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Ma R, Salinas ND, Orr-Gonzalez S, Richardson B, Ouahes T, Torano H, Jenkins BJ, Dickey TH, Neal J, Duan J, Morrison RD, Gittis AG, Doritchamou JYA, Zaidi I, Lambert LE, Duffy PE, Tolia NH. Structure-guided design of VAR2CSA-based immunogens and a cocktail strategy for a placental malaria vaccine. PLoS Pathog 2024; 20:e1011879. [PMID: 38437239 PMCID: PMC10939253 DOI: 10.1371/journal.ppat.1011879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Revised: 03/14/2024] [Accepted: 11/29/2023] [Indexed: 03/06/2024] Open
Abstract
Placental accumulation of Plasmodium falciparum infected erythrocytes results in maternal anemia, low birth weight, and pregnancy loss. The parasite protein VAR2CSA facilitates the accumulation of infected erythrocytes in the placenta through interaction with the host receptor chondroitin sulfate A (CSA). Antibodies that prevent the VAR2CSA-CSA interaction correlate with protection from placental malaria, and VAR2CSA is a high-priority placental malaria vaccine antigen. Here, structure-guided design leveraging the full-length structures of VAR2CSA produced a stable immunogen that retains the critical conserved functional elements of VAR2CSA. The design expressed with a six-fold greater yield than the full-length protein and elicited antibodies that prevent adhesion of infected erythrocytes to CSA. The reduced size and adaptability of the designed immunogen enable efficient production of multiple variants of VAR2CSA for use in a cocktail vaccination strategy to increase the breadth of protection. These designs form strong foundations for the development of potent broadly protective placental malaria vaccines.
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Affiliation(s)
- Rui Ma
- Host-Pathogen Interactions and Structural Vaccinology Section, Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Nichole D Salinas
- Host-Pathogen Interactions and Structural Vaccinology Section, Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Sachy Orr-Gonzalez
- Vaccine Development Unit, Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Brandi Richardson
- Vaccine Development Unit, Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Tarik Ouahes
- Vaccine Development Unit, Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Holly Torano
- Vaccine Development Unit, Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Bethany J Jenkins
- Pathogenesis and Immunity Section, Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Thayne H Dickey
- Host-Pathogen Interactions and Structural Vaccinology Section, Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Jillian Neal
- Vaccine Development Unit, Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Junhui Duan
- Vaccine Development Unit, Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Robert D Morrison
- Vaccine Development Unit, Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Apostolos G Gittis
- Structural Biology Section, Research Technologies Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Justin Y A Doritchamou
- Pathogenesis and Immunity Section, Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Irfan Zaidi
- Vaccine Development Unit, Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Lynn E Lambert
- Vaccine Development Unit, Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Patrick E Duffy
- Vaccine Development Unit, Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
- Pathogenesis and Immunity Section, Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Niraj H Tolia
- Host-Pathogen Interactions and Structural Vaccinology Section, Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
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Naheda A, Aqeel S, Khan K, Khan W, Khan T. Immunohistopathological changes in the placenta of malaria-infected women in unstable transmission setting of Aligarh. Placenta 2022; 127:52-61. [PMID: 35970103 DOI: 10.1016/j.placenta.2022.07.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Revised: 07/16/2022] [Accepted: 07/24/2022] [Indexed: 10/15/2022]
Abstract
INTRODUCTION Pregnant women are more susceptible to malaria due to a combination of physiological and immunological changes. The infection may even affect the growth and survival of the foetus, which mainly occur when parasite enters the placenta. The sequestration of infected erythrocytes may trigger the host response, leading to placental inflammation and altered development, affecting the structure and nutrient transport of placenta. These factors collectively impair placental functions and affect foetal growth. METHODS Pregnant women with peripheral parasitaemia for P. falciparum and P. vivax (20 each) were included in the present study, along with 15 age-matched uninfected healthy pregnant women. Placentae were analysed for the presence of local parasitaemia along with pathological lesions caused due to the parasite. Immunohistochemical staining for CD20, CD45 and CD68 cells was performed for examining the specific leucocytes in the intervillous space of the placenta. RESULTS Of the 20 individuals with P. falciparum, only seven placentae showed parasitaemia, whereas individuals with P. vivax showed no placental infection. The pathological changes observed in the P. falciparum-infected placenta include syncytial knotting, excess fibrinoid deposition, syncytiotrophoblast necrosis, syncytial rupture, thickening of trophoblast basement membrane and increased collagen deposition. Immunohistochemical staining showed a significant increase in B cells (CD20), leucocytes (CD45) and monocytes and macrophages (CD68) in the P. falciparum-infected placenta (p < 0.0001). DISCUSSION The result implies that P. falciparum is responsible for pathological alterations in placenta, affecting the nutrient transport across placenta and foetal growth. The immune cells also migrate to the placenta and accumulate in the intervillous space to show humoral and cell-mediated immunity against the parasite.
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Affiliation(s)
- Ansari Naheda
- Section of Parasitology, Department of Zoology, Aligarh Muslim University, Aligarh, 202002, India.
| | - Sana Aqeel
- Section of Parasitology, Department of Zoology, Aligarh Muslim University, Aligarh, 202002, India
| | - Khadija Khan
- Section of Parasitology, Department of Zoology, Aligarh Muslim University, Aligarh, 202002, India
| | - Wajihullah Khan
- Section of Parasitology, Department of Zoology, Aligarh Muslim University, Aligarh, 202002, India.
| | - Tamkin Khan
- Department of Obstetrics & Gynaecology, Jawaharlal Nehru Medical College & Hospital, Aligarh Muslim University, Aligarh, 202002, India
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Kana MA, Shi M, Ahmed J, Ibrahim JM, Ashir AY, Abdullahi K, Bello-Manga H, Taingson M, Mohammed-Durosinlorun A, Shuaibu M, Tabari AM, London SJ. Biomass fuel use and birth weight among term births in Nigeria. PLOS GLOBAL PUBLIC HEALTH 2022; 2:e0000419. [PMID: 36962417 PMCID: PMC10022098 DOI: 10.1371/journal.pgph.0000419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2021] [Accepted: 04/22/2022] [Indexed: 11/18/2022]
Abstract
Despite the high burden of household air pollution from biomass fuel in sub-Saharan Africa, the association of prenatal biomass fuel exposure and birth weight as a continuous variable among term births has not been extensively studied. In this study, our primary aim is to estimate the association between biomass cooking fuel and birth weight among term births in Kaduna, northwestern Nigeria. For replication, we also evaluated this association in a larger and nationally representative sample from the 2018 Nigerian Demographic and Health Survey (DHS). Our primary analysis included 1,514 mother-child pairs recruited from Kaduna, in northwestern Nigeria, using the Child Electronic Growth Monitoring System (CEGROMS). Replication analysis was conducted using data from 6,975 mother-child pairs enrolled in 2018 Nigerian DHS. The outcome variable was birth weight, and the exposure was cooking fuel type, categorized in CEGROMS as liquefied petroleum gas, kerosene, or biomass fuel, and in the DHS as low pollution fuel, kerosene, or biomass fuel. We estimated covariate adjusted associations between birth weight and biomass fuel exposure in CEGROMS using linear regression and using linear mixed model in the DHS. In CEGROMS, adjusting for maternal age, education, parity, BMI at birth, and child sex, mothers exposed to biomass fuel gave birth to infants who were on average 113g lighter (95% CI -196 to -29), than those using liquified petroleum gas. In the 2018 Nigeria DHS data, compared to low pollution fuel users, mothers using biomass had infants weighing 50g (95% CI -103 to 2) lower at birth. Exposure to biomass cooking fuel was associated with lower birth weight in our study of term newborns in Kaduna, Nigeria. Data from the nationally representative DHS provide some support for these findings.
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Affiliation(s)
- Musa Abubakar Kana
- National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, Durham, North Carolina, United States of America
- Department of Epidemiology and Community Medicine, Federal University of Lafia, Lafia, Nasarawa State, Nigeria
- College of Medicine, Kaduna State University, Kaduna, Kaduna State, Nigeria
- Barau Dikko Teaching Hospital, Kaduna, Kaduna State, Nigeria
| | - Min Shi
- National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, Durham, North Carolina, United States of America
| | - Jennifer Ahmed
- Barau Dikko Teaching Hospital, Kaduna, Kaduna State, Nigeria
| | - Jimoh Muhammad Ibrahim
- College of Medicine, Kaduna State University, Kaduna, Kaduna State, Nigeria
- Barau Dikko Teaching Hospital, Kaduna, Kaduna State, Nigeria
| | | | | | - Halima Bello-Manga
- College of Medicine, Kaduna State University, Kaduna, Kaduna State, Nigeria
- Barau Dikko Teaching Hospital, Kaduna, Kaduna State, Nigeria
| | - Matthew Taingson
- College of Medicine, Kaduna State University, Kaduna, Kaduna State, Nigeria
- Barau Dikko Teaching Hospital, Kaduna, Kaduna State, Nigeria
| | - Amina Mohammed-Durosinlorun
- College of Medicine, Kaduna State University, Kaduna, Kaduna State, Nigeria
- Barau Dikko Teaching Hospital, Kaduna, Kaduna State, Nigeria
| | - Musa Shuaibu
- College of Medicine, Kaduna State University, Kaduna, Kaduna State, Nigeria
- Barau Dikko Teaching Hospital, Kaduna, Kaduna State, Nigeria
| | - Abdulkadir Musa Tabari
- College of Medicine, Kaduna State University, Kaduna, Kaduna State, Nigeria
- Barau Dikko Teaching Hospital, Kaduna, Kaduna State, Nigeria
| | - Stephanie J. London
- National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, Durham, North Carolina, United States of America
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Talundzic E, Scott S, Owino SO, Campo DS, Lucchi NW, Udhayakumar V, Moore JM, Peterson DS. Polymorphic Molecular Signatures in Variable Regions of the Plasmodium falciparum var2csa DBL3x Domain Are Associated with Virulence in Placental Malaria. Pathogens 2022; 11:520. [PMID: 35631041 PMCID: PMC9147263 DOI: 10.3390/pathogens11050520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 04/15/2022] [Accepted: 04/24/2022] [Indexed: 11/17/2022] Open
Abstract
The Plasmodium falciparum protein VAR2CSA allows infected erythrocytes to accumulate within the placenta, inducing pathology and poor birth outcomes. Multiple exposures to placental malaria (PM) induce partial immunity against VAR2CSA, making it a promising vaccine candidate. However, the extent to which VAR2CSA genetic diversity contributes to immune evasion and virulence remains poorly understood. The deep sequencing of the var2csa DBL3X domain in placental blood from forty-nine primigravid and multigravid women living in malaria-endemic western Kenya revealed numerous unique sequences within individuals in association with chronic PM but not gravidity. Additional analysis unveiled four distinct sequence types that were variably present in mixed proportions amongst the study population. An analysis of the abundance of each of these sequence types revealed that one was inversely related to infant gestational age, another was inversely related to placental parasitemia, and a third was associated with chronic PM. The categorization of women according to the type to which their dominant sequence belonged resulted in the segregation of types as a function of gravidity: two types predominated in multigravidae whereas the other two predominated in primigravidae. The univariate logistic regression analysis of sequence type dominance further revealed that gravidity, maternal age, placental parasitemia, and hemozoin burden (within maternal leukocytes), reported a lack of antimalarial drug use, and infant gestational age and birth weight influenced the odds of membership in one or more of these sequence predominance groups. Cumulatively, these results show that unique var2csa sequences differentially appear in women with different PM exposure histories and segregate to types independently associated with maternal factors, infection parameters, and birth outcomes. The association of some var2csa sequence types with indicators of pathogenesis should motivate vaccine efforts to further identify and target VAR2CSA epitopes associated with maternal morbidity and poor birth outcomes.
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Affiliation(s)
- Eldin Talundzic
- Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA 30329, USA; (E.T.); (N.W.L.); (V.U.)
| | - Stephen Scott
- Department of Infectious Diseases, University of Georgia, Athens, GA 30602, USA;
| | - Simon O. Owino
- Boehringer Ingelheim Animal Health, Athens, GA 30601, USA;
| | - David S. Campo
- Molecular Epidemiology and Bioinformatics Laboratory, Division of Viral Hepatitis, Centers for Disease Control and Prevention, Atlanta, GA 30329, USA;
| | - Naomi W. Lucchi
- Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA 30329, USA; (E.T.); (N.W.L.); (V.U.)
| | - Venkatachalam Udhayakumar
- Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA 30329, USA; (E.T.); (N.W.L.); (V.U.)
| | - Julie M. Moore
- Department of Infectious Diseases and Immunology, University of Florida, Gainesville, FL 32611, USA
| | - David S. Peterson
- Department of Infectious Diseases, University of Georgia, Athens, GA 30602, USA;
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA 30602, USA
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Gill J, Chakraborti S, Bharti P, Sharma A. Structural insights into global mutations in the ligand-binding domain of VAR2CSA and its implications on placental malaria vaccine. Int J Infect Dis 2021; 112:35-39. [PMID: 34450283 DOI: 10.1016/j.ijid.2021.08.054] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 08/18/2021] [Accepted: 08/21/2021] [Indexed: 11/17/2022] Open
Abstract
Placental malaria is a public health burden particularly in Africa as it causes severe symptoms and results in stillbirths or maternal deaths. Plasmodium falciparum protein VAR2CSA drives placental malaria (PM) in pregnant women by adhering to chondroitin sulfate A (CSA) on the placenta. VAR2CSA is a primary vaccine candidate for PM with two vaccines based on it already under clinical trials. The first cryo-EM three-dimensional structure of Pf CSA-VAR2CSA complex revealed crucial interacting residues considered to be highly conserved across P. falciparum strains. In the current study, we have conducted a global sequence analysis of 1,114 VAR2CSA field isolate sequences from more than nine countries across three continents revealing numerous mutations in CSA-binding residues. Further, structural mapping has revealed significant polymorphisms on the ligand binding surfaces. The variants from this limited set of 1,114 sequences highlight the concerns that are vital in current considerations for development of vaccines based on VAR2CSA for placental malaria.
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Affiliation(s)
- Jasmita Gill
- ICMR-National Institute of Malaria Research, New Delhi, India.
| | | | - Praveen Bharti
- ICMR-National Institute of Malaria Research, New Delhi, India
| | - Amit Sharma
- ICMR-National Institute of Malaria Research, New Delhi, India; Molecular Medicine Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
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Aitken EH, Damelang T, Ortega-Pajares A, Alemu A, Hasang W, Dini S, Unger HW, Ome-Kaius M, Nielsen MA, Salanti A, Smith J, Kent S, Hogarth PM, Wines BD, Simpson JA, Chung AW, Rogerson SJ. Developing a multivariate prediction model of antibody features associated with protection of malaria-infected pregnant women from placental malaria. eLife 2021; 10:e65776. [PMID: 34181872 PMCID: PMC8241440 DOI: 10.7554/elife.65776] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 06/16/2021] [Indexed: 12/15/2022] Open
Abstract
Background Plasmodium falciparum causes placental malaria, which results in adverse outcomes for mother and child. P. falciparum-infected erythrocytes that express the parasite protein VAR2CSA on their surface can bind to placental chondroitin sulfate A. It has been hypothesized that naturally acquired antibodies towards VAR2CSA protect against placental infection, but it has proven difficult to identify robust antibody correlates of protection from disease. The objective of this study was to develop a prediction model using antibody features that could identify women protected from placental malaria. Methods We used a systems serology approach with elastic net-regularized logistic regression, partial least squares discriminant analysis, and a case-control study design to identify naturally acquired antibody features mid-pregnancy that were associated with protection from placental malaria at delivery in a cohort of 77 pregnant women from Madang, Papua New Guinea. Results The machine learning techniques selected 6 out of 169 measured antibody features towards VAR2CSA that could predict (with 86% accuracy) whether a woman would subsequently have active placental malaria infection at delivery. Selected features included previously described associations with inhibition of placental binding and/or opsonic phagocytosis of infected erythrocytes, and network analysis indicated that there are not one but multiple pathways to protection from placental malaria. Conclusions We have identified candidate antibody features that could accurately identify malaria-infected women as protected from placental infection. It is likely that there are multiple pathways to protection against placental malaria. Funding This study was supported by the National Health and Medical Research Council (Nos. APP1143946, GNT1145303, APP1092789, APP1140509, and APP1104975).
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Affiliation(s)
- Elizabeth H Aitken
- Department of Medicine, University of Melbourne, the Doherty InstituteMelbourneAustralia
| | - Timon Damelang
- Department of Microbiology and Immunology, University of Melbourne, the Doherty InstituteMelbourneAustralia
| | - Amaya Ortega-Pajares
- Department of Medicine, University of Melbourne, the Doherty InstituteMelbourneAustralia
| | - Agersew Alemu
- Department of Medicine, University of Melbourne, the Doherty InstituteMelbourneAustralia
| | - Wina Hasang
- Department of Medicine, University of Melbourne, the Doherty InstituteMelbourneAustralia
| | - Saber Dini
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of MelbourneMelbourneAustralia
| | - Holger W Unger
- Department of Medicine, University of Melbourne, the Doherty InstituteMelbourneAustralia
- Department of Obstetrics and Gynaecology, Royal Darwin HospitalDarwinAustralia
- Menzies School of Health ResearchDarwinAustralia
| | - Maria Ome-Kaius
- Walter and Eliza Hall Institute of Medical ResearchParkvilleAustralia
| | - Morten A Nielsen
- Centre for Medical Parasitology, Department of Microbiology and immunology, University of CopenhagenCopenhagenDenmark
| | - Ali Salanti
- Centre for Medical Parasitology, Department of Microbiology and immunology, University of CopenhagenCopenhagenDenmark
- Department of Infectious Disease, Copenhagen University HospitalCopenhagenDenmark
| | - Joe Smith
- Seattle Children’s Research InstituteSeattleUnited States
- Department of Pediatrics, University of WashingtonSeattleUnited States
| | - Stephen Kent
- Department of Microbiology and Immunology, University of Melbourne, the Doherty InstituteMelbourneAustralia
| | - P Mark Hogarth
- Seattle Children’s Research InstituteSeattleUnited States
- Immune Therapies Group, Centre for Biomedical Research, Burnet InstituteMelbourneAustralia
- Department of Clinical Pathology, University of MelbourneMelbourneAustralia
- Department of Immunology and Pathology, Monash UniversityMelbourneAustralia
| | - Bruce D Wines
- Immune Therapies Group, Centre for Biomedical Research, Burnet InstituteMelbourneAustralia
- Department of Clinical Pathology, University of MelbourneMelbourneAustralia
- Department of Immunology and Pathology, Monash UniversityMelbourneAustralia
| | - Julie A Simpson
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of MelbourneMelbourneAustralia
| | - Amy W Chung
- Department of Microbiology and Immunology, University of Melbourne, the Doherty InstituteMelbourneAustralia
| | - Stephen J Rogerson
- Department of Medicine, University of Melbourne, the Doherty InstituteMelbourneAustralia
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Piccioni MG, Del Negro V, Vena F, Capone C, Merlino L, Moore JM, Giancotti A, Porpora MG, Brunelli R. Diagnosis & management of imported malaria in pregnant women in non-endemic countries. Indian J Med Res 2021; 152:449-455. [PMID: 33707386 PMCID: PMC8157900 DOI: 10.4103/ijmr.ijmr_851_18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Malaria in pregnancy is an important cause of maternal and foetal morbidity and is a potentially life-threatening infection. With ever-growing global exchanges, imported malaria in pregnancy is becoming an issue of concern in non-endemic countries where women, because of low immunity, have higher risk of severe diseases and death. Malaria in pregnancy is a dangerous condition which can be associated with important consequences for both mother and child such as stillbirth, low birth weight, maternal anaemia. In non-endemic-countries it is more frequent in its severe form which can lead to maternal death if not treated adequately. Specific anti-malarial interventions such as the use of repellents and insecticide treated bed nets in addition to chemoprophylaxis should be used by pregnant women if they are travelling to endemic areas. In cases of confirmed infection, specific treatment regimens vary according to gestational age and the presence of complications. Malaria should be considered a global health problem, increasingly involving western countries. Clinicians all over the world need to be prepared for this emerging disease both in terms of prevention and therapy.
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Affiliation(s)
- Maria Grazia Piccioni
- Department of Gynecological, Obstetrical & Urological Sciences, Sapienza University of Rome, Rome, Italy
| | - Valentina Del Negro
- Department of Gynecological, Obstetrical & Urological Sciences, Sapienza University of Rome, Rome, Italy
| | - Flaminia Vena
- Department of Gynecological, Obstetrical & Urological Sciences, Sapienza University of Rome, Rome, Italy
| | - Carmela Capone
- Department of Gynecological, Obstetrical & Urological Sciences, Sapienza University of Rome, Rome, Italy
| | - Lucia Merlino
- Department of Gynecological, Obstetrical & Urological Sciences, Sapienza University of Rome, Rome, Italy
| | - James Matthaus Moore
- Department of Uro-Gynaecology, Gynaecology Oncology, University Hospital of Wales, Cardiff, Wales, United Kingdom
| | - Antonella Giancotti
- Department of Gynecological, Obstetrical & Urological Sciences, Sapienza University of Rome, Rome, Italy
| | - Maria Grazia Porpora
- Department of Gynecological, Obstetrical & Urological Sciences, Sapienza University of Rome, Rome, Italy
| | - Roberto Brunelli
- Department of Gynecological, Obstetrical & Urological Sciences, Sapienza University of Rome, Rome, Italy
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Chua CLL, Hasang W, Rogerson SJ, Teo A. Poor Birth Outcomes in Malaria in Pregnancy: Recent Insights Into Mechanisms and Prevention Approaches. Front Immunol 2021; 12:621382. [PMID: 33790894 PMCID: PMC8005559 DOI: 10.3389/fimmu.2021.621382] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Accepted: 02/23/2021] [Indexed: 12/13/2022] Open
Abstract
Pregnant women in malaria-endemic regions are susceptible to malaria in pregnancy, which has adverse consequences on birth outcomes, including having small for gestational age and preterm babies. These babies are likely to have low birthweights, which predisposes to infant mortality and lifelong morbidities. During malaria in pregnancy, Plasmodium falciparum-infected erythrocytes express a unique variant surface antigen, VAR2CSA, that mediates sequestration in the placenta. This process may initiate a range of host responses that contribute to placental inflammation and dysregulated placental development, which affects placental vasculogenesis, angiogenesis and nutrient transport. Collectively, these result in the impairment of placental functions, affecting fetal development. In this review, we provide an overview of malaria in pregnancy and the different pathological pathways leading to malaria in pregnancy-associated low birthweight. We also discuss current prevention and management strategies for malaria in pregnancy, and some potential therapeutic interventions that may improve birth outcomes. Lastly, we outline some priorities for future research that could bring us one step closer to reducing this health burden.
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Affiliation(s)
| | - Wina Hasang
- Department of Medicine at Royal Melbourne Hospital, Peter Doherty Institute, University of Melbourne, Melbourne, VIC, Australia
| | - Stephen J Rogerson
- Department of Medicine at Royal Melbourne Hospital, Peter Doherty Institute, University of Melbourne, Melbourne, VIC, Australia
| | - Andrew Teo
- Department of Medicine at Royal Melbourne Hospital, Peter Doherty Institute, University of Melbourne, Melbourne, VIC, Australia.,Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
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Ma R, Lian T, Huang R, Renn JP, Petersen JD, Zimmerberg J, Duffy PE, Tolia NH. Structural basis for placental malaria mediated by Plasmodium falciparum VAR2CSA. Nat Microbiol 2021; 6:380-391. [PMID: 33452495 PMCID: PMC7914210 DOI: 10.1038/s41564-020-00858-9] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Accepted: 12/17/2020] [Indexed: 01/29/2023]
Abstract
Plasmodium falciparum VAR2CSA binds to chondroitin sulfate A (CSA) on the surface of the syncytiotrophoblast during placental malaria. This interaction facilitates placental sequestration of malaria parasites resulting in severe health outcomes for both the mother and her offspring. Furthermore, CSA is presented by diverse cancer cells and specific targeting of cells by VAR2CSA may become a viable approach for cancer treatment. In the present study, we determined the cryo-electron microscopy structures of the full-length ectodomain of VAR2CSA from P. falciparum strain NF54 in complex with CSA, and VAR2CSA from a second P. falciparum strain FCR3. The architecture of VAR2CSA is composed of a stable core flanked by a flexible arm. CSA traverses the core domain by binding within two channels and CSA binding does not induce major conformational changes in VAR2CSA. The CSA-binding elements are conserved across VAR2CSA variants and are flanked by polymorphic segments, suggesting immune selection outside the CSA-binding sites. This work provides paths for developing interventions against placental malaria and cancer.
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Affiliation(s)
- Rui Ma
- Host-Pathogen Interactions and Structural Vaccinology Section, Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Tengfei Lian
- Laboratory of Membrane Proteins and Structural Biology, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Rick Huang
- Laboratory of Cell Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Jonathan P. Renn
- Vaccine Development Unit, Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Jennifer D. Petersen
- Section on Integrative Biophysics, Division of Basic and Translational Biophysics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Joshua Zimmerberg
- Section on Integrative Biophysics, Division of Basic and Translational Biophysics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Patrick E. Duffy
- Vaccine Development Unit, Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA,Pathogenesis and Immunity Section, Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Niraj H. Tolia
- Host-Pathogen Interactions and Structural Vaccinology Section, Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA,Correspondence: (N.H.T.)
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10
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Gamain B, Chêne A, Viebig NK, Tuikue Ndam N, Nielsen MA. Progress and Insights Toward an Effective Placental Malaria Vaccine. Front Immunol 2021; 12:634508. [PMID: 33717176 PMCID: PMC7947914 DOI: 10.3389/fimmu.2021.634508] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Accepted: 01/06/2021] [Indexed: 12/03/2022] Open
Abstract
In areas where Plasmodium falciparum transmission is endemic, clinical immunity against malaria is progressively acquired during childhood and adults are usually protected against the severe clinical consequences of the disease. Nevertheless, pregnant women, notably during their first pregnancies, are susceptible to placental malaria and the associated serious clinical outcomes. Placental malaria is characterized by the massive accumulation of P. falciparum infected erythrocytes and monocytes in the placental intervillous spaces leading to maternal anaemia, hypertension, stillbirth and low birth weight due to premature delivery, and foetal growth retardation. Remarkably, the prevalence of placental malaria sharply decreases with successive pregnancies. This protection is associated with the development of antibodies directed towards the surface of P. falciparum-infected erythrocytes from placental origin. Placental sequestration is mediated by the interaction between VAR2CSA, a member of the P. falciparum erythrocyte membrane protein 1 family expressed on the infected erythrocytes surface, and the placental receptor chondroitin sulfate A. VAR2CSA stands today as the leading candidate for a placental malaria vaccine. We recently reported the safety and immunogenicity of two VAR2CSA-derived placental malaria vaccines (PRIMVAC and PAMVAC), spanning the chondroitin sulfate A-binding region of VAR2CSA, in both malaria-naïve and P. falciparum-exposed non-pregnant women in two distinct Phase I clinical trials (ClinicalTrials.gov, NCT02658253 and NCT02647489). This review discusses recent advances in placental malaria vaccine development, with a focus on the recent clinical data, and discusses the next clinical steps to undertake in order to better comprehend vaccine-induced immunity and accelerate vaccine development.
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Affiliation(s)
- Benoît Gamain
- Université de Paris, Inserm, Biologie Intégrée du Globule Rouge, Paris, France.,Institut National de la Transfusion Sanguine, Paris, France
| | - Arnaud Chêne
- Université de Paris, Inserm, Biologie Intégrée du Globule Rouge, Paris, France.,Institut National de la Transfusion Sanguine, Paris, France
| | - Nicola K Viebig
- European Vaccine Initiative, UniversitätsKlinikum Heidelberg, Heidelberg, Germany
| | | | - Morten A Nielsen
- Centre for Medical Parasitology at Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark
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11
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Tomlinson A, Semblat JP, Gamain B, Chêne A. VAR2CSA-Mediated Host Defense Evasion of Plasmodium falciparum Infected Erythrocytes in Placental Malaria. Front Immunol 2021; 11:624126. [PMID: 33633743 PMCID: PMC7900151 DOI: 10.3389/fimmu.2020.624126] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 12/23/2020] [Indexed: 12/04/2022] Open
Abstract
Over 30 million women living in P. falciparum endemic areas are at risk of developing malaria during pregnancy every year. Placental malaria is characterized by massive accumulation of infected erythrocytes in the intervillous space of the placenta, accompanied by infiltration of immune cells, particularly monocytes. The consequent local inflammation and the obstruction of the maternofetal exchanges can lead to severe clinical outcomes for both mother and child. Even if protection against the disease can gradually be acquired following successive pregnancies, the malaria parasite has developed a large panel of evasion mechanisms to escape from host defense mechanisms and manipulate the immune system to its advantage. Infected erythrocytes isolated from placentas of women suffering from placental malaria present a unique phenotype and express the pregnancy-specific variant VAR2CSA of the Plasmodium falciparum Erythrocyte Membrane Protein (PfEMP1) family at their surface. The polymorphic VAR2CSA protein is able to mediate the interaction of infected erythrocytes with a variety of host cells including placental syncytiotrophoblasts and leukocytes but also with components of the immune system such as non-specific IgM. This review summarizes the described VAR2CSA-mediated host defense evasion mechanisms employed by the parasite during placental malaria to ensure its survival and persistence.
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Affiliation(s)
- Alice Tomlinson
- Université de Paris, Biologie Intégrée du Globule Rouge, UMR_S1134, BIGR, INSERM, Paris, France.,Institut National de la Transfusion Sanguine, Paris, France.,Laboratory of Excellence GR-Ex, Paris, France
| | - Jean-Philippe Semblat
- Université de Paris, Biologie Intégrée du Globule Rouge, UMR_S1134, BIGR, INSERM, Paris, France.,Institut National de la Transfusion Sanguine, Paris, France.,Laboratory of Excellence GR-Ex, Paris, France
| | - Benoît Gamain
- Université de Paris, Biologie Intégrée du Globule Rouge, UMR_S1134, BIGR, INSERM, Paris, France.,Institut National de la Transfusion Sanguine, Paris, France.,Laboratory of Excellence GR-Ex, Paris, France
| | - Arnaud Chêne
- Université de Paris, Biologie Intégrée du Globule Rouge, UMR_S1134, BIGR, INSERM, Paris, France.,Institut National de la Transfusion Sanguine, Paris, France.,Laboratory of Excellence GR-Ex, Paris, France
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12
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Doritchamou JYA, Suurbaar J, Tuikue Ndam N. Progress and new horizons toward a VAR2CSA-based placental malaria vaccine. Expert Rev Vaccines 2021; 20:215-226. [PMID: 33472449 DOI: 10.1080/14760584.2021.1878029] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Introduction: Several malaria vaccines are under various phases of development with some promising results. In placental malaria (PM) a deliberately anti-disease approach is considered as many studies have underlined the key role of VAR2CSA protein, which therefore represents the leading vaccine candidate. However, evidence indicates that VAR2CSA antigenic polymorphism remains an obstacle to overcome.Areas covered: This review analyzes the progress made thus far in developing a VAR2CSA-based vaccine, and addresses the current issues and challenges that must be overcome to develop an effective PM vaccine.Expert opinion: Phase I trials of PAMVAC and PRIMVAC VAR2CSA vaccines have shown more or less satisfactory results with regards to safety and immunogenicity. The second generation of VAR2CSA-based vaccines could benefit from optimization approaches to broaden the activity spectrum against various placenta-binding isolates through continued advances in the structural understanding of the interaction with CSA.
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Affiliation(s)
- Justin Yai Alamou Doritchamou
- Laboratory of Malaria Immunology & Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Jennifer Suurbaar
- Université de Paris, MERIT, IRD, F-75006 Paris, France.,Noguchi Memorial Institute for Medical Research, Department of Immunology, University of Ghana, Accra, Ghana
| | - Nicaise Tuikue Ndam
- Université de Paris, MERIT, IRD, F-75006 Paris, France.,Noguchi Memorial Institute for Medical Research, Department of Immunology, University of Ghana, Accra, Ghana
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13
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Kana MA, Safiyan H, Yusuf HE, Musa ASM, Richards-Barber M, Harmon QE, London SJ. Association of intimate partner violence during pregnancy and birth weight among term births: a cross-sectional study in Kaduna, Northwestern Nigeria. BMJ Open 2020; 10:e036320. [PMID: 33268398 PMCID: PMC7716372 DOI: 10.1136/bmjopen-2019-036320] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
OBJECTIVE To determine the association of prenatal exposure to intimate partner violence (IPV) with birth weight as a continuous variable among term births in a Nigerian population. DESIGN Cross-sectional study. SETTING Mother-child pairs recruited when their newborns were brought for BCG or other vaccines shortly after birth at the Child Welfare Clinic of Barau Dikko Teaching Hospital, Kaduna, Nigeria. PARTICIPANTS 293 women with term birth infants. MAIN EXPOSURE AND OUTCOME MEASURES Emotional, physical and sexual IPV were measured postnatally by interview using the Conflict Tactics Scale. Birth weight in grams was the main outcome measure. Linear regression, with adjustment for covariates, was used to estimate associations between birth weight and exposure to the presence, and frequency, of IPV. RESULTS Sixty-seven per cent of mothers experienced at least one of the three forms of IPV during pregnancy. Relative to the 33% of women with no prenatal exposure to any form of IPV, we observed a reduction in birth weight of 94 g (95% CI: -202 to 15) for prenatal exposure to emotional IPV, 162 g (95% CI -267 to -58) for physical IPV and 139 g (95% CI -248 to -30) for sexual IPV. The combination of all three forms of IPV was associated with a 223 g reduction in birth weight (95% CI -368 to -77). Increasing occurrences of each of the three types of IPV were associated with greater reductions in birth weight. For physical IPV, relative to no exposure to any form of IPV, birth weight was lower by 112 g (95% CI -219 to -4) with 1-5 instances and 380 g (95% CI -553 to -206) for >5 instances over the pregnancy. CONCLUSIONS Maternal exposure to IPV was associated with shifting of the birth weight distribution among term newborns. A dose-response relationship was observed between frequency of IPV and birth weight.
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Affiliation(s)
- Musa Abubakar Kana
- Epidemiology Branch, National Institute of Environmental Health Sciences, National Institutes of Health, Durham, North Carolina, USA
- Department of Epidemiology and Community Medicine, Federal University Lafia, Lafia, Nigeria
- Department of Community Medicine, Kaduna State University, Kaduna, Nigeria
| | - Halima Safiyan
- Department of Social Sciences, Kaduna Polytechnic, Kaduna, Nigeria
| | | | | | | | - Quaker E Harmon
- Epidemiology Branch, National Institute of Environmental Health Sciences, National Institutes of Health, Durham, North Carolina, USA
| | - Stephanie J London
- Epidemiology Branch, National Institute of Environmental Health Sciences, National Institutes of Health, Durham, North Carolina, USA
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14
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Abstract
Purpose of Review Placental malaria is the primary mechanism through which malaria in pregnancy causes adverse perinatal outcomes. This review summarizes recent work on the significance, pathogenesis, diagnosis, and prevention of placental malaria. Recent Findings Placental malaria, characterized by the accumulation of Plasmodium-infected red blood cells in the placental intervillous space, leads to adverse perinatal outcomes such as stillbirth, low birth weight, preterm birth, and small-for-gestational-age neonates. Placental inflammatory responses may be primary drivers of these complications. Associated factors contributing to adverse outcomes include maternal gravidity, timing of perinatal infection, and parasite burden. Summary Placental malaria is an important cause of adverse birth outcomes in endemic regions. The main strategy to combat this is intermittent preventative treatment in pregnancy; however, increasing drug resistance threatens the efficacy of this approach. There are studies dissecting the inflammatory response to placental malaria, alternative preventative treatments, and in developing a vaccine for placental malaria.
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15
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Tette EMA, Nartey ET, Nuertey BD, Azusong EA, Akaateba D, Yirifere J, Alandu A, Seneadza NAH, Gandau NB, Renner LA. The pattern of neonatal admissions and mortality at a regional and district hospital in the Upper West Region of Ghana; a cross sectional study. PLoS One 2020; 15:e0232406. [PMID: 32365073 PMCID: PMC7197810 DOI: 10.1371/journal.pone.0232406] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Accepted: 04/14/2020] [Indexed: 12/17/2022] Open
Abstract
Background High global neonatal deaths have triggered efforts to improve facility-based care. However, the outcomes achievable at different levels of care are unclear. This study compared morbidity and mortality patterns of newborns admitted to a regional and a district hospital in Ghana to determine outcome, risk and modifiable factors associated with mortality. Objective This study compared morbidity and mortality patterns of newborns admitted to a regional and a district hospital in Ghana to determine outcome, risk and modifiable factors associated with mortality Methods A cross-sectional study involving a records-review over one year at the Upper West Regional Hospital, and three years at St Joseph’s District Hospital, Jirapa was carried out. Age, sex, gestational age, weight, duration of admission, diagnosis, among others were examined. The data were analysed and statistical inference made. Results Altogether, 2004 newborns were examined, comprising 1,241(62%) from St Joseph’s District Hospital and 763(38%) from Upper West Regional Hospital. The proportion of neonatal deaths was similar, 8.94% (St Joseph’s District Hospital) and 8.91% (Upper West Regional Hospital). Prematurity, neonatal sepsis, birth asphyxia, low birth weight, neonatal jaundice and pneumonia contributed the most to mortality and suspected infections including malaria accounted for almost half (45.5%). Mortality was significantly associated with duration of stay of 48 hours, being premature, and being younger than 3 days. Conclusion Majority of the mortality among the neonates admitted was due to preventable causes. Better stabilization and further studies on the epidemiology of sepsis, prematurity, low birth weight, including the contribution of malaria to these and outcome of transferred neonates are needed.
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Affiliation(s)
- Edem M. A. Tette
- Department of Community Health, University of Ghana Medical School, Accra, Ghana
- * E-mail: (EMAT); (ETN)
| | - Edmund T. Nartey
- Centre for Tropical Clinical Pharmacology and Therapeutics, University of Ghana Medical School, Accra, Ghana
- * E-mail: (EMAT); (ETN)
| | - Benjamin D. Nuertey
- Department of Community Health, University of Ghana Medical School, Accra, Ghana
- Public Health Department, Tamale Teaching Hospital, Tamale, Ghana
| | | | | | | | | | | | - Naa Barnabas Gandau
- Upper West Regional Hospital, Wa, Ghana
- School of Medical Sciences, University for Development Studies, Tamale, Ghana
| | - Lorna A. Renner
- Department of Child Health, University of Ghana Medical School, Accra, Ghana
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16
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PRIMVAC vaccine adjuvanted with Alhydrogel or GLA-SE to prevent placental malaria: a first-in-human, randomised, double-blind, placebo-controlled study. THE LANCET. INFECTIOUS DISEASES 2020; 20:585-597. [DOI: 10.1016/s1473-3099(19)30739-x] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 10/22/2019] [Accepted: 12/03/2019] [Indexed: 10/25/2022]
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17
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Nelson CS, Sumner KM, Freedman E, Saelens JW, Obala AA, Mangeni JN, Taylor SM, O'Meara WP. High-resolution micro-epidemiology of parasite spatial and temporal dynamics in a high malaria transmission setting in Kenya. Nat Commun 2019; 10:5615. [PMID: 31819062 PMCID: PMC6901486 DOI: 10.1038/s41467-019-13578-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Accepted: 11/14/2019] [Indexed: 01/03/2023] Open
Abstract
Novel interventions that leverage the heterogeneity of parasite transmission are needed to achieve malaria elimination. To better understand spatial and temporal dynamics of transmission, we applied amplicon next-generation sequencing of two polymorphic gene regions (csp and ama1) to a cohort identified via reactive case detection in a high-transmission setting in western Kenya. From April 2013 to July 2014, we enrolled 442 symptomatic children with malaria, 442 matched controls, and all household members of both groups. Here, we evaluate genetic similarity between infected individuals using three indices: sharing of parasite haplotypes on binary and proportional scales and the L1 norm. Symptomatic children more commonly share haplotypes with their own household members. Furthermore, we observe robust temporal structuring of parasite genetic similarity and identify the unique molecular signature of an outbreak. These findings of both micro- and macro-scale organization of parasite populations might be harnessed to inform next-generation malaria control measures. Here, Nelson et al. use amplicon next-generation sequencing of two P. falciparum polymorphic gene regions to investigate the genetic similarity of parasite populations across time and space in a pediatric cohort in Kenya. They identify both micro- and macro-scale structuring of malaria parasites in this high-transmission setting, which could inform future intervention strategies.
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Affiliation(s)
- Cody S Nelson
- Duke Global Health Institute, Duke University, Durham, North Carolina, USA.
| | - Kelsey M Sumner
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina, USA.,Division of Infectious Diseases, Duke University School of Medicine, Durham, North Carolina, USA
| | - Elizabeth Freedman
- Division of Infectious Diseases, Duke University School of Medicine, Durham, North Carolina, USA
| | - Joseph W Saelens
- Division of Infectious Diseases, Duke University School of Medicine, Durham, North Carolina, USA
| | - Andrew A Obala
- School of Medicine, Moi University College of Health Sciences, Eldoret, Kenya
| | - Judith N Mangeni
- School of Nursing, Moi University College of Health Sciences, Eldoret, Kenya
| | - Steve M Taylor
- Duke Global Health Institute, Duke University, Durham, North Carolina, USA.,Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina, USA.,Division of Infectious Diseases, Duke University School of Medicine, Durham, North Carolina, USA
| | - Wendy P O'Meara
- Duke Global Health Institute, Duke University, Durham, North Carolina, USA.,Division of Infectious Diseases, Duke University School of Medicine, Durham, North Carolina, USA
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18
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Early AM, Daniels RF, Farrell TM, Grimsby J, Volkman SK, Wirth DF, MacInnis BL, Neafsey DE. Detection of low-density Plasmodium falciparum infections using amplicon deep sequencing. Malar J 2019; 18:219. [PMID: 31262308 PMCID: PMC6604269 DOI: 10.1186/s12936-019-2856-1] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Accepted: 06/25/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Deep sequencing of targeted genomic regions is becoming a common tool for understanding the dynamics and complexity of Plasmodium infections, but its lower limit of detection is currently unknown. Here, a new amplicon analysis tool, the Parallel Amplicon Sequencing Error Correction (PASEC) pipeline, is used to evaluate the performance of amplicon sequencing on low-density Plasmodium DNA samples. Illumina-based sequencing of two Plasmodium falciparum genomic regions (CSP and SERA2) was performed on two types of samples: in vitro DNA mixtures mimicking low-density infections (1-200 genomes/μl) and extracted blood spots from a combination of symptomatic and asymptomatic individuals (44-653,080 parasites/μl). Three additional analysis tools-DADA2, HaplotypR, and SeekDeep-were applied to both datasets and the precision and sensitivity of each tool were evaluated. RESULTS Amplicon sequencing can contend with low-density samples, showing reasonable detection accuracy down to a concentration of 5 Plasmodium genomes/μl. Due to increased stochasticity and background noise, however, all four tools showed reduced sensitivity and precision on samples with very low parasitaemia (< 5 copies/μl) or low read count (< 100 reads per amplicon). PASEC could distinguish major from minor haplotypes with an accuracy of 90% in samples with at least 30 Plasmodium genomes/μl, but only 61% at low Plasmodium concentrations (< 5 genomes/μl) and 46% at very low read counts (< 25 reads per amplicon). The four tools were additionally used on a panel of extracted parasite-positive blood spots from natural malaria infections. While all four identified concordant patterns of complexity of infection (COI) across four sub-Saharan African countries, COI values obtained for individual samples differed in some cases. CONCLUSIONS Amplicon deep sequencing can be used to determine the complexity and diversity of low-density Plasmodium infections. Despite differences in their approach, four state-of-the-art tools resolved known haplotype mixtures with similar sensitivity and precision. Researchers can therefore choose from multiple robust approaches for analysing amplicon data, however, error filtration approaches should not be uniformly applied across samples of varying parasitaemia. Samples with very low parasitaemia and very low read count have higher false positive rates and call for read count thresholds that are higher than current default recommendations.
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Affiliation(s)
- Angela M Early
- Infectious Disease and Microbiome Program, Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA.
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA, 02115, USA.
| | - Rachel F Daniels
- Infectious Disease and Microbiome Program, Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA, 02115, USA
| | - Timothy M Farrell
- Infectious Disease and Microbiome Program, Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA, 02115, USA
| | - Jonna Grimsby
- Genomics Platform, Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA
| | - Sarah K Volkman
- Infectious Disease and Microbiome Program, Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA, 02115, USA
- College of Natural, Behavioral, and Health Sciences, Simmons University, Boston, MA, 02115, USA
| | - Dyann F Wirth
- Infectious Disease and Microbiome Program, Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA, 02115, USA
| | - Bronwyn L MacInnis
- Infectious Disease and Microbiome Program, Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA, 02115, USA
| | - Daniel E Neafsey
- Infectious Disease and Microbiome Program, Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA, 02115, USA
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19
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Progress towards vaccines to protect pregnant women from malaria. EBioMedicine 2019; 42:12-13. [PMID: 30904605 PMCID: PMC6491615 DOI: 10.1016/j.ebiom.2019.03.042] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Accepted: 03/15/2019] [Indexed: 11/21/2022] Open
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20
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Abstract
The blood stage of the malaria parasite life cycle is responsible for all the clinical symptoms of malaria. During the blood stage, Plasmodium merozoites invade and multiply within host red blood cells (RBCs). Here, we review the progress made, challenges faced, and new strategies available for the development of blood stage malaria vaccines. We discuss our current understanding of immune responses against blood stages and the status of clinical development of various blood stage malaria vaccine candidates. We then discuss possible paths forward to develop effective blood stage malaria vaccines. This includes a discussion of protective immune mechanisms that can be elicited to target blood stage parasites, novel delivery systems, immunoassays and animal models to optimize vaccine candidates in preclinical studies, and use of challenge models to get an early readout of vaccine efficacy.
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21
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Waltmann A, Patel JC, Thwai KL, Hathaway NJ, Parobek CM, Massougbodji A, Fievet N, Bailey JA, Deloron P, Juliano JJ, Ndam NT, Meshnick SR. Matched Placental and Circulating Plasmodium falciparum Parasites are Genetically Homologous at the var2csa ID1-DBL2X Locus by Deep Sequencing. Am J Trop Med Hyg 2018; 98:77-82. [PMID: 29342401 DOI: 10.4269/ajtmh.17-0529] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
In pregnancy-associated malaria, infected erythrocytes accumulate in the placenta. It is unclear if in polyclonal infections this results in distinct peripheral and placental parasite populations. We used long amplicon deep sequencing of Plasmodium falciparum var2csa ID1-DBL2X from 15 matched peripheral and placental samples collected at delivery from a high transmission area to determine genetic homology. Despite substantial sequence variation and detecting 23 haplotypes, the matched pairs mostly contained the same genetic variants, with 11 pairs sharing 100% of their variants, whereas others showed some heterogeneity. Thus, at delivery, peripheral and placental parasites appear to intermix and placental genotypes can be inferred through peripheral sampling.
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Affiliation(s)
- Andreea Waltmann
- Institute for Global Health and Infectious Diseases, School of Medicine, University of North Carolina, Chapel Hill, North Carolina
| | - Jaymin C Patel
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina
| | - Kyaw L Thwai
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina
| | - Nicholas J Hathaway
- Program in Bioinformatics and Integrative Biology, University of Massachusetts, Worcester, Massachusetts
| | - Christian M Parobek
- Curriculum in Genetics and Molecular Biology, University of North Carolina, Chapel Hill, North Carolina
| | - Achille Massougbodji
- Centre d'Etude et de Recherche sur le paludisme associé à la Grossesse et à l'Enfance, Université d'Abomey-Calavi, Cotonou, Benin
| | - Nadine Fievet
- UMR216 - MERIT, Institut de Recherche pour le Développement, COMUE Sorbonne Paris Cité, Université Paris Descartes, Paris, France
| | - Jeffery A Bailey
- Division of Transfusion Medicine, Department of Medicine, University of Massachusetts, Worcester, Massachusetts.,Program in Bioinformatics and Integrative Biology, University of Massachusetts, Worcester, Massachusetts
| | - Philippe Deloron
- UMR216 - MERIT, Institut de Recherche pour le Développement, COMUE Sorbonne Paris Cité, Université Paris Descartes, Paris, France
| | - Jonathan J Juliano
- Curriculum in Genetics and Molecular Biology, University of North Carolina, Chapel Hill, North Carolina.,Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina.,Institute for Global Health and Infectious Diseases, School of Medicine, University of North Carolina, Chapel Hill, North Carolina
| | - Nicaise Tuikue Ndam
- UMR216 - MERIT, Institut de Recherche pour le Développement, COMUE Sorbonne Paris Cité, Université Paris Descartes, Paris, France
| | - Steven R Meshnick
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina.,Institute for Global Health and Infectious Diseases, School of Medicine, University of North Carolina, Chapel Hill, North Carolina
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22
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Global genetic diversity of var2csa in Plasmodium falciparum with implications for malaria in pregnancy and vaccine development. Sci Rep 2018; 8:15429. [PMID: 30337594 PMCID: PMC6193930 DOI: 10.1038/s41598-018-33767-3] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 10/06/2018] [Indexed: 12/24/2022] Open
Abstract
Malaria infection during pregnancy, caused by the sequestering of Plasmodium falciparum parasites in the placenta, leads to high infant mortality and maternal morbidity. The parasite-placenta adherence mechanism is mediated by the VAR2CSA protein, a target for natural occurring immunity. Currently, vaccine development is based on its ID1-DBL2Xb domain however little is known about the global genetic diversity of the encoding var2csa gene, which could influence vaccine efficacy. In a comprehensive analysis of the var2csa gene in >2,000 P. falciparum field isolates across 23 countries, we found that var2csa is duplicated in high prevalence (>25%), African and Oceanian populations harbour a much higher diversity than other regions, and that insertions/deletions are abundant leading to an underestimation of the diversity of the locus. Further, ID1-DBL2Xb haplotypes associated with adverse birth outcomes are present globally, and African-specific haplotypes exist, which should be incorporated into vaccine design.
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23
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Zhong D, Koepfli C, Cui L, Yan G. Molecular approaches to determine the multiplicity of Plasmodium infections. Malar J 2018; 17:172. [PMID: 29685152 PMCID: PMC5914063 DOI: 10.1186/s12936-018-2322-5] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Accepted: 04/18/2018] [Indexed: 12/26/2022] Open
Abstract
Multiplicity of infection (MOI), also termed complexity of infection (COI), is defined as the number of genetically distinct parasite strains co-infecting a single host, which is an important indicator of malaria epidemiology. PCR-based genotyping often underestimates MOI. Next generation sequencing technologies provide much more accurate and genome-wide characterization of polyclonal infections. However, complete haplotype characterization of multiclonal infections remains a challenge due to PCR artifacts and sequencing errors, and requires efficient computational tools. In this review, the advantages and limitations of current molecular approaches to determine multiplicity of malaria parasite infection are discussed.
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Affiliation(s)
- Daibin Zhong
- Program in Public Health, University of California, Irvine, CA, 92617, USA.
| | - Cristian Koepfli
- Program in Public Health, University of California, Irvine, CA, 92617, USA
| | - Liwang Cui
- Department of Entomology, Pennsylvania State University, University Park, PA, 16802, USA
| | - Guiyun Yan
- Program in Public Health, University of California, Irvine, CA, 92617, USA.
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Verity R, Hathaway NJ, Waltmann A, Doctor SM, Watson OJ, Patel JC, Mwandagalirwa K, Tshefu AK, Bailey JA, Ghani AC, Juliano JJ, Meshnick SR. Plasmodium falciparum genetic variation of var2csa in the Democratic Republic of the Congo. Malar J 2018; 17:46. [PMID: 29361940 PMCID: PMC5782373 DOI: 10.1186/s12936-018-2193-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Accepted: 01/17/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The Democratic Republic of the Congo (DRC) bears a high burden of malaria, which is exacerbated in pregnant women. The VAR2CSA protein plays a crucial role in pregnancy-associated malaria (PAM), and hence quantifying diversity at the var2csa locus in the DRC is important in understanding the basic epidemiology of PAM, and in developing a robust vaccine against PAM. METHODS Samples were taken from the 2013-14 Demographic and Health Survey conducted in the DRC, focusing on children under 5 years of age. A short subregion of the var2csa gene was sequenced in 115 spatial clusters, giving country-wide estimates of sequence polymorphism and spatial population structure. RESULTS Results indicate that var2csa is highly polymorphic, and that diversity is being maintained through balancing selection, however, there is no clear signal of phylogenetic or geographic structure to this diversity. Linear modelling demonstrates that the number of var2csa variants in a cluster correlates directly with cluster prevalence, but not with other epidemiological factors such as urbanicity. CONCLUSIONS Results suggest that the DRC fits within the global pattern of high var2csa diversity and little genetic differentiation between regions. A broad multivalent VAR2CSA vaccine candidate could benefit from targeting stable regions and common variants to address the substantial genetic diversity.
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Affiliation(s)
- Robert Verity
- Medical Research Council Centre for Outbreak Analysis & Modelling, Department of Infectious Disease Epidemiology, Imperial College London, London, UK.
| | - Nicholas J Hathaway
- Program in Bioinformatics and Integrative Biology, University of Massachusetts, Worcester, MA, USA
- Division of Transfusion Medicine, Department of Medicine, University of Massachusetts, Worcester, MA, USA
| | - Andreea Waltmann
- Institute for Global Health and Infectious Diseases, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, USA
| | - Stephanie M Doctor
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, USA
| | - Oliver J Watson
- Medical Research Council Centre for Outbreak Analysis & Modelling, Department of Infectious Disease Epidemiology, Imperial College London, London, UK
| | - Jaymin C Patel
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, USA
| | - Kashamuka Mwandagalirwa
- Kinshasa School of Public Health, Hôpital General Provincial de Reference de Kinshasa, Kinshasa, Democratic Republic of Congo
| | - Antoinette K Tshefu
- Community Health, Kinshasa School of Public Health, School of Medicine, University of Kinshasa, Kinshasa, Democratic Republic of Congo
| | - Jeffrey A Bailey
- Program in Bioinformatics and Integrative Biology, University of Massachusetts, Worcester, MA, USA
- Division of Transfusion Medicine, Department of Medicine, University of Massachusetts, Worcester, MA, USA
| | - Azra C Ghani
- Medical Research Council Centre for Outbreak Analysis & Modelling, Department of Infectious Disease Epidemiology, Imperial College London, London, UK
| | - Jonathan J Juliano
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, USA
- Division of Infectious Diseases, University of North Carolina at Chapel Hill, 130 Mason Farm Road, Chapel Hill, 27599, USA
- Curriculum in Genetics and Microbiology, University of North Carolina at Chapel Hill, 321 South Columbia Street, Chapel Hill, NC, 27516, USA
| | - Steven R Meshnick
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, USA
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