Data from: The complex relationship of exposure to new Plasmodium infections and incidence of clinical malaria in Papua New Guinea

The molecular force of blood-stage infection (molFOB) is a quantitative surrogate metric for malaria transmission at population level and for exposure at individual level. Relationships between molFOB, parasite prevalence and clinical incidence were assessed in a treatment-to-reinfection cohort, where P.vivax (Pv) hypnozoites were eliminated in half the children by primaquine (PQ). Discounting relapses, children acquired equal numbers of new P. falciparum (Pf) and Pv blood-stage infections/year (Pf-molFOB=0-18, Pv-molFOB=0-23) resulting in comparable spatial and temporal patterns in incidence and prevalence of infections. Including relapses, Pv-molFOB increased >3-fold (relative to PQ-treated children) showing greater heterogeneity at individual (Pv-molFOB=0-36) and village levels. Pf- and Pv-molFOB were strongly associated with clinical episode risk. Yearly Pf clinical incidence rate (IR=0.28) was higher than for Pv (IR=0.12) despite lower Pf-molFOB. These relationships between molFOB, clinical incidence and parasite prevalence reveal a comparable decline in Pf and Pv transmission that is normally hidden by the high burden of Pv relapses.

血液期感染分子作用力（molecular force of blood-stage infection, molFOB）是人群层面疟疾传播与个体层面疟疾暴露的定量替代指标。研究在一项治疗后再感染队列中评估了molFOB与寄生虫患病率、临床发病率之间的关联；该队列中，半数儿童经伯氨喹（primaquine, PQ）治疗后清除了间日疟原虫（Plasmodium vivax, Pv）的休眠子（hypnozoites）。若不考虑复发因素，儿童每年新感染的恶性疟原虫（Plasmodium falciparum, Pf）与间日疟原虫血液期感染数量基本相当（恶性疟molFOB范围为0~18，间日疟molFOB范围为0~23），由此使得两类感染的发病率与患病率在时空分布上具有可比性。若纳入复发因素，间日疟molFOB较经伯氨喹治疗的儿童升高3倍以上，在个体（间日疟molFOB范围为0~36）与村落层面均呈现出更强的异质性。恶性疟与间日疟的molFOB均与临床发作风险显著相关。尽管恶性疟molFOB水平更低，但其年度临床发病率（IR=0.28）仍高于间日疟（IR=0.12）。上述molFOB、临床发病率与寄生虫患病率之间的关联揭示，恶性疟与间日疟的传播水平下降幅度相当——这一现象通常会因间日疟复发的高疾病负担而被掩盖。