Spatial and temporal patterns of the distribution of Salmonella on swine farms in Illinois
An ecological study was conducted to identify possible reservoirs of Sa/monelln. From March to November 1998 there were 4 visits to each of 6 selected swine farms in lllinois. Fecal samples were collected from swine in longitudinal and cross-sectional groups on each visit to each farm. Fecal samples were also collected from chickens, cattle, cats, dogs, rodents, and other wildlife. Overnight trapping and hand capture techniques were used to obtain samples from wildlife, cats, and arthropods. Environmental samples including feed, water, pen floor material, bootdebris, and bird feces were collected. All samples were evaluated as Salmonel/n positive or negative by culture. A total of 3564 samples representing 40 sample types were collected and cultured. Of 2442 swine fecal samples, 935 were from longitudinal cohorts, and 1507 were from cross sectional groups. Non-swine fecal samples and environmental samples comprised the remaining 1123 samples. Salmonella was cultured from 157 samples in 19 different sample types. All positive samples are mapped with representation of location and time of collection on the farm.