Control of Phlebotomus argentipes (Diptera: Psychodidae) sand fly in Bangladesh: A cluster randomized controlled trial
Control of Phlebotomus argentipes (Diptera: Psychodidae) sand fly in Bangladesh: A cluster randomized controlled trial
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DOI：
10.1371/journal.pntd.0005890
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发表时间：
2017-09-01
影响因子：
3.8
通讯作者：
Banu, Qamar
中科院分区：
文献类型：
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作者：
Chowdhury, Rajib;Faria, Shyla;Banu, Qamar
背景在过去的十年中，人们对内脏利什曼病（VL）媒介控制进行了大量的研究，有时得出非常不同的结论。本研究对大样本进行了调查，调查了部分尚未探索的不同方案，包括：（1）使用甲-氯氰菊酯5 WP进行室内滞留喷洒;（2）长效杀虫剂浸渍蚊帐;（3）使用缓释杀虫剂K-O TAB 1-2-3浸渍当地蚊帐;（4）使用毒死蜱20 EC（OUT）在屋外潜在的滋生地喷洒杀虫剂方法采用整群随机对照试验，将11个自然村的3089户居民分为10个区，每个区有6个集群，每个集群有大约50个房屋。根据基线调查期间的病媒密度（男性加女性），将60个群集分为3组：（1）高，（2）中，（3）低。每组有20个集群。从这三个组中，每种类型的干预和对照组随机选择6个群组（约300个家庭）。媒介密度测量之前和2，4，5，7，11，14，15，18和22个月后，使用CDC光陷阱干预。干预措施的影响进行了测量，通过使用的差异差异回归model.ResultsA共收集了17,434沙蝇在基线和9个月后进行的基线测量的调查。在基线时，对照组每户平均银足蚤密度为10.6（SD = 11.5），干预组为7.3（SD = 8.46）至11.5（SD = 20.2）。干预结果表示为22个月内9次测量中白蛉（雄性+雌性）减少百分比和比率的范围。在单一类型的干预措施中，与对照组相比，IRS与2轮喷洒（由研究小组应用）的效果范围为13%至75%，P. argentipes密度降低（率比[RR]范围为0.25至0.87）。LLIN导致载体减少9%至78%（RR，0.22至0.91）。KOTAB将载体减少了4%至73%（RR，0.27至0.96）。LLIN和OUT的组合导致向量减少26%至86%（RR，0.14至0.74）。IRS和OUT联合使用的减少率为8%至88%（RR，0.12至0.92）。IRS和LLIN组合导致媒介减少13%至85%（RR，0.15至0.77）。IRS和KOTAB组合使病媒密度降低了16%至86%（RR，0.14至0.84）。KOTAB单独和IRS加LLIN以及IRS加KOTAB的一些中间测量值在统计学上不显著。对喷洒的表面或网材料进行的生物测定显示出22个月的良好结果（死亡率> 80%）（IRS测试12个月）。在KOTAB中，6个月后观察到逐渐下降。结论LLIN和OUT是降低VL载体密度22个月或更长时间的最佳组合。在操作上，这比IRS更容易应用。随后将对首选工具进行成本分析。应调查病媒密度（雄性加雌性）与利什曼病发病率之间的关系，这将需要估计昆虫接种率。
BackgroundA number of studies on visceral leishmaniasis (VL) vector control have been conducted during the past decade, sometimes came to very different conclusion. The present study on a large sample investigated different options which are partially unexplored including: (1) indoor residual spraying (IRS) with alpha cypermethrin 5WP; (2) long lasting insecticide impregnated bed-net (LLIN); (3) impregnation of local bed-nets with slow release insecticide K-O TAB 1-2-3 (KOTAB); (4) insecticide spraying in potential breeding sites outside of house using chlorpyrifos 20EC (OUT) and different combinations of the above.MethodsThe study was a cluster randomized controlled trial where 3089 houses from 11 villages were divided into 10 sections, each section with 6 clusters and each cluster having approximately 50 houses. Based on vector density (males plus females) during baseline survey, the 60 clusters were categorized into 3 groups: (1) high, (2) medium and (3) low. Each group had 20 clusters. From these three groups, 6 clusters (about 300 households) were randomly selected for each type of intervention and control arms. Vector density was measured before and 2, 4, 5, 7, 11, 14, 15, 18 and 22 months after intervention using CDC light traps. The impact of interventions was measured by using the difference-in-differences regression model.ResultsA total of 17,434 sand flies were collected at baseline and during the surveys conducted over 9 months following the baseline measurements. At baseline, the average P. argentipes density per household was 10.6 (SD = 11.5) in the control arm and 7.3 (SD = 8.46) to 11.5 (SD = 20.2) in intervention arms. The intervention results presented as the range of percent reductions of sand flies (males plus females) and rate ratios in 9 measurements over 22 months. Among single type interventions, the effect of IRS with 2 rounds of spraying (applied by the research team) ranged from 13% to 75% reduction of P. argentipes density compared to the control arm (rate-ratio [RR] ranged from 0.25 to 0.87). LLINs caused a vector reduction of 9% to 78% (RR, 0.22 to 0.91). KOTAB reduced vectors by 4% to 73% (RR, 0.27 to 0.96). The combination of LLIN and OUT led to a vector reduction of 26% to 86% (RR, 0.14 to 0.74). The reduction for the combination of IRS and OUT was 8% to 88% (RR, 0.12 to 0.92). IRS and LLIN combined resulted in a vector reduction of 13% to 85% (RR, 0.15 to 0.77). The IRS and KOTAB combination reduced vector densities by 16% to 86% (RR, 0.14 to 0.84). Some intermediate measurements for KOTAB alone and for IRS plus LLIN; and IRS plus KOTAB were not statistically significant. The bioassays on sprayed surfaces or netting materials showed favourable results (> 80% mortality) for 22 months (IRS tested for 12 months). In the KOTAB, a gradual decline was observed after 6 months.ConclusionsLLIN and OUT was the best combination to reduce VL vector densities for 22 months or longer. Operationally, this is much easier to apply than IRS. A cost analysis of the preferred tools will follow. The relationship between vector density (males plus females) and leishmaniasis incidence should be investigated, and this will require estimates of the Entomological Inoculation Rate.