Universidade Federal do Maranhão, São Luís, MA, Brasil.
Mem Inst Oswaldo Cruz. 2011 Mar;106(2):207-11. doi: 10.1590/s0074-02762011000200015.
Leishmania infection in humans, dogs and sandflies was examined in the endemic visceral leishmaniasis (VL) municipality of Raposa, state of Maranhão, Brazil. In this study, we examined Leishmania chagasi infection in the blood serum of both humans and Canis familiaris and the natural Leishmania sp. infection rate in the sandfly vector, Lutzomyia longipalpis. Enzyme-linked immunosorbent assay, indirect immunofluorescence reaction and polymerase chain reaction were performed to detect Leishmania infections in humans, dogs and sandflies, respectively. Overall, 186 out of 986 studied human beings were infected with L. chagasi parasites, representing an infection prevalence of 18.9%. An even higher infection rate was detected in dogs, where 66 (47.8%) out of 138 were infected. Among all Lu. longipalpis captured (n = 1,881), only 26.7% were females. The Leishmania infection frequency for the vector Lu. longipalpis was 1.56%. Remarkably, all infected sandflies were found in the peridomiciliary area. Furthermore, a high incidence of asymptomatic forms of VL in the human and canine populations was observed. The results of this study suggest autochthonous transmission of L. chagasi in this endemic area for visceral leishmaniasis because infection by Leishmania sp. was identified in all important elements of the transmission chain.
在巴西马拉尼昂州罗萨波萨地方性内脏利什曼病（VL）流行地区，对人类、狗和沙蝇中的利什曼原虫感染进行了研究。在这项研究中，我们检查了人类和犬血液血清中的恰加斯利什曼原虫感染情况，以及沙蝇媒介卢氏长须沙蝇中的自然利什曼原虫感染率。通过酶联免疫吸附试验、间接免疫荧光反应和聚合酶链反应分别检测了人类、犬和沙蝇中的利什曼感染。总的来说，在 986 名研究对象中，有 186 人感染了 L. chagasi 寄生虫，感染率为 18.9%。在犬中检测到的感染率更高，在 138 只犬中，有 66 只（47.8%）感染。在所捕获的所有 Lu. longipalpis（n = 1,881）中，只有 26.7%是雌性。该媒介 Lu. longipalpis 的利什曼原虫感染频率为 1.56%。值得注意的是，所有感染的沙蝇都在家庭周围地区发现。此外，在人类和犬类群体中观察到了 VL 无症状形式的高发病率。本研究结果表明，在这个地方性内脏利什曼病流行地区存在 L. chagasi 的本地传播，因为在传播链的所有重要环节都发现了利什曼原虫感染。
