Institut Pierre Richet (IPR), Institut National de la Santé Publique (INSP), Bouaké, Côte d'Ivoire.
MIVEGEC, Univ. Montpellier, CNRS, IRD, Montpellier, France.
Malar J. 2019 Mar 11;18(1):68. doi: 10.1186/s12936-019-2696-z.
In some African cities, urban malaria is a threat to the health and welfare of city dwellers. To improve the control of the disease, it is critical to identify neighbourhoods where the risk of malaria transmission is the highest. This study aims to evaluate the heterogeneity of malaria transmission risk in one city (Bouaké) in a West African country (Côte d'Ivoire) that presents several levels of urbanization.
Two cross-sectional studies were conducted in three neighbourhoods (Dar-es-Salam, Kennedy and N'gattakro) in Bouaké during both the rainy and dry seasons. Data on insecticide-treated net (ITN) use and blood samples were collected from children aged between 6 months and 15 years to determine the parasite density and the prevalence of Plasmodium falciparum and the level of IgG against the Anopheles gSG6-P1 salivary peptide, used as the biomarker of Anopheles bite exposure.
The specific IgG levels to the gSG6-P1 salivary peptide in the rainy season were significantly higher compared to the dry season in all neighbourhoods studied (all p < 0.001). Interestingly, these specific IgG levels did not differ between neighbourhoods during the rainy season, whereas significant differences in IgG level were observed in the dry season (p = 0.034). ITN use could be a major factor of variation in the specific IgG level. Nevertheless, no difference in specific IgG levels to the gSG6-P1 salivary peptide was observed between children who declared "always" versus "never" sleeping under an ITN in each neighbourhood. In addition, the prevalence of P. falciparum in the whole population and immune responders was significantly different between neighbourhoods in each season (p < 0.0001).
This study highlights the high risk of malaria exposure in African urban settings and the high heterogeneity of child exposure to the Anopheles vector between neighbourhoods in the same city. The Anopheles gSG6-P1 salivary peptide could be a suitable biomarker to accurately and quantitatively assess the risk of malaria transmission in urban areas.
在一些非洲城市，城市疟疾对城市居民的健康和福祉构成威胁。为了改善疾病的控制，关键是要确定疟疾传播风险最高的社区。本研究旨在评估一个位于西非国家科特迪瓦的城市（布瓦凯）的疟疾传播风险的异质性，该城市呈现出几个城市化水平。
在布瓦凯的三个社区（达累斯萨拉姆、肯尼迪和恩加塔克罗），在雨季和旱季进行了两项横断面研究。从 6 个月至 15 岁的儿童收集有关驱虫蚊帐（ITN）使用和血液样本的数据，以确定寄生虫密度和恶性疟原虫的流行率以及对按蚊唾液肽 gSG6-P1 的 IgG 水平，用作按蚊叮咬暴露的生物标志物。
在所有研究的社区中，雨季的 gSG6-P1 唾液肽的特异性 IgG 水平明显高于旱季（均 p<0.001）。有趣的是，雨季各社区的特异性 IgG 水平没有差异，而旱季的 IgG 水平则存在显著差异（p=0.034）。ITN 的使用可能是特异性 IgG 水平变化的主要因素。尽管如此，在每个社区中，声称“总是”或“从不”在 ITN 下睡觉的儿童之间，gSG6-P1 唾液肽的特异性 IgG 水平没有差异。此外，在每个季节，整个人群和免疫反应者中恶性疟原虫的流行率在各社区之间存在显著差异（p<0.0001）。
本研究强调了非洲城市环境中疟疾暴露的高风险，以及同一城市内不同社区中儿童接触按蚊媒介的高度异质性。按蚊 gSG6-P1 唾液肽可能是准确和定量评估城市地区疟疾传播风险的合适生物标志物。
