title: Viral hemorrhagic septicemia IVb status in the United States: inferences from surveillance activities and regional context.
abstract: The United States (U.S.) response to viral hemorrhagic septicemia virus (VHSV) IVb emergence in the Laurentian Great Lakes (GL) included risk-based surveillance for cost-effective decision support regarding the health of fish populations in open systems. All U.S. VHSV IVb isolations to date derive from free-ranging fish from GL States. Most originate in the region designated by US Geological Survey hydrologic unit code (HUC) 04, with the exception of two detections in neighboring Upper Mississippi (HUC 05) and Ohio (HUC 07) regions. For States outside the GL system, disease probability was assessed using multiple evidence sources. None substantiated VHSV IVb absence using surveillance alone, in part due to the limited temporal relevance of data in open systems. However, Bayesian odds risk-based analysis of surveillance and population context, coupled with exclusions where water temperatures likely preclude viral replication, achieved VHSV IVb freedom assurance for 14 non-GL States by the end of 2012, with partial evidence obtained for another 17 States. The non-GL region (defined as the aggregate of 4-digit HUCs located outside of GL States) met disease freedom targets for 2012 and is projected to maintain this status through 2016 without additional active surveillance. Projections hinge on continued basic biosecurity conditions such as movement restrictions and passive surveillance. Areas with navigable waterway connections to VHSV IVb-affected HUCs (and conducive water temperatures) should receive priority for resources in future surveillance or capacity building efforts. However, 6 years of absence of detections in non-GL States suggests that existing controls limit pathogen spread, and that even spread via natural pathways (e.g., water movement or migratory fish) appears contained to the Great Lakes system. This report exemplifies the cost-effective use of risk-based surveillance in decision support to assess and manage aquatic animal population health in open systems.
authors.affiliation: National Surveillance Unit, Centers for Epidemiology and Animal Health, Veterinary Services, Animal and Plant Health Inspection Service, United States Department of Agriculture, 2150 Centre Avenue, Fort Collins, CO, USA. Electronic address: lori.l.gustafson@aphis.usda.gov.
authors.forename: L L
authors.initials: LL
authors.lastname: Gustafson
authors.affiliation: National Surveillance Unit, Centers for Epidemiology and Animal Health, Veterinary Services, Animal and Plant Health Inspection Service, United States Department of Agriculture, 2150 Centre Avenue, Fort Collins, CO, USA.
authors.forename: M D
authors.initials: MD
authors.lastname: Remmenga
authors.affiliation: Department of Health Management, Atlantic Veterinary College, Charlottetown, Prince Edward Island C1A 4P3, Canada.
authors.forename: I A
authors.initials: IA
authors.lastname: Gardner
authors.affiliation: Eastern Regional Office, Veterinary Services, Animal and Plant Health Inspection Service, United States Department of Agriculture, 1408 24th Street SE, Ruskin, FL, USA.
authors.forename: K H
authors.initials: KH
authors.lastname: Hartman
authors.affiliation: Western Regional Office, Veterinary Services, Animal and Plant Health Inspection Service, United States Department of Agriculture, 2150 Centre Avenue, Fort Collins, CO, USA.
authors.forename: L H
authors.initials: LH
authors.lastname: Creekmore
authors.affiliation: United States Fish and Wildlife Service, Pacific Region, 911 NE 11th Avenue, Portland, OR 97232, USA.
authors.forename: A E
authors.initials: AE
authors.lastname: Goodwin
authors.affiliation: Aquaculture Program, Veterinary Services, Animal and Plant Health Inspection Service, United States Department of Agriculture, 4700 River Road, Riverdale, MD, USA.
authors.forename: J E
authors.initials: JE
authors.lastname: Whaley
authors.affiliation: Diagnostic Virology Laboratory, National Veterinary Services Laboratories, Animal and Plant Health Inspection Service, United States Department of Agriculture, 1920 Dayton Avenue, Ames, IA, USA.
authors.forename: J V
authors.initials: JV
authors.lastname: Warg
authors.affiliation: National Surveillance Unit, Centers for Epidemiology and Animal Health, Veterinary Services, Animal and Plant Health Inspection Service, United States Department of Agriculture, 2150 Centre Avenue, Fort Collins, CO, USA.
authors.forename: S L
authors.initials: SL
authors.lastname: Gardner
authors.affiliation: National Surveillance Unit, Centers for Epidemiology and Animal Health, Veterinary Services, Animal and Plant Health Inspection Service, United States Department of Agriculture, 2150 Centre Avenue, Fort Collins, CO, USA.
authors.forename: A E
authors.initials: AE
authors.lastname: Scott
mesh_terms: D000818:Animals; D021821:Communicable Diseases, Emerging; D005399:Fishes; D006114:Great Lakes Region / Q000453:epidemiology; D031941:Hemorrhagic Septicemia, Viral / Q000453:epidemiology / Q000821:virology*; D029141:Novirhabdovirus / Q000145:classification*; D011159:Population Surveillance; D012307:Risk Factors
keywords: Aquatic animal health; Context-based surveillance; Disease freedom; Risk-based surveillance; Viral hemorrhagic septicemia