1Division of Epidemiology and Community Health, University of Minnesota School of Public Health, Minneapolis, Minnesota.
2Macha Research Trust, Macha, Zambia.
Am J Trop Med Hyg. 2020 Nov 23;104(2):671-679. doi: 10.4269/ajtmh.20-0947.
Malaria elimination strategies are designed to more effectively identify and treat infected individuals to interrupt transmission. One strategy, reactive screen-and-treat, starts with passive detection of symptomatic cases at health facilities. Individuals residing within the index case and neighboring households are screened with a malaria rapid diagnostic test (RDT) and treated if positive. However, it is unclear to what extent this strategy is effective in reducing transmission. Reactive screen-and-treat was implemented in Choma district, Southern Province, Zambia, in 2013, in which residents of the index case and neighboring households within 140 m were screened with an RDT. From March 2016 to July 2018, the screening radius was extended to 250-m, and additional follow-up visits at 30 and 90 days were added to evaluate the strategy. Plasmodium falciparum parasite prevalence was measured using an RDT and by quantitative PCR (qPCR). A 24-single nucleotide polymorphism molecular bar-code assay was used to genotype parasites. Eighty-four index case households with 676 residents were enrolled between March 2016 and March 2018. Within each season, parasite prevalence declined significantly in index households at the 30-day visit and remained low at the 90-day visit. However, parasite prevalence was not reduced to zero. Infections identified by qPCR persisted between study visits and were not identified by RDT. Parasites identified within the same household were most genetically related; however, overall parasite relatedness was low and similar across time and space. Thus, despite implementation of a reactive screen-and-treat program, parasitemia was not eliminated, and persisted in targeted households for at least 3 months.
消除疟疾策略旨在更有效地发现和治疗感染者，以阻断传播。一种策略是反应性筛查和治疗，从医疗机构被动检测有症状的病例开始。对居住在病例和邻近家庭的个体进行疟疾快速诊断检测（RDT），如果检测结果阳性则进行治疗。然而，这种策略在多大程度上能有效减少传播尚不清楚。2013 年，赞比亚南部省乔马地区实施了反应性筛查和治疗策略，对病例和 140 米内的邻近家庭居民进行 RDT 筛查。从 2016 年 3 月到 2018 年 7 月，筛查半径扩大到 250 米，并增加了 30 天和 90 天的后续随访，以评估该策略。使用 RDT 和定量 PCR（qPCR）测量恶性疟原虫寄生虫的流行率。使用 24 个单核苷酸多态性分子条码分析来对寄生虫进行基因分型。2016 年 3 月至 2018 年 3 月期间，共有 84 个有 676 名居民的病例家庭入组。在每个季节，30 天访视时，病例家庭的寄生虫流行率显著下降，90 天访视时仍保持较低水平。然而，寄生虫流行率并未降至零。qPCR 检测到的感染在研究期间持续存在，而 RDT 未检测到。在同一家庭中发现的寄生虫最具遗传相关性；然而，总体寄生虫相关性较低，且在时间和空间上相似。因此，尽管实施了反应性筛查和治疗计划，但寄生虫血症并未消除，在目标家庭中至少持续了 3 个月。
