tailieunhanh - Báo cáo thú y: "Variant -and individual dependent nature of persistent Anaplasma phagocytophilum infection"

Tuyển tập các báo cáo nghiên cứu về bệnh học thý y được đăng trên tạp chí Acta Veterinaria Scandinavica cung cấp cho các bạn kiến thức về bệnh thú yđề tài: Variant -and individual dependent nature of persistent Anaplasma phagocytophilum infection. | Granquist et al. Acta Veterinaria Scandinavica 2010 52 25 http content 52 1 25 AVS ACTAVETERINARIA Scatand n SCANDINAVICA RESEARCH Open Access Variant -and individual dependent nature of persistent Anaplasma phagocytophilum infection Erik G Granquist 1 Kjetil Bârdsen1 Karin Bergstrom2 and Snorre Stuen1 Abstract Background Anaplasmaphagocytophilum is the causative agent of tick-borne fever in ruminants and human granulocytotropic anaplasmosis HGA . The bacterium is able to survive for several months in immune-competent sheep by modifying important cellular and humoral defence mechanisms. Little is known about how different strains of A. phagocytophilum propagate in their natural hosts during persistent infection. Methods Two groups of five lambs were infected with each of two 16S rRNA gene variants of A. phagocytophilum . 16Svariant 1 which is identical to GenBank no M73220 and 16S variant 2 which is identical to GenBank no AF336220 respectively. The lambs were infected intravenously and followed by blood sampling for six months. A. phagocytophilum infection in the peripheral blood was detected by absolute quantitative real-time PCR. Results Both 16S rRNA gene variants of A. phagocytophilum established persistent infection for at least six months and showed cyclic bacteraemias but variant 1 introduced more frequent periods of bacteraemia and higher number of organisms than 16S rRNA gene variant 2 in the peripheral blood. Conclusion Organisms were available from blood more or less constantly during the persistent infection and there were individual differences in cyclic activity of A. phagocytophilum in the infected animals. Two 16S rRNA gene variants of A. phagocytophilum show differences in cyclic activity during persistent infection in lambs. Background Anaplasma phagocytophilum is an obligate intracellular bacterium transmitted by Ixodes ticks and is recognized as the causative agent of TBF tick-borne fever in sheep and HGA human .