Spatial and temporal heterogeneity of infectious hematopoietic necrosis virus in Pacific Northwest salmonids.
The aquatic rhaboviral pathogen infectious hematopoietic necrosis virus (IHNV) causes acute disease in juvenile fish of a number of populations of Pacific salmonid species. Heavily managed in both marine and freshwater environments, these fish species are cultured during the juvenile stage in freshwater conservation hatcheries, where IHNV is one of the top three infectious diseases that cause serious morbidity and mortality. Therefore, a comprehensive study of viral genetic surveillance data representing 2590 field isolates collected between 1958 and 2014 was conducted to determine the spatial and temporal patterns of IHNV in the Pacific Northwest of the contiguous United States. Prevalence of infection varied over time, fluctuating over a rough 5-7yearcycle. The genetic analysis revealed numerous subgroups of IHNV, each of which exhibited spatial heterogeneity. Within all subgroups, dominant genetic types were apparent, though the temporal patterns of emergence of these types varied among subgroups. Finally, the affinity or fidelity of subgroups to specific host species also varied, where UC subgroup viruses exhibited a more generalist profile and all other subgroups exhibited a specialist profile. These complex patterns are likely synergistically driven by numerous ecological, pathobiological, and anthropogenic factors. Since only a few anthropogenic factors are candidates for managed intervention aimed at improving the health of threatened or endangered salmonid fish populations, determining the relative impact of these factors is a high priority for future studies.
Cary Institute for Ecosystems Studies, 2801 Sharon Turnpike (Route 44), 12545-0129 Millbrook, N.Y., United States; US Geological Survey Western Fisheries Research Center, Seattle WA. Electronic address: rbjmax@uw.edu.
Rachel
R
Breyta
Cary Institute for Ecosystems Studies, 2801 Sharon Turnpike (Route 44), 12545-0129 Millbrook, N.Y., United States; US Geological Survey Western Fisheries Research Center, Seattle WA.
Allison
A
Black
Cary Institute for Ecosystems Studies, 2801 Sharon Turnpike (Route 44), 12545-0129 Millbrook, N.Y., United States; Oregon Department of Fish and Wildlife, Corvallis, OR.
John
J
Kaufman
Cary Institute for Ecosystems Studies, 2801 Sharon Turnpike (Route 44), 12545-0129 Millbrook, N.Y., United States; US Geological Survey Western Fisheries Research Center, Seattle WA.
Gael
G
Kurath
D000818:Animals; D005393:Fish Diseases / Q000453:epidemiology / Q000821:virology*; D029142:Infectious hematopoietic necrosis virus / Q000235:genetics*; D017720:Molecular Epidemiology; D015205:Northwestern United States / Q000453:epidemiology; D010802:Phylogeny; D018353:Rhabdoviridae Infections / Q000453:epidemiology / Q000662:veterinary / Q000821:virology*; D012487:Salmonidae / Q000821:virology*
Aquatic; Epidemiology; IHNV; Salmonid; Virus