Malaria Research Unit, Centre Pasteur Cameroon, P.O. Box 1274, Yaoundé, Cameroon.
Department of Microbiology and Parasitology, Faculty of Sciences, The University of Buea, P.O. Box 63, Buea, Cameroon.
Sci Rep. 2024 Jun 21;14(1):14294. doi: 10.1038/s41598-024-58337-8.
The applicability of the specific human IgG antibody response to Anopheles gambiae salivary Gland Protein-6 peptide 1 (gSG6-P1 salivary peptide) as a biomarker able to distinguish the level of exposure to mosquito bites according to seasonal variations has not yet been evaluated in Central African regions. The study aimed to provide the first reliable data on the IgG anti-gSG6-P1 response in rural area in Cameroon according to the dry- and rainy-season. Between May and December 2020, dry blood samples were collected from people living in the Bankeng village in the forest area of the Centre region of Cameroon. Malaria infection was determined by thick-blood smear microscopy and multiplex PCR. The level of IgG anti-gSG6-P1 response, was assessed by enzyme-linked immunosorbent assay. Anopheles density and aggressiveness were assessed using human landing catches. The prevalence of malaria infection remains significantly higher in the rainy season than in the dry season (77.57% vs 61.44%; p = 0.0001). The specific anti-gSG6-P1 IgG response could be detected in individuals exposed to few mosquito bites and showed inter-individual heterogeneity even when living in the same exposure area. In both seasons, the level of anti-gSG6-P1 IgG response was not significantly different between Plasmodium infected and non-infected individuals. Mosquito bites were more aggressive in the rainy season compared to the dry season (human biting rate-HBR of 15.05 b/p/n vs 1.5 b/p/n) where mosquito density was very low. Infected mosquitoes were found only during the rainy season (sporozoite rate = 10.63% and entomological inoculation rate-EIR = 1.42 ib/p/n). The level of IgG anti-gSG6-P1 response was significantly higher in the rainy season and correlated with HBR (p ˂ 0.0001). This study highlights the high heterogeneity of individual's exposure to the Anopheles gambiae s.l vector bites depending on the transmission season in the same area. These findings reinforce the usefulness of the anti-gSG6-P1 IgG response as an accurate immunological biomarker for detecting individual exposure to Anopheles gambiae s.l. bites during the low risk period of malaria transmission in rural areas and for the differentiating the level of exposure to mosquitoes.
冈比亚按蚊唾液腺蛋白 6 肽 1（gSG6-P1 唾液肽）特异性人 IgG 抗体反应作为一种生物标志物，能够根据季节性变化来区分蚊子叮咬的暴露水平，但其在中非地区的适用性尚未得到评估。本研究旨在根据旱季和雨季，首次提供喀麦隆农村地区 gSG6-P1 反应的可靠 IgG 数据。2020 年 5 月至 12 月期间，从喀麦隆中心地区森林区班根村居住的人中采集干血样。通过厚血涂片显微镜检查和多重 PCR 确定疟疾感染。通过酶联免疫吸附试验评估 IgG 抗 gSG6-P1 反应水平。使用人体着陆捕获评估按蚊密度和侵袭性。雨季疟疾感染的流行率明显高于旱季（77.57%对 61.44%；p=0.0001）。即使生活在同一暴露区域，接触少量蚊子叮咬的个体也能检测到特异性抗 gSG6-P1 IgG 反应，且个体间存在异质性。在两个季节中，感染和未感染个体之间的抗 gSG6-P1 IgG 反应水平均无显著差异。雨季蚊子叮咬的侵袭性高于旱季（人叮咬率-HBR 为 15.05 b/p/n 对 1.5 b/p/n），此时蚊子密度非常低。仅在雨季发现感染蚊子（孢子率=10.63%，昆虫接种率-EIR=1.42 ib/p/n）。雨季的 IgG 抗 gSG6-P1 反应水平显著升高，与 HBR 相关（p<0.0001）。本研究强调了在同一地区，根据传播季节的不同，个体对冈比亚按蚊 s.l. 传播媒介叮咬的暴露存在高度异质性。这些发现加强了抗 gSG6-P1 IgG 反应作为一种准确的免疫生物学标志物的实用性，可用于检测农村地区疟疾低传播风险期个体对冈比亚按蚊 s.l. 叮咬的暴露程度，并区分蚊子叮咬的程度。
