Prevalence and survival of Escherichia coli 0157:H7 and Salmonella spp. in surface waters of Southern Alberta

xi, 268 leaves ; 28 cm.E. coli 0157:H7 were isolated from 0.86% (n=1520) water samples and Salmonella species from 6.04% (n=1456) samples collected within the Oldman River watershed in southern Alberta. Peak prevalence of E. coli0157:H7 in July 2000 was 6.3% (n=48). Peak prevalence of Salmonella was 16.2% (n=11) in August 1999 and 33.% (n=42) in July 2000. Prevalence was greater in water from some sampling locations than from others. In non-filtered surface water E. coli0157:H7 and S. typhimurium numbers decreased significantly faster at 20 degrees celsius than at 10 degrees celsius (P=0.000); however this difference did not exist when the same water was filtered (P=0.439). Pathogen survival in one water sample was greater when it was filtered (0.2um pore) than when it was not filtered even though there were no autochthonous bacteria in the water prior to filtration