tailieunhanh - Báo cáo khoa học: " Low numbers of intestinal Shiga toxin-producing E. coli correlate with a poor prognosis in sheep infected with bovine leukemia virus"

Tuyển tập các báo cáo nghiên cứu khoa học quốc tế về bệnh thú y đề tài: Low numbers of intestinal Shiga toxin-producing E. coli correlate with a poor prognosis in sheep infected with bovine leukemia virus | J. Vet. Sci. 2008 9 4 375-379 JOURNAL OF Veterinary Science Low numbers of intestinal Shiga toxin-producing E. coli correlate with a poor prognosis in sheep infected with bovine leukemia virus Witold A. Ferens1 Julius Haruna2 t Rowland Cobbold3 i Carolyn J. Hovde1 Department of Microbiology Molecular Biology and Biochemistry University of Idaho Moscow ID 83844-3052 USA 2Department of Veterinary Microbiology and Pathology Washington Animal Disease Diagnostic Laboratory College of Veterinary Medicine Washington State University Pullman WA 99164 USA 3Field Disease Investigation Unit Washington State University Pullman WA 99164-6610 USA Healthy ruminants carry intestinal Shiga toxin Stx -producing Escherichia coli STEC . Stx has antiviral activities in vitro and STEC numbers correlate with reduced early viremia in sheep experimentally infected with bovine leukemia virus BLV . This study assessed the impact of intestinal STEC on BLV-induced disease for one year post-BLV-challenge. High STEC scores CFU g feces X frequency of STEC-positive samples correlated with good health whereas poor weight gain distress and tumor development occurred only among animals with low STEC scores. STEC carriage was associated with increased percentages of B cells in peripheral blood. Keywords bovine leukemia virus sheep Shiga toxin-producing Escherichia coli Introduction Some serotypes of Shiga toxin Stx -producing Escherichia coli STEC such as O157 H7 can cause severe illness in humans in which toxin s cause systemic damage 4 11 . However healthy ruminants carry intestinal STEC 1-3 with high prevalence. It is not known what if any are the benefits of Stx genes or proteins for the bacteria or their ruminant hosts. Stxs belong to a family of ribosomeinactivating proteins RIPs prevalent among plants 7 . RIPs are important in the innate plant defense against virus Corresponding author Tel 1-208-885-5906 Fax 1-208-885-6518 E-mail cbohach@ Present address Charles River Laboratories .