Malaria infection and disease in an area with pyrethroid-resistant vectors in southern Benin
Malaria infection and disease in an area with pyrethroid-resistant vectors in southern Benin
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DOI：
10.1186/1475-2875-9-380
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发表时间：
2010-12-31
期刊：
影响因子：
3
通讯作者：
Henry, Marie-Claire
中科院分区：
文献类型：
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作者：
Damien, Georgia B.;Djenontin, Armel;Henry, Marie-Claire
背景资料：本研究旨在对疟疾基线数据进行调查，然后在病媒对拟除虫菊酯具有抗药性的地区评价新的病媒控制战略。疟疾的负担估计感染（患病率和寄生虫密度）和临床epissions.Methods：2007年12月至2008年12月期间，在卫生区的维达- Kpomasse -托里博西托（贝宁南部），疟疾的描述性流行病学调查进行。从28个选定的村庄中，随机抽取了7个村庄，从中随机抽取了440名0至5岁的儿童。临床和寄生虫学信息是通过在每六周一次的连续六天的八个周期内对疟疾发作进行主动病例检测和对无症状感染者进行横断面调查获得的。还收集了昆虫学信息。结果：无症状儿童恶性疟原虫平均密度为586个无性型/mu L血（95%CI 504-680）。发热性寄生虫的临界值估计为2，000个恶性疟原虫无性血型/μ L。疟疾的临床发病率为每名儿童每年1.5次（95%CI 1.2-1.9）。寄生虫学和临床变量没有随季节变化。冈比亚按蚊L.是主要的媒介，其次是按蚊funestus。昆虫接种率为每人每年5.3（95% CI 1.1-25.9）次感染性叮咬。L1014 F kdr（West）等位基因的频率约为50%。恶性疟原虫无症状感染者的年患病率为21.8%（95%CI 19.1-24.4），且随年龄增长而增加。长效驱虫蚊帐的平均拥有率和使用率分别为92%和70%。唯一正确使用长效驱虫蚊帐（63%）的个体仅对感染有26%的保护作用（OR = 0.74（95%IC 0.62-0.87），p = 0.005）。结论：维达-Kpomasse-Tori Bossido卫生区是一个中度流行区，媒介对拟除虫菊酯具有中等水平的耐药性。长效驱虫蚊帐的使用率很高，只有正确使用长效驱虫蚊帐才能在不影响疟疾发病率的情况下减少疟疾感染。
Background: This study aimed to investigate baseline data on malaria before the evaluation of new vector control strategies in an area of pyrethroid-resistance of vectors. The burden of malaria was estimated in terms of infection (prevalence and parasite density) and of clinical episodes.Methods: Between December 2007 and December 2008 in the health district of Ouidah - Kpomasse - Tori Bossito (southern Benin), a descriptive epidemiological survey of malaria was conducted. From 28 selected villages, seven were randomized from which a total of 440 children aged 0 to 5 years were randomly selected. Clinical and parasitological information was obtained by active case detection of malaria episodes carried out during eight periods of six consecutive days scheduled at six weekly intervals and by cross-sectional surveys of asymptomatic infection. Entomological information was also collected. The ownership, the use and the correct use of long-lasting insecticide-treated nets (LLINs) were checked over weekly-survey by unannounced visits at home in the late evening.Results: Mean parasite density in asymptomatic children was 586 P. falciparum asexual forms per mu L of blood (95% CI 504-680). Pyrogenic parasite cut-off was estimated 2,000 P. falciparum asexual blood forms per mu L. The clinical incidence of malaria was 1.5 episodes per child per year (95% CI 1.2-1.9). Parasitological and clinical variables did not vary with season. Anopheles gambiae s. l. was the principal vector closely followed by Anopheles funestus. Entomological inoculation rate was 5.3 (95% CI 1.1-25.9) infective bites per human per year. Frequency of the L1014F kdr (West) allele was around 50%. Annual prevalence rate of Plasmodium falciparum asymptomatic infection was 21.8% (95% CI 19.1-24.4) and increased according to age. Mean rates of ownership and use of LLINs were 92% and 70% respectively. The only correct use of LLINs (63%) conferred 26% individual protection against only infection (OR = 0.74 (95% IC 0.62-0.87), p = 0.005).Conclusion: The health district of Ouidah-Kpomasse-Tori Bossito is a mesoendemic area with a moderate level of pyrethroid-resistance of vectors. The used LLINs rate was high and only the correct use of LLINs was found to reduce malaria infection without influencing malaria morbidity.