Yale School of Public Health, Yale University, New Haven, Connecticut.
Department of Biomedical Sciences and Technology, School of Public Health and Community Development, Maseno University, Kisumu, Kenya.
Am J Trop Med Hyg. 2018 Oct;99(4):945-953. doi: 10.4269/ajtmh.18-0154.
The tsetse fly , the major vector of the parasite that causes animal African trypanosomiasis in Kenya, has been subject to intense control measures with only limited success. The population dynamics and dispersal patterns that underlie limited success in vector control campaigns remain unresolved, and knowledge on genetic connectivity can provide insights, and thereby improve control and monitoring efforts. We therefore investigated the population structure and estimated migration and demographic parameters in using genotypic data from 11 microsatellite loci scored in 250 tsetse flies collected from eight localities in Kenya. Clustering analysis identified two genetically distinct eastern and western clusters (mean between-cluster = 0.202) separated by the Great Rift Valley. We also found evidence of admixture and migration between the eastern and western clusters, isolation by distance, and a widespread signal of inbreeding. We detected differences in population dynamics and dispersal patterns between the western and eastern clusters. These included lower genetic diversity (allelic richness; 7.48 versus 10.99), higher relatedness (percent related individuals; 21.4% versus 9.1%), and greater genetic differentiation (mean within-cluster ; 0.183 versus 0.018) in the western than the eastern cluster. Findings are consistent with the presence of smaller, less well-connected populations in Western relative to eastern Kenya. These data suggest that recent anthropogenic influences such as land use changes and vector control programs have influenced population dynamics in in Kenya, and that vector control efforts should include some region-specific strategies to effectively control this disease vector.
采采蝇是肯尼亚动物非洲锥虫病寄生虫的主要传播媒介，尽管采取了密集的控制措施，但收效甚微。在媒介控制活动中，导致收效有限的种群动态和扩散模式仍未得到解决，而关于遗传连通性的知识可以提供深入的了解，从而改进控制和监测工作。因此，我们利用从肯尼亚 8 个地点采集的 250 只采采蝇中 11 个微卫星基因座的基因型数据，研究了肯尼亚采采蝇的种群结构，并估计了迁移和人口参数。聚类分析确定了两个在遗传上明显不同的东部和西部聚类（聚类间平均值为 0.202），由大裂谷隔开。我们还发现了东部和西部聚类之间存在混合和迁移、隔离距离以及广泛的近亲繁殖信号的证据。我们检测到西部和东部聚类之间的种群动态和扩散模式存在差异。这些差异包括西部聚类的遗传多样性（等位基因丰富度；7.48 对 10.99）、亲缘关系（相关个体百分比；21.4% 对 9.1%）和遗传分化（聚类内平均值；0.183 对 0.018）均高于东部聚类。这些发现与肯尼亚西部采采蝇种群规模较小、连通性较差的情况一致。这些数据表明，最近的人为影响，如土地利用变化和媒介控制计划，已经影响了肯尼亚采采蝇的种群动态，而媒介控制工作应包括一些特定区域的策略，以有效控制这种疾病媒介。
