低水平间日疟原虫感染、母传抗体与儿童早期贫血：巴西亚马孙地区基于人群的出生队列研究。
Low-level Plasmodium vivax exposure, maternal antibodies, and anemia in early childhood: Population-based birth cohort study in Amazonian Brazil.
机构信息
Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil.
Department of Nutrition, School of Public Health, University of São Paulo, São Paulo, Brazil.
出版信息
PLoS Negl Trop Dis. 2021 Jul 15;15(7):e0009568. doi: 10.1371/journal.pntd.0009568. eCollection 2021 Jul.
BACKGROUND
Malaria causes significant morbidity and mortality in children under 5 years of age in sub-Saharan Africa and the Asia-Pacific region. Neonates and young infants remain relatively protected from clinical disease and the transplacental transfer of maternal antibodies is hypothesized as one of the protective factors. The adverse health effects of Plasmodium vivax malaria in early childhood-traditionally viewed as a benign infection-remain largely neglected in relatively low-endemicity settings across the Amazon.
METHODOLOGY/PRINCIPAL FINDINGS: Overall, 1,539 children participating in a birth cohort study in the main transmission hotspot of Amazonian Brazil had a questionnaire administered, and blood sampled at the two-year follow-up visit. Only 7.1% of them experienced malaria confirmed by microscopy during their first 2 years of life- 89.1% of the infections were caused by P. vivax. Young infants appear to be little exposed to, or largely protected from infection, but children >12 months of age become as vulnerable to vivax malaria as their mothers. Few (1.4%) children experienced ≥4 infections during the 2-year follow-up, accounting for 43.4% of the overall malaria burden among study participants. Antenatal malaria diagnosed by microscopy during pregnancy or by PCR at delivery emerged as a significant correlate of subsequent risk of P. vivax infection in the offspring (incidence rate ratio, 2.58; P = 0.002), after adjusting for local transmission intensity. Anti-P. vivax antibodies measured at delivery do not protect mothers from subsequent malaria; whether maternal antibodies transferred to the fetus reduce early malaria risk in children remains undetermined. Finally, recent and repeated vivax malaria episodes in early childhood are associated with increased risk of anemia at the age of 2 years in this relatively low-endemicity setting.
CONCLUSIONS/SIGNIFICANCE: Antenatal infection increases the risk of vivax malaria in the offspring and repeated childhood P. vivax infections are associated with anemia at the age of 2 years.
背景
在撒哈拉以南非洲和亚太地区，疟疾在 5 岁以下儿童中造成了重大的发病率和死亡率。新生儿和婴儿相对免受临床疾病的影响，母体抗体的胎盘转移被认为是一种保护因素。在亚马逊地区相对低流行地区，人们在很大程度上忽视了间日疟原虫疟疾对幼儿健康的不良影响——传统上认为这是一种良性感染。
方法/主要发现：总体而言，在巴西亚马逊主要传播热点地区参与出生队列研究的 1539 名儿童在两年随访时接受了问卷调查和血样采集。他们中只有 7.1%在生命的头两年中经显微镜检查确诊患有疟疾——其中 89.1%的感染是由间日疟原虫引起的。婴儿似乎很少接触或受到很大的保护而免受感染，但 12 个月以上的儿童感染间日疟原虫的风险与他们的母亲一样高。在两年的随访中，只有少数（1.4%）儿童经历了≥4次感染，占研究参与者总疟疾负担的 43.4%。在怀孕期间通过显微镜检查或在分娩时通过 PCR 诊断的产前疟疾是后代随后发生间日疟原虫感染的显著相关因素（发病率比，2.58；P=0.002），在调整了当地传播强度后。分娩时测量的抗间日疟原虫抗体不能保护母亲免受随后的疟疾；母体抗体转移到胎儿是否降低儿童早期疟疾的风险仍不确定。最后，在这个相对低流行地区，幼儿期近期和反复的间日疟原虫感染与 2 岁时贫血的风险增加有关。
结论/意义：产前感染会增加后代患间日疟的风险，儿童期反复感染间日疟原虫与 2 岁时贫血有关。
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