Cate Dewey

Patterns of crossfostering and piglet mortality on commercial U.S. and Canadian swine farms

A data base of 300 farms using computerized records was used to examine the extent and timing of crossfostering being practiced in commercial herds in the Midwestern U.S. and Canada in 1994-1995. Crossfostering was used on 98% of farms. Across all farms, the mean percent of piglets crossfostered was 8.6%. Farms varied greatly in the age at which they moved piglets. The 20 farms that moved piglets the earliest after birth were classified as early-move farms and the 20 that moved the oldest piglets were classified as late-move farms. Early-move and late-move farms did not differ in herd size (P = 0.14), average parity of farrowed sows (P = 0.47) or age at weaning (P = 0.37). There were differences between early-move and late-move farms in percent of piglets fostered (P = 0.0001), pigs born alive/litter (P = 0.04), and pre-weaning mortality (P = 0.0005). A subset of late-move farms that were part of an integrated production group had unique production parameters that suggested inaccurate record-keeping.

Prevalence and antimicrobial resistance in Campylobacter spp. isolated from retail chicken in two health units in Ontario.

Campylobacter is an important enteric pathogen of humans and can cause diarrhea, fever, and abdominal pain. Campylobacter infections have frequently been associated with the handling and consumption of raw and undercooked poultry. Antimicrobial resistance among Campylobacter strains is of concern in the treatment of campylobacteriosis in vulnerable populations. A 2-year multidisciplinary study was conducted in the Perth and Wellington-Dufferin-Guelph public health units in Ontario, Canada, to investigate the prevalence and antimicrobial resistance of Campylobacter spp. in retail chicken. Retail chicken samples were collected from randomly selected stores in these health units. Resulting Campylobacter isolates were tested for susceptibility to amoxicillin-clavulanic acid (AMC), ampicillin (AMP), chloramphenicol (CHL), ciprofloxacin (CIP), clindamycin (CLI), erythromycin (ERY), gentamicin (GEN), nalidixic acid (NAL), tetracycline (TCY), and trimethoprim-sulfamethoxazole (SXT) using the E test. The prevalence of Campylobacter in 1,256 retail chicken samples was 59.6%. Of these positive samples, 9% contained Campylobacter coli, 1% contained Campylobacter lari, and 90% contained Campylobacter jejuni. Of the chicken isolates that were resistant to one or more antimicrobial agents, 301 isolates (40%) were resistant to one agent, 374 (50%) were resistant to two, 39 (5%) were resistant to three, 20 (3%) were resistant to four, and 6 (1%) were resistant to five. Nine isolates (1%) were susceptible to all antimicrobial agents tested. All isolates were susceptible to AMC, CHL, and GEN. Less than 10% of isolates were resistant to NAL, CIP, CLI, ERY, and AMP. Resistance to TCY was common (56%). No isolates had a resistance pattern that included all three antimicrobials important in the treatment of human campylobacteriosis (CIP, ERY, and TCY); however, 24 isolates (3.2%) were resistant to at least two of these antimicrobials.

Illness Severity Scores in Veterinary Medicine: What Can We Learn?

Illness severity scores are gaining increasing popularity in veterinary medicine. This article discusses their applications in both clinical medicine and research, reviews the caveats pertaining to their use, and discusses some of the issues that arise in appropriate construction of a score. Illness severity scores can be used to decrease bias and confounding and add important contextual information to research by providing a quantitative and objective measure of patient illness. In addition, illness severity scores can be used to benchmark performance, and establish protocols for triage and therapeutic management. Many diagnosis-specific and diagnosis-independent veterinary scores have been developed in recent years. Although score use in veterinary research is increasing, the scores available are currently underutilized, particularly in the context of observational studies. Analysis of treatment effect while controlling for illness severity by an objective measure can improve the validity of the conclusions of observational studies. In randomized trials, illness severity scores can be used to demonstrate effective randomization, which is of particular utility when group sizes are small. The quality of veterinary scoring systems can be improved by prospective multicenter validation. The prevalence of euthanasia in companion animal medicine poses a unique challenge to scores based on a mortality outcome.

Flock Prevalence of Exposure to Avian Adeno-Associated Virus, Chicken Anemia Virus, Fowl Adenovirus, and Infectious Bursal Disease Virus Among Ontario Broiler Chicken Flocks

SUMMARY Samples from 231 randomly selected commercial broiler chicken flocks in Ontario were tested at slaughter for exposure to chicken anemia virus (CAV), fowl adenovirus (FAdV), and infectious bursal disease virus (IBDV). Fifteen blood samples per flock were collected and analyzed for the presence of antibodies against CAV, FAdV, and IBDV by ELISA or agar gel immunodiffusion test. Fifteen cecal tonsils and cloacal swabs per flock were analyzed for the presence of CAV, FAdV, and IBDV by PCR. The prevalence of exposure to avian adeno-associated virus (AAAV) was estimated by a PCR test on a subset of FAdV–PCR-positive samples from 178 flocks. Genotypes of FAdV and IBDV were identified on a subset of isolates (n  =  353 and 45, respectively). The flock-level period prevalence of exposure to AAAV, CAV, FAdV, and IBDV during grow-out were 88.76% (95% CI: 84.08–93.45%), 77.06% (95% CI: 71.59–82.52%), 96.54% (95% CI: 94.16–98.91%), and 48.92% (95% CI: 42.42–55.41%), respectively. Results of a multivariable logistic regression model showed a significant association of exposure to FAdV with exposure to AAAV (OR  =  18.57, 95% CI: 3.67–93.86, P  =  0.004) but not with exposure to CAV (P  =  0.7752) or exposure to IBDV (P  =  0.2274). Pathogenic FAdV genotypes (FAdV-02, FAdV-08, and FAdV-11) constituted 39.38% of the isolates. The most-common IBDV genotypes identified were IBDV NC171 (60%) and IBDV 05SA8 (28.89%). This is the first large-scale study to estimate the baseline flock prevalence of exposure to AAAV, CAV, FAdV, and IBDV in commercial broiler flocks in Canada. Potentially pathogenic genotypes of FAdV and IBDV that can guide vaccine development and disease control efforts in Ontario were identified. RESUMEN Prevalencia de la exposición a virus adeno-asociados aviares, al virus de la anemia infecciosa y al virus de la enfermedad infecciosa de la bolsa de Fabricio en parvadas de pollo de engorde en Ontario. Se analizaron muestras de 231 parvadas de pollos de engorde comerciales seleccionados aleatoriamente en Ontario recolectadas durante el procesamiento, para determinar la exposición al virus de la anemia infecciosa (CAV), a adenovirus aviares (FAdV) y para el virus de la enfermedad infecciosa de la bolsa (IBDV). Se recolectaron y analizaron quince muestras por parvada para detectar la presencia de anticuerpos contra el virus de la anemia, adenovirus aviar y virus de la enfermedad de Gumboro mediante ELISA o por la prueba de inmunodifusión en gel de agar. Se analizaron quince muestras de tonsilas cecales e hisopos cloacales por parvada para detectar la presencia de los tres virus por PCR. Se estimó la prevalencia de la exposición a virus aviares adeno-asociados (AAAV) mediante una prueba de PCR en un subconjunto de muestras positivas a la presencia de adenovirus aviares por PCR de 178 parvadas. Los genotipos de adenovirus aviares y del virus de Gumboro se identificaron en un subconjunto de los aislados (n =  353 y 45, respectivamente). El nivel de prevalencia en la parvada a la exposición contra virus adeno asociados, de anemia del pollo y de Gumboro durante el periodo de engorde fueron de 88.76% (Intervalo de confianza del 95%: 84.08 al 93.45%), 77.06 % (IC del 95%: 71.59 al 82.52 %), 96.54 % (IC del 95%: 94.16 al 98.91 %) y 48.92 % (IC del 95%: 42.42 al 55.41 %), respectivamente. Los resultados de un modelo de regresión logística multivariable mostraron una asociación significativa de la exposición a adenovirus aviares con la exposición a los virus adeno asociados (OR  =  18.57, IC del 95%: 3.67 a 93.86, P  =  0.0005), pero no con la exposición a la al virus de la anemia (P  =  0.7752) o con la exposición al virus de Gumboro (P  =  0.2274). Los genotipos patógenos de adenovirus (FAdV-02, FAdV-08, y FAdV-11) constituyeron el 39.38 % de los aislamientos. Los genotipos de Gumboro más comúnmente identificados fueron NC171 (60 %) y IBDV 05SA8 (28.89 %). Este es el primer estudio a gran escala para estimar la línea base de la prevalencia en parvadas a la exposición con virus adeno-asociados aviares, al virus de la anemia, a adenovirus aviares y al virus de la enfermedad de Gumboro en parvadas comerciales en Canadá. Se identificaron genotipos potencialmente patógenos de adenovirus y de Gumboro que pueden guiar los esfuerzos para el desarrollo de vacunas y el control de enfermedades en Ontario.

Biomarkers in the assessment of acute and chronic kidney diseases in the dog and cat

In both human and veterinary medicine, diagnosing and staging renal disease can be difficult. Measurement of glomerular filtration rate is considered the gold standard for assessing renal function but methods for its assessment can be technically challenging and impractical. The main parameters used to diagnose acute and chronic kidney disease include circulating creatinine and urea concentrations, and urine-specific gravity. However, these parameters can be insensitive. Therefore, there is a need for better methods to diagnose and monitor patients with renal disease. The use of renal biomarkers is increasing in human and veterinary medicine for the diagnosis and monitoring of acute and chronic kidney diseases. An ideal biomarker would identify site and severity of injury, and correlate with renal function, among other qualities. This article will review the advantages and limitations of renal biomarkers that have been used in dogs and cats, as well as some markers used in humans that may be adapted for veterinary use. In the future, measuring a combination of biomarkers will likely be a useful approach in the diagnosis of kidney disorders.

Low central venous oxygen saturation is associated with increased mortality in critically ill dogs.

OBJECTIVES To investigate relationships between central venous oxygen saturation (ScvO(2)) and survival to hospital discharge in dogs. Central venous oxygen saturation is an accessible measure of the balance between systemic oxygen delivery and consumption. METHODS Prospective observational cohort study, enrolling 126 client-owned dogs with central venous catheters. Central venous oxygen saturation was measured over the 24 hours following intensive care unit admission. Poor outcome was defined as death or euthanasia performed for moribund status. Regression analysis identified independent predictors of non-survival and physiologic parameters associated with central venous oxygen saturation. Area under the receiver operator curve analysis identified a cut-off point of central venous oxygen saturation, below which central venous oxygen saturation decrease was associated with increased mortality risk. RESULTS Mortality risk was 30·9%. Low central venous oxygen saturation was associated with poor outcome (P<0·05). Area under the receiver operator curve analysis selected a central venous oxygen saturation of 68% as the point below which a fall in central venous oxygen saturation was associated with increased mortality risk. For each 10% drop in central venous oxygen saturation below 68%, odds of non-survival increased by 2·66 times (P=0·0002, 95% confidence interval of odds ratio=1·45 to 4·85). Central venous oxygen saturation was equivalent to lactate in predicting non-survival. Predictors of central venous oxygen saturation (packed cell volume, mean arterial blood pressure, fever, % arterial haemoglobin saturation as measured by pulse oximeter) were consistent with hypothesised physiologic mechanisms. CLINICAL SIGNIFICANCE Central venous oxygen saturation was a strong mortality predictor. Further work is needed to determine if therapy targeting central venous oxygen saturation can reduce mortality in canine intensive care unit patients.

A systematic review and meta-analysis of the proportion of dogs surrendered for dog-related and owner-related reasons.

Companion-animal relinquishment is a worldwide phenomenon that leaves companion animals homeless. Knowing why humans make the decision to end their relationship with a companion-animal can help in our understanding of this complex societal issue and can help to develop preventive strategies. A systematic review and meta-analysis was conducted to summarize reasons why dogs are surrendered, and determine if certain study characteristics were associated with the reported proportions of reasons for surrender. Articles investigating one or more reasons for dog surrender were selected from the references of a published scoping review. Two reviewers assessed the titles and abstracts of these articles, identifying 39 relevant articles. From these, 21 articles were further excluded because of ineligible study design, insufficient data available for calculating a proportion, or no data available for dogs. Data were extracted from 18 articles and meta-analysis was conducted on articles investigating reasons for dog surrender to a shelter (n=9) or dog surrender for euthanasia (n=5). Three studies were excluded from meta-analysis because they were duplicate populations. Other reasons for excluding studies from meta-analysis were, (1) the study only investigated reasons for dog re-relinquishment (n=2) and (2) the study sample size was <10 (n=1). Two articles investigated reasons for both dog surrender to a shelter and dog surrender for euthanasia. Results of meta-analysis found owner health/illness as a reason for dog surrender to a shelter had an overall estimate of 4.6% (95% CI: 4.1%, 5.2%). For all other identified reasons for surrender there was significant variation in methodology among studies preventing further meta-analysis. Univariable meta-regression was conducted to explore sources of variation among these studies. Country was identified as a significant source of variation (p<0.01) among studies reporting behavioural problems as a reason for dog surrender for euthanasia. The overall estimate for studies from Australia was 10% (95% CI: 8.0%, 12.0%; I(2)=15.5%), compared to 16% (95% CI: 15.0%, 18.0%; I(2)=20.2%) for studies from other countries. The present systematic review and meta-analysis highlights the need for further research and standardization of data collection to improve understanding of the reasons for dog relinquishment.

Bayesian analysis of risk factors for infection with a genotype of porcine reproductive and respiratory syndrome virus in Ontario swine herds using monitoring data.

Porcine reproductive and respiratory syndrome (PRRS) has a worldwide distribution. This economically important endemic disease causes reproductive failure in breeding stock and respiratory tract illness in young pigs. In Ontario restricted fragment length polymorphism (RFLP) 1-18-4 has been determined as one of the most common virus genotypes. Individual-level models (ILMs) for infectious diseases, fitted in a Bayesian MCMC framework, have been used to describe both the spatial and temporal spread of diseases. They are an intuitive and flexible class of models that can take into account population heterogeneity via various individual-level covariates. The objective of this study is to identify relative importance of risk factors for the spread of the genotype 1-18-4 from monitoring data in southern Ontario using ILMs. Specifically, we explore networks through which resources are obtained or delivered, as well as the ownership structure of herds, and identify factors that may be contributing to high risk of infection. A population of 316 herds which experienced their PRRS outbreaks between September 2004 and August 2007 are included in the analyses, in which 194 (61%) are sow herds. During the study period, 45 herds (27 sow herds) experienced their first outbreak due to RFLP 1-18-4. Our results show that the three relatively most important factors for the spread of 1-18-4 genotype in Ontario swine herds were sharing the same herd ownership, gilt source and market trucks. All other networks had relatively smaller impact on spread of this PRRSV genotype. Spatial proximity could not be identified as important contributor to spread. Our findings also suggest that gilt acclimation should be practiced whenever possible and appropriate to reduce the risk for the herd and for others as it is already widely implemented and recommended in the North American swine industry.

Evaluating the Efficacy of Teaching Methods Regarding Prevention of Human Epilepsy Caused by Taenia solium Neurocysticercosis in Western Kenya

Taenia solium neurocysticercosis is a major cause of adult-onset epilepsy in developing countries. A questionnaire was administered to 282 Kenyan farmers, followed by a workshop, a second questionnaire, one-on-one training, and a third questionnaire. People who attended workshops were more likely to know how T. solium causes epilepsy in humans in the third visit than the second (P = 0.001). The likelihood that farmers would tether their pigs 100% of the time, limiting exposure to tapeworm eggs, increased after the first (P < 0.001) and second visits (P < 0.001). Farmers were more likely to have heard of Cysticercus cellulosae in the second (P = 0.001) and third visits (P = 0.007), and to know how pigs acquire infection in the second (P = 0.03) and third visits (P = 0.003). Farmers with at least a grade 8 education were more likely to know how T. solium is transmitted to humans in the second (P = 0.001) and third visits (P = 0.009), and were more likely to understand the relationship between epilepsy and T. solium in the second (P = 0.03) and third visits (P = 0.03). Grade 8 education may enhance learning from written material. Workshops followed by individual on-farm training enhanced knowledge acquisition and behavior changes. Training local government extension workers contributed to the sustainability of this project.

Risk factors associated with calcium oxalate urolithiasis in dogs evaluated at general care veterinary hospitals in the United States.

Calcium oxalate urolithiasis results from the formation of aggregates of calcium salts in the urinary tract. Difficulties associated with effectively treating calcium oxalate urolithiasis and the proportional increase in the prevalence of calcium oxalate uroliths relative to other urolith types over the last 2 decades has increased the concern of clinicians about this disease. To determine factors associated with the development of calcium oxalate urolithiasis in dogs evaluated at general care veterinary hospitals in the United States, a retrospective case-control study was performed. A national electronic database of medical records of all dogs evaluated between October 1, 2007 and December 31, 2010 at 787 general care veterinary hospitals in the United States was reviewed. Dogs were selected as cases at the first-time diagnosis of a laboratory-confirmed urolith comprised of at least 70% calcium oxalate (n=452). Two sets of control dogs with no history of urolithiasis diagnosis were randomly selected after the medical records of all remaining dogs were reviewed: urinalysis examination was a requirement in the selection of one set (n=1808) but was not required in the other set (n=1808). Historical information extracted included urolith composition, dogs diet, age, sex, neuter status, breed size category, hospital location, date of diagnosis, and urinalysis results. Multivariable analysis showed that the odds of first-time diagnosis of calcium oxalate urolithiasis were significantly (P<0.05) greater for dogs<7 years, males (OR: 7.77, 95% CI: 4.93-12.26), neutered (OR: 2.58, 1.44-4.63), toy- vs. medium-sized breeds (OR: 3.15, 1.90-5.22), small- vs. medium-sized breeds (OR: 3.05, 1.83-5.08), large- vs. medium-sized breeds (OR: 0.05, 0.01-0.19), and those with a diagnosis of cystitis within the previous year (OR: 6.49, 4.14-10.16). Urinary factors significantly associated with first-time diagnosis of calcium oxalate urolithiasis were acidic vs. basic pH (OR: 1.94, 1.22-3.10), presence of RBCs (OR: 6.20, 3.91-9.83) or WBCs (OR: 1.62, 1.03-2.54), and protein concentration>30 mg/dL (OR: 1.55, 1.04-2.30). Patient demographics and urinalysis results are important factors that can support risk assessment and early identification of canine oxalate urolithiasis. Therefore, periodic urolith screening and monitoring of urine parameters should be encouraged for dogs at risk of developing these uroliths.