Centro de Investigação em Saúde de Manhiça, Maputo, Mozambique.
ISGlobal, Barcelona Center for International Health Research, Hospital Clínic-Universitat de Barcelona, Spain.
Clin Infect Dis. 2018 Sep 14;67(7):1045-1052. doi: 10.1093/cid/ciy219.
Afebrile Plasmodium falciparum infections usually remain undetected and untreated in the community and could potentially contribute to sustaining local malaria transmission in areas aiming for malaria elimination.
Thirty-two men with afebrile P. falciparum infections detected with rapid diagnostic test (RDTs) were followed for 28 days. Kaplan-Meier estimates were computed to estimate probability of parasite positivity and of reducing parasitemia by half of its initial level by day 28. Trends of parasite densities quantified by microscopy and real-time quantitative polymerase chain reaction (qPCR) were assessed using Poisson regression models, and the microscopy-to-qPCR positivity ratio was calculated at each time point. Three survival distributions (Gompertz, Weibull, and gamma) were used to evaluate their strength of fit to the data and to predict the median lifetime of infection.
The cumulative probability of parasite qPCR positivity by day 28 was 81% (95% confidence interval [CI], 60.2-91.6). Geometric mean parasitemia at recruitment was 516.1 parasites/μL and fell to <100 parasites/μL by day 3, reaching 56.7 parasites/μL on day 28 (P < .001). The ratio of P. falciparum-positive samples by microscopy to qPCR decreased from 0.9 to 0.52 from recruitment to day 28. The best model fit to the data was obtained assuming a Gompertz distribution.
Afebrile P. falciparum infections detectable by RDT in semi-immune adults fall and stabilize at low-density levels during the first 4 days after detection, suggesting a rapid decline of potential transmissibility in this hidden parasite reservoir.
NCT02698748.
无热的恶性疟原虫感染在社区中通常未被发现和治疗，可能会导致正在消除疟疾的地区持续存在疟疾传播。
对 32 例通过快速诊断检测（RDT）检测到无热恶性疟原虫感染的男性进行了 28 天的随访。使用 Kaplan-Meier 估计来估计寄生虫阳性的概率和在第 28 天降低初始水平一半的寄生虫减少率。使用泊松回归模型评估显微镜和实时定量聚合酶链反应（qPCR）定量的寄生虫密度趋势，并计算每个时间点的显微镜-qPCR 阳性率比值。使用三个生存分布（Gompertz、Weibull 和 gamma）来评估它们对数据的拟合程度，并预测感染的中位寿命。
第 28 天时 qPCR 阳性的累积概率为 81%（95%置信区间[CI]，60.2-91.6）。招募时的几何平均寄生虫血症为 516.1 个/μL，第 3 天降至<100 个/μL，第 28 天降至 56.7 个/μL（P<.001）。从招募到第 28 天，显微镜检测到的疟原虫阳性样本与 qPCR 的比值从 0.9 降至 0.52。数据拟合最好的模型是假设存在 Gompertz 分布。
在半免疫成年人中，RDT 可检测到的无热恶性疟原虫感染在检测后的前 4 天内下降并稳定在低密度水平，表明这个隐藏的寄生虫库中潜在的传染性迅速下降。
NCT02698748。
