Malaria vectors in Angola:: distribution of species and molecular forms of the Anopheles gambiae complex, their pyrethroid insecticide knockdown resistance (kdr) status and Plasmodium falciparum sporozoite rates -: art. no. 2
Malaria vectors in Angola:: distribution of species and molecular forms of the Anopheles gambiae complex, their pyrethroid insecticide knockdown resistance (kdr) status and Plasmodium falciparum sporozoite rates -: art. no. 2
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DOI：
10.1186/1475-2875-5-2
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发表时间：
2006-01-18
期刊：
影响因子：
3
通讯作者：
Townson, H
中科院分区：
文献类型：
--
作者：
Cuamba, N;Choi, KS;Townson, H
背景：到目前为止，疟疾是安哥拉发病率和死亡率的最大原因，占所有门诊就诊的50%，占所有住院死亡的22%，但到2003年，只有2%的5岁以下儿童使用驱虫蚊帐。昆虫学研究是使用驱虫蚊帐和室内滞留喷洒合理控制疟疾的重要基础，但直到2002年结束的27年内战期间，还没有关于安哥拉疟疾病媒的公开研究。方法：2001年4月，在半干旱沿海省份罗安达和本格拉的4个地点和湿润热带高原的万博省的2个地点，通过室内除虫菊酯喷雾采集蚊子样本。结果：冈比亚按蚊复合体的聚合酶链式反应检测结果显示，冈比亚按蚊复合体中以按蚊复合体为主。冈比亚，室内栖息密度在每栋房子0.9到23.5之间。403An.冈比亚亚种鉴定为分子型，M型占93.5%，S型占6.5%。M和S在4个位点上是同域的，没有检测到M/S杂交种。S型的比例最高(20%)来自湿润高原的万博市。在罗安达附近的一个地点发现了按蚊。经酶联免疫吸附试验检测，蚊子孢子率为1.9%。冈比亚(n=580)，按蚊0.7%。Funestus(n=140)。218An.冈比亚(M型195例，S型23例)携带西非KDR抗性等位基因，均为纯合子易感。冈比亚M型是研究地区最重要和分布最广的疟疾病媒，但需要对疟疾病媒进行更广泛的研究，以支持安哥拉的疟疾控制方案。这些措施应该包括标准的抗药性生物检疫和分子检测，既能检测新陈代谢抗药性，又能检测靶点不敏感。
Background: Malaria is by far the greatest cause of morbidity and mortality in Angola, being responsible for 50% of all outpatient attendance and around 22% of all hospital deaths, yet by 2003 only 2% of under-5s used insecticide-treated nets. Entomological studies are an essential foundation for rational malaria control using insecticide-treated nets and indoor residual spraying, but there have been no published studies of malaria vectors in Angola over the 27 years of the civil war, to its end in 2002. This paper describes studies arising from a WHO-sponsored visit in support of the National Malaria Control Programme.Methods: During April 2001, mosquitoes were sampled by indoor pyrethrum spray collection from four sites in the semi-arid coastal provinces of Luanda and Benguela and two sites in Huambo province, in the humid tropical highlands. Collections took place towards the end of the rainy season and were used to determine the Anopheles species present, their sporozoite rates and the frequency of a kdr allele conferring resistance to pyrethroid insecticides.Results: A PCR test for the Anopheles gambiae complex showed a preponderance of An. gambiae, with indoor resting densities ranging from 0.9 to 23.5 per house. Of 403 An. gambiae identified to molecular form, 93.5% were M-form and 6.5% S-form. M and S were sympatric at 4 sites but no M/ S hybrids were detected. The highest proportion of S-form (20%) was in samples from Huambo, in the humid highlands. Anopheles funestus was found at one site near Luanda. The sporozoite rate of mosquitoes, determined by an ELISA test, was 1.9% for An. gambiae (n = 580) and 0.7% for An. funestus ( n = 140). Of 218 An. gambiae (195 M-form and 23 S-form) genotyped for the West African kdr-resistance allele, all were homozygous susceptible.Conclusion: An. gambiae M-form is the most important and widespread malaria vector in the areas studied but more extensive studies of malaria vectors are required to support the malaria control programme in Angola. These should include standard insecticide resistance biossays and molecular assays that can detect both metabolic resistance and target site insensitivity.