The Center for Microbial Genetics and Genomics, Northern Arizona University, Flagstaff, Arizona, United States of America.
Instituto de Microbiologia, Colegio de Ciencias Biologicas y Ambientales, Universidad San Francisco de Quito, Quito, Ecuador.
PLoS Negl Trop Dis. 2016 Sep 13;10(9):e0004990. doi: 10.1371/journal.pntd.0004990. eCollection 2016 Sep.
Leptospirosis is a zoonotic disease responsible for high morbidity around the world, especially in tropical and low income countries. Rats are thought to be the main vector of human leptospirosis in urban settings. However, differences between urban and low-income rural communities provide additional insights into the epidemiology of the disease.
METHODOLOGY/PRINCIPAL FINDINGS: Our study was conducted in two low-income rural communities near the coast of Ecuador. We detected and characterized infectious leptospira DNA in a wide variety of samples using new real time quantitative PCR assays and amplicon sequencing. We detected infectious leptospira in a high percentage of febrile patients (14.7%). In contrast to previous studies on leptospirosis risk factors, higher positivity was not found in rats (3.0%) but rather in cows (35.8%) and pigs (21.1%). Six leptospira species were identified (L. borgpetersenii, L kirschnerii, L santarosai, L. interrogans, L noguchii, and an intermediate species within the L. licerasiae and L. wolffii clade) and no significant differences in the species of leptospira present in each animal species was detected (χ2 = 9.89, adj.p-value = 0.27).
CONCLUSIONS/SIGNIFICANCE: A large portion of the world's human population lives in low-income, rural communities, however, there is limited information about leptospirosis transmission dynamics in these settings. In these areas, exposure to peridomestic livestock is particularly common and high prevalence of infectious leptospira in cows and pigs suggest that they may be the most important reservoir for human transmission. Genotyping clinical samples show that multiple species of leptospira are involved in human disease. As these genotypes were also detected in samples from a variety of animals, genotype data must be used in conjunction with epidemiological data to provide evidence of transmission and the importance of different potential leptospirosis reservoirs.
钩端螺旋体病是一种人畜共患疾病，在全球范围内发病率很高，尤其是在热带和低收入国家。人们认为，在城市环境中，老鼠是人类钩端螺旋体病的主要传播媒介。然而，城市和低收入农村社区之间的差异为该疾病的流行病学提供了更多的见解。
方法/主要发现：我们的研究在厄瓜多尔沿海的两个低收入农村社区进行。我们使用新的实时定量 PCR 检测和扩增子测序方法，对各种样本中的传染性钩端螺旋体 DNA 进行了检测和特征分析。我们在高比例的发热患者（14.7%）中检测到了传染性钩端螺旋体。与之前关于钩端螺旋体病危险因素的研究不同，在老鼠（3.0%）中并没有发现更高的阳性率，而是在牛（35.8%）和猪（21.1%）中发现了更高的阳性率。鉴定出了 6 种钩端螺旋体（L. borgpetersenii、L kirschnerii、L santarosai、L. interrogans、L noguchii 和 L. licerasiae 和 L. wolffii 分支中的中间种），并且在每种动物物种中存在的钩端螺旋体的种类没有明显差异（χ2 = 9.89，adj.p-value = 0.27）。
结论/意义：世界上很大一部分人口生活在低收入的农村社区，但这些地区关于钩端螺旋体病传播动力学的信息有限。在这些地区，接触围场家畜尤其普遍，牛和猪中高比例的传染性钩端螺旋体表明，它们可能是人类传播的最重要的储存库。对临床样本的基因分型表明，多种钩端螺旋体参与了人类疾病。由于这些基因型也在来自各种动物的样本中检测到，因此基因型数据必须与流行病学数据结合使用，以提供传播证据和不同潜在钩端螺旋体储存库的重要性。
