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Abstract：
Several countries have come close to eliminating leprosy, but leprosy cases continue to be detected at low levels. Due to the long, highly variable delay from infection to detection, the relationship between observed cases and transmission is uncertain. The World Health Organization\'s new technical guidance provides a path for countries to reach elimination. We use a simple probabilistic model to simulate the stochastic dynamics of detected cases as transmission declines, and evaluate progress through the new public health milestones. In simulations where transmission is halted, 5 years of zero incidence in autochthonous children, combined with 3 years of zero incidence in all ages is a flawed indicator that transmission has halted (54% correctly classified). A further 10 years of only occasional sporadic cases is associated with a high probability of having interrupted transmission (99%). If, however, transmission continues at extremely low levels, it is possible that cases could be misidentified as historic cases from the tail of the incubation period distribution, although misleadingly achieving all three milestones is unlikely (less than 1% probability across a 15-year period of ongoing low-level transmission). These results demonstrate the feasibility and challenges of a phased progression of milestones towards interruption of transmission, allowing assessment of programme status. This article is part of the theme issue \'Challenges and opportunities in the fight against neglected tropical diseases: a decade from the London Declaration on NTDs\'.
摘要：
几个国家已经接近消灭麻风病,但是麻风病病例仍然处于低水平。由于时间长,从感染到检测的高度可变的延迟，观察到的病例与传播之间的关系是不确定的。世界卫生组织的新技术指南为各国实现消除污染提供了一条途径。我们使用一个简单的概率模型来模拟传播下降时检测到的案例的随机动态，并通过新的公共卫生里程碑评估进展。在传输暂停的模拟中，本地儿童的5年零发病率，再加上所有年龄段的3年零发病率是一个有缺陷的指标，表明传播已经停止（54％正确分类）。再过10年的偶发病例与传播中断的可能性很高（99％）。如果,然而,传播继续以极低的水平进行，从潜伏期分布的尾部可能会将病例误认为是历史病例，尽管不可能误导地实现所有三个里程碑（在持续的15年低水平传播期间，概率低于1％）。这些结果证明了阶段性进展的可行性和挑战，逐步实现传输中断，允许评估方案状况。本文是主题为“抗击被忽视的热带病的挑战和机遇：《伦敦NTDs宣言》十年”的一部分。
