de Sousa Ferreira Tauana, Timbó Renata Velôzo, Minuzzi-Souza Thaís T C, de Almeida Rocha Douglas, Neiva Mariana, de Albuquerque Ribeiro Joana, de Almeida Paulo Silva, Hecht Mariana, Nitz Nadjar, Gurgel-Gonçalves Rodrigo
Laboratório de Parasitologia Médica e Biologia de Vetores, Faculdade de Medicina, Universidade de Brasília, Brazil.
Laboratório Regional de Entomologia, Núcleo Regional de Saúde da Secretaria Estadual de Saúde, Dourados, Mato Grosso do Sul, Brazil.
Vet Parasitol. 2018 Aug 15;259:80-84. doi: 10.1016/j.vetpar.2018.07.004. Epub 2018 Jul 7.
Leishmaniases are endemic in Brazil, where Leishmania infantum has been detected in humans, dogs, cats, and phlebotomine vectors. Monitoring synanthropic vector populations is critical for leishmaniasis control-surveillance in such transmission-prone areas. Here, a suite of molecular approaches were used to assess Leishmania infection prevalence and to identify blood-meal sources in a large sample of sand flies collected in anthropic environments of a Leishmania-transmission area in Mato Grosso do Sul State (Rio Verde de Mato Grosso municipality), Central-West Brazil. We sampled sand flies monthly (January-June 2014 and 2016) in one peri-domestic site within each of six neighborhoods with recent records of human visceral and/or tegumentary leishmaniasis. kDNA-qPCR plus rDNA ITS-sequencing were used to detect and identify Leishmania in pooled female sand flies. Individual engorged females (n = 58) were used for blood-meal analyses through High-Resolution Melting (HRM) targeting the mtDNA cytb gene. Overall, 90.5% of 420 CDC trap-nights yielded vectors, for a total catch of 24,989 sand flies. We sub-sampled and identified 3088 sand flies of 12 species, including 2775 Lutzomyia longipalpis (the most abundant species at all sampling sites) and 297 Nyssomyia whitmani. Female sand flies (n = 1261) were grouped in 159 pools, of which 92 Lu. longipalpis (minimum infection rate [MIR] 8%) and 7 Ny. whitmani pools (MIR 7%) were Leishmania kDNA-positive. Most positive Lu. longipalpis were collected in the 2016 rainy season. Sequencing confirmed L. infantum in Lu. longipalpis samples. HRM analyses identified chicken DNA in 57 sand flies (98.3%), 37 of which were Leishmania DNA-positive (64.9%); human blood was found in just one (Leishmania-negative) female. Our data show ongoing risk of L. infantum transmission to humans in the study area, where Leishmania-infected sandfly vectors are common and heavily rely on chicken blood in the peri-domestic environment.
利什曼病在巴西呈地方性流行，在人类、狗、猫和白蛉传播媒介中均检测到婴儿利什曼原虫。监测共栖媒介种群对于在这类易传播地区进行利什曼病控制监测至关重要。在此，我们使用了一系列分子方法来评估利什曼原虫感染率，并在巴西中西部南马托格罗索州（马托格罗索州绿河市）一个利什曼原虫传播地区的人类居住环境中采集的大量白蛉样本中确定血餐来源。我们于2014年1月至6月以及2016年每月在六个社区中各一个家庭周边地点对白蛉进行采样，这些社区近期有人类内脏和/或皮肤利什曼病记录。使用kDNA-qPCR加上rDNA ITS测序来检测和鉴定混合的雌性白蛉中的利什曼原虫。通过针对线粒体DNA细胞色素b基因的高分辨率熔解（HRM）对58只饱血雌性白蛉个体进行血餐分析。总体而言，在420个疾控中心诱捕夜中，90.5%捕获到了媒介，共捕获24,989只白蛉。我们对其中12个物种的3088只白蛉进行了子样本采集和鉴定，包括2775只长须罗蛉（所有采样地点中数量最多的物种）和297只惠氏白蛉。雌性白蛉（n = 1261）被分成159组，其中92组长须罗蛉（最低感染率[MIR] 8%）和7组惠氏白蛉（MIR 7%）的利什曼原虫kDNA呈阳性。大多数阳性长须罗蛉是在2016年雨季采集到的。测序在长须罗蛉样本中确认了婴儿利什曼原虫。HRM分析在57只白蛉（98.3%）中鉴定出鸡的DNA，其中37只（64.9%）利什曼原虫DNA呈阳性；仅在一只（利什曼原虫阴性）雌性白蛉中发现了人类血液。我们的数据表明，在研究区域内婴儿利什曼原虫传播给人类的风险持续存在，在该区域感染利什曼原虫的白蛉媒介很常见，并且在家庭周边环境中严重依赖鸡血。
