Modiano D, Petrarca V, Sirima B S, Nebié I, Luoni G, Esposito F, Coluzzi M
Dipartimento di Biologia Molecolare, Cellulare e Animale, Università di Camerino, Italy.
Am J Trop Med Hyg. 1998 Aug;59(2):336-40. doi: 10.4269/ajtmh.1998.59.336.
It has been shown that insecticide-treated bed nets or curtains may reduce morbidity and mortality from malaria in hyper-holoendemic areas of sub-Saharan Africa. This protection could partially depend on the transitory imbalance between the anti-malaria immunity acquired by the population before the intervention and the lowered sporozoite load resulting from the anti-vector measure. To verify if the efficacy of the intervention is influenced by the baseline immune status of the population, we compared the protective effect of permethrin-impregnated curtains (PIC) against malaria infection among groups with different baseline levels of anti-malaria immunity. We analyzed the impact of PIC on the Plasmodium falciparum infection rate in two rural villages of Burkina Faso inhabited by three ethnic groups: the Fulani, Mossi, and Rimaibé. These have been previously shown to differ for several malariologic indices, with the Fulani being characterized by lower infection and disease rates and by higher immune response to P. falciparum with respect to the other ethnic groups. The PIC were distributed in June 1996 and their impact on malaria infection was evaluated in groups whose baseline levels of immunity to malaria differed because of their age and ethnic group. Age- and ethnic-dependent efficacy of the PIC was observed. Among the Mossi and Rimaibé, the impact (parasite rate reduction after PIC installation with respect to the pre-intervention surveys) was 18.8% and 18.5%, respectively. A more than two-fold general impact (42.8%) was recorded in the Fulani. The impact of the intervention on infection rates appears positively correlated with the levels of anti-malaria immunity. Since decreased transmission entails a reduction of immunity, the efficacy of the intervention in the long term cannot be taken for granted. The expected complementary role of a hypothetical vaccine is stressed by these results, which also emphasize the importance of the genetic background of the population in the evaluation and application of malaria control strategies.
研究表明，在撒哈拉以南非洲的高度疟疾流行区，经杀虫剂处理的蚊帐或窗帘可降低疟疾的发病率和死亡率。这种保护作用可能部分取决于干预措施实施前人群获得的抗疟疾免疫力与抗媒介措施导致的子孢子负荷降低之间的暂时失衡。为了验证干预措施的效果是否受人群基线免疫状态的影响，我们比较了不同基线抗疟疾免疫水平组中，氯菊酯浸渍窗帘（PIC）对疟疾感染的保护作用。我们分析了PIC对布基纳法索两个乡村中恶性疟原虫感染率的影响，这两个乡村居住着富拉尼、莫西和里马贝三个民族。此前已表明，这三个民族在多个疟疾学指标上存在差异，富拉尼族的感染率和发病率较低，对恶性疟原虫的免疫反应高于其他民族。PIC于1996年6月分发，并在因年龄和民族不同而疟疾免疫基线水平不同的组中评估其对疟疾感染的影响。观察到PIC的效果因年龄和民族而异。在莫西族和里马贝族中，PIC安装后相对于干预前调查的影响（寄生虫率降低）分别为18.8%和18.5%。在富拉尼族中记录到的总体影响超过两倍（42.8%）。干预措施对感染率的影响似乎与抗疟疾免疫水平呈正相关。由于传播减少会导致免疫力下降，因此不能想当然地认为干预措施的长期效果会持续存在。这些结果强调了假设疫苗预期的补充作用，也强调了人群遗传背景在疟疾控制策略评估和应用中的重要性。
