Epidemiological investigation of infectious hematopoietic necrosis virus in salt water net-pen reared Atlantic salmon in British Columbia, Canada

Aquaculture
By: , and 

Links

Abstract

An epidemiological study of infectious hematopoietic necrosis viral disease (IHN) in farmed Atlantic salmon in British Columbia was conducted to better understand the management of this disease. The study consisted of a descriptive retrospective investigation of 18 IHN outbreaks on farms between 1992 and 1996, and a prospective surveillance program for the viral disease, after an area management plan was implemented to reduce the viral load around farms and farm-to-farm spread of the virus.

The crude cumulative mortality associated with IHNV in Atlantic salmon was high (average 47%), and outbreaks lasted 5.8 months on average. On the two farms where the virus was detected during the surveillance program, IHNV was confirmed in all pens within 1 month. On two of three sites where fish were kept on farms after the initial disease outbreak subsided, IHN reoccurred within 30 weeks.

The presentation of IHNV on farms, the spatial and temporal patterns of the outbreaks between 1992 and 1996, and the genetic similarity between isolates collected from nine outbreaks spanning a 5-year period, all supported the plausibility of farm-to-farm spread of the virus. Furthermore, the marked decrease in the incidence rate of IHN in farmed Atlantic salmon after the implementation of an area-based management plan aimed at reducing farm-to-farm spread of the virus also supported this hypothesis. Although the source of IHNV for the index case was not determined in this study, secondary spread of the virus between farms via management practices, such as movement of fish, co-habiting naı̈ve fish with survivors of the viral disease, and movement of equipment, likely accounted for some farm outbreaks. This suggested that many cases of IHN may be preventable using good on-farm biosecurity.

Study Area

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Epidemiological investigation of infectious hematopoietic necrosis virus in salt water net-pen reared Atlantic salmon in British Columbia, Canada
Series title Aquaculture
DOI 10.1016/S0044-8486(02)00201-6
Volume 212
Issue 1-4
Year Published 2002
Language English
Publisher Elsevier
Contributing office(s) Western Fisheries Research Center
Description 19 p.
First page 49
Last page 67
Country Canada
Online Only (Y/N) N
Additional Online Files (Y/N) N
Google Analytic Metrics Metrics page
Additional metadata about this publication, not found in other parts of the page is in this table