There were 2 PCR (16S rDNA-PCR and gyrB-PCR) used to detect R. anatipestifer while one PCR for gene phoA was used to detect E. coli The result showed that R. anatipestifer was found on both disease and non-disease ducks. However, the 2 PCRs to detect R. anatipestifer did not agree well. The fact that these bacteria were found on 22% farms (disease and non-disease ones) means it is complicated to confirm them in causing the mentioned disease. | Determination of Riemerella anatipestifer and Escherichia coli suspected to cause a syndrome including shaking head and trembling greenish diarrhea on duck farms in Long An