标题： Lawsonia intracellularis 在猪中的传播动力学评估 显示英文标题

标题： Evaluation of the transmission dynamics of Lawsonia intracellularis in swine

摘要： 这种常见肠道病原体 Lawsonia intracellularis 的传播动力学尚未完全了解。为了评估该病原体的传播参数，将一和两只常规断奶猪接种了 L. intracellularis 的纯培养物，然后放置在相应的哨兵猪群体（#1 和 #2）中，9 天后进行。两个实验暴露组（每组 n = 31 只猪）和一个对照组（n = 5 只猪）分别饲养。在整个 38 天的暴露期中监测了粪便排泄、血清转换、口腔液检测和临床症状，这是在引入实验接种猪之后进行的。传播率是根据随时间推移检测到的感染猪的数量来估计的。定量 PCR 在暴露后 14 天首次在两个实验组中检测到 L. intracellularis。到第 38 天，第 1 组和第 2 组哨兵猪中有 63% 和 86% 被感染。估计的基本繁殖数 (R0) 为 3.35 (95% CI: 1.62 - 7.03)，传播率为 0.096 (0.046 - 0.2)。这些结果表明，将单一传染源的 L. intracellularis 引入易感保育期猪群就足以在较长时间内维持传播，在五周内导致大多数猪被感染。这些发现强调了 L. intracellularis 在群体中持续和传播的能力，加强了检测和控制措施的重要性。 显示英文摘要

摘要： The transmission dynamics of the common enteric pathogen Lawsonia intracellularis are not fully understood. To evaluate the transmission parameters of this pathogen, one and two conventional weaned pigs, were inoculated with a pure culture of L. intracellularis, then placed among respective groups (#1 and #2) of a sentinel cohort of pigs, 9 days later. The two experimentally exposed groups (n = 31 pigs each) and a control group (n = 5 pigs) were separately housed. Fecal shedding, seroconversion, oral fluid detection, and clinical signs were monitored throughout a 38-day exposure period following the introduction of the experimentally inoculated pigs. Transmission rates were estimated based on the number of infected pigs detected over time. Quantitative PCR first detected L. intracellularis in the two experimental groups 14 days post-exposure. By day 38, 63% of Group 1 and 86% of Group 2 sentinel pigs were infected. The estimated basic reproduction number (R0) was 3.35 (95% CI: 1.62 - 7.03), and the transmission rate was 0.096 (0.046 - 0.2). These results demonstrate that introducing a single infectious source of L. intracellularis into a group of susceptible nursery age pigs is sufficient to sustain transmission over a prolonged period, resulting in infection in the majority of pigs within a five-week period. These findings underscore the ability of L. intracellularis to persist and propagate within a group, reinforcing the importance of detection and control measures.