Cate Dewey
University of Guelph, Population Medicine, Faculty Member
Research Interests:
Neurocysticercosis caused by the larval stage of the pork tapeworm, Taenia solium, is the major preventable cause of adult-onset epilepsy in developing countries in Africa, Asia, and Latin America. 15 The T. solium life cycle includes... more
Neurocysticercosis caused by the larval stage of the pork tapeworm, Taenia solium, is the major preventable cause of adult-onset epilepsy in developing countries in Africa, Asia, and Latin America. 15 The T. solium life cycle includes the pig as an intermediate host, having ...
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Restriction fragment length polymorphism (RFLP) was first proposed to classify porcine reproductive and respiratory syndrome virus (PRRSV) in 1998. The primary objective of this study was to identify associations between different PRRSV... more
Restriction fragment length polymorphism (RFLP) was first proposed to classify porcine reproductive and respiratory syndrome virus (PRRSV) in 1998. The primary objective of this study was to identify associations between different PRRSV RFLP types in swine herds in southern Ontario and clinical signs of disease in those herds. Herds included in the study submitted samples to the Animal Health Laboratory at the University of Guelph between September 2004 and August 2007. Each farm owner was surveyed to describe the clinical disease in the herd and the RFLP pattern of an isolate of PRRSV was obtained from a diagnostic sample. The most frequent isolates were RFLP types 1_4 (25.1%), 252 (14.7%), 134 (12%), and 1_2 (7.7%). The distribution of RFLP types in this study was found to be different from a previous investigation in Ontario. Those RFLP types most associated with clinical disease in the farrowing phase of production were 1_4, 1_2, and 134. The only virus type to be significantly associated with disease in the finisher phase was RFLP type 262. During the study period RFLP type 184 emerged in the population in November 2005.
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ABSTRACT Anemia is a severe public health problem with serious consequences for both human and socio-economic health. Previously, we reported on a pilot study of a uniquely-shaped iron ingot that can be used during cooking to provide... more
ABSTRACT Anemia is a severe public health problem with serious consequences for both human and socio-economic health. Previously, we reported on a pilot study of a uniquely-shaped iron ingot that can be used during cooking to provide additional iron to an otherwise deficient diet. Currently, we discuss a long-term investigation of the ingot in rural Cambodia to determine the effect of regular use of the iron ingot. A randomized controlled trial was conducted in Kandal Province, Cambodia. Participants were allocated to one of three groups: control, intervention, or intervention with follow-up nutrition education. The purpose of the follow-up sessions was to encourage integration of the intervention and to providing basic nutritional information. Distribution of a re-usable, fish-shaped iron ingot to both intervention groups occurred at baseline. Participants were instructed to use the ingot daily, while preparing soup or boiling drinking water. Data on compliance, hemoglobin and iron status was measured regularly throughout the 12-month trial period. Participants in the intervention groups had improved hemoglobin levels and indices of iron stores, and were also less likely to be anemic at endline. Decreased loss-to-follow-up and increased compliance to the treatment regime was observed in the intervention with follow-up group. The current study demonstrates the long-term acceptability and effectiveness of the iron ingot at ameliorating iron deficiency and anemia in rural Cambodia. A laboratory study confirms the bioavailability of the iron leached from the ingot, suggesting that approximately 75% of daily iron requirements can be met by using the ingot each daily. The iron fish represents an affordable and promising adventitious iron source for the amelioration of iron deficiency anemia. The development of a novel intervention that can be used throughout Asia, and beyond, will dramatically improve the quality of life for millions of women and children.
We carried out a cross-sectional study to investigate antimicrobial resistance patterns of Campylobacter coli isolated from Ontario grower-finisher pigs. From January to June 2004, 1200 samples were collected from 80 farms by obtaining a... more
We carried out a cross-sectional study to investigate antimicrobial resistance patterns of Campylobacter coli isolated from Ontario grower-finisher pigs. From January to June 2004, 1200 samples were collected from 80 farms by obtaining a constant number (15) of fecal samples per farm. Susceptibility of the isolates to 11 antimicrobial drugs was determined by the agar-dilution technique. The overall prevalence of resistance to 1 or more antimicrobials among the isolates was 99.2%. High levels of resistance were observed for azithromycin, clindamycin, erythromycin, streptomycin, and tetracycline: 91.7%, 82.5%, 81.4%, 70.7%, and 63.7%, respectively. For sulfamethoxazole, ampicillin, and nalidixic acid, resistance was observed in 40.3%, 26.6%, and 22.7% of the isolates, respectively. Although at very low levels, resistance was observed for ciprofloxacin (a fluoroquinolone), chloramphenicol, and gentamicin: in 2.4%, 1.7%, and 0.2%, respectively. Many of the isolates (29.7%) were resistant to 5 antimicrobials, the most common being azithromycin, clindamycin, erythromycin, streptomycin, and tetracycline. Isolates from the same farm showed at least 5 patterns of resistance. Results from this study indicate high levels of resistance to the antimicrobial drugs most commonly used in the Canadian swine industry (macrolides, lincosamides, and tetracyclines) among C. coli isolated from grower-finisher pigs in Ontario. Macrolides and fluoroquinolones are the drugs most commonly used to treat severe human campylobacteriosis. Fortunately, at present, there is little resistance to fluoroquinolones among C. coli from pigs in Ontario.
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... to diagnose the causes of lameness in sows that were culled for lameness and to determine if the gross postmortem lesions ... Reprint requests to Dr. CE Dewey, University of Nebraska-Lincoln, Great Plains Veterinary EducationalCenter,... more
... to diagnose the causes of lameness in sows that were culled for lameness and to determine if the gross postmortem lesions ... Reprint requests to Dr. CE Dewey, University of Nebraska-Lincoln, Great Plains Veterinary EducationalCenter, Box 187, Clay Center, Nebraska, USA ...
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The objective of this study was to determine the association between body weight of pigs at 7 wk of age, specific management factors, and previous body weight. Among 3736 pigs from 8 commercial farms, greater 7-wk weight was associated... more
The objective of this study was to determine the association between body weight of pigs at 7 wk of age, specific management factors, and previous body weight. Among 3736 pigs from 8 commercial farms, greater 7-wk weight was associated with greater birth weight (P = 0.001), greater weaning weight (P = 0.001), and earlier age at weaning (P = 0.001). Farms with the earliest average weaning age had the highest health status. Farms with later weaning ages tended to use nurse sows for light-weight pigs. Pigs from farms using all-in/all-out management in the nursery had greater 7-wk weights (P = 0.01). The total mortality and culling rate during the nursery phase (weaning to approximately 7 wk of age) was 6.8%. Higher losses were observed among pigs with low weaning weights (< 4.1 kg) compared with those with higher weaning weights. More of the variation due to 7-wk weight was due to individual sow rather than to farm of origin.
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Antibiotic use was described using a convenience sample of 90 Alberta swine farms representing approximately 25% of the Alberta market swine production. Data on the use of antibiotics were collected through an on-farm interview... more
Antibiotic use was described using a convenience sample of 90 Alberta swine farms representing approximately 25% of the Alberta market swine production. Data on the use of antibiotics were collected through an on-farm interview questionnaire. The vast majority of antibiotics were used in feed. The chlortetracycline/sulfamethazine/penicillin combination and tylosin were the most frequently used in-feed antibiotics in weaners and growers/finishers, respectively. The use of antibiotics through water was reported mostly occasionally in all categories. The use of injectable antibiotics was reported mostly in sick pigs. Penicillin was the most common in-water and injectable antibiotic in all categories. The apparent low frequency of critically important antimicrobials for use in humans (quinolones and 3rd generation cephalosporins) is an encouraging finding from a public health perspective. The widespread and frequently reported use of penicillin and tetracycline are of public health conc...
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Swine influenza (SI) is a disease of significance for the swine industry, and vaccination is often recommended as a way to reduce its impact on production. The efficacy of SI vaccines is well established under experimental conditions, but... more
Swine influenza (SI) is a disease of significance for the swine industry, and vaccination is often recommended as a way to reduce its impact on production. The efficacy of SI vaccines is well established under experimental conditions, but information about field efficacy is scarce. The objective of this study was to evaluate the efficacy of a commercial inactivated bivalent (H1N1/H3N2) vaccine under conditions of natural exposure to a field SI variant. To accomplish our goal we used a randomized, blinded, field trial in 2 cohorts of finisher pigs in a multi-site swine production system located in southern Ontario. During the trial, this herd experienced an outbreak of porcine circovirus associated disease (PCVAD). The efficacy of the SI vaccine was assessed through its effect on average daily weight gain, and serological responses to SI over time. The effect of vaccination on pig growth was different in the 2 cohorts. Weight gain was higher in vaccinated pigs than in control pigs in...
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Risk-based surveillance is becoming increasingly important in the veterinary and public health fields. It serves as a means of increasing surveillance sensitivity and improving cost-effectiveness in an increasingly resource-limited... more
Risk-based surveillance is becoming increasingly important in the veterinary and public health fields. It serves as a means of increasing surveillance sensitivity and improving cost-effectiveness in an increasingly resource-limited environment. Our approach for developing a tool for the risk-based geographical surveillance of contagious diseases of swine incorporates information about animal density and external biosecurity practices within swine herds in southern Ontario. The objectives of this study were to group the sample of herds into discrete biosecurity groups, to develop a map of southern Ontario that can be used as a tool in the risk-based geographical surveillance of contagious swine diseases, and to identify significant predictors of biosecurity group membership. A subset of external biosecurity variables was selected for 2-step cluster analysis and latent class analysis (LCA). It was determined that 4 was the best number of groups to describe the data, using both analyti...
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An observational study was conducted to determine the prevalence of Isospora suis oocysts in fecal samples from suckling piglets in Ontario, and to evaluate the relationship between the presence of I. suis oocysts and diarrhea. Fifty... more
An observational study was conducted to determine the prevalence of Isospora suis oocysts in fecal samples from suckling piglets in Ontario, and to evaluate the relationship between the presence of I. suis oocysts and diarrhea. Fifty farms and 709 litters of piglets were included in the study. Oocysts were detected on 70% of farms, with 187 litters infected. A litter of pigs that was positive for oocysts was significantly more likely to exhibit diarrhea than a litter that was negative [odds ratio (OR) = 4.0; 95% confidence interval (CI) = 2.8 to 5.8; P < 0.001]. Management and housing factors were examined with respect to risk factors for the presence of I. suis. Farms that did not use a detergent when cleaning farrowing crates were 10-times more likely to be positive for I. suis than those that used a detergent (P = 0.007). It was concluded that coccidiosis is a common problem on Ontario swine farms.
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The purposes of this study were to describe the clinical signs observed in PRRS positive herds during a porcine reproductive and respiratory syndrome (PRRS) outbreak in Ontario and to determine associations between these clinical signs... more
The purposes of this study were to describe the clinical signs observed in PRRS positive herds during a porcine reproductive and respiratory syndrome (PRRS) outbreak in Ontario and to determine associations between these clinical signs and herd demographics and PRRS control strategies. All PRRS polymerase chain reaction-(PCR)-positive submissions to a diagnostic laboratory between September 1, 2004 and August 31, 2007 were identified (n = 1864). After meeting eligibility requirements and agreeing to voluntary study participation, producers from 455 of these submissions were surveyed for information on clinical signs observed in their herds, herd demographics, and PRRS control strategies used in their herds at the time that the PCR-positive samples were taken. Larger herd size was associated with an increased risk of reporting abortion, weakborn piglets, off-feed sows, and sow mortality in sow herds, and with an increased risk of reporting mortality in finishing herds. When disease c...
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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.... more
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 th...
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This study aimed to establish the prevalence of Campylobacter spp. in 80 Ontario grower-finisher pig herds. Ninety-nine percent of the isolates yielded Campylobacter, C coli being the most common species detected. Control of this... more
This study aimed to establish the prevalence of Campylobacter spp. in 80 Ontario grower-finisher pig herds. Ninety-nine percent of the isolates yielded Campylobacter, C coli being the most common species detected. Control of this microorganism must rely on careful food processing and storage of pork, rather than on an on-farm approach.
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The purpose of this study was to compare results from 2 serological assays at the individual- and herd-level for porcine proliferative enteropathy diagnosis. Cohen's kappa coefficient (k) was used to measure agreement. The tests tend... more
The purpose of this study was to compare results from 2 serological assays at the individual- and herd-level for porcine proliferative enteropathy diagnosis. Cohen's kappa coefficient (k) was used to measure agreement. The tests tend to show better agreement when used at the herd level.
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A case-control epidemiological study was conducted to determine whether an increased diagnostic rate for group A rotavirus in swine herds in Ontario was associated with specific management factors. The number of new herds tested per year... more
A case-control epidemiological study was conducted to determine whether an increased diagnostic rate for group A rotavirus in swine herds in Ontario was associated with specific management factors. The number of new herds tested per year and the proportion of new positive herds increased between 1994 and 1997. Herd size was larger and weaning age was younger in rotavirus-positive herds compared with rotavirus-negative herds. Pigs raised in all-in all-out nurseries were 3.4 times more likely to have a positive group A rotavirus diagnosis than pigs in continuous flow facilities. This study demonstrates that the changes seen in group A rotavirus disease herd status in Ontario are associated with changes in farm management practices, including farm expansion, early weaning, and all-in all-out production.
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Objective: To assess the relative importance of age and maternal antibodies on antibody responses of neonatal piglets to a commercial Mycoplasma hyopneumoniae vaccine. Methods: Piglets from 20 sows in each of two commercial swine... more
Objective: To assess the relative importance of age and maternal antibodies on antibody responses of neonatal piglets to a commercial Mycoplasma hyopneumoniae vaccine. Methods: Piglets from 20 sows in each of two commercial swine operations (with serological evidence of M hyopneumoniae exposure) were vaccinated once at 2, 3, or 4 weeks of age with an M hyopneumoniae bacterin, or were nonvaccinated controls. Serum IgG antibodies were assayed by ELISA, using surface antigens of M hyopneumoniae, in serum samples collected from pigs in the first week of life and at prevaccination, 3 weeks postvaccination, and 2.5 months of age. Sows were vacci-nated against M hyopneumoniae in Herd B, but not in Herd A.
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In the study described in this article, the authors investigated the perceptions and needs of public health inspectors (PHIs) in the province of Ontario, Canada, with regard to food safety issues and information resources. A... more
In the study described in this article, the authors investigated the perceptions and needs of public health inspectors (PHIs) in the province of Ontario, Canada, with regard to food safety issues and information resources. A cross-sectional online survey of 239 Ontario PHIs was conducted between April and June 2009. Questions pertained to their perceptions of key food safety issues and foodborne pathogens, knowledge confidence, available resources, and resource needs. All respondents rated time-temperature abuse, inadequate hand washing, and cross contamination as important food safety issues. Salmonella, Campylobacter, and E. coli O157:H7 were pathogens reported to be of concern to 95% of respondents (221/233). Most respondents indicated that they were confident in their knowledge of food safety issues and foodborne pathogens, but wanted a central, online resource for food safety information and ongoing food safety education training for PHIs. The data from the authors' study c...
Research Interests: Food Safety, Environmental Health, Information Services, Humans, Needs Assessment, and 12 moreFemale, Male, Ontario, Middle Aged, Information Dissemination, Public Administration and Policy, Adult, Public health systems and services research, Cross Sectional Studies, Education Continuing, Food Inspection, and ENVIRONMENTAL SCIENCE AND MANAGEMENT
To evaluate the content aspects of the information expectations of clients accessing oncology care services at a tertiary referral center for dogs with life-limiting cancer. Qualitative analysis of data acquired during in-person single... more
To evaluate the content aspects of the information expectations of clients accessing oncology care services at a tertiary referral center for dogs with life-limiting cancer. Qualitative analysis of data acquired during in-person single and dyadic interviews. Sample-43 dog owners participating in 30 interviews. Independent in-person interviews were conducted with standardized open- and closed-ended questions from April to October 2009. Thematic analysis was performed on transcripts of the interview discussions. For the clients, the central qualification was that the information given had to be the truth. Information was expected about all aspects of their dog&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s cancer and its treatment, varying in relation to clients&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; basic understanding of cancer, their previous experience with cancer, and their information preferences. Provision of information generated the trust and confidence necessary to engage in treatment, the ability to make informed decisions, and the ability to be prepared for the future. Provision of information also engendered a sense of control and capability and fostered hope. When dealing with owners of dogs with life-limiting cancer, results indicated that in addition to abiding by the principle of truth-telling, it is important for health-care service providers to ascertain clients&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; understanding of and experiences with cancer as well as their information preferences and thereby adopt a tailored approach to information giving. Provision of information enabled client action and patient intervention but also enhanced clients&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; psychosocial well-being. Veterinary healthcare service providers can purposely provide information to build and sustain clients&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; ability to successfully cope with their pet&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s condition.
Research Interests: Veterinary Medicine, Adolescent, Ownership, Dogs, Humans, and 9 moreFemale, Animals, Male, Young Adult, Aged, Middle Aged, Adult, Neoplasms, and Veterinary Sciences
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Restriction fragment length polymorphism (RFLP) was first proposed to classify porcine reproductive and respiratory syndrome virus (PRRSV) in 1998. The primary objective of this study was to identify associations between different PRRSV... more
Restriction fragment length polymorphism (RFLP) was first proposed to classify porcine reproductive and respiratory syndrome virus (PRRSV) in 1998. The primary objective of this study was to identify associations between different PRRSV RFLP types in swine herds in southern Ontario and clinical signs of disease in those herds. Herds included in the study submitted samples to the Animal Health Laboratory at the University of Guelph between September 2004 and August 2007. Each farm owner was surveyed to describe the clinical disease in the herd and the RFLP pattern of an isolate of PRRSV was obtained from a diagnostic sample. The most frequent isolates were RFLP types 1_4 (25.1%), 252 (14.7%), 134 (12%), and 1_2 (7.7%). The distribution of RFLP types in this study was found to be different from a previous investigation in Ontario. Those RFLP types most associated with clinical disease in the farrowing phase of production were 1_4, 1_2, and 134. The only virus type to be significantly ...
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To determine the effect of within-litter neonatal-weight variation on pre-weaning mortality and weight gain, we analyzed piglet survival and weight gain within 400 litters from 10 commercial farms. Neonatal-weight variation (independent... more
To determine the effect of within-litter neonatal-weight variation on pre-weaning mortality and weight gain, we analyzed piglet survival and weight gain within 400 litters from 10 commercial farms. Neonatal-weight variation (independent of mean neonatal weight, litter size and sow parity) was associated with pre-weaning survival and weaning-weight variation-but not with mean weaning weight. Neonatal piglets with weights well below the range of most of the litter (low-birth-weight piglets) had an increased risk of dying and were unable to obtain normal weight gains by weaning if they survived. These piglets experienced lower survival and poorer weight gain in larger litters. These piglets also tended to have lower survival but normal (albeit low) weaning weights if they survived in litters from middle-aged and old sows. High neonatal-weight variation resulted in lower survival and more variable weaning weights. Small piglets had a greater risk for poor survival and weight gain compared to their heavier litter-mates (a disadvantage that was exacerbated in large litters).
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Research Interests: Food Safety, Publishing, Writing, Animal Welfare, Multidisciplinary, and 12 morePreventive Veterinary Medicine, Biological Sciences, Humans, Animals, Livestock Production, Randomized Trial, United States of America, Editorial Policies, Randomized Controlled Trial, Veterinary Sciences, Veterinary Public Health ZOONOSES, and Veterinary Internal Medicine
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More than 3.5 billion people are affected by iron-deficiency anaemia (IDA). Previous studies have shown that the use of iron pots in daily cooking ameliorates IDA. We report a study on the use of a novel treatment to address IDA in rural... more
More than 3.5 billion people are affected by iron-deficiency anaemia (IDA). Previous studies have shown that the use of iron pots in daily cooking ameliorates IDA. We report a study on the use of a novel treatment to address IDA in rural women in Cambodia, where the use of iron pots is not common. A community-wide randomized controlled trial was conducted in the village of Preak Ruessei, Kandal Province, Cambodia. Rural women (n = 189) were enrolled and randomly assigned by household to one of three groups: (i) control, (ii) iron treatment with no follow-up and (iii) iron treatment with follow-up visits to provide IDA education. Haemoglobin, serum iron and C-reactive protein concentrations were measured at baseline, 3 and 6 months. A reusable fish-shaped iron ingot was distributed to the two treatment groups and participants were directed to use them daily for cooking. We hypothesized that iron from the ingot would leach iron into food providing an effective iron source. Blood iron levels were higher in women in the iron fish plus follow-up at 3 months compared with controls, but this was not maintained. At 6 months, haemoglobin and serum iron had fallen in all groups and the proportion of anaemic women had increased. This study shows that the iron ingot was effective in the short but not longer-term against IDA. Though a novel treatment option, further research is warranted to determine bioavailability of leached iron and whether or not the surface area is large enough for sufficient iron leaching.
Research Interests: Cambodia, European Public Health Policies, Rural Health, Humans, Cooking, and 12 moreFemale, Dietary Supplements, Iron, Iron supplementation, Middle Aged, C reactive protein, Longitudinal Studies, Adult, Public health systems and services research, Iron Deficiency Anaemia, Iron Deficiency Anemia, and Hemoglobins
The spread of PRRSV among pig herds has been investigated experimentally, but few observational studies have investigated this subject. Because PRRSV is endemic and live modified vaccines are used in Ontario, the spatial and temporal... more
The spread of PRRSV among pig herds has been investigated experimentally, but few observational studies have investigated this subject. Because PRRSV is endemic and live modified vaccines are used in Ontario, the spatial and temporal distributions of 6 PRRSV genotypes were investigated in the province during the period from 2004-2007. The purpose was to find evidence of spread of PRRSV genotypes and determine if spread could be attributed to supplier or ownership connections between herds. Sequence information from PRRSV ORF5 and related source-herd demographic information were obtained from diagnostic submissions to the Animal Health Laboratory, University of Guelph. A spatial cluster that could not be attributed to supplier or ownership connections among herds in the cluster was detected for RFLP type 1-3-4. Because of genetic dissimilarity among members of the cluster, it was considered to be a result of past spread of the RFLP type. A spatio-temporal cluster detected for RFLP type 1-18-4 was attributed to a shared gilt supplier among the herds in the cluster. Significant spatio-temporal patterns detected for RFLP type 2-5-2, which is considered to be a vaccine-type virus were most likely due to grouping of herds in an ownership that used the corresponding vaccine. Clustering within herd-ownership was a risk factor for presence of five of the six genotypes investigated in the present study. Although the literature indicates that PRRSV can spread via aerosol between pig herds, the present study found no strong evidence of this occurring in Ontario. The evidence pointed toward transmission of PRRSV occurring in this population by common sources of animals or similarity of herd ownership, which is a proxy measure for other connections between herds. It is also apparent that the recognition and testing of these connections between herds is a necessary part of interpreting spatio-temporal patterns of PRRSV genotypes.
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Research Interests: Food Safety, Focus Groups, Content Analysis, Qualitative Research, Public Health, and 19 moreSafety, Information Services, Information Access, Canada, Humans, Female, Male, Focus Group, Information Gathering, Questionnaires, Qualitative Data, Adult, Public health systems and services research, Food Contamination, Focus Group Discussion, Professional Competence, Information Need, Food Handling & Hygiene, and Food Inspection
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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... more
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.