Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.
J Infect Dis. 2013 Jan 15;207(2):351-61. doi: 10.1093/infdis/jis675. Epub 2012 Nov 7.
In malaria-endemic settings, asymptomatic parasitemia complicates the diagnosis of malaria. Histidine-rich protein 2 (HRP2) is produced by Plasmodium falciparum, and its plasma concentration reflects the total body parasite burden. We aimed to define the malaria-attributable fraction of severe febrile illness, using the distributions of plasma P. falciparum HRP2 (PfHRP2) concentrations from parasitemic children with different clinical presentations.
Plasma samples were collected from and peripheral blood slides prepared for 1435 children aged 6-60 months in communities and a nearby hospital in northeastern Tanzania. The study population included children with severe or uncomplicated malaria, asymptomatic carriers, and healthy control subjects who had negative results of rapid diagnostic tests. The distributions of plasma PfHRP2 concentrations among the different groups were used to model severe malaria-attributable disease.
The plasma PfHRP2 concentration showed a close correlation with the severity of infection. PfHRP2 concentrations of >1000 ng/mL denoted a malaria-attributable fraction of severe disease of 99% (95% credible interval [CI], 96%-100%), with a sensitivity of 74% (95% CI, 72%-77%), whereas a concentration of <200 ng/mL denoted severe febrile illness of an alternative diagnosis in >10% (95% CI, 3%-27%) of patients. Bacteremia was more common among patients in the lowest and highest PfHRP2 concentration quintiles.
The plasma PfHRP2 concentration defines malaria-attributable disease and distinguishes severe malaria from coincidental parasitemia in African children in a moderate-to-high transmission setting.
在疟疾流行地区，无症状寄生虫血症使疟疾的诊断复杂化。裂殖体表面蛋白 2（HRP2）由恶性疟原虫产生，其血浆浓度反映了全身寄生虫负荷。我们旨在使用不同临床表现的寄生虫血症儿童的血浆恶性疟原虫 HRP2（PfHRP2）浓度分布来定义严重发热疾病的疟疾归因部分。
从坦桑尼亚东北部社区和附近医院的 1435 名 6-60 个月大的儿童中采集血浆样本并制备外周血涂片。研究人群包括患有严重或无并发症疟疾、无症状携带者和快速诊断检测结果为阴性的健康对照者。不同组别的血浆 PfHRP2 浓度分布用于对严重疟疾归因疾病进行建模。
血浆 PfHRP2 浓度与感染的严重程度密切相关。PfHRP2 浓度>1000ng/mL 表示疟疾归因于严重疾病的比例为 99%（95%置信区间[CI]，96%-100%），灵敏度为 74%（95%CI，72%-77%），而浓度<200ng/mL 表示在>10%（95%CI，3%-27%）的患者中出现了另一种诊断的严重发热疾病。最低和最高 PfHRP2 浓度五分位数的患者中更常见菌血症。
血浆 PfHRP2 浓度定义了疟疾归因疾病，并在中高传播地区的非洲儿童中区分了严重疟疾和偶然寄生虫血症。
