Iriarte María V, Gonzáles José L, Gil Andrés D, de Jong Mart C M
Quantitative Veterinary Epidemiology, Wageningen University and Research, Wageningen, Netherlands.
Department of Epidemiology, Bioinformatics and Animal Models, Wageningen Bioveterinary Research, Lelystad, Netherlands.
Transbound Emerg Dis. 2023 Nov 11;2023:8883502. doi: 10.1155/2023/8883502. eCollection 2023.
During the 2001 foot-and-mouth disease (FMD) epidemic in Uruguay, many farms were already infected and foot-and-mouth disease virus (FMDV) had spread throughout the country by the time the first outbreak was detected and a ban on animal movements was implemented. Before this ban, movements of infected animals between livestock premises were probably one of the main factors contributing to the spread of the disease. Understanding and quantifying this contribution allow identifying risk premises or risk areas to help policymakers to implement effective interventions and enhance targeted surveillance. The aim of this study was to describe, visualize, and analyze the network of livestock movements between livestock premises during the initial phase of the 2001 FMD epidemic in Uruguay and gain insight into the risk of transmission by estimating the between herd basic reproduction number ( ) before a ban on animal movements was implemented. Here, we derived from the average number of outcontacts of infected premises and the average probability that a contact leads to infection. Additionally, we analyzed the current (2022) network of livestock movements in Uruguay, for the same period as in 2001, and estimated assuming the same probability of infection as in 2001. We found that the movements of infected animals during the high-risk period of this epidemic-i.e., the period between FMDV introduction and the detection of the index case-had an important contribution to the virus spread among premises ( = 1.48). Livestock markets and highly connected farms were responsible for the early long-distance spread of FMDV. The analysis of the 2022 network shows that this network is similar to that of 2001 and highlights the importance of targeting highly connected premises, particularly livestock markets, for surveillance, target early detection, and implement interventions during epidemics.
在2001年乌拉圭口蹄疫疫情期间，许多农场已被感染，在首次疫情爆发被检测到并实施动物移动禁令时，口蹄疫病毒已在全国传播。在该禁令实施之前，感染动物在牲畜饲养场所之间的移动可能是导致疾病传播的主要因素之一。了解并量化这种影响有助于识别风险场所或风险区域，以帮助政策制定者实施有效的干预措施并加强针对性监测。本研究的目的是描述、可视化并分析2001年乌拉圭口蹄疫疫情初期牲畜饲养场所之间的牲畜移动网络，并通过在实施动物移动禁令之前估计群体间基本繁殖数（ ）来深入了解传播风险。在此，我们从受感染场所的平均外联接触数以及接触导致感染的平均概率推导出 。此外，我们分析了乌拉圭当前（2022年）与2001年同期相同的牲畜移动网络，并在假设感染概率与2001年相同的情况下估计 。我们发现，在此次疫情的高风险时期，即口蹄疫病毒引入到首例病例被检测出之间的这段时间里，感染动物的移动对病毒在各场所之间的传播起到了重要作用（ = 1.48）。牲畜市场和联系紧密的农场是口蹄疫病毒早期远距离传播的原因。对2022年网络的分析表明，该网络与2001年的网络相似，并突出了针对联系紧密的场所，特别是牲畜市场进行监测、早期检测以及在疫情期间实施干预措施的重要性。
