Comparison of genomic sequence of infectious hypodermal and hematopoietic necrosis virus (IHHNV) between Taiwan and other geographical isolates

ABSTRAC--Five isolates of infectious hypodermal and hematopoietic necrosis virus (IHHNV) (three from Taiwan, one from Thailand and one from Ecuador) were sequenced and compared with two other previously sequenced isolates, one from Hawaii and one from the Gulf of California, Mexico. An unrooted neighbor-joining (NJ) phylogenetic tree analysis and a pairwise comparison both show that the variation among these seven different isolates was low. Despite this sequence similarity, our data suggest that two of the three Taiwan isolates may have been imported from the Americas, while the other isolate and the Thailand isolate may be instances of a local (South East Asian) strain. This has implications for the epidemiology of IHHNV, and suggests that geographic isolation has allowed the virus to evolve into two distinct groups.