Risk assessment of Bovine Viral Diarrhea by animal movement and vaccination

2022 Fiscal Year Final Research Report

• Project/Area Number: 19K06377
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 42020:Veterinary medical science-related
• Research Institution: Hokkaido University
• Principal Investigator: Isoda Norikazu 北海道大学, 獣医学研究院, 准教授 (80615732)
• Project Period (FY): 2019-04-01 – 2023-03-31
• Keywords: 牛ウイルス性下痢 / 獣医疫学 / 疾病モデル

Outline of Final Research Achievements

Comprehensive filed study of bovine viral diarrhea (BVD) was performed to elucidate its dynamics inherent in Japan. Virological and epidemiological analyses of the BVD outbreak in a region revealed that specific genotype of BVD viruses were traced to movement of the persistently infected cattle which go through market where many of animals have opportunity to be contacted with. Network analysis indicated that risk of BVD virus infection would be associated with the frequency of the cattle movements. Based on the antibody positive rates in age-group introduced by the serological survey, basic reproduction number of BVD virus was estimated following to calculation of BVD virus spread in a farm. Indeed, significant risk factor to BVD virus infection related to vaccination history and cattle movement was not found in the filed study in an area where BVD vaccination was not implemented.

Free Research Field

獣医疫学

Academic Significance and Societal Importance of the Research Achievements

日本におけるBVD対策の基本はワクチン接種であるが、BVDの制圧までには至っていない。そのリスク要因と思われる動物の移動に伴うBVD拡大についてウイルス学的および疫学的見地から関連性を示したことは、本邦における今後のBVD対策に大きく貢献を与える。BVDの拡大には持続感染牛が重要視されてきたが、欧米などでは一過性感染によるBVDの拡大リスクも懸念されている。野外調査でBVDの一過性感染の動態を調査するのが非常に困難なため、血清検査の結果を用いて一過性感染の動態の推定を行った。限られたデータによる結果のため、引き続き精査が必要かと思われる。