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Genotypes and phylogeographical relationships of infectious hematopoietic necrosis virus in California, USA

Diseases of Aquatic Organisms

By:
, , , , and
DOI: 10.3354/dao01811

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Abstract

Infectious hematopoietic necrosis virus (IHNV) contains 3 major genogroups in North America with discreet geographic ranges designated as upper (U), middle (M), and lower (L). A comprehensive genotyping of 237 IHNV isolates from hatchery and wild salmonids in California revealed 25 different sequence types (a to y) all in the L genogroup; specifically, the genogroup contained 14 sequence types that were unique to individual isolates as well as 11 sequence types representing 2 or more identical isolates. The most evident trend was the phylogenetic and geographical division of the L genogroup into 2 distinct subgroups designated as LI and LII. Isolates within Subgroup LI were primarily found within waterways linked to southern Oregon and northern California coastal rivers. Isolates in Subgroup LII were concentrated within inland valley watersheds that included the Sacramento River, San Joaquin River, and their tributaries. The temporal and spatial patterns of virus occurrence suggested that infections among adult Chinook salmon in the hatchery or that spawn in the river are a major source of virus potentially infecting other migrating or resident salmonids in California. Serum neutralization results of the California isolates of IHNV corroborated a temporal trend of sequence divergence; specifically, 2 progressive shifts in which more recent virus isolates represent new serotypes. A comparison of the estimates of divergence rates for Subgroup LI (1 ?? ICT5 mutations per nucleotide site per year) indicated stasis similar to that observed in the U genogroup, while the Subgroup LII rate (1 ?? 10 3 mutations per nucleotide site per year) suggested a more active evolution similar to that of the M genogroup. ?? Inter-Research 2007.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Genotypes and phylogeographical relationships of infectious hematopoietic necrosis virus in California, USA
Series title:
Diseases of Aquatic Organisms
DOI:
10.3354/dao01811
Volume
77
Issue:
1
Year Published:
2007
Language:
English
Publisher:
Inter-Research
Publisher location:
Oldendorf, Germany
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Diseases of Aquatic Organisms
First page:
29
Last page:
40
Number of Pages:
12