This thesis is an investigation of various sources of animal health data used in disease surveillance for the swine industry in Ontario, Canada. Health data derived from veterinary diagnostic laboratory submission rates, veterinary diagnostic test results, an abattoir, and swine sentinel herds are examined. Based on data from 1998 to 2009, the rate of submissions to a veterinary diagnostic laboratory are dependent on economic variables associated with the swine industry and include: the price paid to swine producers for pigs, the cost of feed (corn), the United States/Canadian dollar exchange rate, and lean-hog futures. An outbreak of porcine circovirus-associated disease (PCVAD) that occurred in the Ontario swine industry from 2004-2006 increased the rate of diagnostic submissions despite the poor economic state of the swine industry at the time. The positivity of porcine reproductive and respiratory syndrome virus (PRRSV) polymerase chain reaction (PCR) tests ordered by veterinary practitioners decreased during the PCVAD outbreak. There was a strong seasonal and yearly affect in the model influencing the positivity of PRRSV PCR tests. However, there was no association between the positivity of PRRSV enzyme-linked immunosorbent assays (ELISA) and the PCVAD outbreak. These findings suggest that the results of tests ordered by veterinarians at diagnostic laboratories have the potential to be used as a form of syndromic surveillance. Swine tonsils (n=395) were collected from a federally-inspected abattoir to determine the prevalence of porcine pathogens, and the most predominant bacterial pathogens isolated were Streptococcus suis (53.7%), Arcanobacterium pyogenes (29.9%), Pasteurella multocida (27.3%), and Streptococcus porcinus (19.5%). Tonsils collected from the held-rail were more likely to be positive for, Staphylococcus hyicus, Streptococcus porcinus, and Streptococcus suis. PRRSV and porcine circovirus-2 were detected in 22.0% and 11.9% of the samples, respectively. Stored serum samples (n=500) from 50 Ontario swine sentinel herds and samples from 2 case herds with clinical disease suggestive of pestivirus infection were tested for Bovine Viral Diarrhea Virus (BVDV) to determine the prevalence of BVDV on Ontario swine farms. The prevalence of BVDV on Ontario swine farms was negligible and the presence of cattle on the same farm was not an identified risk factor.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:OGU.10214/2649 |
| Date | 21 April 2011 |
| Creators | O'Sullivan, Terri Lynne |
| Contributors | Friendship, Robert, Dewey, Cate |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Thesis |
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