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Yaemkasem S, Boonyawiwat V, Sukmak M, Thongratsakul S, Poolkhet C. Spatial and temporal patterns of white spot disease in Rayong Province, Thailand, from october 2015 to september 2018. Prev Vet Med 2021; 199:105560. [PMID: 34933216 DOI: 10.1016/j.prevetmed.2021.105560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 12/09/2021] [Accepted: 12/12/2021] [Indexed: 10/19/2022]
Abstract
This study aimed to analyze the spatial and temporal patterns of white spot disease (WSD) in shrimp farms in Rayong Province, Thailand, between October 2015 and September 2018. The longitudinal data of all active shrimp farms were collected and categorized into two groups: cases and non-cases. A space-time permutation scan, epidemic curve, and time-series analysis were used to evaluate the spatiotemporal patterns. We assessed a total of 1126 ponds across 176 farms in two districts (Klaeng and Mueang Rayong) and identified three significant (P < 0.05) clusters of WSD cases. The biggest cluster encompassed 21 geographical coordinates. This cluster had a radius of 1.14 km and occurred between January 31, 2017, and February 28, 2017. The epidemic curve showed that the biggest outbreak peaked from December 2017 to February 2018. In the time-series analysis, the highest probability of actual WSD cases was at the beginning of each calendar year, consistent with the prominent high probability recorded in WSD forecasts. Our analysis presents the interaction between hotspot areas and time period. These results should help the relevant authorities implement appropriate surveillance programs and control measures to limit the occurrence and transmission of WSD.
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Affiliation(s)
- Sompit Yaemkasem
- Graduate Program of Animal Health and Biomedical Science, Faculty of Veterinary Medicine, Kasetsart University, Bangkok, 10900, Thailand; Section of Epidemiology, Faculty of Veterinary Medicine, Kasetsart University, Kamphaeng Saen, Nakhon Pathom, 73140, Thailand; Rayong Coastal Aquaculture Research and Development Center, Rayong, 21000, Thailand
| | - Visanu Boonyawiwat
- Section of Aquatic Animal Diseases, Faculty of Veterinary Medicine, Kasetsart University, Kamphaeng Saen, Nakhon Pathom, 73140, Thailand
| | - Manakorn Sukmak
- Section of Aquatic Animal Diseases, Faculty of Veterinary Medicine, Kasetsart University, Kamphaeng Saen, Nakhon Pathom, 73140, Thailand
| | - Sukanya Thongratsakul
- Section of Epidemiology, Faculty of Veterinary Medicine, Kasetsart University, Kamphaeng Saen, Nakhon Pathom, 73140, Thailand
| | - Chaithep Poolkhet
- Section of Epidemiology, Faculty of Veterinary Medicine, Kasetsart University, Kamphaeng Saen, Nakhon Pathom, 73140, Thailand.
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Rimstad E, Markussen T. Infectious salmon anaemia virus-molecular biology and pathogenesis of the infection. J Appl Microbiol 2020; 129:85-97. [PMID: 31885186 DOI: 10.1111/jam.14567] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 12/20/2019] [Accepted: 12/23/2019] [Indexed: 11/29/2022]
Abstract
Aquaculture has a long history in many parts of the world, but it is still young at an industrial scale. Marine fish farming in open nets of a single fish species at high densities compared to their wild compatriots opens a plethora of possible infections. Infectious salmon anaemia (ISA) is an example of disease that surfaced after large-scale farming of Atlantic salmon (Salmo salar) appeared. Here, a review of the molecular biology of the ISA virus (ISAV) with emphasis on its pathogenicity is presented. The avirulent HPR0 variant of ISAV has resisted propagation in cell cultures, which has restricted the ability to perform in vivo experiments with this variant. The transition from avirulent HPR0 to virulent HPRΔ has not been methodically studied under controlled experimental conditions, and the triggers of the transition from avirulent to virulent forms have not been mapped. Genetic segment reassortment, recombination and mutations are important mechanisms in ISAV evolution, and for the development of virulence. In the 25 years since the ISAV was identified, large amounts of sequence data have been collected for epidemiologic and transmission studies, however, the lack of good experimental models for HPR0 make the risk evaluation of the presence of this avirulent, ubiquitous variant uncertain. This review summarizes the current knowledge related to molecular biology and pathogenicity of this important aquatic orthomyxovirus.
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Affiliation(s)
- E Rimstad
- Department of Food Safety and Infection Biology, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Oslo, Norway
| | - T Markussen
- Department of Food Safety and Infection Biology, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Oslo, Norway
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Cárdenas C, Ojeda N, Labra Á, Marshall SH. Molecular features associated with the adaptive evolution of Infectious Salmon Anemia Virus (ISAV) in Chile. INFECTION GENETICS AND EVOLUTION 2018; 68:203-211. [PMID: 30592977 DOI: 10.1016/j.meegid.2018.12.028] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Revised: 12/12/2018] [Accepted: 12/24/2018] [Indexed: 02/05/2023]
Abstract
Infectious salmon anemia virus (ISAV) is an Orthomyxovirus challenging salmon production, with a particular impact in Chile. During 2007-2010 a devastating and of unexpected consequences epizootic event almost destroyed a blooming industry in the country. The event was caused by an aggressive variant with a distinctive deletion in Segment 6, one of the eight genomic segments of the virus. After the outburst, although the infective viral variant seemed to have disappeared, a non-infective variant, not previously reported, was discovered and is characterized by a complete, non-deleted coding segment 6, which has prevailed in the fish population until now. This variant, known as HPR0, appears to be the ancestor strain of ISAV from which novel infective variants are generated. Additional variations in segment 5 have also been associated with the virulence observed in the field, an analysis of the differences in these two protein coding segments has been performed. It appears to us that a combinatorial effect exists between the features displayed by segments 5 and 6 which modulate the intensity of viral outbursts. As a result, a theoretical integrative model is presented which explains the different degree of virulence observed in the field based only on molecular data, this could help estimating the intensity of damage a given variant might exert over a productive farm.
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Affiliation(s)
- Constanza Cárdenas
- Núcleo de Biotecnología Curauma Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile.
| | - Nicolás Ojeda
- Laboratorio de Genética e Inmunología Molecular, Instituto de Biología, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile.
| | - Álvaro Labra
- Laboratorio de referencia ISAV - OIE- Sernapesca, Instituto de Biología, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile.
| | - Sergio H Marshall
- Laboratorio de Genética e Inmunología Molecular, Instituto de Biología, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile; Núcleo de Biotecnología Curauma Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile; Laboratorio de referencia ISAV - OIE- Sernapesca, Instituto de Biología, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile.
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Lyngstad TM, Qviller L, Sindre H, Brun E, Kristoffersen AB. Risk Factors Associated With Outbreaks of Infectious Salmon Anemia (ISA) With Unknown Source of Infection in Norway. Front Vet Sci 2018; 5:308. [PMID: 30574509 PMCID: PMC6292176 DOI: 10.3389/fvets.2018.00308] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Accepted: 11/21/2018] [Indexed: 12/12/2022] Open
Abstract
The occurrence of infectious salmon anemia (ISA) outbreaks in marine farmed Atlantic salmon constitutes a recurring challenge in Norway. Here, we aim to identify risk factors associated with ISA outbreaks with an unknown source of infection (referred to as primary ISA outbreaks). Primary ISA outbreaks are here defined by an earlier published transmission model. We explored a wide range of possible risk factors with logistic regression analysis, trying to explain occurrence of primary ISA with available data from all Norwegian farm sites from 2004 to June 2017. Explanatory variables included site latitude and a range of production and disease data. The mean annual risk of having a primary outbreak of ISA in Norway was 0.7% during this study period. We identified the occurrence of infectious pancreatic necrosis (IPN), having a stocking period longer than 2 months, having the site located at high latitude and high fish density (biomass per cage volume) in the first six months after transfer to sea site as significant risk factors (p < 0.05). We have identified factors related to management routines, other disease problems, and latitude that may help to understand the hitherto unidentified drivers behind the emergence of primary ISA outbreaks. Based on our findings, we also provide management advice that may reduce the incidence of primary ISA outbreaks.
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Affiliation(s)
| | | | | | - Edgar Brun
- Norwegian Veterinary Institute, Oslo, Norway
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Gustafson LL, Creekmore LH, Snekvik KR, Ferguson JA, Warg JV, Blair M, Meyers TR, Stewart B, Warheit KI, Kerwin J, Goodwin AE, Rhodes LD, Whaley JE, Purcell MK, Bentz C, Shasa D, Bader J, Winton JR. A systematic surveillance programme for infectious salmon anaemia virus supports its absence in the Pacific Northwest of the United States. JOURNAL OF FISH DISEASES 2018; 41:337-346. [PMID: 29159889 DOI: 10.1111/jfd.12733] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Revised: 08/25/2017] [Accepted: 08/28/2017] [Indexed: 06/07/2023]
Abstract
In response to reported findings of infectious salmon anaemia virus (ISAV) in British Columbia (BC), Canada, in 2011, U.S. national, state and tribal fisheries managers and fish health specialists developed and implemented a collaborative ISAV surveillance plan for the Pacific Northwest region of the United States. Accordingly, over a 3-1/2-year period, 4,962 salmonids were sampled and successfully tested by real-time reverse-transcription PCR. The sample set included multiple tissues from free-ranging Pacific salmonids from coastal regions of Alaska and Washington and farmed Atlantic salmon (Salmo salar L.) from Washington, all representing fish exposed to marine environments. The survey design targeted physiologically compromised or moribund animals more vulnerable to infection as well as species considered susceptible to ISAV. Samples were handled with a documented chain of custody and testing protocols, and criteria for interpretation of test results were defined in advance. All 4,962 completed tests were negative for ISAV RNA. Results of this surveillance effort provide sound evidence to support the absence of ISAV in represented populations of free-ranging and marine-farmed salmonids on the northwest coast of the United States.
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Affiliation(s)
| | | | - K R Snekvik
- Washington Animal Disease Diagnostic Laboratory, College of Veterinary Medicine, Washington State University, Pullman, WA, USA
| | - J A Ferguson
- Fish Pathology Laboratory, Division of Commercial Fisheries, Alaska Department of Fish and Game, Anchorage, AK, USA
| | | | - M Blair
- USFWS Idaho Fish Health Center, Orofino, ID, USA
| | - T R Meyers
- Twin Lakes Fish Pathology Laboratory, Division of Commercial Fisheries, Alaska Department of Fish and Game, Juneau, AK, USA
| | - B Stewart
- Northwest Indian Fisheries Commission, Olympia, WA, USA
| | - K I Warheit
- Fish Program, Washington Department of Fish and Wildlife, Olympia, WA, USA
| | - J Kerwin
- Washington Department of Fish and Wildlife, Olympia, WA, USA
| | - A E Goodwin
- Pacific Region, U.S. Fish and Wildlife Service, Portland, OR, USA
| | - L D Rhodes
- National Marine Fisheries Service, NOAA, Seattle, WA, USA
| | - J E Whaley
- National Marine Fisheries Service, NOAA, Silver Spring, MD, USA
| | - M K Purcell
- USGS Western Fisheries Research Center, Seattle, WA, USA
| | - C Bentz
- Fish Pathology Laboratory, Division of Commercial Fisheries, Alaska Department of Fish and Game, Anchorage, AK, USA
| | - D Shasa
- USDA, APHIS, VS, Fort Collins, CO, USA
| | - J Bader
- U.S. Fish and Wildlife Service Headquarters, Falls Church, VA, USA
| | - J R Winton
- USGS Western Fisheries Research Center, Seattle, WA, USA
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