Kotsakiozi Panayiota, Gloria-Soria Andrea, Caccone Adalgisa, Evans Benjamin, Schama Renata, Martins Ademir Jesus, Powell Jeffrey R
Department of Ecology and Evolutionary Biology, Yale University, New Haven, Connecticut, United States of America.
Laboratório de Biologia Computacional e Sistemas, IOC-Fiocruz, Rio de Janeiro, Brazil.
PLoS Negl Trop Dis. 2017 Jul 25;11(7):e0005653. doi: 10.1371/journal.pntd.0005653. eCollection 2017 Jul.
Aedes aegypti, commonly known as "the yellow fever mosquito", is of great medical concern today primarily as the major vector of dengue, chikungunya and Zika viruses, although yellow fever remains a serious health concern in some regions. The history of Ae. aegypti in Brazil is of particular interest because the country was subjected to a well-documented eradication program during 1940s-1950s. After cessation of the campaign, the mosquito quickly re-established in the early 1970s with several dengue outbreaks reported during the last 30 years. Brazil can be considered the country suffering the most from the yellow fever mosquito, given the high number of dengue, chikungunya and Zika cases reported in the country, after having once been declared "free of Ae. aegypti".
METHODOLOGY/PRINCIPAL FINDINGS: We used 12 microsatellite markers to infer the genetic structure of Brazilian Ae. aegypti populations, genetic variability, genetic affinities with neighboring geographic areas, and the timing of their arrival and spread. This enabled us to reconstruct their recent history and evaluate whether the reappearance in Brazil was the result of re-invasion from neighboring non-eradicated areas or re-emergence from local refugia surviving the eradication program. Our results indicate a genetic break separating the northern and southern Brazilian Ae. aegypti populations, with further genetic differentiation within each cluster, especially in southern Brazil.
CONCLUSIONS/SIGNIFICANCE: Based on our results, re-invasions from non-eradicated regions are the most likely scenario for the reappearance of Ae. aegypti in Brazil. While populations in the northern cluster are likely to have descended from Venezuela populations as early as the 1970s, southern populations seem to have derived more recently from northern Brazilian areas. Possible entry points are also revealed within both southern and northern clusters that could inform strategies to control and monitor this important arbovirus vector.
埃及伊蚊，通常被称为“黄热病蚊子”，如今在医学上备受关注，主要是因为它是登革热、基孔肯雅热和寨卡病毒的主要传播媒介，尽管在某些地区黄热病仍然是一个严重的健康问题。埃及伊蚊在巴西的历史尤其引人关注，因为该国在20世纪40年代至50年代经历了一项记录详尽的根除计划。在该运动停止后，这种蚊子在20世纪70年代初迅速重新出现，在过去30年里有几次登革热疫情报告。鉴于巴西报告的登革热、基孔肯雅热和寨卡病例数量众多，且该国曾一度宣布“无埃及伊蚊”，巴西可被视为受黄热病蚊子影响最严重的国家。
方法/主要发现：我们使用12个微卫星标记来推断巴西埃及伊蚊种群的遗传结构、遗传变异性、与邻近地理区域的遗传亲缘关系以及它们的到达和传播时间。这使我们能够重建它们的近期历史，并评估在巴西的再次出现是来自邻近未根除地区的重新入侵还是根除计划中幸存的当地避难所的重新出现的结果。我们的结果表明，巴西北部和南部埃及伊蚊种群之间存在遗传断裂，每个集群内进一步存在遗传分化，特别是在巴西南部。
结论/意义：根据我们的结果，来自未根除地区的重新入侵是埃及伊蚊在巴西再次出现的最可能情况。虽然北部集群的种群可能早在20世纪70年代就源自委内瑞拉种群，但南部种群似乎最近更多地源自巴西北部地区。在南部和北部集群中还揭示了可能的入境点，这可为控制和监测这种重要虫媒病毒载体的策略提供信息。
