Triatominae (Hemiptera, Reduviidae) in the Pantanal region: association with Trypanosoma cruzi, different habitats and vertebrate hosts

ABSTRACTINTRODUCTION: The transmission cycle of Trypanosoma cruzi in the Brazilian Pantanal region has been studied during the last decade. Although considerable knowledge is available regarding the mammalian hosts infected by T. cruzi in this wetland, no studies have investigated its vectors in this region. This study aimed to investigate the presence of sylvatic triatomine species in different habitats of the Brazilian Pantanal region and to correlate their presence with the occurrences of vertebrate hosts and T. cruzi infection.METHODS: The fieldwork involved passive search by using light traps and Noireau traps and active search by visual inspection. The light traps were placed at five selected points along forested areas for seven nights during each of the nine excursions. At each point where a light trap was set, eight Noireau traps were placed in palm trees and bromeliads.RESULTS: In all, 88 triatomine bugs were collected: two and one individuals from light traps and Noireau traps, respectively; three from peridomestic areas; 23 in coati nests; and 59 in thornbird nests. In this study, active search in microhabitats showed higher efficiency than passive search, since 95% of the triatomine bugs were caught in nests. Further, triatomine bugs were only found to be infected by T. cruzi in coati nests.CONCLUSIONS: Coati nests might act as a point of convergence and dispersion for triatomine bugs and mammal hosts infected by T. cruzi, thereby playing an important role in the sylvatic cycle of T. cruziin the Pantanal region.引言与研究背景：过去十年间，学界针对巴西潘塔纳尔湿地（Brazilian Pantanal region）内克氏锥虫（Trypanosoma cruzi）的传播循环展开了相关研究。尽管目前对于该湿地内受克氏锥虫感染的哺乳类宿主已有较为充分的认知，但尚无研究聚焦于此区域内的传播媒介。本研究旨在调查巴西潘塔纳尔湿地不同生境中野生锥蝽（triatomine）物种的存在情况，并将其出现频次与脊椎动物宿主及克氏锥虫感染事件进行关联分析。 方法：本次野外工作采用灯光诱捕器（light traps）与诺雷奥诱捕器（Noireau traps）开展被动诱捕，同时辅以目视检视进行主动搜寻。在9次野外考察期间，于林区选定的5个采样点各布设灯光诱捕器，连续放置7晚。于每个布设灯光诱捕器的采样点，在棕榈树与凤梨科植物上各放置8个诺雷奥诱捕器。 结果：本次研究共采集到88只锥蝽虫：其中灯光诱捕器与诺雷奥诱捕器分别捕获2只与1只；3只捕获于人居周边区域；23只发现于长鼻浣熊（coati）巢穴；59只发现于刺莺（thornbird）巢穴。本研究显示，微生境主动搜寻的效率高于被动诱捕——95%的锥蝽虫均捕获于各类巢穴中。此外，仅在长鼻浣熊巢穴内发现的锥蝽虫携带克氏锥虫感染。 结论：长鼻浣熊巢穴可能作为锥蝽虫与受克氏锥虫感染的哺乳类宿主的聚集与扩散节点，进而在潘塔纳尔湿地内克氏锥虫的野生传播循环中发挥重要作用。