title: Genetic variation and geographic distribution of megalocytiviruses.
abstract: Viruses belonging to the genus Megalocytivirus in the family Iridoviridae have caused mass mortalities in marine and freshwater fish in Asian countries. In this study, partial major capsid protein (MCP) gene of seven Japanese and six Korean megalocytiviruses was sequenced and compared with the known megalocytiviruses to evaluate genetic variation and geographic distribution of the viruses. Comparison of MCP gene nucleotide sequences revealed sequence identity of 92.8% or greater among these 48 isolates. A phylogenetic tree clearly revealed three clusters: genotype I including nine Japanese isolates, thirteen Korean isolates, one Chinese isolates, one Thailand isolate and one South China Sea isolate; genotype II including five freshwater fish isolates in Southeast Asian countries and Australia; and the remaining genotype III mainly consisted of flatfish isolate in Korea and China. This suggests that viruses belonging to the genotype I widely distribute among various fish species in many Asian countries. Conversely, the epidemic viruses belonged to genotype II and III are may be still locally spreading and constrained in their prevalence to the limited host fish species, i.e., genotype II viruses mainly distribute in Southeast Asian countries, whereas genotype III viruses distribute in flatfish species in Korea and China.
authors.affiliation: Center for Marine Environmental Studies, Ehime University, Matsuyama 790-8577, Japan.
authors.forename: Jun-Young
authors.initials: JY
authors.lastname: Song
authors.forename: Shin-Ichi
authors.initials: S
authors.lastname: Kitamura
authors.forename: Sung-Ju
authors.initials: SJ
authors.lastname: Jung
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Miyadai
authors.forename: Shinji
authors.initials: S
authors.lastname: Tanaka
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Fukuda
authors.forename: Seok-Ryel
authors.initials: SR
authors.lastname: Kim
authors.forename: Myung-Joo
authors.initials: MJ
authors.lastname: Oh
mesh_terms: D000818:Animals; D001208:Asia; D036022:Capsid Proteins / Q000235:genetics; D004266:DNA Virus Infections / Q000235:genetics / Q000662:veterinary*; D004279:DNA, Viral / Q000235:genetics; D005393:Fish Diseases / Q000235:genetics / Q000821:virology*; D005399:Fishes / Q000821:virology; D014644:Genetic Variation; D005843:Geography; D007497:Iridoviridae / Q000145:classification / Q000235:genetics*; D008969:Molecular Sequence Data; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D012689:Sequence Homology, Nucleic Acid
chemical_list: D036022:Capsid Proteins; D004279:DNA, Viral