Impact of placental malaria on maternal, placental and fetal cord responses and its role in pregnancy outcomes in women from Blue Nile State, Sudan

Early-life matters: The role of fetal adrenal steroids in the relationship between cytokines within the placental circulation and cognitive development among infants in the Philippines

Prenatal exposure to inflammation is related to the risk for cognitive impairment in offspring. However, mechanisms underlying the link between inflammatory cytokines at the maternal-fetal interface and human cognitive development are largely unknown. This study addressed this research gap by examining whether i) cytokines within the placenta are associated with different domains of neurocognitive development during infancy, and ii) if DHEA-S in cord blood mediates these associations. We also explored the role of early-life socioeconomic status (SES) in moderating the effect of fetal adrenal steroids on cognitive development in low- and middle-income country contexts. A cohort of 242 mother-infant dyads in Leyte, the Philippines participated in the study and all of them were followed from early pregnancy until 12-months. Concentrations of pro- and anti-inflammatory cytokines in the placenta, and DHEA-S in cord blood collected at delivery were evaluated. The multifactorial aspects of the infant's cognitive functioning were assessed based on the Bayley Scales of Infant Development, third edition (BSID-III). We used Structural Equation Modelling (SEM) with an orthogonal rotation to examine associated paths among latent variables of pro- and anti-inflammatory cytokines in the placenta, fetal neuroendocrine factors, and cognitive development. Pathway analyses showed that both pro- and anti-inflammatory cytokines in the placenta were indirectly related to cognitive (p < 0.05) and language developmental outcomes (p < 0.1) via DHEA-S in cord blood among the low SES group. Yet, we found no statistically significant indirect effect of pro- or anti-inflammatory cytokines on neurocognitive development among the high SES sub-sample. This study extends our understanding of how early-life socioeconomic conditions modify biological pathways underlying the relationship between prenatal factors and postpartum cognitive development.

Plasmodium Parasitaemia and Urine Alterations among Pregnant Women Attending Antenatal Care in Aba Metropolis, Abia State, Nigeria

Malaria presents a huge threat to pregnant women, their foetus, and children below five years. This study is aimed at assessing malaria prevalence, associated clinical symptoms, and urine abnormalities among pregnant women in Aba metropolis, Abia State, Nigeria. A cross-sectional study involving 450 pregnant women purposively selected from nine health care centres was conducted. Data were analysed using SPSS version 26. The overall malaria prevalence rate was 68.4% (n = 308). Age group of 21-25 years had the highest prevalence rate of 20.4% (n = 92) while the least was recorded among the age group of 41-45 years (17 (3.8%)). Pregnant women in their first trimester had the greatest prevalence rate of 28.6% (n = 129), and the least prevalence was recorded among those in their third trimester (7 (15.6%)). The primigravidae were mostly infected at the rate of 27.7% (n = 125) whereas the multigravidae recorded the least prevalence of 85 (18.9%). Participants with secondary education were the most susceptible at the rate of 38.6% (n = 174). The infected participants exhibited significantly higher frequencies of reported fever (p > 0.001, OR 12.881, 95% CI 3.977-41.725) and headaches (p < 0.001, OR 4.688, 95% CI 1.819-12.083). However, cold, cough, body pains, poor appetite, and catarrh showed no significant association with malaria infection at p > 0.05. Participants using long-lasting insecticidal nets (LLINs) showed significantly lower prevalence rate of malaria infection (p < 0.001, OR 2.485, 95% CI 1.619-3.814). Malaria-infected participants showed statistically significant frequencies of proteinuria (p < 0.001, OR 274.14, 95% CI 16.91-4444.0), bilirubinuria (p < 0.001, OR 49.29, 95% CI 11.01-186.34), and urobilinogenuria (p < 0.001, OR 65.16, 95% CI 4.00-1062.40) than those not infected. Ascorbic acid, nitrate, and ketone showed no significant associations with malaria infection at p > 0.005. Infected participants had statistically significant amber and clear urine colour whereas there was no statistically significant difference between the pH levels of urine of the malaria-infected and malaria-noninfected pregnant women.

Malaria-specific Type 1 regulatory T cells are more abundant in first pregnancies and associated with placental malaria

BACKGROUND

Malaria in pregnancy (MIP) causes higher morbidity in primigravid compared to multigravid women; however, the correlates and mechanisms underlying this gravidity-dependent protection remain incompletely understood. We aimed to compare the cellular immune response between primigravid and multigravid women living in a malaria-endemic region and assess for correlates of protection against MIP.

METHODS

We characterised the second trimester cellular immune response among 203 primigravid and multigravid pregnant women enrolled in two clinical trials of chemoprevention in eastern Uganda, utilizing RNA sequencing, flow cytometry, and functional assays. We compared responses across gravidity and determined associations with parasitaemia during pregnancy and placental malaria.

FINDINGS

Using whole blood RNA sequencing, no significant differentially expressed genes were identified between primigravid (n = 12) and multigravid (n = 11) women overall (log 2(FC) > 2, FDR < 0.1). However, primigravid (n = 49) women had higher percentages of malaria-specific, non-naïve CD4+ T cells that co-expressed IL-10 and IFNγ compared with multigravid (n = 85) women (p = 0.000023), and higher percentages of these CD4+ T cells were associated with greater risks of parasitaemia in pregnancy (Rs = 0.49, p = 0.001) and placental malaria (p = 0.0073). These IL-10 and IFNγ co-producing CD4+ T cells had a genomic signature of Tr1 cells, including expression of transcription factors cMAF and BATF and cell surface makers CTLA4 and LAG-3.

INTERPRETATION

Malaria-specific Tr1 cells were highly prevalent in primigravid Ugandan women, and their presence correlated with a higher risk of malaria in pregnancy. Understanding whether suppression of Tr1 cells plays a role in naturally acquired gravidity-dependent immunity may aid the development of new vaccines or treatments for MIP.

FUNDING

This work was funded by NIH (PO1 HD059454, U01 AI141308, U19 AI089674, U01 AI155325, U01 AI150741), the March of Dimes (Basil O'Connor award), and the Bill and Melinda Gates Foundation (OPP 1113682).

Frequency of placental malaria and its associated factors in northwestern Colombia, pooled analysis 2009–2020

Knowledge about placental malaria (PM) is insufficient in the world, and incipient in Colombia where studies are few and recent. In this country, PM has been reported by Plasmodium vivax, Plasmodium falciparum, and mixed infection. The objective was to determine the frequency of PM and its associated clinical-epidemiological factors in mothers and neonates in northwestern Colombia, 2009–2020. A Retrospective pooled analysis with 602 placentas captured in five investigations. The diagnosis of PM was made with thick blood smear (TBS) and qPCR. The groups with and without PM were compared using the Chi-square test, Mann-Whitney test, and crude and adjusted prevalence ratios in a log-binomial model. The prevalence of PM was 27.7% with 92% (155/167) of submicroscopic cases; 41.3% by P. vivax, 44,3% by P. falciparum, and 14.4% by mixed infections. In the multivariate adjustment, PM was associated with the diagnosis of congenital malaria, low neonatal weight, gestational malaria, maternal anemia, previous malaria during pregnancy, and age between 25–43 years. This research is the investigation with the largest number of subjects for studying PM in Colombia, in the ecoepidemiological zone that produces more cases of malaria per year, finding a high prevalence of submicroscopic PM that caused serious maternal (anemia) and neonatal (congenital malaria and low neonatal weight) effects. The results show limitations in the timely diagnosis and treatment, given that the epidemiological surveillance program in Colombia is based on thick blood smear, which generates a substantial underestimation of the magnitude of PM, with serious effects and clinical risks. It is urgent to demand that the health authorities adopt measures such as prenatal control visits as soon as the pregnancy begins, monthly implementation of TBS, and active search for infected pregnant women in their homes and workplaces.

Congenital malaria: Frequency and epidemiology in Colombia, 2009-2020

Congenital Malaria (CM) is an underestimated and under-researched problem in Colombia, despite its severe clinical, epidemiological, economic, and public health consequences. The objective was to determine the general frequency of CM, the specific frequency of CM by diagnostic test and plasmodial species, and identify its associated factors. A retrospective study was carried out using the records of 567 newborns. qPCR and Thick Blood Smear (TBS) were performed. The frequency of infection was determined with a 95% confidence interval. Associated factors were identified by non-parametric tests and odds ratios; the confusion was controlled with a logistic regression model. All cases corresponded to submicroscopic CM (negative with TBS and positive with PCR), and the frequency was 12.2% (95%CI = 9.4–14.9). The detection was statistically higher in the umbilical cord with 16,2% (95%CI = 12.4–19.9) versus peripheral blood of the newborn with 2.2% (95%CI = 0.7–4.9). CM was statistically higher in newborn whose mothers had malaria in the last year, gestational and placental malaria. The median birth weight in newborn infected with CM was lower compared to the one of healthy neonates. Because the control program in Colombia is based on TBS, it must be improved with the inclusion of other tests that allow the detection of submicroscopic CM. In addition, the program has other limitations such as do not have specific actions for pregnant women and have a passive surveillance system. These difficulties do not allow to show the magnitude of CM, its consequences on neonatal and infant health, constituting a serious problem of health injustice.

Urban malaria in sub-Saharan Africa: dynamic of the vectorial system and the entomological inoculation rate

Sub-Saharan Africa is registering one of the highest urban population growth across the world. It is estimated that over 75% of the population in this region will be living in urban settings by 2050. However, it is not known how this rapid urbanization will affect vector populations and disease transmission. The present study summarizes findings from studies conducted in urban settings between the 1970s and 2020 to assess the effects of urbanization on the entomological inoculation rate pattern and anopheline species distribution. Different online databases such as PubMed, ResearchGate, Google Scholar, Google were screened. A total of 90 publications were selected out of 1527. Besides, over 200 additional publications were consulted to collate information on anopheline breeding habitats and species distribution in urban settings. The study confirms high malaria transmission in rural compared to urban settings. The study also suggests that there had been an increase in malaria transmission in most cities after 2003, which could also be associated with an increase in sampling, resources and reporting. Species of the Anopheles gambiae complex were the predominant vectors in most urban settings. Anopheline larvae were reported to have adapted to different aquatic habitats. The study provides updated information on the distribution of the vector population and the dynamic of malaria transmission in urban settings. The study also highlights the need for implementing integrated control strategies in urban settings.