Banaras Hindu University, Varanasi, India.
PLoS Negl Trop Dis. 2011 Sep;5(9):e1296. doi: 10.1371/journal.pntd.0001296. Epub 2011 Sep 13.
Visceral leishmaniasis is the world' second largest vector-borne parasitic killer and a neglected tropical disease, prevalent in poor communities. Long-lasting insecticidal nets (LNs) are a low cost proven vector intervention method for malaria control; however, their effectiveness against visceral leishmaniasis (VL) is unknown. This study quantified the effect of LNs on exposure to the sand fly vector of VL in India and Nepal during a two year community intervention trial.
As part of a paired-cluster randomized controlled clinical trial in VL-endemic regions of India and Nepal we tested the effect of LNs on sand fly biting by measuring the antibody response of subjects to the saliva of Leishmania donovani vector Phlebotomus argentipes and the sympatric (non-vector) Phlebotomus papatasi. Fifteen to 20 individuals above 15 years of age from 26 VL endemic clusters were asked to provide a blood sample at baseline, 12 and 24 months post-intervention.
A total of 305 individuals were included in the study, 68 participants provided two blood samples and 237 gave three samples. A random effect linear regression model showed that cluster-wide distribution of LNs reduced exposure to P. argentipes by 12% at 12 months (effect 0.88; 95% CI 0.83-0.94) and 9% at 24 months (effect 0.91; 95% CI 0.80-1.02) in the intervention group compared to control adjusting for baseline values and pair. Similar results were obtained for P. papatasi.
This trial provides evidence that LNs have a limited effect on sand fly exposure in VL endemic communities in India and Nepal and supports the use of sand fly saliva antibodies as a marker to evaluate vector control interventions.
内脏利什曼病是世界上第二大由媒介传播的寄生虫杀手，也是一种被忽视的热带病，流行于贫困社区。长效杀虫蚊帐（LNs）是一种经过验证的低成本媒介干预方法，可用于控制疟疾；然而，其对内脏利什曼病（VL）的效果尚不清楚。本研究量化了 LNs 在印度和尼泊尔进行的为期两年的社区干预试验中对 VL 传播媒介沙蝇接触的影响。
作为印度和尼泊尔 VL 流行地区配对聚类随机对照临床试验的一部分，我们通过测量对象对利什曼原虫唾液的抗体反应来测试 LNs 对沙蝇叮咬的影响。这种唾液来自于 VL 的媒介白蛉属 Phlebotomus argentipes 和共生（非媒介）白蛉属 Phlebotomus papatasi。从 26 个 VL 流行区的 26 个聚类中招募了 15 至 20 名 15 岁以上的个体，在干预后 12 和 24 个月时提供血液样本。
共有 305 人参与了这项研究，68 名参与者提供了两份血液样本，237 名参与者提供了三份血液样本。随机效应线性回归模型显示，在干预组中，与对照组相比，在 12 个月时，LN 对 P. argentipes 的分布范围减少了 12%（效果 0.88；95%置信区间 0.83-0.94），在 24 个月时减少了 9%（效果 0.91；95%置信区间 0.80-1.02），调整了基线值和对子。对于 P. papatasi 也得到了类似的结果。
这项试验提供了证据表明，在印度和尼泊尔的 VL 流行社区中，LNs 对沙蝇暴露的影响有限，并支持使用沙蝇唾液抗体作为评估媒介控制干预措施的标志物。
