Universidad de Concepción, Facultad de Ciencias Naturales y Oceanográficas, Concepción, Chile.
Centro de Estudios Parasitológicos y de Vectores CEPAVE (CONICET CCT-La Plata-UNLP), La Plata, Argentina.
Parasit Vectors. 2020 Oct 17;13(1):523. doi: 10.1186/s13071-020-04388-5.
Rickettsial diseases are considered important in public health due to their dispersal capacity determined by the particular characteristics of their reservoirs and/or vectors. Among the latter, fleas play an important role, since the vast majority of species parasitize wild and invasive rodents, so their detection is relevant to be able to monitor potential emerging diseases. The aim of this study was to detect, characterize, and compare Rickettsia spp. from the fleas of micromammals in areas with different human population densities in Chile.
The presence of Rickettsia spp. was evaluated by standard polymerase chain reaction (PCR) and sequencing in 1315 fleas collected from 1512 micromammals in 29 locations, with different human population densities in Chile. A generalized linear model (GLM) was used to identify the variables that may explain Rickettsia prevalence in fleas.
DNA of Rickettsia spp. was identified in 13.2% (174 of 1315) of fleas tested. Fifteen flea species were found to be Rickettsia-positive. The prevalence of Rickettsia spp. was higher in winter, semi-arid region and natural areas, and the infection levels in fleas varied between species of flea. The prevalence of Rickettsia among flea species ranged between 0-35.1%. Areas of lower human density showed the highest prevalence of Rickettsia. The phylogenetic tree showed two well-differentiated clades with Rickettsia bellii positioned as basal in one clade. The second clade was subdivided into two subclades of species related to Rickettsia of the spotted fever group.
To our knowledge, this is the first report of the occurrence and molecular characterization of Rickettsia spp. in 15 flea species of micromammals in Chile. In this study, fleas were detected carrying Rickettsia DNA with zoonotic potential, mainly in villages and natural areas of Chile. Considering that there are differences in the prevalence of Rickettsia in fleas associated with different factors, more investigations are needed to further understand the ecology of Rickettsia in fleas and their implications for human health.
由于其储存库和/或媒介的特殊特征决定的传播能力，立克次体病被认为对公共卫生很重要。在后者中，跳蚤起着重要作用，因为绝大多数物种寄生在野生和入侵的啮齿动物上，因此检测它们对于监测潜在的新发疾病很重要。本研究旨在检测、鉴定和比较智利不同人口密度地区的微小哺乳动物跳蚤中的立克次体 spp。
通过标准聚合酶链反应（PCR）和测序，评估了来自智利 29 个地点的 1512 只微小哺乳动物的 1315 只跳蚤中是否存在立克次体 spp。使用广义线性模型（GLM）来确定可能解释跳蚤中立克次体流行率的变量。
在所测试的 1315 只跳蚤中，有 13.2%（174 只）检测到立克次体 spp 的 DNA。发现 15 种跳蚤为立克次体阳性。冬季、半干旱地区和自然地区的立克次体 spp 流行率较高，跳蚤种类的感染水平也有所不同。跳蚤种类间的立克次体感染率在 0-35.1%之间。人口密度较低的地区的立克次体流行率最高。系统发育树显示了两个分化良好的分支，其中立氏立克次体位于一个分支的基部。第二个分支进一步细分为两个与斑点热群立克次体相关的亚分支。
据我们所知，这是首次在智利的 15 种微小哺乳动物的跳蚤中报告立克次体 spp 的发生和分子特征。在这项研究中，在智利的村庄和自然地区发现携带具有人畜共患潜力的立克次体 DNA 的跳蚤。考虑到与不同因素相关的跳蚤中立克次体的流行率存在差异，需要进行更多的调查，以进一步了解跳蚤中立克次体的生态学及其对人类健康的影响。
