Cargando…

Infectious Salmon Anemia and Farm-Level Culling Strategies

Infectious salmon anemia (ISA) is an infectious disease, and outbreaks must be handled to avoid spread between salmon sea farms. Intensive culling at infected farms is an important biosecurity measure to avoid further spread but is also a costly intervention that farmers try to avoid. A lack of acti...

Descripción completa

Detalles Bibliográficos
Autores principales: Qviller, Lars, Kristoffersen, Anja B., Lyngstad, Trude M., Lillehaug, Atle
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Frontiers Media S.A. 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6974534/
https://www.ncbi.nlm.nih.gov/pubmed/32010710
http://dx.doi.org/10.3389/fvets.2019.00481
_version_ 1783490117053186048
author Qviller, Lars
Kristoffersen, Anja B.
Lyngstad, Trude M.
Lillehaug, Atle
author_facet Qviller, Lars
Kristoffersen, Anja B.
Lyngstad, Trude M.
Lillehaug, Atle
author_sort Qviller, Lars
collection PubMed
description Infectious salmon anemia (ISA) is an infectious disease, and outbreaks must be handled to avoid spread between salmon sea farms. Intensive culling at infected farms is an important biosecurity measure to avoid further spread but is also a costly intervention that farmers try to avoid. A lack of action, however, may lead to new outbreaks in nearby salmon sea farms, with severe impacts on both economy and animal welfare. Here, we aim to explore how a time delay between a detected outbreak and the culling of both infected cages and entire farms affects the further spread of the disease. We use a previously published model to calculate how many salmon sea farms were directly infected in each outbreak. To investigate the effect of culling on the further spread of disease, we use the number of months elapsed from the detected outbreak to (a) the first cage being depopulated, and (b) to the entire salmon sea farm being depopulated as predictors of how many new farms the virus was transmitted to, after controlling for contact between the farms. We show that the lapse in time before the first cage is depopulated correlates positively with how many new salmon sea farms are infected, indicating that infected cages should be culled with as little time delay as possible. The model does not have sufficient power to separate between culling of only cages assumed to be infected and the entire farm, and, consequently, provides no direct empirical evidence for the latter. Lack of evidence is not evidence, however, and we argue that a high probability of spread between cages in infected salmon sea farms still supports the depopulation of entire farms as the safest option.
format Online
Article
Text
id pubmed-6974534
institution National Center for Biotechnology Information
language English
publishDate 2020
publisher Frontiers Media S.A.
record_format MEDLINE/PubMed
spelling pubmed-69745342020-01-31 Infectious Salmon Anemia and Farm-Level Culling Strategies Qviller, Lars Kristoffersen, Anja B. Lyngstad, Trude M. Lillehaug, Atle Front Vet Sci Veterinary Science Infectious salmon anemia (ISA) is an infectious disease, and outbreaks must be handled to avoid spread between salmon sea farms. Intensive culling at infected farms is an important biosecurity measure to avoid further spread but is also a costly intervention that farmers try to avoid. A lack of action, however, may lead to new outbreaks in nearby salmon sea farms, with severe impacts on both economy and animal welfare. Here, we aim to explore how a time delay between a detected outbreak and the culling of both infected cages and entire farms affects the further spread of the disease. We use a previously published model to calculate how many salmon sea farms were directly infected in each outbreak. To investigate the effect of culling on the further spread of disease, we use the number of months elapsed from the detected outbreak to (a) the first cage being depopulated, and (b) to the entire salmon sea farm being depopulated as predictors of how many new farms the virus was transmitted to, after controlling for contact between the farms. We show that the lapse in time before the first cage is depopulated correlates positively with how many new salmon sea farms are infected, indicating that infected cages should be culled with as little time delay as possible. The model does not have sufficient power to separate between culling of only cages assumed to be infected and the entire farm, and, consequently, provides no direct empirical evidence for the latter. Lack of evidence is not evidence, however, and we argue that a high probability of spread between cages in infected salmon sea farms still supports the depopulation of entire farms as the safest option. Frontiers Media S.A. 2020-01-15 /pmc/articles/PMC6974534/ /pubmed/32010710 http://dx.doi.org/10.3389/fvets.2019.00481 Text en Copyright © 2020 Qviller, Kristoffersen, Lyngstad and Lillehaug. http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
spellingShingle Veterinary Science
Qviller, Lars
Kristoffersen, Anja B.
Lyngstad, Trude M.
Lillehaug, Atle
Infectious Salmon Anemia and Farm-Level Culling Strategies
title Infectious Salmon Anemia and Farm-Level Culling Strategies
title_full Infectious Salmon Anemia and Farm-Level Culling Strategies
title_fullStr Infectious Salmon Anemia and Farm-Level Culling Strategies
title_full_unstemmed Infectious Salmon Anemia and Farm-Level Culling Strategies
title_short Infectious Salmon Anemia and Farm-Level Culling Strategies
title_sort infectious salmon anemia and farm-level culling strategies
topic Veterinary Science
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6974534/
https://www.ncbi.nlm.nih.gov/pubmed/32010710
http://dx.doi.org/10.3389/fvets.2019.00481
work_keys_str_mv AT qvillerlars infectioussalmonanemiaandfarmlevelcullingstrategies
AT kristoffersenanjab infectioussalmonanemiaandfarmlevelcullingstrategies
AT lyngstadtrudem infectioussalmonanemiaandfarmlevelcullingstrategies
AT lillehaugatle infectioussalmonanemiaandfarmlevelcullingstrategies