INRA, CBGP, Campus international de Baillarguet, CS 30016, Montferrier-sur-Lez, France.
Institut Pasteur, Unité de Biologie des Spirochètes, National Reference Center and WHO Collaborating Center for Leptospirosis, Paris, France.
PLoS Negl Trop Dis. 2014 Jun 5;8(6):e2902. doi: 10.1371/journal.pntd.0002902. eCollection 2014 Jun.
Leptospirosis is the most common bacterial zoonoses and has been identified as an important emerging global public health problem in Southeast Asia. Rodents are important reservoirs for human leptospirosis, but epidemiological data is lacking.
METHODOLOGY/PRINCIPAL FINDINGS: We sampled rodents living in different habitats from seven localities distributed across Southeast Asia (Thailand, Lao PDR and Cambodia), between 2009 to 2010. Human isolates were also obtained from localities close to where rodents were sampled. The prevalence of Leptospira infection was assessed by real-time PCR using DNA extracted from rodent kidneys, targeting the lipL32 gene. Sequencing rrs and secY genes, and Multi Locus Variable-number Tandem Repeat (VNTR) analyses were performed on DNA extracted from rat kidneys for Leptospira isolates molecular typing. Four species were detected in rodents, L. borgpetersenii (56% of positive samples), L. interrogans (36%), L. kirschneri (3%) and L. weilli (2%), which were identical to human isolates. Mean prevalence in rodents was approximately 7%, and largely varied across localities and habitats, but not between rodent species. The two most abundant Leptospira species displayed different habitat requirements: L. interrogans was linked to humid habitats (rice fields and forests) while L. borgpetersenii was abundant in both humid and dry habitats (non-floodable lands).
CONCLUSION/SIGNIFICANCE: L. interrogans and L. borgpetersenii species are widely distributed amongst rodent populations, and strain typing confirmed rodents as reservoirs for human leptospirosis. Differences in habitat requirements for L. interrogans and L. borgpetersenii supported differential transmission modes. In Southeast Asia, human infection risk is not only restricted to activities taking place in wetlands and rice fields as is commonly accepted, but should also include tasks such as forestry work, as well as the hunting and preparation of rodents for consumption, which deserve more attention in future epidemiological studies.
钩端螺旋体病是最常见的细菌性人畜共患病，已被确定为东南亚地区一个重要的新出现的全球公共卫生问题。啮齿动物是人类钩端螺旋体病的重要储存宿主，但流行病学数据却很缺乏。
方法/主要发现：我们于 2009 年至 2010 年期间，在东南亚七个不同地区（泰国、老挝人民民主共和国和柬埔寨）的不同生境中采集了啮齿动物样本。还从靠近采集啮齿动物的地点获得了人类分离株。通过实时 PCR 用从啮齿动物肾脏中提取的 DNA 检测钩端螺旋体感染的流行率，检测目标是 lipL32 基因。对从大鼠肾脏中提取的 DNA 进行 rrs 和 secY 基因测序以及多位点可变数串联重复（VNTR）分析，对从大鼠肾脏中提取的 DNA 进行钩端螺旋体分离株分子分型。在啮齿动物中检测到四种钩端螺旋体，分别为伯氏疏螺旋体（56%的阳性样本）、问号钩端螺旋体（36%）、克里希纳疏螺旋体（3%）和魏氏疏螺旋体（2%），这些与人类分离株完全相同。啮齿动物的平均流行率约为 7%，并且在不同的地点和生境中差异很大，但在不同的啮齿动物物种之间没有差异。两种最丰富的钩端螺旋体物种具有不同的生境要求：问号钩端螺旋体与潮湿的生境（稻田和森林）有关，而伯氏疏螺旋体则在潮湿和干燥的生境（非洪水泛滥的土地）中丰富。
结论/意义：问号钩端螺旋体和伯氏疏螺旋体物种在啮齿动物种群中广泛分布，菌株分型证实了啮齿动物是人类钩端螺旋体病的储存宿主。问号钩端螺旋体和伯氏疏螺旋体的生境要求差异支持不同的传播模式。在东南亚，人类感染的风险不仅限于人们普遍认为的湿地和稻田活动，还应包括林业工作以及猎捕和准备食用啮齿动物等活动，在未来的流行病学研究中应更加关注这些活动。
