In this study 51 aquatic birnaviruses were isolated from environmental
samples (molluscs, wild fish and sediments) during routine surveys ar
ound fish farms located in Galicia (NW of Spain). These viruses were i
dentified as IPN-like viruses based on their physical and chemical cha
racteristics. Furthermore, these isolates were molecular and serologic
ally compared to the reference strains VR-299, Sp and Ab. Although the
y caused no mortalities in oysters and showed varying degrees of virul
ence in trout, all isolates were recovered from the inoculated animals
, indicating that oysters can become carriers. The results obtained in
this study indicate the role of the molluscs, sediments or fish feed
as important agents to consider in the epidemiology of bimaviruses.