Wong Yim Yan, Sornosa Macias Karen Jeniffer, Guale Martínez Doris, Solorzano Luis F, Ramirez-Sierra Maria Jesus, Herrera Claudia, Dumonteil Eric
Centro de Referencia Nacional de Parasitología, Instituto Nacional de Investigación en Salud Pública Leopoldo Izquieta Perez (INSPI), Guayaquil, Ecuador.
Laboratorio de Parasitología, Centro de Investigaciones Regionales "Hideyo Noguchi", Universidad Autónoma de Yucatán, Merida, Yucatan, Mexico.
Infect Genet Evol. 2016 Jul;41:207-212. doi: 10.1016/j.meegid.2016.04.001. Epub 2016 Apr 12.
Chagas disease is a neglected tropical disease caused by the protozoan parasite Trypanosoma cruzi. In Ecuador, Triatoma dimidiata and Rhodnius ecuadoriensis are the main vector species, responsible for over half of the cases of T. cruzi infection in the country. T. dimidiata is believed to have been introduced in Ecuador during colonial times, and its elimination from the country is thus believed to be feasible. We investigated here the molecular ecology of T. dimidiata and T. cruzi in costal Ecuador to further guide control efforts. Analysis of the Internal Transcribed Spacer 2 (ITS-2) of 23 specimens from Progreso, Guayas, unambiguously supported the likely importation of T. dimidiata from Central America to Ecuador. The observation of a very high parasite infection rate (54%) and frequent feeding on humans (3/5) confirmed a continued risk of transmission to humans. All genotyped parasites corresponded to TcI DTU and Trypanosoma rangeli was not detected in T. dimidiata. TcI subgroups corresponded to TcIa (25%), and mixed infections with TcIa and TcId (75%). Further studies should help clarify T. cruzi genetic structure in the country, and the possible impact of the introduction of T. dimidiata on the circulating parasite strains. The elevated risk posed by this species warrants continuing efforts for its control, but its apparent mobility between peridomestic and domestic habitats may favor reinfestation following insecticide spraying.
恰加斯病是一种由原生动物寄生虫克氏锥虫引起的被忽视的热带疾病。在厄瓜多尔，二点锥猎蝽和厄瓜多尔红猎蝽是主要的病媒物种，该国一半以上的克氏锥虫感染病例由它们导致。据信二点锥猎蝽是在殖民时期被引入厄瓜多尔的，因此认为从该国消除这种昆虫是可行的。我们在此调查了厄瓜多尔沿海地区二点锥猎蝽和克氏锥虫的分子生态学，以进一步指导防控工作。对来自瓜亚斯省普罗格雷索的23个样本的内转录间隔区2（ITS-2）进行分析，明确支持了二点锥猎蝽可能是从美国中部引入厄瓜多尔的。观察到非常高的寄生虫感染率（54%）以及频繁叮咬人类（3/5），证实了其向人类传播的持续风险。所有基因分型的寄生虫均对应于TcI离散型单位（DTU），在二点锥猎蝽中未检测到赖氏锥虫。TcI亚群对应于TcIa（25%），以及TcIa和TcId的混合感染（75%）。进一步的研究应有助于阐明该国克氏锥虫的遗传结构，以及引入二点锥猎蝽对循环寄生虫菌株可能产生的影响。该物种带来的高风险促使人们继续努力对其进行控制，但其在住宅周边和室内栖息地之间明显的移动性可能有利于在喷洒杀虫剂后再次滋生。
