Overview of the genetic relationships between the two main identified genotypes of ISAV. Publically available ISAV sequences were imported into Bioedit version 18.104.22.168 and a multiple alignment performed using Clustal X . Identical sequences were identified and only a single representative of each sequence type retained in the dataset to reduce subsequent analytical bias. The final alignment consisted of 38 unique sequences spanning a region of 987 (positions 25-1012 with respect to the open reading frame of ISAV segment 6). The phylogenetic relationship among ISAV isolates was inferred using the method described in the legend of Figure 2.