Characteristics of the human host have little influence on which local Schistosoma mansoni populations are acquired.
Characteristics of the human host have little influence on which local Schistosoma mansoni populations are acquired.
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DOI：
10.1371/journal.pntd.0002572
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发表时间：
2013
影响因子：
3.8
通讯作者：
Blanton RE
中科院分区：
文献类型：
--
作者：
Barbosa LM;Silva LK;Reis EA;Azevedo TM;Costa JM;Blank WA;Reis MG;Blanton RE
巴西仍然是美洲血吸虫病流行率最高的国家。然而，控制努力和发展相结合，大大降低了其强度和分布。特定血吸虫种群的获取可能取决于宿主特征，如性别、年龄、地理、工作、习惯和文化。这些和其他寄主特征如何与寄生虫亚群相匹配，可能会指导改进控制的方法。巴西两个农村社区90%以上的居民参加了一项关于人口、社会经济和行为特征的流行病学调查。变量的性别、年龄、感染强度、社会经济指数、在现场度过的寿命百分比、既往感染和区外旅行被用来对感染个体的寄生虫进行分组。曼氏血吸虫感染情况由3天内提交的粪便检查确定。根据15个微卫星的等位基因频率确定群体分化程度。这些社区的感染率为41%，流行病学特征与巴西和世界上许多流行区相似。观察到两个社区之间的寄生虫种群结构(Jost‘s D 0.046，CI95%0.042-0.051)，尽管两个社区之间只有8公里的距离，并由一条高速公路连接。当根据宿主的生物学、人口学或流行病学特征对感染者进行分层时，没有观察到结构性。那些感染最严重的人最能反映出这些社区的整体寄生虫多样性。村庄内部缺乏区分表明，个体很可能在相同的地点感染，或者在大多数地点可以找到相同的寄生虫多位点基因类型。村庄之间的地理结构，以及缺乏按宿主年龄划分的结构，进一步支持了人口几乎不受迁徙或漂移影响的印象。血吸虫病是世界上最重要的寄生虫病之一。事实证明，即使在巴西等容易获得治疗的国家，消除这种疾病也很困难。感染是人类接触地表水的结果，那里有受感染的蜗牛，因此人类的生物学和习惯可能会使不同的人接触不同的寄生虫群体。识别血吸虫亚群可能有助于了解传播模式并指导控制工作。我们比较了两个小村庄所有感染者的微卫星等位基因频率，确定寄生虫在它们之间的移动是有限的。个体感染是寄生虫的不同组合，但如果按人口统计学和流行病学特征对受感染的人进行分组，没有证据表明在这些类型的宿主中选择了特定的寄生虫亚群。当按宿主年龄分层时，感染也没有区分，这表明种群随着时间的推移是稳定的。由于感染周期需要人类粪便污染水源，因此可以从血吸虫亚群的分布模式在一定程度上推断当地的人类行为。
Brazil remains the country in the Americas with the highest prevalence of schistosomiasis. A combination of control efforts and development, however, has sharply reduced its intensity and distribution. The acquisition of specific schistosome populations may be dependent on host characteristics such as sex, age, geography, work, habits and culture. How these and other host characteristics align with parasite subpopulations may guide approaches to improve control. A cohort of more than 90% of the residents in two rural communities in Brazil participated in an epidemiologic survey of demographic, socio-economic and behavioral characteristics. The variables sex, age, intensity of infection, socio-economic index, % lifetime spent on site, previous infection, and trips outside the district were used to group parasites infecting individuals. Schistosoma mansoni infection status was determined by examination of stools submitted on 3 different days. The aggregate of eggs collected from the whole stool was used to determine degree of population differentiation from allele frequencies for 15 microsatellites. Infection prevalence was 41% for these communities, and the epidemiologic characteristics were similar to many of the endemic areas of Brazil and the world. Parasite population structuring was observed between the two communities (Jost's D 0.046, CI95% 0.042–0.051), although separated by only 8 km and connected by a highway. No structuring was observed when infected individuals were stratified by host's biologic, demographic or epidemiologic characteristics. Those most heavily infected best reflected the communities' overall parasite diversity. The lack of differentiation within villages suggests that individuals are likely to get infected at the same sites or that the same parasite multilocus genotypes can be found at most sites. The geographic structuring between villages and the lack of structuring by age of the host further supports the impression of a population little affected by migration or drift. Schistosomiasis is one of the world's most important parasitic infections. Its elimination has proved difficult even in countries such as Brazil where access to treatment is readily available. Infection is the result of human contact with surface water where there are infected snails, so that human biology and habits may bring different individuals in contact with different groups of parasites. Identification of schistosome subpopulations may assist understanding transmission patterns and guide control efforts. We compared microsatellite allele frequencies from all of the infections in 2 small villages and determined that the movement of parasites between them was limited. Individual infections were distinct composites of parasites, but if infected humans were grouped by demographic and epidemiologic characteristics, there was no evidence that specific parasite subpopulations were being selected in these types of hosts. Infections were also not differentiated when stratified by host's age indicating that the populations were stable over time. Since the infection cycle requires human fecal contamination of water, local human behavior can to some degree be inferred from the patterns of schistosome subpopulation distribution.
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影响因子：
2.7
作者：
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通讯作者：
Mkoji GM
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3.3
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4
作者：
Blanton, Ronald E.;Blank, Walter A.;Reis, Mitermayer G.
通讯作者：
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影响因子：
2.8
作者：
Carmo, E H;Barreto, M L
通讯作者：
Barreto, M L
影响因子：
4.9
作者：
Jost, Lou
通讯作者：
Jost, Lou