Fondation Congolaise Pour La Recherche Médicale (FCRM), Brazzaville, Republic of Congo.
Faculty of Sciences and Techniques, University Marien Ngouabi, Brazzaville, Republic of Congo.
Malar J. 2022 Apr 2;21(1):114. doi: 10.1186/s12936-022-04105-w.
Investigating whether the multiplicity of Plasmodium falciparum infection (MOI) is related to pregnancy outcomes, is of interest in sub-Saharan area where malaria is highly endemic. The present study aimed to characterize the genetic diversity of P. falciparum in women at delivery from Southern Brazzaville, and investigate whether the MOI is associated with maternal anaemia, preterm delivery, or low birth weight.
This was a cross sectional study carried out with samples collected between March 2014 and April 2015 from 371 women recruited at delivery at a Health Centre in southern Brazzaville, Republic of Congo. Matched peripheral, placental, and cord blood collected from each of the women at delivery were used for the detection of P. falciparum microscopic and submicroscopic parasitaemia, and parasite DNA genotyping by nested PCR.
From 371 recruited women, 27 were positive to microscopic malaria parasitaemia while 223 women harboured submicroscopic parasitaemia. All msp-1 block 2 family allelic types (K1, MAD20 and RO33) were observed in all the three compartments of blood, with K1 being most abundant. K1 (with 12, 10, and 08 alleles in the peripheral, placental, and cord blood respectively) and MAD20 (with 10, 09, and 06 alleles in the respective blood compartments) were more diverse compared to RO33 (with 06, 06, and 05 alleles in the respective blood compartments). From the 250 women with microscopic and/or submicroscopic parasitaemia, 38.5%, 30.5%, and 18.4% of peripheral, placental and cord blood sample, respectively, harboured more than one parasite clone, and polyclonal infection was more prevalent in the peripheral blood of women with microscopic parasitaemia (54.5%) compared to those with submicroscopic parasitaemia (36.7%) (p = 0.02). The mean multiplicity of genotypes per microscopic and submicroscopic infection in peripheral blood was higher in anemic women (2.00 ± 0.23 and 1.66 ± 0.11, respectively) than in non-anaemic women (1.36 ± 0.15 and 1.45 ± 0.06, respectively) (p = 0.03 and 0.06). In logistic regression, women infected with four or more clones of the parasite were 9.4 times more likely to be anaemic than women harbouring one clone. This association, however, was only observed with the peripheral blood infection. No significant association was found between the MOI and low birth weight or preterm delivery.
These results indicate that the genetic diversity of P. falciparum is high in pregnant women from southern Brazzaville in the Republic of Congo, and the multiplicity of the infection might represent a risk for maternal anaemia.
在疟疾高度流行的撒哈拉以南非洲地区，研究疟原虫感染的多重性（MOI）与妊娠结局的关系具有重要意义。本研究旨在描述刚果共和国南部布拉柴维尔分娩妇女中疟原虫的遗传多样性，并探讨 MOI 是否与母亲贫血、早产或低出生体重有关。
这是一项横断面研究，于 2014 年 3 月至 2015 年 4 月期间在刚果共和国南部布拉柴维尔的一个卫生中心对 371 名分娩妇女进行了采样。从每位妇女分娩时采集的外周血、胎盘血和脐带血中检测疟原虫的镜下和亚镜下寄生虫血症，并通过巢式 PCR 对寄生虫 DNA 进行基因分型。
在 371 名被招募的妇女中，27 名妇女的疟原虫镜检呈阳性，而 223 名妇女存在亚镜下寄生虫血症。在所有三种血液部位均观察到 msp-1 块 2 家族的所有等位基因类型（K1、MAD20 和 RO33），其中 K1 最为丰富。与 RO33（在相应的血液部位分别为 06、06 和 05 个等位基因）相比，K1（在外周血、胎盘血和脐带血中分别有 12、10 和 08 个等位基因）和 MAD20（在相应的血液部位分别有 10、09 和 06 个等位基因）的多样性更高。在有镜下和/或亚镜下寄生虫血症的 250 名妇女中，分别有 38.5%、30.5%和 18.4%的外周血、胎盘血和脐带血样本携带了多个寄生虫克隆，并且镜下寄生虫血症妇女的外周血中多克隆感染更为普遍（54.5%）比亚镜下寄生虫血症妇女（36.7%）更为常见（p=0.02）。外周血中镜下和亚镜下感染的平均基因型多重性在贫血妇女中高于非贫血妇女（分别为 2.00±0.23 和 1.66±0.11）（p=0.03 和 0.06）。在逻辑回归中，感染 4 个或更多寄生虫克隆的妇女贫血的可能性是感染 1 个克隆的妇女的 9.4 倍。然而，这种关联仅在周围血液感染中观察到。MOI 与低出生体重或早产之间没有显著关联。
这些结果表明，刚果共和国南部布拉柴维尔孕妇的疟原虫遗传多样性很高，感染的多重性可能是母亲贫血的一个风险因素。
