The role of submicroscopic parasitemia in malaria transmission: what is the evidence?

Achieving malaria elimination requires targeting the human reservoir of infection, including those with asymptomatic infection. Smear-positive asymptomatic infections detectable by microscopy are an important reservoir because they often persist for months and harbor gametocytes, the parasite stage infectious to mosquitoes. However, many asymptomatic infections are submicroscopic and can only be detected by molecular methods. Although there is some evidence that individuals with submicroscopic malaria can infect mosquitoes, transmission is much less likely to occur at submicroscopic gametocyte levels. As malaria elimination programs pursue mass screening and treatment of asymptomatic individuals, further research should strive to define the degree to which submicroscopic malaria contributes to the infectious reservoir and, in turn, what diagnostic detection threshold is needed to effectively interrupt transmission.

实现疟疾消除需要针对人类感染源，包括无症状感染者。通过显微镜可检测到的涂片阳性无症状感染是一个重要的感染源，因为它们往往持续数月，并携带配子体，即对蚊子具有传染性的寄生虫阶段。然而，许多无症状感染是亚微观的，只能通过分子方法检测到。尽管有一些证据表明患有亚微观疟疾的个体能够感染蚊子，但在亚微观配子体水平上发生传播的可能性要小得多。随着疟疾消除计划对无症状个体进行大规模筛查和治疗，进一步的研究应努力确定亚微观疟疾对感染源的贡献程度，进而确定有效阻断传播所需的诊断检测阈值。