Department of Immunology, Aggeu Magalhães Institute, Oswaldo Cruz Foundation (Fiocruz), Recife, Brazil.
State Secretary of Health of Pernambuco, Recife, Brazil.
Parasit Vectors. 2019 Mar 26;12(1):118. doi: 10.1186/s13071-019-3383-1.
From 2012 to 2013, an outbreak of cutaneous leishmaniasis by Leishmania braziliensis was detected in indigenous villages located in a remote rural area of Pernambuco state, north-eastern Brazil. Considering that the principal activities of this indigenous community are farming and crop plantation, and also that the outbreak involved many children, we investigated the presence of sand fly vectors inside human houses and also the exposure of dogs to leishmanial parasites. Our general objective was to gather epidemiological data that could indicate the occurrence of a peri-domestic/domestic transmission cycle of L. braziliensis in these indigenous villages.
From March 2015 to March 2016, sand flies were collected using light traps in the indoor and immediate outdoor environments in the three indigenous villages that reported the most cutaneous leishmaniasis cases during the 2012-2013 outbreak. Moreover, samples obtained from 300 dogs living in the outbreak villages and two nearby villages were tested by a rapid immunochromatographic test and by a real-time PCR for detecting anti-Leishmania antibodies and Leishmania DNA, respectively.
In total, 5640 sand flies belonging to 11 species were identified. Males (n = 3540) predominated over females (n = 2100). Migonemyia migonei (84.3%) was the most abundant species, followed by Evandromyia lenti (5.5%), Lutzomyia longipalpis (4.1%), Nyssomyia intermedia (1.6%) and Micropygomyia capixaba (1.4%), representing together ~97% of the sand flies collected. Nine out of the 11 species identified in this study were found indoors, including M. migonei, L. longipalpis and N. intermedia, which are proven vectors of Leishmania spp. Out of 300 dogs tested, 26 (8.7%) presented anti-Leishmania antibodies and six (2%) were Leishmania DNA-positive. The level of exposure in dogs living in the indigenous villages where the 2012-2013 outbreak of human CL was detected was almost 2-fold higher than in the two nearby villages (11.0 vs 6.2% for serology and 2.6 vs 1.4% for real-time PCR).
The results suggest that different sand fly vectors may be adapted to human dwellings, thus increasing the risk of transmission in the indoor and immediate outdoor environments. The adaptation of sand flies to the indoor environment in the studied indigenous villages may be partly explained by the poor housing conditions and the proximity of the houses to crop plantations and forest fragments.
2012 年至 2013 年，巴西东北部伯南布哥州偏远农村的土著村落爆发了巴西利什曼原虫引起的皮肤利什曼病。考虑到该土著社区的主要活动是农业和作物种植，而且疫情涉及许多儿童，我们调查了屋内和附近环境中沙蝇媒介的存在情况，以及狗对利什曼原虫寄生虫的暴露情况。我们的总体目标是收集流行病学数据，以表明在这些土著村落中存在巴西利什曼原虫的家庭/家庭内传播周期。
2015 年 3 月至 2016 年 3 月，在 2012-2013 年疫情期间报告皮肤利什曼病病例最多的三个土著村落，使用诱捕器在室内和室外环境中收集沙蝇。此外，对居住在疫情村和两个附近村庄的 300 只狗的样本进行了快速免疫层析试验和实时 PCR 检测，以检测抗利什曼原虫抗体和利什曼原虫 DNA。
共鉴定出 5640 只沙蝇，属于 11 种。雄性（n=3540）多于雌性（n=2100）。米戈尼米亚·米戈内（Migonemyia migonei）（84.3%）是最丰富的物种，其次是埃文达米亚·伦蒂（Evandromyia lenti）（5.5%）、鲁氏利什曼原虫（Lutzomyia longipalpis）（4.1%）、尼西米亚·因特梅迪亚（Nyssomyia intermedia）（1.6%）和米克洛皮加米亚·卡皮萨巴（Micropygomyia capixaba）（1.4%），这 11 种沙蝇占采集沙蝇的 97%左右。本研究鉴定的 11 种中有 9 种在室内发现，包括米戈内米亚·米戈内（Migonemyia migonei）、鲁氏利什曼原虫（Lutzomyia longipalpis）和尼西米亚·因特梅迪亚（Nyssomyia intermedia），它们是利什曼原虫属的已知媒介。在 300 只接受检测的狗中，有 26 只（8.7%）呈抗利什曼原虫抗体阳性，6 只（2%）呈利什曼原虫 DNA 阳性。在检测到 2012-2013 年人类 CL 疫情的土著村落中，生活的狗的暴露水平几乎是两个附近村庄的两倍（血清学为 11.0%对 6.2%，实时 PCR 为 2.6%对 1.4%）。
结果表明，不同的沙蝇媒介可能适应人类居住环境，从而增加了室内和室外环境中的传播风险。在研究的土著村落中，沙蝇适应室内环境的部分原因可能是住房条件差，房屋靠近种植园和森林碎片。
