SURVEY OF A RIEMERELLA ANATIPESTIFER OUTBREAK IN SOUTHERN TAIWAN DUCK FARMS

A septicemic outbreak in southern Taiwan duck farms in 2014 resulted in high mortality of ducklings. Samples from oral or cloacal sites of affected Muscovy and Pekin ducks were collected and the identity of the field isolates was confirmed using Riemerella anatipestifer (RA) 16S rRNA and outer membrane protein A (OmpA)-specific primers in polymerase chain reactions (PCR), with 15 isolates found positive for both 16S rRNA and OmpA. Detection of both the 16S rRNA and OmpA genes could be a rapid PCR test for RA. Serotyping of the isolates using gel-diffusion precipitin test identified serotypes 1, 4, 6, 17, and 19 while a number of isolates were unidentifiable. Sequence analysis of the OmpA gene found high identity (99.0–99.7%) among isolates in Taiwan. These results indicate that RA remains as a significant cause of duck septicemic disease in southern Taiwan.