Department of Internal Medicine, B.P. Koirala Institute of Health Sciences, Dharan, Nepal.
Department of Microbiology, B.P. Koirala Institute of Health Sciences, Dharan, Nepal.
PLoS One. 2024 Apr 17;19(4):e0289578. doi: 10.1371/journal.pone.0289578. eCollection 2024.
In Nepal, visceral leishmaniasis (VL) has been targeted for elimination as a public health problem by 2026. Recently, increasing numbers of VL cases have been reported from districts of doubtful endemicity including hills and mountains, threatening the ongoing VL elimination program in Nepal. We conducted a multi-disciplinary, descriptive cross-sectional survey to assess the local transmission of Leishmania donovani in seven such districts situated at altitudes of up to 1,764 meters in western Nepal from March to December 2019. House-to-house surveys were performed for socio-demographic data and data on past and current VL cases. Venous blood was collected from all consenting individuals aged ≥2 years and tested with the rK39 RDT. Blood samples were also tested with direct agglutination test, and a titer of ≥1:1600 was taken as a marker of infection. A Leishmania donovani species-specific PCR (SSU-rDNA) was performed for parasite species confirmation. We also captured sand flies using CDC light traps and mouth aspirators. The house-to-house surveys documented 28 past and six new VL cases of which 82% (28/34) were without travel exposure. Overall, 4.1% (54/1320) of healthy participants tested positive for L. donovani on at least one serological or molecular test. Among asymptomatic individuals, 17% (9/54) were household contacts of past VL cases, compared to 0.5% (6/1266) among non-infected individuals. Phlebotomus argentipes, the vector of L. donovani, was found in all districts except in Bajura. L. donovani was confirmed in two asymptomatic individuals and one pool of sand flies of Phlebotomus (Adlerius) sp. We found epidemiological and entomological evidence for local transmission of L. donovani in areas previously considered as non-endemic for VL. The national VL elimination program should revise the endemicity status of these districts and extend surveillance and control activities to curb further transmission of the disease.
在尼泊尔，内脏利什曼病（VL）已被作为一个公共卫生问题进行消除，目标是在 2026 年实现。最近，越来越多的 VL 病例报告来自可疑流行地区，包括丘陵和山区，这对尼泊尔正在进行的 VL 消除计划构成了威胁。我们在 2019 年 3 月至 12 月期间，对尼泊尔西部海拔高达 1764 米的七个这样的地区进行了多学科、描述性的横断面调查，以评估利什曼原虫的本地传播情况。对社会人口学数据和过去及当前 VL 病例的数据进行了逐户调查。对所有同意的年龄≥2 岁的个体采集静脉血，并使用 rK39 RDT 进行检测。还对血样进行了直接凝集试验，将滴度≥1:1600 作为感染的标志物。对利什曼原虫物种特异性 PCR（SSU-rDNA）进行了寄生虫物种确认。我们还使用 CDC 诱捕器和口腔抽吸器捕获了沙蝇。逐户调查记录了 28 例过去和 6 例新的 VL 病例，其中 82%（28/34）没有旅行接触。总体而言，在至少一项血清学或分子检测中，有 4.1%（54/1320）的健康参与者呈利什曼原虫阳性。在无症状个体中，17%（9/54）是过去 VL 病例的家庭接触者，而在未感染者中，这一比例为 0.5%（6/1266）。发现了利什曼原虫的媒介白蛉属（Phlebotomus）argentipes 在所有地区都有发现，除了巴朱拉区。在两名无症状个体和一个白蛉（Adlerius）属的沙蝇群中，确认了利什曼原虫。我们发现了利什曼原虫在以前被认为是非 VL 流行地区的地方传播的流行病学和昆虫学证据。国家 VL 消除计划应修改这些地区的流行状况，并扩大监测和控制活动，以遏制疾病的进一步传播。
