Abstract:
The global spread of avian influenza A viruses in domestic birds is causing increasing socioeconomic devastation. Various mechanistic models have been developed to better understand avian influenza transmission and evaluate the effectiveness of control measures in mitigating the socioeconomic losses caused by these viruses. However, the results of models of avian influenza transmission and control have not yet been subject to a comprehensive review. Such a review could help inform policy makers and guide future modeling work. To help fill this gap, we conducted a systematic review of the mechanistic models that have been applied to field outbreaks. Our three objectives were to: (1) describe the type of models and their epidemiological context, (2) list estimates of commonly used parameters of low pathogenicity and highly pathogenic avian influenza transmission, and (3) review the characteristics of avian influenza transmission and the efficacy of control strategies according to the mechanistic models. We reviewed a total of 46 articles. Of these, 26 articles estimated parameters by fitting the model to data, one evaluated the effectiveness of control strategies, and 19 did both. Values of the between-individual reproduction number ranged widely: from 2.18 to 86 for highly pathogenic avian influenza viruses, and from 4.7 to 45.9 for low pathogenicity avian influenza viruses, depending on epidemiological settings, virus subtypes and host species. Other parameters, such as the durations of the latent and infectious periods, were often taken from the literature, limiting the models\' potential insights. Concerning control strategies, many models evaluated culling (n = 15), while vaccination received less attention (n = 6). According to the articles reviewed, optimal control strategies varied between virus subtypes and local conditions, and depended on the overall objective of the intervention. For instance, vaccination was optimal when the objective was to limit the overall number of culled flocks. In contrast, pre-emptive culling was preferred for reducing the size and duration of an epidemic. Early implementation consistently improved the overall efficacy of interventions, highlighting the need for effective surveillance and epidemic preparedness.
摘要:
禽流感病毒在家禽中的全球传播正在造成越来越多的社会经济破坏。已经开发了各种机制模型,以更好地了解禽流感的传播,并评估控制措施在减轻这些病毒造成的社会经济损失方面的有效性。然而,禽流感传播和控制模式的结果尚未得到全面审查。这种审查可以帮助决策者了解情况,并指导未来的建模工作。为了填补这一空白,我们对已应用于现场暴发的机制模型进行了系统评价.我们的三个目标是:(1)描述模型的类型及其流行病学背景,(2)列出低致病性和高致病性禽流感传播的常用参数的估计,(3)根据机理模型回顾禽流感的传播特征和控制策略的有效性。我们共审查了46篇文章。其中,26篇文章通过将模型拟合到数据来估计参数,一个人评估了控制策略的有效性,19都做到了。个体间繁殖数量的值范围很广:高致病性禽流感病毒的繁殖数量为2.18至86,低致病性禽流感病毒从4.7到45.9,根据流行病学设置,病毒亚型和宿主物种。其他参数,例如潜伏期和感染期的持续时间,通常取自文学,限制模型的潜在见解。关于控制策略,许多模型评估了剔除(n=15),而疫苗接种受到的关注较少(n=6)。根据审查的文章,最佳控制策略在病毒亚型和当地条件之间有所不同,并取决于干预的总体目标。例如,当目标是限制被扑杀鸡群的总数时,疫苗接种是最佳的.相比之下,先发制人的剔除是减少流行病的规模和持续时间的首选。早期实施持续提高了干预措施的整体效果,强调需要进行有效的监测和防疫。