Farm-level risk factors for the presence of Salmonella in 89 Alberta swine-finishing barns.

This study investigated potential risk factors for the presence of Salmonella on 89 Alberta swine-finishing farms with the use of a questionnaire. Salmonella status was regressed on each fixed effect in a logistic mixed regression model, with farm as the random effect. Eleven variables were significant at the 10% level: farm type, number of square feet per pen, number of pigs per pen, source of feed, ration type, dust control measures, cat presence, reported effective mouse-control measures, time required to be away from pigs before visiting the farm, precautions taken when entering or leaving the farm, and reported use of antimicrobials through water. Three factors remained significant at the 5% level in the multivariable analysis: farm type, ration type, and precautions taken when entering or leaving the farm. Finishing barns at multisite operations or individual grow-to-finish farms had a greater risk of the presence of Salmonella at a single visit than did finishing barns at farrow-to-finish farms. The use of pelleted and wet feed was associated with higher odds of the presence of Salmonella than was the use of meal feed. Farms that required their personnel or visitors to shower before entering and before leaving had increased odds of the presence of Salmonella compared with farms that provided boots and coveralls; no significant difference was observed between the latter category and farms that used boot disinfection. Further work is necessary to better understand the effectiveness of all-in/all-out pig management and disinfection practices in reducing the presence of Salmonella in swine and to evaluate the association with certain types of feed.

An outbreak of sheep-associated malignant catarrhal fever in bison (Bison bison) after exposure to sheep at a public auction sale.

An outbreak of malignant catarrhal fever (MCF) among bison sold at an auction market was studied for an 18-month period. Forty-five of 163 bison submitted for sale from 8 different bison farms died on 7 other destination farms. The outbreak began on day 50 after the sale, peaked between days 60 and 70, and ended on day 220. Twenty-one dead bison were confirmed to be MCF cases by clinical histories, pathology, and detection of ovine herpesvirus-2 DNA in their tissues with polymerase chain reaction assays. Twenty-four dead bison were classified as suspect MCF cases from clinical histories. No cases of MCF were observed among bison remaining on originating farms or resident bison mixed with sale bison on destination farms. There were no sheep reported within 3 km of originating or destination farms, limiting bison exposure to sheep to the auction facility, where sheep were present for less than 1 day. The outbreak provides an illustration of the temporal distribution of MCF mortality expected in bison and an estimate of the time from exposure until death from MCF after a single short exposure to sheep. The study provides evidence that bison with MCF do not transmit MCF to other bison.

Longitudinal study of Salmonella species in 90 Alberta swine finishing farms.

The aim of this study was to determine the farm prevalence of Salmonella in 90 Alberta finishing swine farms over a 5-month period, to evaluate Salmonella distribution in the farm environment and to describe Salmonella serovar diversity on these farms. Ten veterinary practitioners selected 90 Alberta swine farms based on an annual production of > or =2000 market pigs per farm and the willingness of the producers to participate in the study. Between May and September 2000, twenty samples were collected from finishing swine and the environment of each farm. The annual production of selected farms represented approximately 25% of the market swine production in Alberta. Participating farms were geographically representative of major swine production areas in Alberta. Sixty (66.7%) farms had at least one Salmonella-positive sample, with confidence interval (CI) of 57.1-77.2%. Salmonella were detected in 14.3% of fecal and 20.1% of environmental samples. The number of Salmonella-positive samples per farm ranged from 1 to 19. Among environmental samples, Salmonella were most frequently recovered from boots (38.6%) and the main drain (31.8%). Twenty-two serovars were detected on the 60 Salmonella-positive farms. Serovars Typhimurium (78 isolates), Derby (71 isolates) and Infantis (47 isolates) were the most common. A single serovar was detected on 58 farms, while 2, 3 and >3 serovars were detected on 15, 10 and 7 farms, respectively. The Salmonella farm status changed frequently over the 5-month period indicating the dynamic nature of Salmonella infections on these farms.

Clinical West Nile virus infection in 2 horses in western Canada.

Two horses had a history of ataxia and weakness or recumbency. One recovered and was diagnosed with West Nile virus (WNV) infection by serologic testing. The other was euthanized; it had meningoencephalomyelitis, WNV was detected by polymerase chain reaction. West Nile virus infection is an emerging disease. Year 2002 is the first year in which cases have been seen in Saskatchewan.

Jejunal hemorrhage syndrome in 2 Canadian beef cows.

Two beef cows were presented with a history of anorexia and abdominal pain. Both cows were euthanized. Necropsy revealed the presence of a segmental area of ulceration, necrosis, and intraluminal blood clots in the jejunum. Jejunal hemorrhage syndrome is an emerging disease and has not been reported previously in beef cattle.