| an investigation of duck circovirus and co-infection in cherry valley ducks in shandong province, china. | the co-infection of duck circovirus (ducv) with riemerella anatipestifer (ra) or/and escherichia coli (e. coli) or/and duck hepatitis virus i (dhv-i) in cherry valley ducks in china's shandong province was investigated by using polymerase-chain-reaction (pcr)-based methods. for this study, 742 ducks sampled at random from 70 duck farms during 2006-2007 were examined using pcr and dot-blot hybridisation (dbh) tests. overall the ducv infection rate was 33.29%. compared with those at 2 weeks of age ... | 2009 | 18760549 |