Ocaña-Mayorga Sofía, Bustillos Juan José, Villacís Anita G, Pinto C Miguel, Brenière Simone Frédérique, Grijalva Mario J
Centro de Investigación para la Salud en América Latina (CISeAL), Escuela de Ciencias Biológicas, Facultad de Ciencias Exactas y Naturales, Pontificia Universidad Católica del Ecuador, Calle San Pedro y Pamba Hacienda, Nayón 170530, Ecuador.
Department of Biomedical Sciences, Infectious and Tropical Disease Institute, Heritage College of Osteopathic Medicine, Ohio University, Athens, OH 45701, USA.
Pathogens. 2021 Jan 7;10(1):42. doi: 10.3390/pathogens10010042.
Understanding the blood meal patterns of insects that are vectors of diseases is fundamental in unveiling transmission dynamics and developing strategies to impede or decrease human-vector contact. Chagas disease has a complex transmission cycle that implies interactions between vectors, parasites and vertebrate hosts. In Ecuador, limited data on human infection are available; however, the presence of active transmission in endemic areas has been demonstrated. The aim of this study was to determine the diversity of hosts that serve as sources of blood for triatomines in domestic, peridomestic and sylvatic transmission cycles, in two endemic areas of Ecuador (central coastal and southern highland regions). Using conserved primers and DNA extracted from 507 intestinal content samples from five species of triatomines (60 , 17 , 1 , 427 and 2 ) collected from 2006 to 2013, we amplified fragments of the mitochondrial gene. After sequencing, blood meal sources were identified in 416 individuals (146 from central coastal and 270 from southern highland regions), achieving ≥ 95% identity with GenBank sequences (NCBI-BLAST tool). The results showed that humans are the main source of food for triatomines, indicating that human-vector contact is more frequent than previously thought. Although other groups of mammals, such as rodents, are also an available source of blood, birds (particularly chickens) might have a predominant role in the maintenance of triatomines in these areas. However, the diversity of sources of blood found might indicate a preference driven by triatomine species. Moreover, the presence of more than one source of blood in triatomines collected in the same place indicated that dispersal of vectors occurs regardless the availability of food. Dispersal capacity of triatomines needs to be evaluated to propose an effective strategy that limits human-vector contact and, in consequence, to decrease the risk of transmission.
了解作为疾病传播媒介的昆虫的血餐模式，对于揭示传播动态以及制定阻碍或减少人与媒介接触的策略至关重要。恰加斯病具有复杂的传播周期，这意味着媒介、寄生虫和脊椎动物宿主之间存在相互作用。在厄瓜多尔，关于人类感染的数据有限；然而，已证实流行地区存在活跃传播。本研究的目的是确定在厄瓜多尔的两个流行地区（中部沿海和南部高地地区），在家庭、居家周围和森林传播周期中作为锥蝽血源的宿主多样性。使用保守引物和从2006年至2013年收集的5种锥蝽（60只、17只、1只、427只和2只）的507份肠道内容物样本中提取的DNA，我们扩增了线粒体基因片段。测序后，在416只个体（146只来自中部沿海地区，270只来自南部高地地区）中鉴定出血餐来源，与GenBank序列（NCBI-BLAST工具）的一致性≥95%。结果表明，人类是锥蝽的主要食物来源，这表明人与媒介的接触比以前认为的更为频繁。虽然其他哺乳动物群体，如啮齿动物，也是可用的血源，但鸟类（特别是鸡）可能在这些地区锥蝽的维持中起主要作用。然而，发现的血源多样性可能表明是由锥蝽物种驱动的偏好。此外，在同一地点收集到的锥蝽中存在不止一种血源，这表明无论食物供应情况如何，媒介都会扩散。需要评估锥蝽的扩散能力，以提出一种有效的策略来限制人与媒介的接触，从而降低传播风险。
