基于直接膜饲法和直接皮肤饲法，在不同恶性疟原虫配子体密度下，使用连续两天的血液进行独立饲育的一致性和可重复性。

Consistency and reproducibility of independent feedings using blood from two consecutive days at varying Plasmodium falciparum gametocyte densities based on both direct membrane feeding assay and direct skin feeding assay.

作者信息

Akala Hoseah Miima, Aponte John J, Achola Millicent Anyango, Juma Dennis W, Opot Benjamin H, Maisiba Risper N, Okoth Raphael O, Juma Jackline A, Mwakio Edwin W, Mwalo Maurine A, Oullo David O, Abuom David, Garges Eric C, Eyase Fredrick L, Tina Lucas Otieno, Copeland Nathanial K, Roth Amanda, Mutunga James, Onyango Irene, Johnson Jaree, Ogutu Bernhards R, Sifuna Peter, Hutter Jack, Mercer Laina, Raine Mike, Moore Valerie, Ivinson Karen, Wu Yimin, Andagalu Ben, Ockenhouse Christian F

机构信息

Walter Reed Army Institute of Research-Africa, Kenya Medical Research Institute, Kisumu, Kenya.

PATH, Geneva, Switzerland.

出版信息

Malar J. 2025 May 16;24(1):154. doi: 10.1186/s12936-025-05360-3.

DOI:10.1186/s12936-025-05360-3

PMID:40380146

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC12085032/

Abstract

BACKGROUND

New malaria control tools are needed to prevent the transmission of parasites from the host to the mosquito vector and vice versa. The infectiousness of Plasmodium falciparum gametocytes obtained from individuals to laboratory-reared mosquitoes should be quantified to employ easily applicable assays for evaluating transmission-blocking interventions. This study aimed to establish the relationship between parasite transmission from humans to mosquitoes both within a person and across persons by assessing the variation in the proportion of infected mosquitoes with at least one oocyst (oocyst prevalence) in a direct membrane feeding assay (DMFA) and direct skin landing feeding assay (DSFA) performed at two consecutive time points in the same human subject with P. falciparum gametocytaemia.

METHODS

A total of 400 adults without symptoms of malaria residing in Western Kenya were screened for the presence of P. falciparum gametocytes. Individuals who tested positive had DMFAs and DSFAs on two subsequent days of feeding, baseline and final visit, to compare mosquito infection rates between the two feeds.

RESULTS

Blood samples from 42 individuals testing positive for gametocytes underwent mosquito infection assays. Survival rates of mosquitoes after feeding at baseline and final visit were 13.2 and 11.6 days for DMFA and 12.1 and 11.4 days for DSFA, respectively. The mean oocyst prevalence on feeding at baseline and final visit was 6.3% and 2.2% for DMFA and 5.2% and 2.3% for DSFA, respectively. A not significantly lower prevalence was not observed on at final visit (- 0.016% for DMFA, p = 0.795) and -0.025% for DSFA, p = 0.711 compared to feeding at baseline. The correlation of oocyst prevalence between feeding baseline and final visit for both was low (0.3 95%CI (0.15, 0.51). Exploratory analysis suggests a lower probability of infection on the second day, with lower oocyst density.

CONCLUSIONS

These findings have implications for future studies and limit the utility of before-after designs in testing transmission-blocking interventions. The findings show comparable infection rates in both DMFA and DSFA, which allows use of less invasive membrane assays in future studies. Trial registration NCT04666350.

摘要

背景

需要新的疟疾控制工具来防止寄生虫在宿主与蚊媒之间传播，反之亦然。为了采用易于应用的检测方法来评估传播阻断干预措施，应量化从个体获取的恶性疟原虫配子体对实验室饲养蚊子的感染性。本研究旨在通过评估在同一患有恶性疟原虫配子血症的人类受试者中连续两个时间点进行的直接膜饲试验（DMFA）和直接皮肤接种饲试验（DSFA）中，至少有一个卵囊的感染蚊子比例（卵囊流行率）的变化，来确定人与人之间以及个体内部寄生虫从人传播到蚊子的关系。

方法

对居住在肯尼亚西部的400名无疟疾症状的成年人进行筛查，以检测恶性疟原虫配子体的存在。检测呈阳性的个体在喂食后的两天，即基线和末次访视时进行直接膜饲试验和直接皮肤接种饲试验，以比较两次喂食之间的蚊子感染率。

结果

对42名配子体检测呈阳性的个体的血样进行了蚊子感染试验。在基线和末次访视时喂食后蚊子的存活率，直接膜饲试验分别为13.2天和11.6天，直接皮肤接种饲试验分别为12.1天和11.4天。在基线和末次访视时喂食的平均卵囊流行率，直接膜饲试验分别为6.3%和2.2%，直接皮肤接种饲试验分别为5.2%和2.3%。与基线喂食相比，末次访视时未观察到明显较低的流行率（直接膜饲试验为 -0.016%，p = 0.795），直接皮肤接种饲试验为 -0.025%，p = 0.711。两次喂食的基线和末次访视之间卵囊流行率的相关性较低（0.3 95%CI（0.15, 0.51）。探索性分析表明，第二天感染的可能性较低，卵囊密度也较低。