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Epidemiological analysis of classical swine fever in wild boars in Japan

BACKGROUND: Classical swine fever (CSF) is a contagious disease of pigs and wild boars that is transmitted through direct/indirect contact between animals or CSF virus-contaminated fomites. When the disease re-emerged in 2018 in Japan, a CSF-infected wild boar was reported shortly after the initial...

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Autores principales: Shimizu, Yumiko, Hayama, Yoko, Murato, Yoshinori, Sawai, Kotaro, Yamaguchi, Emi, Yamamoto, Takehisa
Formato: Online Artículo Texto
Lenguaje:English
Publicado: BioMed Central 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8111369/
https://www.ncbi.nlm.nih.gov/pubmed/33975588
http://dx.doi.org/10.1186/s12917-021-02891-0
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author Shimizu, Yumiko
Hayama, Yoko
Murato, Yoshinori
Sawai, Kotaro
Yamaguchi, Emi
Yamamoto, Takehisa
author_facet Shimizu, Yumiko
Hayama, Yoko
Murato, Yoshinori
Sawai, Kotaro
Yamaguchi, Emi
Yamamoto, Takehisa
author_sort Shimizu, Yumiko
collection PubMed
description BACKGROUND: Classical swine fever (CSF) is a contagious disease of pigs and wild boars that is transmitted through direct/indirect contact between animals or CSF virus-contaminated fomites. When the disease re-emerged in 2018 in Japan, a CSF-infected wild boar was reported shortly after the initial pig farm outbreak; subsequently, the disease spread widely. To control the disease spread among wild boars, intensive capturing, fencing, and oral bait vaccination were implemented with concomitant virological and serological surveillance. This study aimed to describe the disease spread in the wild boar population in Japan from September 2018, when the first case was reported, to March 2020, based on the surveillance data. We conducted statistical analyses using a generalized linear mixed model to identify factors associated with CSF infection among wild boars. Moreover, we descriptively assessed the effect of oral bait vaccination, which started in March 2019 in some municipalities in the affected areas. RESULTS: We observed a faster CSF infection spread in the wild boar population in Japan compared with the CSF epidemics in European countries. The infection probability was significantly higher in dead and adult animals. The influence of the multiple rounds of oral bait vaccination was not elucidated by the statistical modeling analyses. There was a decrease and increase in the proportion of infected and immune animals, respectively; however, the immunization in piglets remained insufficient after vaccination for 1 year. CONCLUSIONS: Conditions regarding the wild boar habitat, including forest continuity, higher wild boar population density, and a larger proportion of susceptible piglets, were addressed to increase the infection risk in the wild boar population. These findings could improve the national control strategy against the CSF epidemic among wild boars. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12917-021-02891-0.
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spelling pubmed-81113692021-05-11 Epidemiological analysis of classical swine fever in wild boars in Japan Shimizu, Yumiko Hayama, Yoko Murato, Yoshinori Sawai, Kotaro Yamaguchi, Emi Yamamoto, Takehisa BMC Vet Res Research BACKGROUND: Classical swine fever (CSF) is a contagious disease of pigs and wild boars that is transmitted through direct/indirect contact between animals or CSF virus-contaminated fomites. When the disease re-emerged in 2018 in Japan, a CSF-infected wild boar was reported shortly after the initial pig farm outbreak; subsequently, the disease spread widely. To control the disease spread among wild boars, intensive capturing, fencing, and oral bait vaccination were implemented with concomitant virological and serological surveillance. This study aimed to describe the disease spread in the wild boar population in Japan from September 2018, when the first case was reported, to March 2020, based on the surveillance data. We conducted statistical analyses using a generalized linear mixed model to identify factors associated with CSF infection among wild boars. Moreover, we descriptively assessed the effect of oral bait vaccination, which started in March 2019 in some municipalities in the affected areas. RESULTS: We observed a faster CSF infection spread in the wild boar population in Japan compared with the CSF epidemics in European countries. The infection probability was significantly higher in dead and adult animals. The influence of the multiple rounds of oral bait vaccination was not elucidated by the statistical modeling analyses. There was a decrease and increase in the proportion of infected and immune animals, respectively; however, the immunization in piglets remained insufficient after vaccination for 1 year. CONCLUSIONS: Conditions regarding the wild boar habitat, including forest continuity, higher wild boar population density, and a larger proportion of susceptible piglets, were addressed to increase the infection risk in the wild boar population. These findings could improve the national control strategy against the CSF epidemic among wild boars. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12917-021-02891-0. BioMed Central 2021-05-11 /pmc/articles/PMC8111369/ /pubmed/33975588 http://dx.doi.org/10.1186/s12917-021-02891-0 Text en © The Author(s) 2021 https://creativecommons.org/licenses/by/4.0/Open AccessThis article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/ (https://creativecommons.org/licenses/by/4.0/) . The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/ (https://creativecommons.org/publicdomain/zero/1.0/) ) applies to the data made available in this article, unless otherwise stated in a credit line to the data.
spellingShingle Research
Shimizu, Yumiko
Hayama, Yoko
Murato, Yoshinori
Sawai, Kotaro
Yamaguchi, Emi
Yamamoto, Takehisa
Epidemiological analysis of classical swine fever in wild boars in Japan
title Epidemiological analysis of classical swine fever in wild boars in Japan
title_full Epidemiological analysis of classical swine fever in wild boars in Japan
title_fullStr Epidemiological analysis of classical swine fever in wild boars in Japan
title_full_unstemmed Epidemiological analysis of classical swine fever in wild boars in Japan
title_short Epidemiological analysis of classical swine fever in wild boars in Japan
title_sort epidemiological analysis of classical swine fever in wild boars in japan
topic Research
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8111369/
https://www.ncbi.nlm.nih.gov/pubmed/33975588
http://dx.doi.org/10.1186/s12917-021-02891-0
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