Assessing the Impact of Hematological Changes in Pregnancy on Maternal and Fetal Death: A Narrative Review

Hematological changes during pregnancy encompass a wide range of alterations in blood composition and function, including variations in hemoglobin levels, red blood cell count, and coagulation factors. These changes can be physiological or pathological and may significantly impact maternal and fetal health outcomes. This narrative review examines the relationship between various hematological changes and disorders during pregnancy and their effects on maternal and fetal mortality and morbidity. We explore conditions such as anemia, sickle cell disease, thrombophilia, and blood-borne infections like malaria, as well as the impact of multiple pregnancies on hematological parameters. The review also discusses the effects of COVID-19 on maternal hematology. Key findings include the high prevalence of adverse perinatal outcomes associated with these conditions, including early miscarriages, preterm birth, low birth weight, intrauterine growth restriction, and increased risk of maternal complications. The importance of early screening, diagnosis, and appropriate management of hematological disorders during pregnancy is emphasized. This review highlights the need for a multidisciplinary approach to managing pregnant women with hematological changes to optimize maternal and fetal outcomes.

The readiness of malaria services and uptake of intermittent preventive treatment in pregnancy in six sub-Saharan countries

Background

Malaria infection during pregnancy is associated with an increased risk of maternal death, as well as adverse birth outcomes. Intermittent preventive treatment in pregnancy with sulfadoxine-pyrimethamine (IPTp-SP) is known to improve pregnancy outcomes. However, the coverage of IPTp-SP in antenatal care (ANC) in sub-Saharan Africa remains well below the target. This study aims to estimate to what extent malaria service readiness affects the uptake of IPTp-SP during ANC visits in sub-Saharan African countries.

Methods

This study included 3267 pregnant women attending ANC for the first time and 2797 pregnant women who had attended ANC more than a month ago in six sub-Saharan African countries. The readiness of malaria services at each institution includes four indicators: the presence of IPTp-SP guidelines, SP availability, integration of IPTp-SP service into ANC, and provider training on IPTp-SP. The outcome variable indicates whether a pregnant woman received IPTp-SP at her current ANC visit. A modified Poisson regression model estimated the associations between malaria service readiness and IPTp-SP uptake for women eligible for the first and subsequent doses.

Results

For women eligible for their first dose, visiting an institution with available SP was associated with an increased probability of receiving IPTp-SP (risk ratio (RR) = 1.43; 95% confidence interval (CI) = 1.22 to 1.67, P < 0.001). For women who were eligible for their next dose, the availability of SP (RR = 1.17; 95% CI = 1.04 to 1.32, P = 0.008) and integration of IPTp-SP service into ANC (RR = 1.82; 95% CI = 1.21 to 2.74, P = 0.004) in the institution were associated with increased likelihood of IPTp-SP uptake. Counterfactual predictions indicated that enhanced provider training could boost IPTp-SP uptake in high-uptake countries, while better SP availability and IPTp-SP integration into ANC would significantly impact low-uptake countries.

Conclusions

For better IPTp-SP coverage, strategies should be customised. High uptake countries should focus on provider training, while low uptake ones should ensure IPTp-SP availability and service integration.

IgG and IgM responses to the Plasmodium falciparum asexual stage antigens reflect respectively protection against malaria during pregnancy and infanthood

BACKGROUND

Plasmodium falciparum malaria is a public health issue mostly seen in tropical countries. Until now, there is no effective malaria vaccine against antigens specific to the blood-stage of P. falciparum infection. Because the pathogenesis of malarial disease results from blood-stage infection, it is essential to identify the most promising blood-stage vaccine candidate antigens under natural exposure to malaria infection.

METHODS

A cohort of 400 pregnant women and their infants was implemented in South Benin. An active and passive protocol of malaria surveillance was established during pregnancy and infancy to precisely ascertain malaria infections during the follow-up. Twenty-eight antibody (Ab) responses specific to seven malaria candidate vaccine antigens were repeatedly quantified during pregnancy (3 time points) and infancy (6 time points) in order to study the Ab kinetics and their protective role. Abs were quantified by ELISA and logistic, linear and cox-proportional hazard model were performed to analyse the associations between Ab responses and protection against malaria in mothers and infants, taking into account socio-economic factors and for infants an environmental risk of exposure.

RESULTS

The levels of IgM against MSP1, MSP2 and MSP3 showed an early protective response against the onset of symptomatic malaria infections starting from the 18th month of life, whereas no association was found for IgG responses during infancy. In women, some IgG responses tend to be associated with a protection against malaria risk along pregnancy and at delivery, among them IgG3 against GLURP-R0 and IgG2 against MSP1.

CONCLUSION

The main finding suggests that IgM should be considered in vaccine designs during infanthood. Investigation of the functional role played by IgM in malaria protection needs further attention.

Sub-microscopic Plasmodium falciparum infections and multiple drug resistant single nucleotide polymorphic alleles in pregnant women from southwestern Nigeria

OBJECTIVES

The study evaluated sub-microscopic malaria infections in pregnancy using two malaria Rapid Diagnostic Tests (mRDTs), microscopy and RT-PCR and characterized Plasmodium falciparum dihydrofolate reductase (Pfdhfr) and Plasmodium falciparum dihydropteroate synthase (Pfdhps) drug resistant markers in positive samples.

METHODS

This was a cross sectional survey of 121 pregnant women. Participants were finger pricked, blood drops were collected for rapid diagnosis with P. falciparum histidine-rich protein 11 rapid diagnostic test kit and the ultra-sensitive Alere Pf malaria RDT, Blood smears for microscopy and dried blood spots on Whatman filter paper for molecular analysis were made. Real time PCR targeting the var acidic terminal sequence (varATS) gene of P. falciparum was carried out on a CFX 96 real time system thermocycler (BioRad) in discriminating malaria infections. For each run, laboratory strain of P. falciparum 3D7 and nuclease free water were used as positive and negative controls respectively. Additionally, High resolution melt analyses was employed for genotyping of the different drug resistance markers.

RESULTS

Out of one hundred and twenty-one pregnant women sampled, the SD Bioline™ Malaria Ag P.f HRP2-based malaria rapid diagnostic test (mRDT) detected eight (0.06%) cases, the ultra-sensitive Alere™ malaria Ag P.f rapid diagnostic test mRDT had similar outcome in the same samples as detected by the HRP2-based mRDT. Microscopy and RT-PCR confirmed four out of the eight infections detected by both rapid diagnostic tests as true positive and RT-PCR further detected three false negative samples by the two mRDTs providing a sub-microscopic malaria prevalence of 3.3%. Single nucleotide polymorphism in Pfdhps gene associated with sulphadoxine resistance revealed the presence of S613 mutant genotypes in three of the seven positive isolates and isolates with mixed wild/mutant genotype at codon A613S. Furthermore, four mixed genotypes at the A581G codon were also recorded while the other Pfdhps codons (A436G, A437G and K540E) showed the presence of wild type alleles. In the Pfdhfr gene, there were mutations in 28.6%, 28.6%, and 85.7% at the I51, R59 and N108 codons respectively. Mixed wild and mutant type genotypes were also observed in 28.6% each of the N51I, and C59R codons. For the Pfcrt, two haplotypes CVMNK and CVIET were observed. The SVMNT was altogether absent. Triple mutant CVIET 1(14.3%) and triple mutant + wild genotype CVIET + CVMNK 1(14.3%) were observed. The Pfmdr1 haplotypes were single mutants YYND 1(14.3%); NFND 1(14.3%) and double mutants YFND 4(57.1%); YYDD 1(14.3%).

Plasmodium infections and associated risk factors among parturients in Jawi district, northwest Ethiopia: a cross-sectional study

BACKGROUND

Pregnant women have an increased risk of Plasmodium infections and disease. Malaria in pregnancy is a major public health problem in endemic areas. Assessment of the burden and risk factors of malaria in pregnancy across different malaria transmission settings is required to guide control strategies and for malaria elimination. Thus, the current study is generating such evidence from parturient women in northwest Ethiopia.

METHODS

A cross-sectional study was conducted among 526 pregnant women admitted to the delivery rooms of selected health facilities in Jawi district, northwest Ethiopia, between November 2021 and July 2022. Data on the socio-demographic, clinical, obstetric, and malaria prevention practices of pregnant women were collected using interviewer-administered questionnaires and from women's treatment cards. Malaria was diagnosed by light microscopy, rapid diagnostic test, and multiplex real-time polymerase chain reaction. Risk factors for malaria were evaluated using bivariable and multivariable logistic regression models. A P-value of < 0.05 was considered statistically significant.

RESULTS

Among the examined parturient women, 14.3% (95% CI 11.4-17.5%) had Plasmodium infections. The prevalence of peripheral, placental, and congenital malaria was 12.2% (95% CI 9.5-15.3%), 10.9% (95% CI 8.2-14.1%), and 3.7% (95% CI 2.3-6.1%), respectively. About 90.6% of peripheral and 92% of placental Plasmodium infections were asymptomatic. Plasmodium infection at parturiency was independently predicted by maternal illiteracy (AOR = 2.03, 95% CI 1.11-3.74), primigravidity (AOR = 1.88, 95% CI 1.01-3.49), lack of antenatal care follow-up (AOR = 2.28, 95% CI 1.04-5.03), and history of symptomatic malaria during pregnancy (AOR = 4.2, 95% CI 2.32-7.59). Moreover, the blood group O phenotype was significantly associated with placental malaria among the primiparae.

CONCLUSIONS

Overall, asymptomatic Plasmodium infections were prevalent among parturients in northwest Ethiopia. Maternal illiteracy, primigravidity, lack of antenatal care follow-up, and history of symptomatic malaria during pregnancy were the risk factors for malaria during parturiency. Thus, promotion of a healthy pregnancy through ANC follow-up, strengthening malaria prevention and control practices, and screening of malaria in asymptomatic pregnant women are suggested to reduce its burden in pregnancy.

Impact of Sub-patent Malaria During Pregnancy on Birth-Weight in Odisha, India: Time-to-Event Analysis of Prospective Longitudinal Follow-Up of a Survey

OBJECTIVE

The current study aimed to estimate prevalence of malaria infection, especially sub-patent infection, in pregnant women residing in high malaria-endemic, hard-to-reach pockets of the Indian state of Odisha; and also measure its impact on birth-weight of their new-borns.

METHOD

A time-to-event analysis of prospective longitudinal follow-up study nested within a cross-sectional survey of people residing in high malaria-endemic six districts of Odisha was conducted during July-November 2019. Malaria status in pregnant mothers was categorized as malaria free; sub-patent, and patent. Hazards Ratio (HR) of low birth-weight (LBW; birth-weight < 2500 gms) was estimated in these three categories (n = 308) adjusted for residence (block), gravida, caste, age and gestational age at testing.

RESULTS

50.3% pregnant women had sub-patent malaria infection, 3.9% had patent infection. In fully adjusted model, hazards ratio of LBW was 3.76 (95% CI 1.12, 12.64, p = 0.032) in pregnant women with patent infection and 1.82 (95% CI 0.87, 3.81, p = 0.109) in women with sub-patent infection when compared to no malaria group.

CONCLUSION

The study showed that half of the pregnant women in high-endemic pockets had sub-patent infection which posed deleterious influence on birth-weight of their new-borns. The study thereby flags the prevalence of sub-patent infection as a public health concern, because sub-patent infection in pregnant mothers may persist as a "silent" reservoir, with the potential to derail the malaria control program, especially when the country plans malaria elimination by 2030.

Quality and Integrated Service Delivery: A Cross-Sectional Study of the Effects of Malaria and Antenatal Service Quality on Malaria Intervention Use in Sub-Saharan Africa

Using regionally linked facility and household surveys, we measured the quality of integrated antenatal care and malaria in pregnancy services in Kenya, Namibia, Senegal, and Tanzania. We examined country heterogeneities for the association of integrated antenatal and malaria service quality scores with insecticide-treated bed net (ITN) use in pregnant women and children under-five and intermittent preventive treatment in pregnancy (IPTp-2) uptake. Malaria in pregnancy service quality was low overall. Our findings suggest modest, positive associations between malaria in pregnancy quality and ITN use and IPTp-2 uptake across pooled models and for most studied countries, with evidence of heterogeneity in the strength of associations and relevant confounding factors. Antenatal care quality generally was not associated with the study outcomes, although a positive interaction with malaria in pregnancy quality was present for pooled ITN use models. The improved quality of malaria services delivered during formal antenatal care can help address low coverage and usage rates of preventive malaria interventions in pregnancy and childhood. Study findings may be used to target quality improvement efforts at the sub-national level. Study methods may be adapted to identify low-performing facilities for intervention and adaption to other areas of care, such as HIV/AIDS, child immunizations, and postnatal care.

Homeostasis Maintenance in Plasmodium-Infected Placentas: Is There a Role for Placental Autophagy During Malaria in Pregnancy?

Malaria represents a significant public health burden to populations living in developing countries. The disease takes a relevant toll on pregnant women, who are more prone to developing severe clinical manifestations. Inflammation triggered in response to P. falciparum sequestration inside the placenta leads to physiological and structural changes in the organ, reflecting locally disrupted homeostasis. Altogether, these events have been associated with poor gestational outcomes, such as intrauterine growth restriction and premature delivery, contributing to the parturition of thousands of African children with low birth weight. Despite significant advances in the field, the molecular mechanisms that govern these outcomes are still poorly understood. Herein, we discuss the idea of how some housekeeping molecular mechanisms, such as those related to autophagy, might be intertwined with the outcomes of malaria in pregnancy. We contextualize previous findings suggesting that placental autophagy is dysregulated in P. falciparum-infected pregnant women with complementary research describing the importance of autophagy in healthy pregnancies. Since the functional role of autophagy in pregnancy outcomes is still unclear, we hypothesize that autophagy might be essential for circumventing inflammation-induced stress in the placenta, acting as a cytoprotective mechanism that attempts to ensure local homeostasis and better gestational prognosis in women with malaria in pregnancy.

Multiple Plasmodium falciparum drug resistance polymorphisms identified in a pregnant woman with severe malaria and a concomitant spontaneous abortion in Cross River, Nigeria, West Africa

Background

The development of resistance by Plasmodium falciparum to anti-malarial drugs impedes any benefits of the drug. In addition, absence or delayed availability of current anti-malarial drugs in remote areas has the potential to results to parasite escape and continuous transmission.

Case presentation

The case of a 29-year old pregnant woman from Biase Local Government Area in Cross River State Nigeria presenting with febrile illness and high body temperature of 38.7 °C was reported. She looked pale and vomited twice on arrival at the health facility. Her blood smear on the first day of hospitalization was positive for P. falciparum by RDT, microscopy (21,960 parasite/µl) and real-time PCR, with a PCV of 18%. She was treated with 600 mg intravenous quinine in 500 ml of 5% Dextrose/0.9% Saline 8-hourly for 24 h. On the second day of hospitalization, she complained of weakness, persistent high-grade fever and vaginal bleeding. A bulging amnion from an extended cervix was observed. Following venous blood collection for laboratory investigations, 600 µg of misoprostol was inserted into the posterior fornix of her vagina as part of her obstetric care. Parenteral quinine was discontinued, and she was given full therapeutic regimen of artemether-lumefantrine 80/480 mg tablets to be taken for 3 days beginning from the second day. Her blood samples on the second and third day of hospitalization remained positive for P. falciparum by all three diagnostic methods. Single nucleotide polymorphism (SNP) assay on all three P. falciparum isolates revealed the presence of variants associated with multiple drug resistant markers.

Discussion

Infecting P. falciparum isolates may have been resistant to initial quinine treatment resulting from parasite cross-resistance with other quinoline associated resistant markers such as 86Y and 184 F.

Conclusions

Therefore, the likely transmission of similarly resistant parasites in the study area calls for reinforcement of interventions and adherence to current World Health Organization guidelines in administering only approved drugs to individuals in order to mitigate parasite escape and eventual transmission to other susceptible individuals.

Diagnosis of malaria in pregnancy: accuracy of CareStart™ malaria Pf/PAN against light microscopy among symptomatic pregnant women at the Central Hospital in Yaoundé, Cameroon

Background

The need to start treatment early for pregnant women who present with clinical features of malaria usually conflicts with the need to confirm diagnosis by microscopy (MP) before treatment, due to delays in obtaining results. Parasite sequestration in the placenta is also a problem. Rapid diagnostic tests (RDT), which detect soluble antigens, are a valuable alternative. The objective of this study was to evaluate pretreatment parasite prevalence by microscopy and by RDT and to assess the accuracy of RDT with MP as reference.

Methods

A prospective cross-sectional study was carried out at the obstetrical unit of the Central Hospital in Yaoundé, during the period January-August 2015. Consenting patients with symptoms of suspected malaria in pregnancy were recruited and a blood sample taken for MP and RDT before treatment was started. The estimates of diagnostic performance (with 95% confidence interval) were calculated in OpenEpi online software using the Wilson’s score. The agreement, as reflected by the Cohen’s kappa, was calculated and interpreted using known intervals.

Results

The results showed that, out of the 104 patients recruited, 69.2% (95%CI: 59.1–77.5) were MP positive while 77.94% (95%CI: 63.1–80.9) were RDT positive. The sensitivity of the malaria RDT was 91.67% (95%CI: 83.69–96.77) while the specificity was 53.13% (95%CI: 31.39–65.57). The diagnostic accuracy of the RDT with MP as reference was 79.81% (95%CI: 70.0–86.1). All cases were due to Plasmodium falciparum. A Cohen’s kappa of 0.45 (95%CI: 0.26–0.64) was obtained, consistent with a moderate agreement between the tests.

Conclusions

The diagnostic accuracy of the CareStart™ malaria Pf/PAN compared to microscopy was high, but not as desirable, with a false negative RDT at very high parasitaemia. In tertiary facilities, RDTs appear to provide a better diagnostic solution compared to microscopy. However, future studies with larger sample sizes should make this observation more generalizable; as missing a case could have serious consequences on pregnancy outcome.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12936-022-04109-6.

Schistosomiasis, soil transmitted helminthiasis, and malaria co-infections among women of reproductive age in rural communities of Kwale County, coastal Kenya

BACKGROUND

Schistosoma haematobium, soil transmitted helminthes (STH), and malaria lead to a double burden in pregnancy that eventually leads to poor immunity, increased susceptibility to other infections, and poor pregnancy outcomes. Many studies have been carried out on pre-school and school aged children but very little has been done among the at risk adult population including women of reproductive age (WRA). Our current study sought to establish the risk factors and burden of co-infection with S. haematobium, STH, and Plasmodium sp. among WRA in Kwale County, Coastal Kenya.

METHODS

A total of 534 WRA between the ages of 15-50 were enrolled in this cross-sectional study from four villages; Bilashaka and Mwaluphamba in Matuga sub-County, and Mwachinga and Dumbule in Kinango sub-County. Socio-demographic information was collected using a pre-tested standardized questionnaire. Parasitological examination was done using urine filtration method for Schistosoma haematobium, Kato Katz for STH (Ascaris lumbricoides, Hookworm, Trichuris trichiura), and standard slide microscopy for Plasmodium sp. Statistical analyses were carried out using STATA version 15.1.

RESULTS

The overall prevalence of S. haematobium was 3.8% (95% CI: 2.6-5.4) while that for malaria was 4.9% (95% CI: 2.0-11.7). The prevalence of STH was 5.6% (95% CI: 2.8-11.3) with overall prevalence of 5.3% (95% CI: 2.5-10.9) for hookworm and 0.6% (95% CI: 0.2-1.9) for T. trichiura. The occurrence of co-infection was low and was recorded between S. haematobium and P. falciparum (0.6%), followed by S. haematobium and STH (0.4%). Among pregnant women, 2.6% had co-infection with S. haematobium and P. falciparum. Only 1.3% had co-infection with S. haematobium and hookworm or T. trichiura. Among non-pregnant women, co-infection with S. haematobium and P. falciparum was 0.2%. Similarly, co-infection with S. haematobium and hookworm or T. trichiura was 0.2%. Bed net ownership and usage among pregnant women was 87.8 and 96.6%, respectively. 66.3% of the women reported using improved water sources for drinking while 78.1% reported using improved sanitation facilities.

CONCLUSION

The use of improved WASH activities might have contributed to the low prevalence of STHs and S. haematobium infections. Further, bed net ownership and usage might have resulted in the low prevalence of Plasmodium sp. infections observed.

Blackwater Fever in Pregnancy With Severe Falciparum Malaria: A Case of Imported Malaria From Nigeria to the United Kingdom During the COVID-19 Pandemic

We present the case of imported malaria in pregnancy to the United Kingdom (UK) from Nigeria, where a 28-year-old primigravida presented to our maternity assessment unit (MAU) with complaints of pyrexia, rigors and passing dark coloured urine. She gave a travel history of recent migration from Nigeria 10 days before presenting to our emergency department. She initially became unwell five days after her arrival with general malaise and myalgia. On day six, she developed lower abdominal pain and observed that her urine was dark in colour. This prompted her to contact her general practitioner (GP). Treatment for a urinary tract infection was initiated by the GP after a phone consultation in keeping with COVID-19 contingency guidance, and the patient was prescribed antibiotics for three days. She presented to the emergency department two days after completing the course of antibiotics where she complained of worsening pelvic pain, reduced foetal movements and passing black urine. She was treated as suspected COVID-19 and red flag sepsis. Obstetric review led to investigation and diagnosis of severe malaria in pregnancy, which was accompanied by blackwater fever (BWF). The patient recovered after three doses of artesunate. An ultrasound scan of the foetus revealed a congenital cardiac anomaly, which had not been detected in an earlier scan. There was no evidence of congenital malaria in the neonate after delivery. There are several novel aspects in this case as maternal mortality in severe Plasmodium falciparum can be significantly high. Those who survive the disease in pregnancy are also known to develop several complications such as intrauterine death and preterm labour. There was also the component of blackwater fever, which is a rare event associated with severe malaria, and it also has a mortality rate. Significant in her medical history was a diagnosis of the sickle cell trait, and we postulate that this feature gave an added protection from the complications of severe malaria in pregnancy as well as blackwater fever.

Malaria and curable sexually transmitted and reproductive tract coinfection among pregnant women in rural Burkina Faso

Background

Malaria and sexually transmitted/reproductive tract infections (STI/RTI) are leading and preventable causes of low birthweight in sub-Saharan Africa. Reducing their impact on pregnancy outcomes requires efficient interventions that can be easily integrated into the antenatal care package. The paucity of data on malaria and STI/RTI coinfection, however, limits efforts to control these infections. This study aimed to determine the prevalence and associated factors of malaria and STI/RTI coinfection among pregnant women in rural Burkina Faso.

Methods

A cross-sectional survey was conducted among 402 pregnant women attending antenatal clinics at the Yako health district. Sociodemographic and behavioral data were collected, and pregnant women were tested for peripheral malaria by microscopy. Hemoglobin levels were also measured by spectrophotometry and curable bacterial STI/RTI were tested on cervico-vaginal swabs using rapid diagnostic test for chlamydia and syphilis, and Gram staining for bacterial vaginosis. A multivariate logistic regression model was used to assess the association of malaria and STI/RTI coinfection with the characteristics of included pregnant women.

Results

The prevalence of malaria and at least one STI/RTI coinfection was 12.9% (95% confidence interval, CI: [9.8–16.7]), malaria and bacterial vaginosis coinfection was 12.2% (95% CI: [9.3–15.9]), malaria and chlamydial coinfection was 1.6% (95% CI: [0.6–3.8]). No coinfection was reported for malaria and syphilis. The individual prevalence was 17.2%, 7.2%, 0.6%, 67.7% and 73.3%, respectively, for malaria infection, chlamydia, syphilis, bacterial vaginosis and STI/RTI combination. Only 10% of coinfections were symptomatic, and thus, 90% of women with coinfection would have been missed by the symptoms-based diagnostic approach. In the multivariate analysis, the first pregnancy (aOR = 2.4 [95% CI: 1.2–4.7]) was the only factor significantly associated with malaria and STI/RTI coinfection. Clinical symptoms were not associated with malaria and STI/RTI coinfection.

Conclusion

The prevalence of malaria and curable STI/RTI coinfection was high among pregnant women. The poor performance of the clinical symptoms to predict coinfection suggests that alternative interventions are needed.

Myeloperoxidase and Other Markers of Neutrophil Activation Associate With Malaria and Malaria/HIV Coinfection in the Human Placenta

Introduction

Placental malaria (PM) is characterized by accumulation of inflammatory leukocytes in the placenta, leading to poor pregnancy outcomes. Understanding of the underlying mechanisms remains incomplete. Neutrophils respond to malaria parasites by phagocytosis, generation of oxidants, and externalization of Neutrophil Extracellular Traps (NETs). NETs drive inflammation in malaria but evidence of NETosis in PM has not been reported. Neutrophil activity in the placenta has not been directly investigated in the context of PM and PM/HIV-co-infection.

Methods

Using peripheral and placental plasma samples and placental tissue collected from Kenyan women at risk for malaria and HIV infections, we assessed granulocyte levels across all gravidities and markers of neutrophil activation, including NET formation, in primi- and secundigravid women, by ELISA, western blot, immunohistochemistry and immunofluorescence.

Results

Reduced peripheral blood granulocyte numbers are observed with PM and PM/HIV co-infection in association with increasing parasite density and placental leukocyte hemozoin accumulation. In contrast, placental granulocyte levels are unchanged across infection groups, resulting in enhanced placental: peripheral count ratios with PM. Within individuals, PM- women have reduced granulocyte counts in placental relative to peripheral blood; in contrast, PM stabilizes these relative counts, with HIV coinfection tending to elevate placental counts relative to the periphery. In placental blood, indicators of neutrophil activation, myeloperoxidase (MPO) and proteinase 3 (PRTN3), are significantly elevated with PM and, more profoundly, with PM/HIV co-infection, in association with placental parasite density and hemozoin-bearing leukocyte accumulation. Another neutrophil marker, matrix metalloproteinase (MMP9), together with MPO and PRTN3, is elevated with self-reported fever. None of these factors, including the neutrophil chemoattractant, CXCL8, differs in relation to infant birth weight or gestational age. CXCL8 and MPO levels in the peripheral blood do not differ with infection status nor associate with birth outcomes. Indicators of NETosis in the placental plasma do not vary with infection, and while structures consistent with NETs are observed in placental tissue, the results do not support an association with PM.

Conclusions

Granulocyte levels are differentially regulated in the peripheral and placental blood in the presence and absence of PM. PM, both with and without pre-existing HIV infection, enhances neutrophil activation in the placenta. The impact of local neutrophil activation on placental function and maternal and fetal health remains unclear. Additional investigations exploring how neutrophil activation and NETosis participate in the pathogenesis of malaria in pregnant women are needed.

Assessment of malaria infection among pregnant women and children below five years of age attending rural health facilities of Kenya: A cross-sectional survey in two counties of Kenya

Background

In Kenya, health service delivery and access to health care remains a challenge for vulnerable populations, particularly pregnant women and children below five years. The aim of this study, therefore, was to determine the positivity rate of Plasmodium falciparum parasites in pregnant women and children below five years of age seeking healthcare services at the rural health facilities of Kwale and Siaya counties as well as their access and uptake of malaria control integrated services, like antenatal care (ANC), offered in those facilities.

Methods

Cluster random sampling method was used to select pregnant women and children below five years receiving maternal and child health services using two cross-sectional surveys conducted in eleven rural health facilities in two malaria endemic counties in western and coastal regions of Kenya. Each consenting participant provided single blood sample for determining malaria parasitaemia using microscopy and polymerase chain reaction (PCR) techniques.

Results

Using PCR technique, the overall malaria positivity rate was 27.9% (95%CI: 20.9–37.2), and was 34.1% (95%CI: 27.1–42.9) and 22.0% (95%CI: 13.3–36.3) in children below five years and pregnant women respectively. Additionally, using microscopy, the overall positivity rate was 39.0% (95%CI: 29.5–51.6), and was 50.4% (95%CI: 39.4–64.5) and 30.6% (95%CI: 22.4–41.7) in children below five years and pregnant women respectively. Siaya County in western Kenya showed higher malaria positivity rates for both children (36.4% and 54.9%) and pregnant women (27.8% and 38.5%) using both PCR and microscopy diagnosis techniques respectively, compared to Kwale County that showed positivity rates of 27.2% and 37.9% for children and 5.2% and 8.6% for pregnant women similarly using both PCR and microscopy techniques respectively. Pregnant women presenting themselves for their first ANC visit were up to five times at risk of malaria infection, (adjusted odds ratio = 5.40, 95%CI: 0.96–30.50, p = 0.046).

Conclusion

Despite evidence of ANC attendance and administration of intermittent preventive treatment with sulfadoxine-pyrimethamine (IPTp-SP) dosage during these visits, malaria positivity rate was still high among pregnant women and children below five years in these two rural counties. These findings are important to the Kenyan National Malaria Control Programme and will help contribute to improvement of policies on integration of malaria control approaches in rural health facilities.

Do Antibodies to Malaria Surface Antigens Play a Role in Protecting Mothers From Maternal Anemia?

Pregnancy-associated malaria (PAM) caused by Plasmodium falciparum can result in detrimental outcomes for both mother and infant, including low infant birth weight, preterm birth, maternal anemia, spontaneous abortion, and maternal and/or infant mortality. Maternal anemia is a particularly complex outcome, as the body must both maintain erythropoiesis and tolerance of the growing fetus, while directing a Th1 response against the parasite. Underlying the pathogenesis of PAM is the expression of variant surface antigens (VSA_PAM) on the surface of infected red blood cells (iRBC) that mediate sequestration of the iRBC in the placenta. Naturally acquired antibodies to VSA_PAM can block sequestration and activate opsonic phagocytosis, both associated with improved pregnancy outcomes. In this review, we ask whether VSA_PAM antibodies can also protect mothers against malarial anemia. Studies were identified where VSA_PAM antibody titres and/or function were associated with higher maternal hemoglobin levels, thus supporting additional protective mechanisms for these antibodies against PAM. Yet these associations were not widely observed, and many studies reported no association between protection from maternal anemia and VSA_PAM antibodies. We discuss the epidemiological, biological and technical factors that may explain some of the variability among these studies. We appraise the current evidence of these complex interactions between PAM-specific immunity and maternal anemia, propose potential mechanisms, and discuss knowledge gaps.

Occurrence of septuple and elevated Pfdhfr-Pfdhps quintuple mutations in a general population threatens the use of sulfadoxine-pyrimethamine for malaria prevention during pregnancy in eastern-coast of Tanzania

Background

Plasmodium falciparum dihydrofolate reductase (Pfdhfr) and dihydropteroate synthetase (Pfdhps) mutations compromise the effectiveness of sulfadoxine-pyrimethamine (SP) for treatment of uncomplicated malaria, and are likely to impair the efficiency of intermittent preventive treatment during pregnancy (IPTp). This study was conducted to determine the level of Pfdhfr-Pfdhps mutations, a decade since SP was limited for IPTp use in pregnant women in Tanzania.

Methods

P. falciparum genomic DNA was extracted from dried blood spots prepared from a finger prick. Extracted DNA were sequenced using a single MiSeq lane by combining all PCR products. Genotyping of Pfdhfr and Pfdhps mutations were done using bcftools whereas custom scripts were used to filter and translate genotypes into SP resistance haplotypes.

Results

The Pfdhfr was analyzed from 445 samples, the wild type (WT) Pfdhfr haplotype NCSI was detected in 6 (1.3%) samples. Triple PfdhfrIRNI (mutations are bolded and underlined) haplotype was dominant, contributing to 84% (number [n] = 374) of haplotypes while 446 samples were studied for Pfdhps, WT for Pfdhps (SAKAA) was found in 6.7% (n = 30) in samples. Double Pfdhps haplotype (SGEAA) accounted for 83% of all mutations at Pfdhps gene. Of 447 Pfdhfr-Pfdhps combined genotypes, only 0.9% (n = 4) samples contained WT gene (SAKAA-NCSI). Quintuple (five) mutations, SGEAA-IRNI accounted for 71.4% (n = 319) whereas 0.2% (n = 1) had septuple (seven) mutations (AGKGS-IRNI). The overall prevalence of Pfdhfr K540E was 90.4% (n = 396) while Pfdhps A581G was 1.1% (n = 5).

Conclusions

This study found high prevalence of Pfdhfr–Pfdhps quintuple and presence of septuple mutations. Mutations at Pfdhfr K540E and Pfdhps A581G, major predictors for IPTp-SP failure were within the recommended WHO range. Abandonment of IPTp-SP is recommended in settings where the Pfdhfr K540E prevalence is > 95% and Pfdhps A581G is > 10% as SP is likely to be not effective. Nonetheless, saturation in Pfdhfr and Pfdhps haplotypes is alarming, a search for alternative antimalarial drug for IPTp in the study area is recommended.

Pregnancy and CYP3A5 Genotype Affect Day 7 Plasma Lumefantrine Concentrations

Pregnancy and pharmacogenetics variation alter drug disposition and treatment outcome. The objective of this study was to investigate the effect of pregnancy and pharmacogenetics variation on day 7 lumefantrine (LF) plasma concentration and therapeutic responses in malaria-infected women treated with artemether-lumefantrine (ALu) in Tanzania. A total of 277 (205 pregnant and 72 nonpregnant) women with uncomplicated Plasmodium falciparum malaria were enrolled. Patients were treated with ALu and followed up for 28 days. CYP3A4, CYP3A5, and ABCB1 genotyping were done. Day 7 plasma LF concentration and the polymerase chain reaction (PCR) - corrected adequate clinical and parasitological response (ACPR) at day 28 were determined. The mean day 7 plasma LF concentrations were significantly lower in pregnant women than nonpregnant women [geometric mean ratio = 1.40; 95% confidence interval (CI) of geometric mean ratio (1.119-1.1745), P < 0.003]. Pregnancy, low body weight, and CYP3A5*1/*1 genotype were significantly associated with low day 7 LF plasma concentration (P < 0.01). PCR-corrected ACPR was 93% (95% CI = 89.4-96.6) in pregnant women and 95.7% (95% CI = 90.7-100) in nonpregnant women. Patients with lower day 7 LF concentration had a high risk of treatment failure (mean 652 vs. 232 ng/ml, P < 0.001). In conclusion, pregnancy, low body weight, and CYP3A5*1 allele are significant predictors of low day 7 LF plasma exposure. In turn, lower day 7 LF concentration is associated with a higher risk of recrudescence. SIGNIFICANCE STATEMENT: This study reports a number of factors contributing to the lower day 7 lumefantrine (LF) concentration in women, which includes pregnancy, body weight, and CYP3A5*1/*1 genotype. It also shows that day 7 LF concentration is a main predictor of malaria treatment. These findings highlight the need to look into artemether-LF dosage adjustment in pregnant women so as to be able to maintain adequate drug concentration, which is required to reduce treatment failure rates in pregnant women.

Uptake of intermittent preventive treatment for malaria during pregnancy with Sulphadoxine-Pyrimethamine in Malawi after adoption of updated World Health Organization policy: an analysis of demographic and health survey 2015-2016

Background

Malawi adopted the 2012 updated Word Health Organization (WHO) Intermittent preventive treatment of malaria during pregnancy with sulphadoxine-pyrimethamine (IPTp-SP) policy in 2013. This study aimed to estimate the proportion of and identify factors associated with the uptake of at least three doses of IPTp with SP among pregnant women in Malawi after the adoption and operationalisation of updated WHO IPTp-SP policy.

Methods

The 2015–16 Malawi Demographic and Health Survey dataset was analysed. Of 1219 women aged 15–49 years who had live births and the children were born after the date of July 2015, 1069 women were included in the analysis. Bivariate and multiple logistic regression were used in data analysis. The statistical analysis took into account a complex survey sample design.

Results

Of the 1069 women, 447 (42, 95% CI: 38.1–45.6) received three (optimal) or more doses of IPTp-SP. Less than half (47%) managed to attend at least four antenatal care (ANC) clinics. Only 52% received optimal SP doses among those who made at least four ANC visits. Only the number of ANC visits was associated with the optimal uptake of SP. Women who attended ANC three times only and those who visited ANC once or twice only were less likely to receive at least three doses of SP than those who managed to attend ANC at least four times during pregnancy (AOR = 0.71, 95% CI 0.49–1.02) and (AOR = 0.12, 95% CI 0.06–0.21) respectively.

Conclusions

To achieve effective malaria prevention in pregnancy, IPTP-SP is used alongside other interventions. However, there is low uptake of optimal SP doses in Malawi, and this seems to be associated with the number of ANC visits. Moreover, there is limited effectiveness of an increased number of ANC visits on the uptake of optimal SP doses. Further research should be done to explore health systems factors affecting uptake of optimal IPTp with SP doses during pregnancy.

In utero priming of highly functional effector T cell responses to human malaria

Malaria remains a significant cause of morbidity and mortality worldwide, particularly in infants and children. Some studies have reported that exposure to malaria antigens in utero results in the development of tolerance, which could contribute to poor immunity to malaria in early life. However, the effector T cell response to pathogen-derived antigens encountered in utero, including malaria, has not been well characterized. Here, we assessed the frequency, phenotype, and function of cord blood T cells from Ugandan infants born to mothers with and without placental malaria. We found that infants born to mothers with active placental malaria had elevated frequencies of proliferating effector memory fetal CD4⁺ T cells and higher frequencies of CD4⁺ and CD8⁺ T cells that produced inflammatory cytokines. Fetal CD4⁺ and CD8⁺ T cells from placental malaria-exposed infants exhibited greater in vitro proliferation to malaria antigens. Malaria-specific CD4⁺ T cell proliferation correlated with prospective protection from malaria during childhood. These data demonstrate that placental malaria is associated with the generation of proinflammatory malaria-responsive fetal T cells. These findings add to our current understanding of fetal immunity and indicate that a functional and protective pathogen-specific T cell response can be generated in utero.

The immune response to malaria in utero

Malaria causes tremendous early childhood morbidity and mortality, providing an urgent impetus for the development of a vaccine that is effective in neonates. However, the infant immune response to malaria may be influenced by events that occur well before birth. Placental malaria infection complicates one quarter of all pregnancies in Africa and frequently results in exposure of the fetus to malaria antigens in utero, while the immune system is still developing. Some data suggest that in utero exposure to malaria may induce immunologic tolerance that interferes with the development of protective immunity during childhood. More recently, however, a growing body of evidence suggests that fetal malaria exposure can prime highly functional malaria-specific T- and B-cells, which may contribute to postnatal protection from malaria. In utero exposure to malaria also impacts the activation and maturation of fetal antigen presenting cells and innate lymphocytes, which could have implications for global immunity in the infant. Here, we review recent advances in our understanding of how various components of the fetal immune system are altered by in utero exposure to malaria, discuss factors that may tilt the critical balance between tolerance and adaptive immunity, and consider the implications of these findings for malaria prevention strategies.

Molecular Principles of Intrauterine Growth Restriction in Plasmodium Falciparum Infection

Malaria in pregnancy still constitutes a particular medical challenge in tropical and subtropical regions. Of the five Plasmodium species that are pathogenic to humans, infection with Plasmodium falciparum leads to fulminant progression of the disease with massive impact on pregnancy. Severe anemia of the mother, miscarriage, stillbirth, preterm delivery and intrauterine growth restriction (IUGR) with reduced birth weight are frequent complications that lead to more than 10,000 maternal and 200,000 perinatal deaths annually in sub-Saharan Africa alone. P. falciparum can adhere to the placenta via the expression of the surface antigen VAR2CSA, which leads to sequestration of infected erythrocytes in the intervillous space. This process induces a placental inflammation with involvement of immune cells and humoral factors. Especially, monocytes get activated and change the release of soluble mediators, including a variety of cytokines. This proinflammatory environment contributes to disorders of angiogenesis, blood flow, autophagy, and nutrient transport in the placenta and erythropoiesis. Collectively, they impair placental functions and, consequently, fetal growth. The discovery that women in endemic regions develop a certain immunity against VAR2CSA-expressing parasites with increasing number of pregnancies has redefined the understanding of malaria in pregnancy and offers strategies for the development of vaccines. The following review gives an overview of molecular processes in P. falciparum infection in pregnancy which may be involved in the development of IUGR.

Mass media exposure and its impact on malaria prevention behaviour among adult women in sub-Saharan Africa: results from malaria indicator surveys

BACKGROUND

Mass media exposure plays a pivotal role in health communication and adoption of a healthy lifestyle. In this study, we aimed to measure the prevalence of malaria prevention behaviour among adult women in eight malaria-endemic countries in sub-Saharan Africa (SSA), and assess the influence of mass media exposure in the adoption of those behaviours.

METHODS

For this study, we collected cross-sectional data on 46,822 women aged between 15 and 49 years from the Malaria Indicator Surveys (MIS) conducted in Burkina Faso, Ghana, Mali, Malawi, Kenya, Nigeria, Sierra Leone and Uganda. As the outcome variable, malaria prevention behaviour was proxied by the use of insecticide treated nets (ITNs) and uptake of antimalarial drugs in last pregnancy.

RESULTS

The overall prevalence of sleeping under ITN and that of taking antimalarial drug during the last pregnancy was respectively 67.9% (95%CI = 66.6-69.2) and 72.8% (95%CI = 71.3-74.2). However, there were disparities in the prevalence of using ITN and antimalarial drug use across the study countries. In the multivariable regression analysis, not receiving malaria related information from radio, poster/billboards, community events, and health workers were found to be significantly associated with reduction in the odds of using ITN the previous night. For the use of antimalarial drugs during last pregnancy, the odds were 23% [OR = 0.773, 95%CI = 0.625-0.956] lower for those who did not receive malaria information on radio compared with those who received.

CONCLUSIONS

These findings indicate a potentially important role of malaria information received through mass media on utilisation of ITN among women in SSA. More research is needed to explore the factors that limit the accessibility to malaria information through mass media.

Uptake of intermittent preventive treatment for malaria during pregnancy with Sulphadoxine-Pyrimethamine (IPTp-SP) among postpartum women in Zomba District, Malawi: a cross-sectional study

BACKGROUND

Malaria in pregnancy causes adverse birth outcomes. Intermittent preventive treatment of malaria during pregnancy with sulphadoxine-pyrimethamine (IPTp-SP) is recommended as a chemoprevention therapy. Zomba district IPTp uptake falls far below the national average. The study was conducted to assess determinants of IPTp-SP uptake during pregnancy among postpartum women in Zomba district after adoption of new IPTp-SP policy in 2014.

METHODS

This was a cross-sectional survey. Two public health facilities (HFs) were randomly selected from urban and rural areas in Zomba district. Study participants were postpartum women selected by using exit poll method from HFs. A total of 463 postpartum women were interviewed using structured questionnaire. Bivariate and multiple logistic regression was used in data analysis.

RESULTS

Out of all the enrolled participants (n = 463), 92% women had complete information for analysis. Of these, (n = 426) women, 127 (29.8%, 95% CI: 25.6%-34.3%) received three or more doses of SP, 299 (70.2%, 95% CI: 65.7%-74.4%) received two or less doses. Women receiving SP from rural HF were less likely to get at least three doses of SP than urban women, (AOR = 0.31, 95% CI 0.13-0.70); Others less likely were those with three or few antenatal care (ANC) visits versus four or more visits (AOR = 0.29, 95% CI 0.18-0.48); not taking SP under direct observation therapy (DOT) (AOR = 0.18, 95% CI (0.05-0.63).

CONCLUSIONS

There is low utilisation of at least three doses of SP in this population and this seems to be associated with the number of ANC visits and use of DOTs. These determinants may therefore be important in shaping interventions aimed at increasing the uptake of IPTp in this district. In addition, the rural urban differential suggests the need for further research to understand the barriers and enablers of uptake in each context in order to improve the health of the community.

Use of Intermittent Preventive Treatment among Pregnant Women in Sub-Saharan Africa: Evidence from Malaria Indicator Surveys

Uptake of intermittent preventive therapy in pregnancy (IPTp) with sulfadoxine-pyrimethamine (IPTp-SP) is a clinically-proven method to prevent the adverse outcomes of malaria in pregnancy (MiP) for the mother, her foetus, and the neonates. The majority of countries in sub-Saharan Africa have introduced IPTp policies for pregnant women during the past decade. Nonetheless, progress towards improving IPTp coverage remains dismal, with widespread regional and socioeconomic disparities in the utilisation of this highly cost-effective service. In the present study, our main objective was to measure the prevalence of IPTp uptake in selected malaria-endemic countries in sub-Saharan Africa, and to investigate the patterns of IPTp uptake among different educational and wealth categories adjusted for relevant sociodemographic factors. For this study, cross-sectional data on 18,603 women aged between 15 and 49 years were collected from the Malaria Indicator Surveys (MIS) conducted in Burkina Faso, Ghana, Mali, Malawi, Kenya, Nigeria, Sierra Leone, and Uganda. The outcome variable was taking three doses of IPTp-SP in the last pregnancy, defined as adequate by the WHO. According to the analysis, the overall prevalence of taking three doses of IPTp-SP in the latest pregnancy was 29.5% (95% CI = 28.2–30.5), with the prevalence being highest for Ghana (60%, 95% CI = 57.1–62.8), followed by Kenya (37%, 95% CI = 35.3–39.2) and Sierra Leone (31%, 95% CI = 29.2–33.4). Women from non-poor households (richer—20.7%, middle—21.2%, richest—18.1%) had a slightly higher proportion of taking three doses of IPTp-SP compared with those from poorest (19.0%) and poorer (21.1%) households. Regression analysis revealed an inverse association between uptake of IPTp-SP and educational level. With regard to wealth status, compared with women living in the richest households, those in the poorest, poorer, middle, and richer households had significantly higher odds of not taking at least three doses of IPTp-SP during their last pregnancy. The present study concludes that the prevalence of IPTp-SP is still alarmingly low and is significantly associated with individual education and household wealth gradient. Apart from the key finding of socioeconomic disparities within countries, were the between-country variations that should be regarded as a marker of inadequate policy and healthcare system performance in the respective countries. More in-depth and longitudinal studies are required to understand the barriers to, and preferences of, using IPTp-SP among women from different socioeconomic backgrounds.

Spatial and temporal dynamics of malaria in Madagascar

BACKGROUND

Malaria is one of the primary health concerns in Madagascar. Based on the duration and intensity of transmission, Madagascar is divided into five epidemiological strata that range from low to mesoendemic transmission. In this study, the spatial and temporal dynamics of malaria within each epidemiological zone were studied.

METHODS

The number of reported cases of uncomplicated malaria from 112 health districts between 2010 and 2014 were compiled and analysed. First, a Standardized Incidence Ratio was calculated to detect districts with anomalous incidence compared to the stratum-level incidence. Building on this, spatial and temporal malaria clusters were identified throughout the country and their variability across zones and over time was analysed.

RESULTS

The incidence of malaria increased from 2010 to 2014 within each stratum. A basic analysis showed that districts with more than 50 cases per 1000 inhabitants are mainly located in two strata: East and West. Lower incidence values were found in the Highlands and Fringe zones. The standardization method revealed that the number of districts with a higher than expected numbers of cases increased through time and expanded into the Highlands and Fringe zones. The cluster analysis showed that for the endemic coastal region, clusters of districts migrated southward and the incidence of malaria was the highest between January and July with some variation within strata.

CONCLUSION

This study identified critical districts with low incidence that shifted to high incidence and district that were consistent clusters across each year. The current study provided a detailed description of changes in malaria epidemiology and can aid the national malaria programme to reduce and prevent the expansion of the disease by targeting the appropriate areas.

Risk factors and pregnancy outcomes associated with placental malaria in a prospective cohort of Papua New Guinean women

Background

Plasmodium falciparum in pregnancy results in substantial poor health outcomes for both mother and child, particularly in young, primigravid mothers who are at greatest risk of placental malaria (PM) infection. Complications of PM include maternal anaemia, low birth weight and preterm delivery, which contribute to maternal and infant morbidity and mortality in coastal Papua New Guinea (PNG).

Methods

Placental biopsies were examined from 1451 pregnant women who were enrolled in a malaria prevention study at 14–26 weeks gestation. Clinical and demographic information were collected at first antenatal clinic visits and women were followed until delivery. Placental biopsies were collected and examined for PM using histology. The presence of infected erythrocytes and/or the malaria pigment in monocytes or fibrin was used to determine the type of placental infection.

Results

Of 1451 placentas examined, PM infection was detected in 269 (18.5%), of which 54 (3.7%) were acute, 55 (3.8%) chronic, and 160 (11.0%) were past infections. Risk factors for PM included residing in rural areas (adjusted odds ratio (AOR) 3.65, 95% CI 1.76–7.51; p ≤ 0.001), being primigravid (AOR 2.45, 95% CI 1.26–4.77; p = 0.008) and having symptomatic malaria during pregnancy (AOR 2.05, 95% CI 1.16–3.62; p = 0.013). After adjustment for covariates, compared to uninfected women, acute infections (AOR 1.97, 95% CI 0.98–3.95; p = 0.056) were associated with low birth weight babies, whereas chronic infections were associated with preterm delivery (AOR 3.92, 95% CI 1.64–9.38; p = 0.002) and anaemia (AOR 2.22, 95% CI 1.02–4.84; p = 0.045).

Conclusions

Among pregnant PNG women receiving at least one dose of intermittent preventive treatment in pregnancy and using insecticide-treated bed nets, active PM infections were associated with adverse outcomes. Improved malaria prevention is required to optimize pregnancy outcomes.

Placental Malaria: A New Insight into the Pathophysiology

Malaria in pregnancy poses a great health risk to mother and her fetus and results into complications, such as abortion, still birth, intra uterine growth retardation, and low birth weight. The heavy infiltration of Plasmodium falciparum-infected RBCs in the intervillous spaces of placenta seems to be responsible for all the complications observed. Infected RBCs in the placenta cause an inflammatory environment with increase in inflammatory cells and cytokines which is deleterious to the placenta. Increased inflammatory responses in the infected placenta result into oxidative stress that in turn causes oxidative stress-induced placental cell death. Moreover, heat shock proteins that are produced in high concentration in stressed cells to combat the stress have been reported in fewer concentrations in malaria-infected placenta. Pathologies associated with placental malaria seems to be the effect of a change in immune status from antibody-mediated immune response to cell-mediated immune response resulting into excess inflammation, oxidative stress, apoptosis, and decreased heat shock protein expression. However, we also need to study other aspects of pathologies so that better drugs can be designed with new molecular targets.

Infectious disease research and the gender gap

Historically, women have been less likely to be supported through higher degree training programmes, and they continue to hold more junior positions in science. This paper reviews the current gender research and gender capacity-building efforts led by the UNICEF/UNDP/World Bank/WHO Special Programme for Research and Training in Tropical Diseases (TDR). Created more than 40 years ago as the only United Nations-based Special Programme dedicated to research and research capacity building on infectious diseases, TDR has a longstanding track record both in supporting research into gender-specific questions and in research capacity strengthening among women scientists. We provide an overview of these approaches, then describe a recent pilot programme on Women in Science, designed to understand and remedy the gender gaps in health research. The programme focused on Africa, but it is hoped that the replication of such schemes in TDR and other international funding agencies will lead to more attention being given to women in infectious diseases research in other continents.

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Impact of In Utero Exposure to Malaria on Fetal T Cell Immunity

Pregnancy-associated malaria, including placental malaria, causes significant morbidity and mortality worldwide. Recently, it has been suggested that in utero exposure of the fetus to malaria antigens may negatively impact the developing immune system and result in tolerance to malaria. Here, we review our current knowledge of fetal immunity to malaria, focusing on the dynamic interactions between maternal malaria infection, placental development, and the fetal immune system. A better understanding of the long-term impact of in utero malaria exposure on the development of natural immunity to malaria, immune responses to other childhood pathogens, and vaccine immunogenicity is urgently needed. This may guide the implementation of novel chemoprevention strategies during pregnancy and facilitate the push toward malaria vaccines.

Absence of Association Between Sickle Trait Hemoglobin and Placental Malaria Outcomes

Heterozygous hemoglobin S (HbAS), or sickle trait, protects children from life-threatening falciparum malaria, potentially by attenuating binding of Plasmodium-infected red blood cells (iRBCs) to extracellular ligands. Such binding is central to the pathogenesis of placental malaria (PM). We hypothesized that HbAS would be associated with reduced risks of PM and low birth weight (LBW). We tested this hypothesis in 850 delivering women in southern Malawi. Parasites were detected by polymerase chain reaction in placental and peripheral blood, and placentae were scored histologically for PM. The prevalence of HbAS was 3.7%, and 11.2% of infants were LBW (< 2,500 g). The prevalence of Plasmodium falciparum was 12.7% in placental and 8.5% in peripheral blood; 24.4% of placentae demonstrated histological evidence of P. falciparum HbAS was not associated with reduced prevalence of P. falciparum in placental (odds ratio [OR]: 1.27, 95% confidence interval [CI]: 0.50-3.23, P = 0.61) or peripheral blood (OR: 2.53, 95% CI: 1.08-2.54, P = 0.03), prevalence of histological PM (OR: 0.97, 95% CI: 0.40-2.34, P = 0.95), or prevalence of LBW (OR: 0.82, 95% CI: 0.24-2.73, P = 0.74). Mean (standard deviation) birth weights of infants born to HbAS (2,947 g [563]) and, homozygous hemoglobin A (2,991 g [465]) mothers were similar. Across a range of parasitologic, clinical, and histologic outcomes, HbAS did not confer protection from PM or its adverse effects.

Artemether-Lumefantrine Pharmacokinetics and Clinical Response Are Minimally Altered in Pregnant Ugandan Women Treated for Uncomplicated Falciparum Malaria

Artemether-lumefantrine is a first-line regimen for the treatment of uncomplicated malaria during the second and third trimesters of pregnancy. Previous studies have reported changes in the pharmacokinetics and clinical outcomes following treatment with artemether-lumefantrine in pregnant women compared to nonpregnant adults; however, the results are inconclusive. We conducted a study in rural Uganda to compare the pharmacokinetics of artemether-lumefantrine and the treatment responses between 30 pregnant women and 30 nonpregnant adults with uncomplicated Plasmodium falciparum malaria. All participants were uninfected with HIV, treated with a six-dose regimen of artemether-lumefantrine, and monitored clinically for 42 days. The pharmacokinetics of artemether, its metabolite dihydroartemisinin, and lumefantrine were evaluated for 21 days following treatment. We found no significant differences in the overall pharmacokinetics of artemether, dihydroartemisinin, or lumefantrine in a direct comparison of pregnant women to nonpregnant adults, except for a statistically significant but small difference in the terminal elimination half-lives of both dihydroartemisinin and lumefantrine. There were seven PCR-confirmed reinfections (5 pregnant and 2 nonpregnant participants). The observation of a shorter terminal half-life for lumefantrine may have contributed to a higher frequency of reinfection or a shorter posttreatment prophylactic period in pregnant women than in nonpregnant adults. While the comparable overall pharmacokinetic exposure is reassuring, studies are needed to further optimize antimalarial efficacy in pregnant women, particularly in high-transmission settings and because of emerging drug resistance. (This study is registered at ClinicalTrials.gov under registration no. NCT01717885.)

Parasite accumulation in placenta of non-immune baboons during Plasmodium knowlesi infection

BACKGROUND

Placental malaria (PM) causes adverse pregnancy outcomes in the mother and her foetus. It is difficult to study PM directly in humans due to ethical challenges. This study set out to bridge this gap by determining the outcome of PM in non-immune baboons in order to develop a non-human primate model for the disease.

METHODS

Ten pregnant baboons were acquired late in their third trimester (day 150) and randomly grouped as seven infected and three non-infected. Another group of four nulligravidae (non-pregnant) infected was also included in the analysis of clinical outcome. Malaria infection was intravenously initiated by Plasmodium knowlesi blood-stage parasites through the femoral vein on 160(th) day of gestation (for pregnant baboons). Peripheral smear, placental smear, haematological samples, and histological samples were collected during the study period. Median values of clinical and haematological changes were analysed using Kruskal-Wallis and Dunn's Multiple Comparison Test. Parasitaemia profiles were analysed using Mann Whitney U test. A Spearman's rank correlation was run to determine the relationship between the different variables of severity scores. Probability values of P <0.05 were considered significant.

RESULTS

Levels of white blood cells increased significantly in pregnant infected (34%) than in nulligravidae infected baboons (8%). Placental parasitaemia levels was on average 19-fold higher than peripheral parasitaemia in the same animal. Infiltration of parasitized erythrocytes and inflammatory cells were also observed in baboon placenta. Malaria parasite score increased with increase in total placental damage score (rs = 0.7650, P <0.05) and inflammatory score (rs = 0.8590, P <0.05). Although the sample size was small, absence of parasitized erythrocytes in cord blood and foetal placental region suggested lack of congenital malaria in non-immune baboons.

CONCLUSION

This study has demonstrated accumulation of parasitized red blood cells and infiltration of inflammatory cells in the placental intravillous space (IVS) of baboons that are non-immune to malaria. This is a key feature of placental falciparum malaria in humans. This presents the baboon as a new model for the characterization of malaria during pregnancy.

IFN-gamma and TNF associated with severe falciparum malaria infection in Saudi pregnant women

Background

Tumour necrosis factor (TNF) and interferon gamma (IFN-γ), encoded by TNF-836 C/A (rs 1800630) and IFN-γ -1616 C/T (rs2069705) genes, are key immunological mediators that are believed to both play protective and pathological roles in malaria. The aim of this study was to investigate the relationship between TNF-836 C/A and IFN-γ-1616 C/T polymorphism and susceptibility to severe malaria in pregnant women.

Methods

A prospective cohort (cross-sectional) study was conducted in pregnant women attending the out-patient clinic in King Fahad Specialist Hospital in Jazan (KFSHJ), with a clinical diagnosis of malaria. A total of one hundred and eighty six pregnant women were genotyped for single nucleotide polymorphism (SNP) for TNF and IFN-γ using Taqman® MGB Probes. Serum cytokine concentrations were measured by sandwich ELISA method.

Results

A hospital case–control study of severe malaria in a Saudi population identified strong associations with individual single-nucleotide polymorphisms in the TNF and IFN-γ genes, and defined TNF-836 C and IFN-γ-1616 T genotypes and alleles which were statistically significantly associated with severe malaria infection. Furthermore, TNF-836 CC and IFN-γ-1616 TT genotypes were associated with higher serum concentration of TNF and IFN-γ, respectively, and with susceptibility to severe malaria.

Conclusions

This data provides a starting point for functional and genetic analysis of the TNF and IFN-γ genomic region in malaria infection affecting Saudi populations.

Dynamics in the cytoadherence phenotypes of Plasmodium falciparum infected erythrocytes isolated during pregnancy

Pregnant women become susceptible to malaria infection despite their acquired immunity to this disease from childhood. The placental sequestration of Plasmodium falciparum infected erythrocytes (IE) is the major feature of malaria during pregnancy, due to ability of these parasites to bind chondroitin sulfate A (CSA) in the placenta through the VAR2CSA protein that parasites express on the surface of IE. We collected parasites at different times of pregnancy and investigated the adhesion pattern of freshly collected isolates on the three well described host receptors (CSPG, CD36 and ICAM-1). Var genes transcription profile and VAR2CSA surface-expression were assessed in these isolates. Although adhesion of IE to CD36 and ICAM-1 was observed in some isolates, CSA-adhesion was the predominant binding feature in all isolates analyzed. Co-existence in the peripheral blood of several adhesion phenotypes in early pregnancy isolates was observed, a diversity that gradually tightens with gestational age in favour of the CSA-adhesion phenotype. Infections occurring in primigravidae were often by parasites that adhered more to CSA than those from multigravidae. Data from this study further emphasize the specificity of CSA adhesion and VAR2CSA expression by parasites responsible for pregnancy malaria, while drawing attention to the phenotypic complexity of infections occurring early in pregnancy as well as in multigravidae.

Population pharmacokinetics and clinical response for artemether-lumefantrine in pregnant and nonpregnant women with uncomplicated Plasmodium falciparum malaria in Tanzania

Artemether-lumefantrine (AL) is the first-line treatment for uncomplicated malaria in the second and third trimesters of pregnancy. Its efficacy during pregnancy has recently been challenged due to altered pharmacokinetic (PK) properties in this vulnerable group. The aim of this study was to determine the PK profile of AL in pregnant and nonpregnant women and assess their therapeutic outcome. Thirty-three pregnant women and 22 nonpregnant women with malaria were treated with AL (80/480 mg) twice daily for 3 days. All patients provided five venous plasma samples for drug quantification at random times over 7 days. Inter- and intraindividual variability was assessed, and the effects of covariates were quantified using a nonlinear mixed-effects modeling approach (NONMEM). A one-compartment model with first-order absorption and elimination with linear metabolism from drug to metabolite fitted the data best for both arthemether (AM) and lumefantrine (LF) and their metabolites. Pregnancy status and diarrhea showed a significant influence on LF PK. The relative bioavailability of lumefantrine and its metabolism rate into desmethyl-lumefantrine were, respectively, 34% lower and 78% higher in pregnant women than in nonpregnant patients. The overall PCR-uncorrected treatment failure rates were 18% in pregnant women and 5% in nonpregnant women (odds ratio [OR] = 4.04; P value of 0.22). A high median day 7 lumefantrine concentration was significantly associated with adequate clinical and parasitological response (P = 0.03). The observed reduction in the relative bioavailability of lumefantrine in pregnant women may explain the higher treatment failure in this group, mostly due to lower posttreatment prophylaxis. Hence, a modified treatment regimen of malaria in pregnancy should be considered.

A morphometric and histological study of placental malaria shows significant changes to villous architecture in both Plasmodium falciparum and Plasmodium vivax infection

BACKGROUND

Malaria in pregnancy remains a major health problem. Placental malaria infection may cause pathophysiological changes in pregnancy and result in morphological changes to placental villi. Quantitative histomorphological image analysis of placental biopsies was performed to compare placental villous architecture between active or treated placental malaria cases and controls.

METHODS

A total of 67 placentas were studied from three clinical groups: control patients who did not have malaria (n = 27), active (n = 14) and treated (n=26) malaria cases, including both Plasmodium falciparum and Plasmodium vivax infections. Image analysis of histological placental sections was performed using ImageJ software to measure the number and size (area) of terminal villi, perimeter measurement per villus and total perimeter per unit area, and number of capillaries per villus (vascularity). Histological features of placental malaria were scored and these results were correlated with malaria status and clinical outcomes.

RESULTS

Villous size correlated with vascularity (p <0.0001) but was inversely correlated with observed villi per unit area, (p = 0.0001). Significantly greater villous area and vascularity was observed in UK controls. Indices of histological malaria infection were significantly greater in active versus treated malaria cases. Active placental malaria cases showed significantly smaller villous area (p <0.0084), vascularity (p <0.0139) and perimeter (p <0.0006) than treated malaria cases or controls, but significantly more villi per unit area (p <0.0001). Villous size in treated malaria cases was significantly larger than active placental malaria cases (p <0.001) and similar to controls. There was a significant relationship between villous number and anaemia at the time of infection (p <0.0034), but not placental weight, birth weight or gestational age at delivery. No differences were found between histology or villous morphology comparing infections with P. falciparum or P. vivax.

CONCLUSIONS

These results imply that villous size, perimeter and vascularity are acutely decreased during active placental malaria, decreasing the surface area available for gas exchange per villus. However the increased number of villi per unit area offsets this change and persists after treatment. Histopathological and villous architectural changes may be reversed by early detection and appropriate anti-malarial treatment.

Severity of maternal HIV-1 disease is associated with adverse birth outcomes in Malawian women: a cohort study

BACKGROUND

Compared with HIV-negative women, HIV-infected women have increased risk of low birthweight (LBW) and preterm delivery (PTD). We assessed whether severity of maternal HIV-1 disease was associated with LBW or PTD.

METHODS

Secondary analysis of The Malaria and HIV in Pregnancy prospective cohort, which enrolled HIV-positive, pregnant Malawian women from 2000 to 2004. Included participants (n = 809) were normotensive antiretroviral treatment-naive women who delivered a live singleton infant. Binomial regression models were used to assess the unadjusted and adjusted prevalence ratios (PRs) and 95% confidence intervals (CI) of the effect of severity of HIV-1 disease, defined by viral load and CD4 T-cell counts, on prevalence of LBW and PTD.

RESULTS

In unadjusted analyses, among those with malaria (n = 198), there was no association between severity of HIV-1 infection and LBW, whereas among women without malaria (n = 611), we observed a harmful association between both increasing peripheral viral load and LBW (PR: 1.44 per 1-log10 increase, 95% CI: 1.12 to 1.86) and placental viral load and LBW (PR: 1.24 per 1-log10 increase, 95% CI: 1.00 to 1.53). We observed a similar association between increasing placental viral load and PTD (PR: 1.33 per one-log10 increase, 95% CI: 1.04 to 1.69). These associations persisted in multivariate models adjusted for residence, maternal education, primigravid status, and maternal anemia.

CONCLUSIONS

In malaria-negative women, maternal HIV-1 disease severity was significantly associated with increased prevalence of LBW and PTD. Such an association was not found in the malaria-infected women.

Malaria in pregnancy in rural Gabon: a cross-sectional survey on the impact of seasonality in high-risk groups

BACKGROUND

Malaria remains one of the most important infectious diseases in pregnancy in sub-Saharan Africa. Whereas seasonal malaria chemoprevention is advocated as public health intervention for children in certain areas of highly seasonal malaria transmission, the impact of seasonality on malaria in pregnancy has not yet been investigated for stable, hyper-endemic transmission settings of Equatorial Africa. The aim of this study was to investigate the influence of seasonality on the prevalence of malaria in pregnancy in Gabon.

METHODS

The study was conducted at a rural district hospital in Gabon between January 2008 and December 2011. At first antenatal care visits demographic data, parity, age, and gestational age of pregnant women were documented and thick blood smears were performed for the diagnosis of malaria. Seasonality and established risk factors were evaluated in univariate and multivariate analysis for their association with Plasmodium falciparum infection.

RESULTS

1,661 pregnant women were enrolled in this study. Participants presenting during high transmission seasons were at significantly higher risk for P. falciparum infection compared to low transmission seasons (adjusted odds ratio [AOR] 1.91, 95% confidence interval [CI] 1.39-2.63, p < 0.001). Established risk factors including parity (AOR 0.45, CI 0.30-0.69, p < 0.001 for multipara versus paucipara) and age (AOR, CI and p-value for women aged 13-17, 18-22, 23-27 and ≥ 28 years, respectively: AOR 0.59, CI 0.40-0.88; AOR 0.57, CI 0.34-0.97; AOR 0.51, CI 0.29-0.91) were significant risk factors for P. falciparum infection. High-risk groups including nulli- and primipara and younger women aged 13-17 years showed a disproportionately increased risk for malaria in high transmission seasons from 17% to 64% prevalence in low and high transmission periods, respectively.

CONCLUSION

Seasonal variations lead to important differences in the risk for P. falciparum infection in pregnancy in the setting of central African regions with stable and hyper-endemic malaria transmission. The seasonal increase in malaria in pregnancy is most pronounced in high-risk groups constituted by young and pauciparous women. The evaluation of tailored seasonal prevention strategies for these high-risk populations may, therefore, be warranted.

Prevalence of gestational, placental and congenital malaria in north-west Colombia

BACKGROUND

The frequency of pregnancy-associated malaria is increasingly being documented in American countries. In Colombia, with higher frequency of Plasmodium vivax over Plasmodium falciparum infection, recent reports confirmed gestational malaria as a serious public health problem. Thick smear examination is the gold standard to diagnose malaria in endemic settings, but in recent years, molecular diagnostic methods have contributed to elucidate the dimension of the problem of gestational malaria. The study was aimed at exploring the prevalence of gestational, placental and congenital malaria in women who delivered at the local hospitals of north-west Colombia, between June 2008 and April 2011.

METHODS

A group of 129 parturient women was selected to explore the prevalence of gestational, placental and congenital malaria in a descriptive, prospective and transversal (prevalence) design. Diagnosis was based on the simultaneous application of two independent diagnostic tests: microscopy of thick blood smears and a polymerase chain reaction assay (PCR).

RESULTS

The prevalence of gestational malaria (thick smear /PCR) was 9.1%/14.0%; placental malaria was 3.3%/16.5% and congenital malaria was absent. A history of gestational malaria during the current pregnancy was significantly associated with gestational malaria at delivery. Plasmodium vivax caused 65% of cases of gestational malaria, whereas P. falciparum caused most cases of placental malaria.

CONCLUSIONS

Gestational and placental malaria are a serious problem in the region, but the risk of congenital malaria is low. A history of malaria during pregnancy may be a practical indicator of infection at delivery.

A molecular switch in the efficiency of translation reinitiation controls expression of var2csa, a gene implicated in pregnancy-associated malaria

Plasmodium falciparum malaria parasites export the protein PfEMP1 to the surface of infected erythrocytes, enabling them to adhere to receptors in the microvasculature and thereby avoid clearance by the spleen. The gene var2csa encodes the form of PfEMP1 that binds specifically within the placenta, causing pregnancy-associated malaria, and appears to not be expressed in the absence of a placenta. We previously described an upstream open reading frame (uORF) that is responsible for repression of translation of the downstream ORF (dORF) that encodes VAR2CSA, thus keeping the gene silent when parasites infect non-pregnant individuals. To elucidate the molecular mechanism by which this repression is overcome during pregnancy, we stably transformed parasites with reporter gene constructs designed to detect switches in the efficiency of dORF translation. We found that proper regulation of switching relies on two separate components, (i) active translation of the uORF and (ii) sequence-specific characteristics of the surrounding transcript, which together control the ability of the ribosome complex to reinitiate a second round of translation and thus express VAR2CSA. These results provide the first details of a molecular switch that allows parasites take advantage of the unique niche provided by the placenta.

Complement activation and the resulting placental vascular insufficiency drives fetal growth restriction associated with placental malaria

Placental malaria (PM) is a major cause of fetal growth restriction, yet the underlying mechanism is unclear. Complement C5a and C5a receptor levels are increased with PM. C5a is implicated in fetal growth restriction in non-infection-based animal models. In a case-control study of 492 pregnant Malawian women, we find that elevated C5a levels are associated with an increased risk of delivering a small-for-gestational-age infant. C5a was significantly increased in PM and was negatively correlated with the angiogenic factor angiopoietin-1 and positively correlated with angiopoietin-2, soluble endoglin, and vascular endothelial growth factor. Genetic or pharmacological blockade of C5a or its receptor in a mouse model of PM resulted in greater fetoplacental vessel development, reduced placental vascular resistance, and improved fetal growth and survival. These data suggest that C5a drives fetal growth restriction in PM through dysregulation of angiogenic factors essential for placental vascular remodeling resulting in placental vascular insufficiency.

Placental malaria in Colombia: histopathologic findings in Plasmodium vivax and P. falciparum infections

Studies on gestational malaria and placental malaria have been scarce in malaria-endemic areas of the Western Hemisphere. To describe the histopathology of placental malaria in Colombia, a longitudinal descriptive study was conducted. In this study, 179 placentas were studied by histologic analysis (112 with gestational malaria and 67 negative for malaria). Placental malaria was confirmed in 22.35%, 50.0% had previous infections, and 47.5% had acute infections. Typical malaria-associated changes were observed in 37%. The most common changes were villitis, intervillitis, deciduitis, increased fibrin deposition, increased syncytial knots, mononuclear (monocytes/macrophages and lymphocytes), polymorphonuclear cell infiltration, and trophozoites in fetal erythrocytes. No association was found between type of placental changes observed and histopathologic classification of placental malaria. The findings are consistent with those reported for placental malaria in other regions. Plasmodium vivax was the main parasite responsible for placental and gestational malaria, but its role in the pathogenesis of placental malaria was not conclusive.

Natural acquisition of immunity to Plasmodium vivax: epidemiological observations and potential targets

Population studies show that individuals acquire immunity to Plasmodium vivax more quickly than Plasmodium falciparum irrespective of overall transmission intensity, resulting in the peak burden of P. vivax malaria in younger age groups. Similarly, actively induced P. vivax infections in malaria therapy patients resulted in faster and generally more strain-transcending acquisition of immunity than P. falciparum infections. The mechanisms behind the more rapid acquisition of immunity to P. vivax are poorly understood. Natural acquired immune responses to P. vivax target both pre-erythrocytic and blood-stage antigens and include humoral and cellular components. To date, only a few studies have investigated the association of these immune responses with protection, with most studies focussing on a few merozoite antigens (such as the Pv Duffy binding protein (PvDBP), the Pv reticulocyte binding proteins (PvRBPs), or the Pv merozoite surface proteins (PvMSP1, 3 & 9)) or the circumsporozoite protein (PvCSP). Naturally acquired transmission-blocking (TB) immunity (TBI) was also found in several populations. Although limited, these data support the premise that developing a multi-stage P. vivax vaccine may be feasible and is worth pursuing.

Malaria and fetal growth alterations in the 3(rd) trimester of pregnancy: a longitudinal ultrasound study

Background

Pregnancy associated malaria is associated with decreased birth weight, but in-utero evaluation of fetal growth alterations is rarely performed. The objective of this study was to investigate malaria induced changes in fetal growth during the 3^rd trimester using trans-abdominal ultrasound.

Methods

An observational study of 876 pregnant women (398 primi- and secundigravidae and 478 multigravidae) was conducted in Tanzania. Fetal growth was monitored with ultrasound and screening for malaria was performed regularly. Birth weight and fetal weight were converted to z-scores, and fetal growth evaluated as fetal weight gain from the 26th week of pregnancy.

Results

Malaria infection only affected birth weight and fetal growth among primi- and secundigravid women. Forty-eight of the 398 primi- and secundigravid women had malaria during pregnancy causing a reduction in the newborns z-score of −0.50 (95% CI: −0.86, −0.13, P = 0.008, multiple linear regression). Fifty-eight percent (28/48) of the primi- and secundigravidae had malaria in the first half of pregnancy, but an effect on fetal growth was observed in the 3^rd trimester with an OR of 4.89 for the fetal growth rate belonging to the lowest 25% in the population (95%CI: 2.03–11.79, P<0.001, multiple logistic regression). At an individual level, among the primi- and secundigravidae, 27% experienced alterations of fetal growth immediately after exposure but only for a short interval, 27% only late in pregnancy, 16.2% persistently from exposure until the end of pregnancy, and 29.7% had no alterations of fetal growth.

Conclusions

The effect of malaria infections was observed during the 3^rd trimester, despite infections occurring much earlier in pregnancy, and different mechanisms might operate leading to different patterns of growth alterations. This study highlights the need for protection against malaria throughout pregnancy and the recognition that observed changes in fetal growth might be a consequence of an infection much earlier in pregnancy.

Opsonization of malaria-infected erythrocytes activates the inflammasome and enhances inflammatory cytokine secretion by human macrophages

Background

Antibody opsonization of Plasmodium falciparum-infected erythrocytes (IE) plays a crucial role in anti-malarial immunity by promoting clearance of blood-stage infection by monocytes and macrophages. The effects of phagocytosis of opsonized IE on macrophage pro-inflammatory cytokine responses are poorly understood.

Methods

Phagocytic clearance, cytokine response and intracellular signalling were measured using IFN-γ-primed human monocyte-derived macrophages (MDM) incubated with opsonized and unopsonized trophozoite-stage CS2 IE, a chondroitin sulphate-binding malaria strain. Cytokine secretion was measured by bead array or ELISA, mRNA using quantitative PCR, and activation of NF-κB by Western blot and electrophoretic mobility shift assay. Data were analysed using the Mann–Whitney U test or the Wilcoxon signed rank test as appropriate.

Results

Unopsonized CS2 IE were not phagocytosed whereas IE opsonized with pooled patient immune serum (PPS) were (Phagocytic index (PI)=18.4, [SE 0.38] n=3). Unopsonized and opsonized IE induced expression of TNF, IL-1β and IL-6 mRNA by MDM and activated NF-κB to a similar extent. Unopsonized IE induced secretion of IL-6 (median= 622 pg/ml [IQR=1,250-240], n=9) but no IL-1β or TNF, whereas PPS-opsonized IE induced secretion of IL-1β (18.6 pg/mL [34.2-14.4]) and TNF (113 pg/ml [421–17.0]) and increased IL-6 secretion (2,195 pg/ml [4,658-1,095]). Opsonized, but not unopsonized, CS2 IE activated caspase-1 cleavage and enzymatic activity in MDM showing that Fc receptor-mediated phagocytosis activates the inflammasome. MDM attached to IgG-coated surfaces however secreted IL-1β in response to unopsonized IE, suggesting that internalization of IE is not absolutely required to activate the inflammasome and stimulate IL-1β secretion.

Conclusions

It is concluded that IL-6 secretion from MDM in response to CS2 IE does not require phagocytosis, whereas secretion of TNF and IL-1β is dependent on Fcγ receptor-mediated phagocytosis; for IL-1β, this occurs by activation of the inflammasome. The data presented in this paper show that generating antibody responses to blood-stage malaria parasites is potentially beneficial both in reducing parasitaemia via Fcγ receptor-dependent macrophage phagocytosis and in generating a robust pro-inflammatory response.

Plasmodium berghei: influence of infection on the oxidant and antioxidants levels in pregnant BALB/c mice

Malarial infection during pregnancy has been associated with maternal anemia and death, abortion, still-birth and is a major cause of low birth weight, an important risk factor for infant morbidity and mortality in endemic areas. The present study was designed to delineate the oxidative stress in various organs (liver, spleen, kidney, brain and placenta) of pregnant Plasmodium berghei infected BALB/c mice. It was observed that pregnant-infected mice had higher parasitaemia than nonpregnant-infected mice. Most notably, levels of malondialdehyde (MDA), a measure of lipid peroxidation, reduced glutathione (GSH) and superoxide dismutase (SOD) levels were significantly higher in the liver, spleen, kidney and brain of pregnant-infected mice compared with pregnant mice. Although MDA levels were significantly higher, GSH and SOD levels remained unaltered in the placenta of pregnant-infected mice compared with pregnant mice. Furthermore, catalase activity was significantly lower in all the organs of pregnant-infected mice compared with pregnant mice. Histopathological observations in the organs clearly show the cellular and morphological alterations that may be occurring due to increased lipid peroxidation. Taken together, the data suggest that the increased severity of malarial infection during pregnancy may be due to accentuated oxidative stress.