an anthelmintic should be used.

Efficacité du fenbendazole et de l'ivermectin pour traiter les infections à nématodes gastrointestinaux dans un troupeau de vaches-veaux en Ontario. L'objectif de cet essai clinique randomisé était de comparer les performances de paires de vaches-veaux dans le sud de l'Ontario traitées avec du fenbendazole ou de l'ivermectin, ou non-traitées, pour des infections à nématodes gastro-intestinaux. Les traitements furent administrés à 128 paires de vaches-veaux sur une période de 2 ans. Le poids, le pointage de l'état corporel, et le dénombrement des oeufs dans les fèces (FEC) furent colligés au moment du traitement et à des intervalles de 28 jours. Traiter des veaux avec un anthelmintique était significativement avantageux comparativement à ne pas les traiter, et il n'y avait pas de différence significative entre un traitement au fenbendazole ou à l'ivermectin. Ni l'un ou l'autre des traitements ou les FEC n'avaient un effet significatif sur le poids au sevrage des veaux. Ceci pourrait être dû au moment du traitement, un FEC initial peu élevé, ou un manque de puissance. Les traitements ont affecté les FEC des vaches (P = 0,003). Les vaches dans le groupe ivermectin avaient les plus bas FEC (P < 0,05), mais étant donné que tous les FEC étaient bas, la signification biologique est questionnable. Du travail supplémentaire est requis pour fournir des recommandations sur le moment où un anthelmintique devrait être utilisé.(Traduit par Dr Serge Messier).

Cardiovascular and sedation reversal effects of intramuscular administration of atipamezole in dogs treated with medetomidine hydrochloride with or without the peripheral α2-adrenoceptor antagonist vatinoxan hydrochloride.

OBJECTIVE: To investigate the cardiovascular and sedation reversal effects of IM administration of atipamezole (AA) in dogs treated with medetomidine hydrochloride (MED) or MED and vatinoxan (MK-467). ANIMALS: 8 purpose-bred, 2-year-old Beagles. PROCEDURES: A randomized, blinded, crossover study was performed in which each dog received 2 IM treatments at a ≥ 2-week interval as follows: injection of MED (20 µg/kg) or MED mixed with 400 µg of vatinoxan/kg (MEDVAT) 30 minutes before AA (100 µg/kg). Sedation score, heart rate, mean arterial and central venous blood pressures, and cardiac output were recorded before and at various time points (up to 90 minutes) after AA. Cardiac and systemic vascular resistance indices were calculated. Venous blood samples were collected at intervals until 210 minutes after AA for drug concentration analysis. RESULTS: Heart rate following MED administration was lower, compared with findings after MEDVAT administration, prior to and at ≥ 10 minutes after AA. Mean arterial blood pressure was lower with MEDVAT than with MED at 5 minutes after AA, when its nadir was detected. Overall, cardiac index was higher and systemic vascular resistance index lower, indicating better cardiovascular function, in MEDVAT-atipamezole-treated dogs. Plasma dexmedetomidine concentrations were lower and recoveries from sedation were faster and more complete after MEDVAT treatment with AA than after MED treatment with AA. CONCLUSIONS AND CLINICAL RELEVANCE: Atipamezole failed to restore heart rate and cardiac index in medetomidine-sedated dogs, and relapses into sedation were observed. Coadministration of vatinoxan with MED helped to maintain hemodynamic function and hastened the recovery from sedation after AA in dogs.

Behavioural alterations in piglets after surgical castration: Effects of analgesia and anaesthesia.

The present study aimed to use behavioural measures to assess pain induced by surgical castration of piglets, and evaluate the efficacy of pain-relief medications. In total, 143 male piglets from 29 sows were used. The treatments included: 1) non-castration (NC; n = 28), 2) castration without medication (SC; n = 29), 3) castration with meloxicam injection 0.4 mg/kg i.m. (ME; n = 28), 4) castration with 0.5 ml of 2% lidocaine in each testicle (LA; n = 29), and 5) castration with general inhalation anaesthesia using isoflurane (1.5%) and meloxicam injection (GA; n = 29). Behaviour was monitored continuously for a ten minute period one hour prior to castration (-1 h), as well as immediately (0 h), one hour (1 h), and two hours (2 h) after castration. Behaviour was also monitored twice (08:00 and 20:00) during the following day. Compared to -1 h, castration induced changes in several behavioural measures in SC piglets at 0 h, suggesting that castration was painful. Furthermore, inactive standing or sitting, tail wagging and aggressive behaviour differed between SC and NC piglets at 0 h. ME and LA piglets spent less time standing or sitting inactively, and LA and GA piglets showed more tail wagging than SC piglets at 0 h (P < 0.05 for all). No other behavioural measures differed among the various groups of castrated piglets. In conclusion, the results indicate that surgical castration is indeed painful. However, the efficacy of various pain-relief protocols in piglets shortly after castration was not verified.

Evaluation of bulk tank milk PCR and bulk tank milk modified ELISA tests for the detection of paratuberculosis at the herd level in goat and sheep dairies in Ontario, Canada.

Early identification of dairy goat herds and dairy sheep flocks infected with Mycobacterium avium ssp. paratuberculosis is important for controlling this infection and minimizing economic losses. The objective of this study was to evaluate 2 bulk tank milk (BTM) paratuberculosis tests (PCR and modified ELISA) as potential herd-level tests. These tests were compared with the results obtained from testing 20 randomly selected lactating animals per farm (>2 yr) with an individual animal test (fecal culture, fecal PCR, serum ELISA, and milk ELISA). The study was conducted using 29 dairy goat herds and 21 dairy sheep flocks in Ontario, Canada, visited between October 2010 and August 2011. The sensitivity of the BTM PCR was poor in both the dairy goat herds (0.0%) and dairy sheep flocks (25.0%), but exhibited 100% specificity in both species. In comparison, the BTM modified ELISA demonstrated higher sensitivity. In goats, sensitivity ranged from 33.3 to 34.8% when fecal culture and PCR were the reference tests, respectively (specificities were both 100%), and 71.4 to 87.5% when the milk and serum ELISA, respectively, were the reference tests (specificities were 86.4 and 95.2%). The BTM modified ELISA in dairy sheep demonstrated comparable sensitivities, but lower specificities. When fecal culture and PCR were the reference test, sensitivities were 50.0 and 46.7%, respectively (specificities were 77.8 and 83.3%). The sensitivities when the milk and serum ELISA were the reference tests were 87.5 and 72.7%, respectively (specificities were 92.3 and 100%). Fecal PCR was the only individual animal test to identify significantly more farms as positive than the BTM PCR and modified ELISA test in both species. Therefore, whereas the BTM modified ELISA may provide an organization or control program with a high level of confidence that a BTM-positive farm is actually positive (high positive predictive value), if a producer wishes to increase the odds that a positive farm will test positive, so as not to miss an infection, then sampling and testing 20 animals with fecal PCR will better meet that objective.

Evaluation of the Precision Xtra meter for monitoring blood ß-hydroxybutyrate concentrations in late-gestation ewes.

Blood samples were collected from late-gestation ewes to determine the agreement of a point-of-care (POC) Precision Xtra meter and a standard laboratory test for ß-hydroxybutyrate (BHBA). Fresh whole blood samples were immediately tested with the POC instrument, and serum samples were analyzed with a standard commercial biochemical analyzer. Ewes were classified as having ketonemia if their BHBA concentrations were ≥800 µmol/L. Scatter plots, paired t-tests, Bland-Altman limits of agreement, and Gwet AC1 tests were used to compare results. The 2 tests had very good agreement. The values between instruments were not statistically different based on paired t-tests ( p = 0.312). The intercept and slope of a linear mixed model, containing the standard test results as an outcome and the POC meter results as a predictor, were 0.02 (95% CI: 0.00, 0.04) and 0.98 (95% CI: 0.96, 1.01), respectively. When the samples were classified into ketonemic classes (non-ketonemic and ketonemic) based on BHBA concentrations obtained from each test, the Gwet AC1 statistic was 0.94 (95% CI: 0.91, 0.97; p < 0.001). The ketosis classification agreed in 95% of samples. Based on the Bland-Altman plot and limits of agreement, the optimal cutoff to diagnose ketonemia with the POC meter was 1,000 µmol/L, which is 200 µmol/L higher than the laboratory BHBA medical decision limit. The Precision Xtra meter provided excellent correlation and substantial agreement with the standard laboratory technique for measuring blood BHBA in late-gestation ewes.

Management of Coxiella burnetii infection in livestock populations and the associated zoonotic risk: A consensus statement.

Infections caused by Coxiella burnetii, commonly referred to as coxiellosis when occurring in animals and Query fever when occurring in humans, are an important cause of abortions, decreased reproductive efficiency, and subclinical infections in ruminants. The organism also represents an important zoonotic concern associated with its ability to aerosolize easily and its low infectious dose. Available diagnostic tests have limited sensitivity, which combined with the absence of treatment options in animals and limited approaches to prevention, result in difficulty managing this agent for optimal animal health and zoonotic disease outcomes. The purpose of this consensus statement is to provide veterinarians and public health officials with a summary of the available information regarding management of C. burnetii infection in livestock populations. A discussion of currently available testing options and their interpretation is provided, along with recommendations on management practices that can be implemented on-farm in the face of an outbreak to mitigate losses. Emphasis is placed on biosecurity measures that can be considered for minimizing the zoonotic transmission risk in both field and veterinary facilities.

The association of serum ß-hydroxybutyrate concentration with fetal number and health indicators in late-gestation ewes in commercial meat flocks in Prince Edward Island.

Late-gestation ewes are susceptible to ketonemia resulting from high energy requirement for fetal growth during the last few weeks of pregnancy. High lamb mortality is a possible consequence of effects of ketonemia on both ewes and lambs. Determining risk factors to ketonemia is a fundamental step to identify ewes at risk, in order to avoid losses caused by ketonemia. Serum ß-hydroxybutyrate (BHBA) concentrations of 384 late-gestation ewe samples were determined. Physical examinations, including body condition, FAMACHA© and hygiene scoring, were performed. Udders and teeth were also examined. Fecal floatation was performed to detect gastrointestinal helminth eggs of the ewe fecal samples. General feeding management practices and season at sampling were recorded. Litter sizes were retrieved from lambing records. Factors associated with log serum BHBA concentration were determined using a linear mixed model, with flock and lambing groups as random effects. The mean serum BHBA concentration was 545.8 (±453.3) µmol/l. Ewes with a body condition score (BCS) of 2.5-3.5 had significantly lower log BHBA concentrations than ewes with a BCS of ≤2.0, by 19.7% (p = 0.035). Ewes with a BCS of >3.5 had a trend toward higher log BHBA concentrations compared to ewes with a BCS of 2.5-3.5. Ewes with a FAMACHA© score of 3 had significantly higher log BHBA concentrations than ewes with a FAMACHA© score of 1 or 2, by 12.1% (p = 0.049). Ewes in which gastrointestinal helminth eggs were detected had significantly higher log BHBA concentrations than ewes in which helminth eggs were not detected, by 12.3% (p = 0.040). An increased litter size was associated with higher log BHBA concentration (p ≤ 0.003), with the log BHBA concentrations of ewes having twins, triplets, and quadruplets or quintuplets were higher than those of ewes having singleton by 19.2%, 30.4%, and 85.2%, respectively. Season at sampling confounded the association between log BHBA concentration and FAMACHA© score, and therefore was retained in the final model even though it was not statistically significant. Intra-class correlation coefficients at the flock and lambing group levels were 0.14 and 0.32, respectively.

Identification of Mycobacterium avium subspecies paratuberculosis strains isolated from dairy goats and dairy sheep in Ontario, Canada.

The main objective of this study was to identify the circulating strains of Mycobacterium avium subspecies paratuberculosis (Map) in fecal isolates obtained from dairy goat (N = 29 farms) and dairy sheep (N = 21 farms) populations in Ontario, Canada. Further subtyping was performed to determine if there was adequate diversity between strains that could be used to establish Map transmission patterns. Type C was the dominant strain of Map isolates (95.2%) identified in dairy goats (n = 21). Sub-typing of the Type C strains, based on variable number tandem repeats (VNTR) and mycobacterial interspersed repetitive units, identified 3 VNTR types: INMV 1 (n = 10), INMV 2 (n = 10), and a type not previously identified (n = 1). Only 2 sheep isolates could be identified; both were Type S, sub-type III. Current typing methods demonstrate little Map diversity in the dairy goat population and are therefore of limited use to investigate infection patterns.

L'objectif principal de la présente étude était d'identifier les souches circulantes de Mycobacterium avium sous-espèces paratuberculosis (MAP) dans des échantillons fécaux obtenus de populations de chèvre laitière (N = 29 fermes) et de brebis laitière (N = 21 fermes) en Ontario, Canada. Du sous-typage supplémentaire a été effectué afin de déterminer s'il y avait suffisamment de diversité entre les souches qui permettrait d'établir des patrons de transmission de MAP. Il a été déterminé que le Type C était la souche dominante d'isolats de MAP (95,2 %) chez les chèvres laitières (n = 21), alors que deux isolats ovins ont été identifiés comme étant du Type S/sous-type III (n = 2). Le sous-typage des souches du Type C, basé sur le nombre variable de séquences répétées en tandem (VNTR) et les unités répétitives entrecoupées des mycobactéries, a permis d'identifier trois types de VNTR : INMV 1 (n = 10), INMV 2 (n = 10), et un type encore non-identifié (n = 1). Les méthodes actuelles de typage ne permettent de démontrer que peu de diversité de MAP dans la population de chèvre laitière et sont ainsi d'utilité limitée pour étudier les patrons d'infection.(Traduit par Docteur Serge Messier).

Prevalence and risk factors for Coxiella burnetii seropositivity in small ruminant veterinarians and veterinary students in Ontario, Canada.

Coxiella burnetii is a zoonotic pathogen that causes Q fever in humans. Serological and questionnaire data on C. burnetii were obtained from 32 small ruminant veterinarians and veterinary students in Ontario, Canada, in February 2012. Overall, 59% of participants were seropositive; advanced stage of career and increased age were associated with seropositivity.

Prévalence et facteurs de risques pour la séropositivité àCoxiella burnetiichez les vétérinaires des petits ruminants et les étudiants en médecine vétérinaire en Ontario, au Canada.Coxiella burnetii est un agent pathogène zoonotique qui cause la fièvre Q chez les humains. Des données sérologiques et provenant de réponses à un questionnaire portant sur C. burnetii ont été obtenues auprès de 32 vétérinaires et étudiants en médecine vétérinaire en Ontario, au Canada, en février 2012. Globalement, 59 % des participants étaient séropositifs; un stade de carrière avancé et un âge supérieur étaient associés à la séropositivité.(Traduit par Isabelle Vallières).

Prevalence of small ruminant lentivirus and Mycobacterium avium subsp. paratuberculosis co-infection in Ontario dairy sheep and dairy goats.

Infection with small ruminant lentiviruses (SRLV) causes a variety of chronic inflammatory conditions that limit production. Mycobacterium avium subsp. paratuberculosis (MAP) is also a major production-limiting disease of sheep and goats, which causes severe inflammation of the small intestine. Previous studies have indicated that both SRLV and MAP are widespread in small ruminants in Ontario. This study estimated the prevalence of SRLV and MAP co-infection. Serum samples that were previously tested for MAP infection were re-tested for SRLV. The apparent prevalence of co-infection was low, with 3.4% [95% confidence interval (CI): 1.9 to 5.9] and 14.3% (95% CI: 11.6 to 17.5) of sheep and goats respectively, positive for both infections. However, co-infection is widespread with 36.8% (95% CI: 19.1 to 59.1) and 71.4% (95% CI: 52.8 to 84.9) of sheep and goat farms with 1 or more co-infected animals. A significant association was found between SRLV seropositivity and MAP fecal culture (P = 0.021), suggesting that co-infected goats may be more likely to shed MAP in their feces.

L'infection par lentivirus des petits ruminants (SRLV) provoque une variété d'états inflammatoires chroniques qui limitent la production. Mycobacterium avium subsp. paratuberculose (MAP) est aussi une maladie limitant la production majeure de moutons et de chèvres, ce qui provoque une inflammation grave de l'intestin grêle. Des études antérieures ont indiqué que les deux infections de SRLV et MAP sont très répandues dans l'Ontario petits ruminants. Cette étude a été réalisée pour estimer la prévalence de SRLV et MAP co-infection. Des échantillons de sérum qui avaient été préalablement testés pour l'infection de MAP ont été utilisés pour détecter des anticorps spécifiques SLRV. La prévalence de la co-infection était faible, avec 3,4 % intervalle de confiance (95% IC : 1,9­5,9) et 14,3 % (95% IC : 11,6­17,5) des ovins et caprins, respectivement, positive pour les deux infections. Cependant la co-infection est très répandue avec 36,8 % (95% IC : 19,1­59,1) et 71,4 % (95% IC : 52,8­84,9) des élevages ovins et caprins avec un ou plusieurs animaux co-infecté. Une association significative a été trouvée entre SRLV et séropositivité MAP culture fécale (P = 0,021), ce qui suggère que les chèvres co-infectés peuvent être plus susceptibles de jeter le MAP dans leurs excréments.(Traduit par les auteurs).