Uneke Chigozie J
Department of Medical Microbiology/Parasitology, Ebonyi State University, Nigeria.
Yale J Biol Med. 2008 Mar;81(1):1-7.
Plasmodium falciparum infections of the placenta remain a major medical challenge among pregnant women in sub-Saharan Africa. A number of factors influence the prevalence of placental malaria in pregnant women, including maternal age, gravidity, use of prophylaxis, nutrition, host genetics, and level of anti-parasite immunity, as well as parasite genetics and transmission rates [1]. Maternal anemia has been shown to be one of the major complications of placental malaria in sub-Saharan Africa. The mechanisms by which malaria causes anemia are fairly well understood. The pathophysiology of malaria-associated anemia is multifactorial. The most likely mechanisms include (i) hemolysis or the direct destruction of parasitized red blood cells that occurs both intravascularly and by sequestration in the microcirculation, mainly in the spleen; (ii) specific/nonspecific immune responses, whereby red cell survival is shortened; (iii) nonspecific, defective, red cell production, which depresses erythropoiesis, inhibits reticulocyte release, and prematurely destructs red cells during maturation in the bone marrow; and (iv) hypersplenism associated with a reduction in all three blood cell series, that is, causing not only anemia but also thrombocytopenia and leucopenia [2,3]. The relationship between maternal anemia with obstetric factors, however, is not fully understood, and, thus, evaluating the link between malaria, obstetric disorders, and maternal death has been recommended [4]. There have been efforts to quantify the contribution of malaria to maternal morbidity and mortality with the expectation that this would provide the evidence necessary to improve the effectiveness of advocacy to incorporate malaria prevention strategies in Safe Motherhood Programs [5,6]. The effects of placental malaria on maternal health can better be understood when considered in relation with various maternal parameters, including maternal age, parity, peripheral malaria infection, anemia, and HIV infection.
在撒哈拉以南非洲地区，孕妇感染恶性疟原虫仍然是一项重大医学挑战。多种因素会影响孕妇胎盘疟疾的患病率，包括产妇年龄、妊娠次数、预防措施的使用、营养状况、宿主遗传学、抗寄生虫免疫力水平，以及寄生虫遗传学和传播率[1]。在撒哈拉以南非洲地区，产妇贫血已被证明是胎盘疟疾的主要并发症之一。疟疾导致贫血的机制已得到较好理解。疟疾相关贫血的病理生理学是多因素的。最可能的机制包括：（i）溶血或被寄生红细胞的直接破坏，这在血管内以及通过在微循环（主要是脾脏）中的滞留而发生；（ii）特异性/非特异性免疫反应，从而缩短红细胞存活时间；（iii）非特异性、有缺陷的红细胞生成，这会抑制红细胞生成、抑制网织红细胞释放，并在骨髓成熟过程中过早破坏红细胞；以及（iv）脾功能亢进，伴有所有三种血细胞系列减少，即不仅导致贫血，还导致血小板减少和白细胞减少[2,3]。然而，产妇贫血与产科因素之间的关系尚未完全明确，因此，建议评估疟疾、产科疾病与产妇死亡之间的联系[4]。人们一直在努力量化疟疾对孕产妇发病率和死亡率的影响，期望这将提供必要证据，以提高宣传效果，将疟疾预防策略纳入安全孕产计划[5,6]。当结合各种孕产妇参数（包括产妇年龄、产次、外周疟疾感染、贫血和艾滋病毒感染）来考虑时，胎盘疟疾对孕产妇健康的影响能得到更好的理解。
