Bockarie M J, Alexander N D, Hyun P, Dimber Z, Bockarie F, Ibam E, Alpers M P, Kazura J W
Papua New Guinea Institute of Medical Research, Madang, Papua New Guinea.
Lancet. 1998 Jan 17;351(9097):162-8. doi: 10.1016/S0140-6736(97)07081-5.
WHO has targeted lymphatic filariasis for elimination. Studies of vector-parasite relations of Wuchereria bancrofti suggest that a reduction in the microfilarial reservoir by mass chemotherapy may interrupt transmission and thereby eliminate infection. However, no field data exist on the impact of chemotherapy alone on vector efficiency and transmission intensity of W bancrofti. We compared the impact of an annual community-wide single-dose treatment with diethylcarbamazine alone or with ivermectin on rate and intensity of microfilaraemia, and transmission intensity in an area of Papua New Guinea endemic for intense W bancrofti transmission.
We carried out clinical and parasitological surveys in 14 communities in matched pairs. People aged 5 years or older in seven communities received randomly assigned diethylcarbamazine 6 mg/kg and people in the other seven communities received diethylcarbamazine 6 mg/kg plus ivermectin 400 micrograms/kg. We made physical examinations for hydroceles and leg oedema and investigated microfilarial densities by membrane filtration before and after treatment. We selected five communities for monthly entomological surveys between September, 1993, and September, 1995. Mosquitoes were collected in these communities by the all-night landing catch method and were individually dissected to identify rates of infection and infectiveness.
2219 (87.6%) of 2534 eligible people received treatment. Microfilarial rate and density had decreased 1 year after treatment in all 14 communities; this decrease was significantly higher in communities given combined therapy than in those given diethylcarbamazine alone (mean decreases 57.5% and 30.6%, respectively; p = 0.0013). Greater decreases were also seen in community-specific microfilarial intensity with combined therapy (mean reductions 91.1% and 69.8%, respectively; p = 0.0047). The rate of leg oedema was not altered, but the frequency of advanced hydroceles decreased by 47% with combined therapy and 56% with diethylcarbamazine alone. 26,641 Anopheles punctulatus mosquitoes were caught during 499 person-nights of landing catches. Exposure to infective third-stage larvae decreased in all monitored five communities. Annual transmission potential decreased by between 75.7% and 98.8% in combined-therapy communities and between 75.6% and 79.4% in communities given diethylcarbamazine alone. Transmission was almost interrupted in two communities treated with combined therapy.
Annual single-dose community-wide treatment with diethylcarbamazine alone or with ivermectin is effective for the control of lymphatic filariasis in highly endemic areas, but combination therapy brings about greater decreases in rates and intensity of microfilaraemia.
世界卫生组织已将淋巴丝虫病列为消除目标。对班氏吴策线虫病媒与寄生虫关系的研究表明，通过群体化疗减少微丝蚴库可能会中断传播，从而消除感染。然而，关于单纯化疗对班氏吴策线虫病媒效率和传播强度影响的实地数据并不存在。我们比较了在巴布亚新几内亚一个班氏吴策线虫高度流行传播地区，每年社区范围内单独使用乙胺嗪或与伊维菌素联合使用单剂量治疗对微丝蚴血症的发生率和强度以及传播强度的影响。
我们在14个配对的社区中进行了临床和寄生虫学调查。7个社区中5岁及以上的人群随机接受6毫克/千克乙胺嗪治疗，另外7个社区的人群接受6毫克/千克乙胺嗪加400微克/千克伊维菌素治疗。我们对鞘膜积液和腿部水肿进行了体格检查，并在治疗前后通过膜过滤法调查微丝蚴密度。我们选择了5个社区在1993年9月至1995年9月期间进行每月一次的昆虫学调查。通过通宵诱捕法在这些社区收集蚊子，并对其进行个体解剖以确定感染率和感染性。
2534名符合条件的人中，2219人（87.6%）接受了治疗。所有14个社区在治疗1年后微丝蚴率和密度均下降；联合治疗社区的下降幅度明显高于单独使用乙胺嗪的社区（平均下降分别为57.5%和30.6%；p = 0.0013）。联合治疗在社区特异性微丝蚴强度方面也有更大幅度的下降（平均降低分别为91.1%和69.8%；p = 0.0047）。腿部水肿的发生率没有改变，但联合治疗使晚期鞘膜积液的频率降低了47%，单独使用乙胺嗪降低了56%。在499人夜的诱捕中捕获了26641只斑点按蚊。在所有监测的5个社区中，感染性三期幼虫的暴露率均下降。联合治疗社区的年传播潜能下降了75.7%至98.8%，单独使用乙胺嗪的社区下降了75.6%至79.4%。联合治疗的两个社区传播几乎中断。
每年社区范围内单独使用乙胺嗪或与伊维菌素联合单剂量治疗在高度流行地区对淋巴丝虫病的控制是有效的，但联合治疗使微丝蚴血症的发生率和强度下降幅度更大。
