Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, USA.
Department of Mathematics and Statistics, University of Missouri-Kansas City, Kansas City, MO, USA.
Epidemiol Infect. 2014 May;142(5):1034-49. doi: 10.1017/S0950268813001805. Epub 2013 Aug 7.
Salmonella Typhimurium (STM) infection in pigs represents a considerable food safety concern. This study used mathematical modelling to evaluate the effectiveness of cleaning (faeces removal) as a measure to control STM spread among grower-finisher pigs. A modified Susceptible-Infected-Recovered-Susceptible (SIRS) model of STM transmission through a contaminated environment was developed. Infected pigs were divided into three states according to the pathogen level being shed in their faeces. Infection transmission was evaluated using the basic reproduction number (R 0) and the prevalence of infectious pigs at slaughter age. Although increased frequency and efficiency of cleaning did reduce the prevalence of STM shedding at the time of slaughter, these efforts alone were not capable of eliminating the infection from the population. The level of STM faecal shedding by infectious pigs strongly influenced the infection spread and prevalence at slaughter. To control STM in pigs, cleaning should be combined with vaccination and/or isolation of high-level shedders.
猪感染沙门氏菌 Typhimurium（STM）是一个相当大的食品安全问题。本研究使用数学模型来评估清洁（粪便清除）作为控制生长-育肥猪 STM 传播的措施的有效性。开发了一种通过污染环境传播 STM 的改良易感染-感染-恢复-易感染（SIRS）模型。根据其粪便中排出的病原体水平，受感染的猪被分为三种状态。使用基本繁殖数（R0）和屠宰时感染性猪的流行率评估感染传播。尽管增加清洁的频率和效率确实降低了屠宰时 STM 排放的流行率，但仅这些努力并不能将感染从人群中消除。感染猪的 STM 粪便排放量水平强烈影响了屠宰时的感染传播和流行率。为了控制猪中的 STM，清洁应与疫苗接种和/或高水平排放者的隔离相结合。
