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Mortazavi SE, Lugaajju A, Nylander M, Danielsson L, Tijani MK, Beeson JG, Persson KEM. Acquisition of complement fixing antibodies targeting Plasmodium falciparum merozoites in infants and their mothers in Uganda. Front Immunol 2023; 14:1295543. [PMID: 38090561 PMCID: PMC10715273 DOI: 10.3389/fimmu.2023.1295543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2023] [Accepted: 11/10/2023] [Indexed: 12/18/2023] Open
Abstract
Background Antibody-mediated complement fixation has previously been associated with protection against malaria in naturally acquired immunity. However, the process of early-life development of complement-fixing antibodies in infants, both in comparison to their respective mothers and to other immune parameters, remains less clear. Results We measured complement-fixing antibodies in newborns and their mothers in a malaria endemic area over 5 years follow-up and found that infants' complement-fixing antibody levels were highest at birth, decreased until six months, then increased progressively until they were similar to birth at five years. Infants with high levels at birth experienced a faster decay of complement-fixing antibodies but showed similar levels to the low response group of newborns thereafter. No difference was observed in antibody levels between infant cord blood and mothers at delivery. The same result was found when categorized into high and low response groups, indicating placental transfer of antibodies. Complement-fixing antibodies were positively correlated with total schizont-specific IgG and IgM levels in mothers and infants at several time points. At nine months, complement-fixing antibodies were negatively correlated with total B cell frequency and osteopontin concentrations in the infants, while positively correlated with atypical memory B cells and P. falciparum-positive atypical memory B cells. Conclusion This study indicates that complement-fixing antibodies against P. falciparum merozoites are produced in the mothers and placentally-transferred, and they are acquired in infants over time during the first years of life. Understanding early life immune responses is crucial for developing a functional, long lasting malaria vaccine.
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Affiliation(s)
- Susanne E. Mortazavi
- Department of Laboratory Medicine, Lund University, Lund, Sweden
- Department of Infectious Diseases, Skåne University Hospital, Lund, Sweden
| | - Allan Lugaajju
- College of Health Sciences, Makerere University, Kampala, Uganda
| | - Maria Nylander
- Department of Laboratory Medicine, Lund University, Lund, Sweden
| | - Lena Danielsson
- Department of Laboratory Medicine, Lund University, Lund, Sweden
- Clinical Chemistry and Pharmacology, Laboratory Medicine, Office for Medical Services, Region Skåne, Lund, Sweden
| | - Muyideen Kolapo Tijani
- Department of Laboratory Medicine, Lund University, Lund, Sweden
- Cellular Parasitology Program, Cell Biology and Genetics Unit, Department of Zoology, University of Ibadan, Ibadan, Nigeria
| | - James G. Beeson
- The Burnet Institute, Melbourne, VIC, Australia
- Department of Infectious Diseases, University of Melbourne, Melbourne, VIC, Australia
- Central Clinical School and Department of Microbiology, Monash University, Melbourne, VIC, Australia
| | - Kristina E. M. Persson
- Department of Laboratory Medicine, Lund University, Lund, Sweden
- Clinical Chemistry and Pharmacology, Laboratory Medicine, Office for Medical Services, Region Skåne, Lund, Sweden
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Natama HM, Moncunill G, Vidal M, Rouamba T, Aguilar R, Santano R, Rovira-Vallbona E, Jiménez A, Somé MA, Sorgho H, Valéa I, Coulibaly-Traoré M, Coppel RL, Cavanagh D, Chitnis CE, Beeson JG, Angov E, Dutta S, Gamain B, Izquierdo L, Mens PF, Schallig HDFH, Tinto H, Rosanas-Urgell A, Dobaño C. Associations between prenatal malaria exposure, maternal antibodies at birth, and malaria susceptibility during the first year of life in Burkina Faso. Infect Immun 2023; 91:e0026823. [PMID: 37754682 PMCID: PMC10580994 DOI: 10.1128/iai.00268-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Accepted: 08/12/2023] [Indexed: 09/28/2023] Open
Abstract
In this study, we investigated how different categories of prenatal malaria exposure (PME) influence levels of maternal antibodies in cord blood samples and the subsequent risk of malaria in early childhood in a birth cohort study (N = 661) nested within the COSMIC clinical trial (NCT01941264) in Burkina Faso. Plasmodium falciparum infections during pregnancy and infants' clinical malaria episodes detected during the first year of life were recorded. The levels of maternal IgG and IgG1-4 to 15 P. falciparum antigens were measured in cord blood by quantitative suspension array technology. Results showed a significant variation in the magnitude of maternal antibody levels in cord blood, depending on the PME category, with past placental malaria (PM) more frequently associated with significant increases of IgG and/or subclass levels across three groups of antigens defined as pre-erythrocytic, erythrocytic, and markers of PM, as compared to those from the cord of non-exposed control infants. High levels of antibodies to certain erythrocytic antigens (i.e., IgG to EBA140 and EBA175, IgG1 to EBA175 and MSP142, and IgG3 to EBA140 and MSP5) were independent predictors of protection from clinical malaria during the first year of life. By contrast, high levels of IgG, IgG1, and IgG2 to the VAR2CSA DBL1-2 and IgG4 to DBL3-4 were significantly associated with an increased risk of clinical malaria. These findings indicate that PME categories have different effects on the levels of maternal-derived antibodies to malaria antigens in children at birth, and this might drive heterogeneity to clinical malaria susceptibility in early childhood.
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Affiliation(s)
- Hamtandi Magloire Natama
- Unité de Recherche Clinique de Nanoro, Institut de Recherche en Sciences de la Santé, Direction Régionale du Centre-Ouest, Nanoro, Burkina Faso
| | - Gemma Moncunill
- Barcelona Institute for Global Health (ISGlobal), Hospital Clínic – Universitat de Barcelona, Barcelona, Spain
- CIBER de Enfermedades Infecciosas (CIBERINFEC), Barcelona, Spain
| | - Marta Vidal
- Barcelona Institute for Global Health (ISGlobal), Hospital Clínic – Universitat de Barcelona, Barcelona, Spain
| | - Toussaint Rouamba
- Unité de Recherche Clinique de Nanoro, Institut de Recherche en Sciences de la Santé, Direction Régionale du Centre-Ouest, Nanoro, Burkina Faso
| | - Ruth Aguilar
- Barcelona Institute for Global Health (ISGlobal), Hospital Clínic – Universitat de Barcelona, Barcelona, Spain
| | - Rebeca Santano
- Barcelona Institute for Global Health (ISGlobal), Hospital Clínic – Universitat de Barcelona, Barcelona, Spain
- CIBER de Enfermedades Infecciosas (CIBERINFEC), Barcelona, Spain
| | - Eduard Rovira-Vallbona
- Barcelona Institute for Global Health (ISGlobal), Hospital Clínic – Universitat de Barcelona, Barcelona, Spain
| | - Alfons Jiménez
- Barcelona Institute for Global Health (ISGlobal), Hospital Clínic – Universitat de Barcelona, Barcelona, Spain
- CIBER de Epidemiologia y Salud Pública (CIBERESP), Barcelona, Spain
| | - M. Athanase Somé
- Unité de Recherche Clinique de Nanoro, Institut de Recherche en Sciences de la Santé, Direction Régionale du Centre-Ouest, Nanoro, Burkina Faso
| | - Hermann Sorgho
- Unité de Recherche Clinique de Nanoro, Institut de Recherche en Sciences de la Santé, Direction Régionale du Centre-Ouest, Nanoro, Burkina Faso
| | - Innocent Valéa
- Unité de Recherche Clinique de Nanoro, Institut de Recherche en Sciences de la Santé, Direction Régionale du Centre-Ouest, Nanoro, Burkina Faso
| | - Maminata Coulibaly-Traoré
- Unité de Recherche Clinique de Nanoro, Institut de Recherche en Sciences de la Santé, Direction Régionale du Centre-Ouest, Nanoro, Burkina Faso
| | - Ross L. Coppel
- Infection and Immunity Program, Department of Microbiology, Monash Biomedicine Discovery Institute, Monash University, Melbourne, Victoria, Australia
| | - David Cavanagh
- Centre for Immunity, Infection & Evolution, Institute of Immunology & Infection Research, Ashworth Laboratories, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Chetan E. Chitnis
- Malaria Parasite Biology and Vaccines Unit, Department of Parasites and Insect Vectors, Institut Pasteur, Université de Paris, Paris, France
| | | | - Evelina Angov
- U.S. Military Malaria Vaccine Program, Walter Reed Army Institute of Research (WRAIR), Silver Spring, Maryland, USA
| | - Sheetij Dutta
- U.S. Military Malaria Vaccine Program, Walter Reed Army Institute of Research (WRAIR), Silver Spring, Maryland, USA
| | | | - Luis Izquierdo
- Barcelona Institute for Global Health (ISGlobal), Hospital Clínic – Universitat de Barcelona, Barcelona, Spain
- CIBER de Enfermedades Infecciosas (CIBERINFEC), Barcelona, Spain
| | - Petra F. Mens
- Academic Medical Centre at the University of Amsterdam, Amsterdam, the Netherlands
| | | | - Halidou Tinto
- Unité de Recherche Clinique de Nanoro, Institut de Recherche en Sciences de la Santé, Direction Régionale du Centre-Ouest, Nanoro, Burkina Faso
| | - Anna Rosanas-Urgell
- Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium
| | - Carlota Dobaño
- Barcelona Institute for Global Health (ISGlobal), Hospital Clínic – Universitat de Barcelona, Barcelona, Spain
- CIBER de Enfermedades Infecciosas (CIBERINFEC), Barcelona, Spain
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Tassi Yunga S, Siriwardhana C, Fouda GG, Bobbili N, Sama G, Chen JJ, Leke RFG, Taylor DW. Characterization of the primary antibody response to Plasmodium falciparum antigens in infants living in a malaria-endemic area. Malar J 2022; 21:346. [PMCID: PMC9675181 DOI: 10.1186/s12936-022-04360-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2022] [Accepted: 11/03/2022] [Indexed: 11/21/2022] Open
Abstract
Background The primary antibody (Ab) response to Plasmodium falciparum is a critical step in developing immunity to malaria. Information on the initial Ab responses of babies in malaria-endemic areas is incomplete, in part, because babies receive maternal IgG via transplacental-transfer and usually become infected before maternal IgG wanes. The study aimed to identify the primary IgM and IgG Ab responses to malarial antigens in Cameroonian babies. Methods Infants (n = 70) living in a high malaria transmission area were followed from birth throughout the first year of life (mean 341 ± 42 days, an average of 8.5 time points per infant). Malaria infection was assessed by microscopy and PCR, and IgM and IgG antibodies (Abs) were measured using a multiplex immunoassay to AMA1, EBA-175, MSP1-42, MSP2, MSP3, RESA, LSA1, and CSP. Results The half-life of maternal IgG varied among the antigens, ranging from 0.7 to 2.5 months. The first infection of 41% of the babies was sub-microscopic and only 11 to 44% of the babies produced IgM to the above antigens; however, when the first infection was detected by microscopy, 59–82% of the infants made IgM Abs to the antigens. Infants were able to produce IgM even when maternal IgG was present, suggesting maternal Abs did not suppress the baby’s initial Ab response. Using longitudinal regression models that incorporated time-varying covariates, infants were found to produce IgG Ab to only AMA-1 when the first infection was sub-microscopic, but they produced IgG Abs to MSP1-42 (3D7, FVO), AMA1 (3D7, FVO) MSP2-FC27, MSP3, RESA, and LSA1, but not MSP 2-3D7, EBA-175, and CSP during their first slide-positive infection. Notably, the primary and secondary IgG responses were short-lived with little evidence of boosting. Conclusions The primary Ab response of babies who had maternal IgG was similar to that reported for primary infections in malaria-naïve adults. Supplementary Information The online version contains supplementary material available at 10.1186/s12936-022-04360-x.
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Affiliation(s)
- Samuel Tassi Yunga
- grid.410445.00000 0001 2188 0957Department of Tropical Medicine, Medical Microbiology and Pharmacology, John A. Burns School of Medicine, University of Hawaii at Manoa, 651 Ilalo Street, Bioscience Building Suite 320, Honolulu, HI 96813 USA ,grid.5288.70000 0000 9758 5690Cancer Early Detection Advanced Research Center (CEDAR), School of Medicine, Knight Cancer Institute, Oregon Health & Science University, 2720 S. Moody Avenue, Portland, OR USA
| | - Chathura Siriwardhana
- grid.410445.00000 0001 2188 0957Department of Quantitative Health Sciences, John A. Burns School of Medicine, University of Hawaii at Manoa, 651 Ilalo Street, MEB411, Honolulu, HI 96813 USA
| | - Genevieve G. Fouda
- grid.5386.8000000041936877XDepartment of Pediatrics, Joan & Sanford I. Weill Medical College of Cornell University, New York, NY USA
| | - Naveen Bobbili
- grid.410445.00000 0001 2188 0957Department of Tropical Medicine, Medical Microbiology and Pharmacology, John A. Burns School of Medicine, University of Hawaii at Manoa, 651 Ilalo Street, Bioscience Building Suite 320, Honolulu, HI 96813 USA
| | - Grace Sama
- grid.412661.60000 0001 2173 8504The Biotechnology Center, University of Yaoundé 1, Messa, BP 3851 Yaoundé, Cameroon
| | - John J. Chen
- grid.410445.00000 0001 2188 0957Department of Quantitative Health Sciences, John A. Burns School of Medicine, University of Hawaii at Manoa, 651 Ilalo Street, MEB411, Honolulu, HI 96813 USA
| | - Rose F. G. Leke
- grid.412661.60000 0001 2173 8504The Biotechnology Center, University of Yaoundé 1, Messa, BP 3851 Yaoundé, Cameroon
| | - Diane Wallace Taylor
- grid.410445.00000 0001 2188 0957Department of Tropical Medicine, Medical Microbiology and Pharmacology, John A. Burns School of Medicine, University of Hawaii at Manoa, 651 Ilalo Street, Bioscience Building Suite 320, Honolulu, HI 96813 USA
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4
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Agbana HB, Rogier E, Lo A, Abukari Z, Jones S, Gyan B, Aidoo M, Amoah LE. Detecting asymptomatic carriage of Plasmodium falciparum in southern Ghana: utility of molecular and serological diagnostic tools. Malar J 2022; 21:57. [PMID: 35183178 PMCID: PMC8858553 DOI: 10.1186/s12936-022-04078-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Accepted: 02/06/2022] [Indexed: 12/04/2022] Open
Abstract
Background Asymptomatic malaria infections can serve as potential reservoirs for malaria transmission. The density of parasites contained in these infections range from microscopic to submicroscopic densities, making the accurate detection of asymptomatic parasite carriage highly dependent on the sensitivity of the tools used for the diagnosis. This study sought to evaluate the sensitivities of a variety of molecular and serological diagnostic tools at determining the prevalence of asymptomatic Plasmodium falciparum parasite infections in two communities with varying malaria parasite prevalence. Methods Whole blood was collected from 194 afebrile participants aged between 6 and 70 years old living in a high (Obom) and a low (Asutsuare) malaria transmission setting of Ghana. Thick and thin blood smears, HRP2 based malaria rapid diagnostic test (RDT) and filter paper dried blood spots (DBS) were prepared from each blood sample. Genomic DNA was extracted from the remaining blood and used in Plasmodium specific photo-induced electron transfer polymerase chain reaction (PET-PCR) and Nested PCR, whilst the HRP2 antigen content of the DBS was estimated using a bead immunoassay. A comparison of malaria parasite prevalence as determined by each method was performed. Results Parasite prevalence in the high transmission site of Obom was estimated at 71.4%, 61.9%, 60%, 37.8% and 19.1% by Nested PCR, the HRP2 bead assay, PET-PCR, HRP2-RDT and microscopy respectively. Parasite prevalence in the low transmission site of Asutsuare was estimated at 50.1%, 11.2%, 5.6%, 0% and 2.2% by Nested PCR, the HRP2 bead assay, PET-PCR, RDT and microscopy, respectively. The diagnostic performance of Nested PCR, PET-PCR and the HRP2 bead assay was similar in Obom but in Asutsuare, Nested PCR had a significantly higher sensitivity than PET-PCR and the HRP2 bead assay, which had similar sensitivity. Conclusions Nested PCR exhibited the highest sensitivity by identifying the highest prevalence of asymptomatic P. falciparum in both the high and low parasite prevalence settings. However, parasite prevalence estimated by the HRP2 bead assay and PET-PCR had the highest level of inter-rater agreement relative to all the other tools tested and have the advantage of requiring fewer processing steps relative to Nested PCR and producing quantitative results. Supplementary Information The online version contains supplementary material available at 10.1186/s12936-022-04078-w.
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5
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Intermittent preventive treatment with Sulphadoxine-Pyrimethamine (IPTp-SP) is associated with protection against sub-microscopic P. falciparum infection in pregnant women during the low transmission dry season in southwestern Cameroon: A Semi - longitudinal study. PLoS One 2022; 17:e0275370. [PMID: 36178962 PMCID: PMC9524640 DOI: 10.1371/journal.pone.0275370] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Accepted: 09/14/2022] [Indexed: 11/19/2022] Open
Abstract
The current guidelines for malaria prevention and control during pregnancy in Africa is predicated on the prevention of infection and/or disease through intermittent preventive treatment in pregnancy (IPTp), insecticide-treated nets (ITNs) and effective malaria case diagnosis and management. Concerns that increasing SP resistance in some areas of SSA may have compromised IPTp-SP efficacy prompted this contemporaneous study, designed to assess the prevalence and risk factors of sub-microscopic infection in parturient women during the low transmission season in Mutengene, a rapidly growing semi-urban area in Southwest Region, Cameroon. Pregnant women originally reporting for the establishment of antenatal clinic care during the dry season were followed-up to term and their pregnancy outcomes recorded. About 2 ml of venous blood was collected for malaria diagnosis using PfHRP2/pLDH malaria rapid diagnostic kit and light microscopy. DNA was extracted from dried blood spots by the Chelex-100 method and the Plasmodium falciparum status detected by nested PCR amplification of the 18SrRNA gene using specific predesigned primers. Of the 300 women enrolled, the proportion of malaria parasite infected as determined by microscopy, RDT and PCR was 12.9%, 16.4% and 29.4% respectively, with 39.9% overall infected with P. falciparum by microscopy and/or RDT and/or PCR and a very low-density infection, averaging 271 parasites per microliter of blood. About 25.0% (68/272) of women who were negative by microscopy were positive by PCR (submicroscopic P. falciparum infection), with primigravidae and IPTp-SP non usage identified as independent risk factors for submicroscopic P. falciparum parasitaemia while fever history (aOR = 4.83, 95% CI = 1.28-18.22, p = 0.020) was associated with risk of malaria parasite infection overall. IPTp-SP use (p = 0.007) and dosage (p = 0.005) significantly influenced whether or not the participant will be malaria parasite negative or carry submicroscopic or microscopic infection. Although Infant birthweight and APGAR score were independent of the mother's P. falciparum infection and submicroscopic status, infant's birthweight varied with the gravidity status (p = 0.001) of the mother, with significantly lower birthweight neonates born to primigravidae compared to secundigravidae (p = 0.001) and multigravidae (p = 0.003). Even in holo-endemic dry season, there exists a large proportion of pregnant women with very low density parasitaemia. IPTp-SP seems to be relevant in controlling submicroscopic P. falciparum infections, which remains common in pregnant women, and are hard to diagnose, with potentially deleterious consequences for maternal and fetal health. Future studies should be carried out in hyperendemic malaria foci where the parasitemia levels are substantially higher in order to confirm the efficacy of IPTp-SP.
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Aheto JMK, Duah HO, Agbadi P, Nakua EK. A predictive model, and predictors of under-five child malaria prevalence in Ghana: How do LASSO, Ridge and Elastic net regression approaches compare? Prev Med Rep 2021; 23:101475. [PMID: 34306999 PMCID: PMC8258678 DOI: 10.1016/j.pmedr.2021.101475] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2021] [Revised: 05/28/2021] [Accepted: 06/23/2021] [Indexed: 11/30/2022] Open
Abstract
Malaria is among the leading causes of mortality and morbidity among children in Ghana. Therefore, identifying the predictors of malaria prevalence in children under-five is among the priorities of the global health agenda. In Ghana, the paradigm shifts from using traditional statistics to machine learning techniques to identifying predictors of malaria prevalence are scarce. Thus, the present study used machine learning techniques to identify variables to build the best fitting predictive model of malaria prevalence in Ghana. We analysed the data on 2867 under-five children with malaria RDT results from the 2019 Ghana Malaria Indicator Survey. LASSO, Ridge, and Elastic Net regression methods were used to select variables to build predictive models. The R freeware version 4.0.2 was used. One out of four children tested positive for malaria (25.04%). The logit models based on selected features by LASSO, Ridge, and Elastic Net contained eleven, fifteen, and thirteen features, respectively. The LASSO regression model is preferred because it contains the smallest number of predictors and the smallest prediction error. The significant predictors of malaria among children were being older than 24 months, residing in the poorest household, being severely anaemic, residing in households without electricity, and residing in a rural area. The predictors identified in our study deserve policy attention and interventions to strengthen malaria control efforts in Ghana. The machine learning techniques employed in our study, especially the LASSO regression technique could be beneficial for identifying predictors of malaria prevalence in this group of children.
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Affiliation(s)
- Justice Moses K. Aheto
- Department of Biostatistics, School of Public Health, College of Health Sciences, University of Ghana, Ghana
- WorldPop, University of Southampton, United Kingdom
| | | | - Pascal Agbadi
- Department of Nursing, Faculty of Allied Health Sciences, College of Health Sciences, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Emmanuel Kweku Nakua
- Department of Epidemiology and Biostatistics, School of Public Health, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
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Botwe AK, Oppong FB, Gyaase S, Owusu-Agyei S, Asghar M, Asante KP, Färnert A, Osier F. Determinants of the varied profiles of Plasmodium falciparum infections among infants living in Kintampo, Ghana. Malar J 2021; 20:240. [PMID: 34051822 PMCID: PMC8164218 DOI: 10.1186/s12936-021-03752-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Accepted: 05/07/2021] [Indexed: 11/22/2022] Open
Abstract
Background Understanding why some infants tolerate infections, remaining asymptomatic while others succumb to repeated symptomatic malaria is beneficial for studies of naturally acquired immunity and can guide control interventions. This study compared demographic, host and maternal factors associated with being either parasite negative or having asymptomatic infections versus developing symptomatic malaria in the first year of life. Methods A birth cohort (n = 1264) was monitored longitudinally over two years for malaria infections in Kintampo, Ghana. Symptomatic and asymptomatic infections were detected actively through monthly home visits, complemented by passive case detection. Light microscopy was used to detect parasitaemia. Based on data from a minimum of eight monthly visits within the first year of life, infants were classified into one of four groups: “parasite negative”, “only-asymptomatic”, “only-symptomatic” or “alternating” i.e., sometimes symptomatic and other times asymptomatic. The host and maternal characteristics and demographic factors in relation to these four groups were compared. Results The parasite negative group formed 36% of the cohort, whilst the only-symptomatic were 35%. The alternating group were 22% and the only-asymptomatic were 7% of the cohort. There were significant associations between residence, socio-economic status (SES), parity, IPTp doses, delivery place of infant and having or not having malaria parasites. Maternal factors such as early commencement and frequency of ante-natal care (ANC) were significantly higher in the parasite negative group compared to all others. ITN use in pregnancy increased the odds of infant having only asymptomatic infections (“protected against disease”). Placental malaria was more common in the groups of infants with symptomatic malaria. Urban residence was significantly higher in the parasite negative group, while birth in the malaria transmission season were significantly more common in the alternating and parasite negative groups. Risk factors for infants with symptomatic malaria included low SES, birth in private maternity homes, sickle cell normal variant, lower MUAC, reported intake of anti-malarials and increased morbidity before the first microscopic infection was detected. Conclusion Strengthening ANC by encouraging early and regular attendance, the use of IPTp, maternal bed nets and improving the nourishment of infants help reduce the frequency of symptomatic malaria over the first year of life. Supplementary Information The online version contains supplementary material available at 10.1186/s12936-021-03752-9.
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Affiliation(s)
- Akua Kyerewaa Botwe
- Kintampo Health Research Centre, Ghana Health Service, Kintampo, Ghana. .,Division of Infectious Diseases, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden. .,Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya.
| | | | - Stephaney Gyaase
- Kintampo Health Research Centre, Ghana Health Service, Kintampo, Ghana
| | - Seth Owusu-Agyei
- Kintampo Health Research Centre, Ghana Health Service, Kintampo, Ghana.,Institute of Health Research, University of Health and Allied Sciences, Ho, Ghana
| | - Muhammad Asghar
- Division of Infectious Diseases, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden.,Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Kwaku Poku Asante
- Kintampo Health Research Centre, Ghana Health Service, Kintampo, Ghana
| | - Anna Färnert
- Kintampo Health Research Centre, Ghana Health Service, Kintampo, Ghana.,Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden.,Department of Infectious Diseases, Karolinska University Hospital, Stockholm, Sweden
| | - Faith Osier
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya.,Centre for Infectious Diseases, Parasitology, Heidelberg University Hospital, Heidelberg, Germany
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8
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Zehner N, Adrama H, Kakuru A, Andra T, Kajubi R, Conrad M, Nankya F, Clark TD, Kamya M, Rodriguez-Barraquer I, Dorsey G, Jagannathan P. Age-related Changes in Malaria Clinical Phenotypes During Infancy are Modified by Sickle Cell Trait. Clin Infect Dis 2021; 73:1887-1895. [PMID: 33738485 PMCID: PMC8599196 DOI: 10.1093/cid/ciab245] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Indexed: 12/02/2022] Open
Abstract
Background Infants are protected against Plasmodium falciparum malaria. Mechanisms that drive this protection remain unclear due to a poor understanding of malaria clinical phenotypes during infancy. Methods We enrolled a birth cohort of 678 infants in Busia, Uganda, an area of high malaria transmission. We followed infants through 12 months of age and quantified protection against parasitemia and clinical disease. Results Symptomatic malaria incidence increased from 1.2 to 2.6 episodes per person-year between 0 and <6 months and between 6 and 12 months of age, while the monthly probability of asymptomatic parasitemia given infection decreased from 32% to 21%. Sickle cell trait (HbAS) was protective against symptomatic malaria (incidence rate ratio = 0.57 comparing HbAS vs hemoglobin AA (HbAA); 95% confidence interval, 0.44–0.74; P < .001), but age modified this relationship (Pint = <0.001), with nonlinear protection that waned between 0 and 9 months of age before increasing. Increasing age was associated with higher parasite densities at the time of infection and, in infants with HbAS, a reduced ability to tolerate high parasite densities without fever. Conclusions Age-dependent changes in HbAS protective efficacy in infancy were accompanied by differential loss of antiparasite and antidisease protection among HbAS and HbAA infants. This provides a framework for investigating the mechanisms that underlie infant protection against malaria. Clinical Trials Registration NCT02793622.
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Affiliation(s)
| | - Harriet Adrama
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Abel Kakuru
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Teddy Andra
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Richard Kajubi
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Melissa Conrad
- Department of Medicine, University of California, San Francisco, USA
| | | | - Tamara D Clark
- Department of Medicine, University of California, San Francisco, USA
| | - Moses Kamya
- Infectious Diseases Research Collaboration, Kampala, Uganda.,Department of Medicine, Makerere University College of Health Sciences, Kampala, Uganda
| | | | - Grant Dorsey
- Department of Medicine, University of California, San Francisco, USA
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9
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Profiles of Plasmodium falciparum infections detected by microscopy through the first year of life in Kintampo a high transmission area of Ghana. PLoS One 2020; 15:e0240814. [PMID: 33075074 PMCID: PMC7571695 DOI: 10.1371/journal.pone.0240814] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Accepted: 10/02/2020] [Indexed: 11/24/2022] Open
Abstract
Although malaria mortality among children under five years of age is high, the characteristics of their infection patterns are not well described. The aim of this study was to examine the longitudinal sequence pattern of Plasmodium falciparum infections in the first year of life within a birth cohort in Kintampo, Ghana (N = 1855). Infants were monitored at home with monthly sampling and also at the clinic for any febrile illness between 2008 and 2011. Light microscopy was performed on monthly scheduled visits and febrile ill visits over twelve months of follow-ups (n = 19231). Microscopy-positive visits accompanied with or without symptoms were rare during the first five months of life but were common from six to twelve months of age. Among 1264 infants with microscopy data over a minimum of eight monthly visits and also throughout in sick visits, some were microscopy negative (36%), and others positive: only-symptomatic (35%), alternating (22%) and only-asymptomatic (7%). The median age of microscopic infection was seven months for the alternating group and eight months for both the only-symptomatic and only-asymptomatic groups. The alternating group had the highest cumulative incidence of microscopic infections, the lowest age at first infection and 87 different infection patterns. Parasite densities detected by microscopy were significantly higher for symptomatic versus asymptomatic infection. We conclude that infants in malaria endemic areas experience diverse infection profiles throughout their first year of life. Further investigations should include submicroscopic reservoir and may shed more light on the factors that determine susceptibility to malaria during infancy.
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10
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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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11
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Diouf I, Rodriguez Fonseca B, Caminade C, Thiaw WM, Deme A, Morse AP, Ndione JA, Gaye AT, Diaw A, Ndiaye MKN. Climate Variability and Malaria over West Africa. Am J Trop Med Hyg 2020; 102:1037-1047. [PMID: 32189612 PMCID: PMC7204584 DOI: 10.4269/ajtmh.19-0062] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Accepted: 02/01/2020] [Indexed: 01/24/2023] Open
Abstract
Malaria is a major public health problem in West Africa. Previous studies have shown that climate variability significantly affects malaria transmission. The lack of continuous observed weather station data and the absence of surveillance data for malaria over long periods have led to the use of reanalysis data to drive malaria models. In this study, we use the Liverpool Malaria Model (LMM) to simulate spatiotemporal variability of malaria in West Africa using daily rainfall and temperature from the following: Twentieth Century Reanalysis (20th CR), National Center for Environmental Prediction (NCEP), European Centre for Medium-Range Weather Forecasts (ECMWF) Atmospheric Reanalysis of the Twentieth Century (ERA20C), and interim ECMWF Re-Analysis (ERA-Interim). Malaria case data from the national surveillance program in Senegal are used for model validation between 2001 and 2016. The warm temperatures found over the Sahelian fringe of West Africa can lead to high malaria transmission during wet years. The rainfall season peaks in July to September over West Africa and Senegal, and the malaria season lasts from September to November, about 1-2 months after the rainfall peak. The long-term trends exhibit interannual and decadal variabilities. The LMM shows acceptable performance in simulating the spatial distribution of malaria incidence. However, some discrepancies are found. These results are useful for decision-makers who plan public health and control measures in affected West African countries. The study would have substantial implications for directing malaria surveillance activities and health policy. In addition, this malaria modeling framework could lead to the development of an early warning system for malaria in West Africa.
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Affiliation(s)
- Ibrahima Diouf
- NOAA Center for Weather and Climate Prediction, College Park, Maryland
- Laboratoire de Physique de L’Atmosphère et de L’Océan-Siméon Fongang, Ecole Supérieure Polytechnique de L’Université Cheikh Anta Diop, Dakar, Sénégal
| | - Belén Rodriguez Fonseca
- Department of Geophysics and Meteorology, Universidad Complutense de Madrid, Madrid, Spain
- Instituto de Geociencias IGEO, CSIC-UCM, Agencia Estatal del Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Cyril Caminade
- Department of Epidemiology and Population Health, Institute of Infection and Global Health, University of Liverpool, Liverpool, United Kingdom
- National Institute for Health Research [M1] (NIHR), Health Protection Research Unit in Emerging and Zoonotic Infections, Liverpool, United Kingdom
| | - Wassila M. Thiaw
- NOAA Center for Weather and Climate Prediction, College Park, Maryland
| | - Abdoulaye Deme
- Unité de Formation et de Recherche de Sciences Appliquées et de Technologie, Université Gaston Berger, Saint Louis, Sénégal
| | - Andrew P. Morse
- National Institute for Health Research [M1] (NIHR), Health Protection Research Unit in Emerging and Zoonotic Infections, Liverpool, United Kingdom
- Department of Geography and Planning, School of Environmental Sciences, University of Liverpool, Liverpool, United Kingdom
| | | | - Amadou Thierno Gaye
- Laboratoire de Physique de L’Atmosphère et de L’Océan-Siméon Fongang, Ecole Supérieure Polytechnique de L’Université Cheikh Anta Diop, Dakar, Sénégal
| | - Anta Diaw
- General Direction of Public Health, Ministry of Health and Social Action, Dakar, Senegal
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12
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Slater HC, Ross A, Felger I, Hofmann NE, Robinson L, Cook J, Gonçalves BP, Björkman A, Ouedraogo AL, Morris U, Msellem M, Koepfli C, Mueller I, Tadesse F, Gadisa E, Das S, Domingo G, Kapulu M, Midega J, Owusu-Agyei S, Nabet C, Piarroux R, Doumbo O, Doumbo SN, Koram K, Lucchi N, Udhayakumar V, Mosha J, Tiono A, Chandramohan D, Gosling R, Mwingira F, Sauerwein R, Paul R, Riley EM, White NJ, Nosten F, Imwong M, Bousema T, Drakeley C, Okell LC. The temporal dynamics and infectiousness of subpatent Plasmodium falciparum infections in relation to parasite density. Nat Commun 2019; 10:1433. [PMID: 30926893 PMCID: PMC6440965 DOI: 10.1038/s41467-019-09441-1] [Citation(s) in RCA: 92] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Accepted: 03/07/2019] [Indexed: 02/08/2023] Open
Abstract
Malaria infections occurring below the limit of detection of standard diagnostics are common in all endemic settings. However, key questions remain surrounding their contribution to sustaining transmission and whether they need to be detected and targeted to achieve malaria elimination. In this study we analyse a range of malaria datasets to quantify the density, detectability, course of infection and infectiousness of subpatent infections. Asymptomatically infected individuals have lower parasite densities on average in low transmission settings compared to individuals in higher transmission settings. In cohort studies, subpatent infections are found to be predictive of future periods of patent infection and in membrane feeding studies, individuals infected with subpatent asexual parasite densities are found to be approximately a third as infectious to mosquitoes as individuals with patent (asexual parasite) infection. These results indicate that subpatent infections contribute to the infectious reservoir, may be long lasting, and require more sensitive diagnostics to detect them in lower transmission settings. The role of subpatent infections for malaria transmission and elimination is unclear. Here, Slater et al. analyse several malaria datasets to quantify the density, detectability, course of infection and infectiousness of subpatent infections.
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Affiliation(s)
- Hannah C Slater
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, Imperial College London, London, W2 1PG, UK.
| | - Amanda Ross
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, 4002, Switzerland.,University of Basel, Basel, 4001, Switzerland
| | - Ingrid Felger
- University of Basel, Basel, 4001, Switzerland.,Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute, Basel, 4002, Switzerland
| | - Natalie E Hofmann
- University of Basel, Basel, 4001, Switzerland.,Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute, Basel, 4002, Switzerland
| | - Leanne Robinson
- Vector-borne Diseases Unit, Papua New Guinea Institute for Medical Research, Madang, Papua New Guinea.,Division of Population Health and Immunity, The Walter and Eliza Hall Institute of Medical Research, Parkville, 3052, VIC, Australia.,Medical Biology, University of Melbourne, Melbourne, 3010, VIC, Australia.,Disease Elimination, Burnet Institute, Melbourne, 3004, VIC, Australia
| | - Jackie Cook
- MRC Tropical Epidemiology Group, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK
| | - Bronner P Gonçalves
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK
| | - Anders Björkman
- Malaria Research, Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, 171 77, Stockholm, Sweden
| | - Andre Lin Ouedraogo
- Département de Sciences Biomédicales, Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, 01 BP 2208, Burkina Faso.,Institute for Disease Modeling, Intellectual Ventures, Bellevue, 98005, Washington, USA
| | - Ulrika Morris
- Malaria Research, Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, 171 77, Stockholm, Sweden
| | - Mwinyi Msellem
- Department of Training and Research, Mnazi Mmoja Hospital, Zanzibar, Tanzania
| | - Cristian Koepfli
- Population Health and Immunity Division, Walter and Eliza Hall Institute, Melbourne, 3052, Victoria, Australia.,Department of Biological Sciences, University of Notre Dame, Indiana, 46556, USA
| | - Ivo Mueller
- Division of Population Health and Immunity, The Walter and Eliza Hall Institute of Medical Research, Parkville, 3052, VIC, Australia.,Department of Parasites and Insect Vectors, Institut Pasteur, Paris, 75015, France.,Medical Biology, University of Melbourne, Melbourne, 3010, VIC, Australia
| | - Fitsum Tadesse
- Radboud Institute for Health Sciences, Radboud University Medical Centre, Nijmegen, 6525, The Netherlands.,Armauer Hansen Research Institute, Addis Ababa, Ethiopia.,Institute of Biotechnology, Addis Ababa University, Addis Ababa, Ethiopia
| | | | - Smita Das
- Diagnostics Program, PATH, Seattle, Washington, 98121, United States of America
| | - Gonzalo Domingo
- Diagnostics Program, PATH, Seattle, Washington, 98121, United States of America
| | - Melissa Kapulu
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, OX3 7FZ, UK.,KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research-Coast, Kilifi, Kenya, Centre for Genomics and Global Health, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, OX3 7BN, UK
| | - Janet Midega
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, OX3 7FZ, UK.,KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research-Coast, Kilifi, Kenya, Centre for Genomics and Global Health, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, OX3 7BN, UK
| | - Seth Owusu-Agyei
- Institute of Health, University of Health and Allied Sciences, Hohoe, PMB 31, Ghana
| | - Cécile Nabet
- Sorbonne Université, INSERM, Institut Pierre-Louis d'Epidémiologie et de Santé Publique, AP- HP, Groupe Hospitalier Pitié-Salpêtrière, Service de Parasitologie-Mycologie, Paris, 75646, France
| | - Renaud Piarroux
- Sorbonne Université, INSERM, Institut Pierre-Louis d'Epidémiologie et de Santé Publique, AP- HP, Groupe Hospitalier Pitié-Salpêtrière, Service de Parasitologie-Mycologie, Paris, 75646, France
| | - Ogobara Doumbo
- Malaria Research and Training Centre, Parasitic Diseases Epidemiology Department, UMI 3189, University of Sciences, Technique and Technology, Bamako, Mali
| | - Safiatou Niare Doumbo
- Malaria Research and Training Centre, Parasitic Diseases Epidemiology Department, UMI 3189, University of Sciences, Technique and Technology, Bamako, Mali
| | - Kwadwo Koram
- Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana
| | - Naomi Lucchi
- Malaria Branch, Division of Parasitic Diseases and Malaria, Centers for Global Health, Centers for Disease Control and Prevention, Atlanta, 30030, GA, United States of America
| | - Venkatachalam Udhayakumar
- Malaria Branch, Division of Parasitic Diseases and Malaria, Centers for Global Health, Centers for Disease Control and Prevention, Atlanta, 30030, GA, United States of America
| | - Jacklin Mosha
- National Institute for Medical Research, Mwanza Medical Research Centre, Mwanza, Tanzania
| | - Alfred Tiono
- Department of Biomedical Sciences, Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, 01 BP 2208, Burkina Faso
| | - Daniel Chandramohan
- Department of Disease Control, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Roly Gosling
- Malaria Elimination Initiative, Global Health Group, University of California, San Francisco, San Francisco, 94158, CA, United States
| | - Felista Mwingira
- Biological Sciences Department, Dar es Salaam University College of Education, P. O. Box 2329, Dar es Salaam, Tanzania
| | - Robert Sauerwein
- Radboud Institute for Health Sciences, Radboud University Medical Centre, Nijmegen, 6525, The Netherlands
| | - Richard Paul
- Institut Pasteur de Dakar, Laboratoire d'Entomologie Médicale, Dakar, Senegal
| | - Eleanor M Riley
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK.,The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, UK
| | - Nicholas J White
- Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, OX3 7FZ, UK.,Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, 10400, Thailand
| | - Francois Nosten
- Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, OX3 7FZ, UK.,Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, 63110, Thailand
| | - Mallika Imwong
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, 10400, Thailand.,Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok, 10400, Thailand
| | - Teun Bousema
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK.,Radboud Institute for Health Sciences, Radboud University Medical Centre, Nijmegen, 6525, The Netherlands
| | - Chris Drakeley
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK
| | - Lucy C Okell
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, Imperial College London, London, W2 1PG, UK
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13
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Natama HM, Rovira-Vallbona E, Somé MA, Zango SH, Sorgho H, Guetens P, Coulibaly-Traoré M, Valea I, Mens PF, Schallig HDFH, Kestens L, Tinto H, Rosanas-Urgell A. Malaria incidence and prevalence during the first year of life in Nanoro, Burkina Faso: a birth-cohort study. Malar J 2018; 17:163. [PMID: 29650007 PMCID: PMC5898041 DOI: 10.1186/s12936-018-2315-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Accepted: 04/09/2018] [Indexed: 12/22/2022] Open
Abstract
Background Infants are thought to be protected against malaria during the first months of life mainly due to passage of maternal antibodies. However, in high transmission settings, malaria in early infancy is not uncommon and susceptibility to the infections varies between individuals. This study aimed to determine malaria morbidity and infection during early childhood in rural Burkina Faso. Methods Malariometric indices were determined over 1-year follow-up in a birth cohort of 734 infants living in Nanoro health district. Clinical malaria episodes were determined by passive case detection at peripheral health centres while asymptomatic malaria infections were identified during 4 cross-sectional surveys at 3, 6, 9 and 12 months of age. Plasmodium falciparum infections were detected by rapid diagnostic test and/or light microscopy (LM) and quantitative PCR (qPCR). Results In total, 717 clinical episodes were diagnosed by qPCR over 8335.18 person-months at risk. The overall malaria incidence was 1.03 per child-year and increased from 0.27 per child-year at 0–3 months of age to 1.92 per child-year at 9–12 months of age. Some 59% of children experienced at least one clinical episode with a median survival time estimated at 9.9 months, while 20% of infants experienced the first episode before 6 months of age. The majority of the clinical episodes were attributable to microscopic parasitaemia (84.2%), and there was a positive correlation between parasite density and age (Spearman’s rho = 0.30; P < 0.0001). Prevalence of asymptomatic infections was similar at 3, 6 and 9 months of age (17.7–20.1%) and nearly 1.6 times higher at 12 months (31.3%). Importantly, gametocyte prevalence among the LM-positive study population was 6.7%, but increased to 10% among asymptomatic infections. In addition, 46% of asymptomatic infections were only detected by qPCR suggesting that infants below 1 year are a potential reservoir for sustaining malaria transmission. Both symptomatic and asymptomatic infections showed marked seasonal distribution with the highest transmission period (July to December) accounting for about 89 and 77% of those infections, respectively. Conclusions These findings indicate high and marked age and seasonal-dependency of malaria infections and disease during the first year of life in Nanoro, calling for intensified efforts to control malaria in rural Burkina Faso.
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Affiliation(s)
- Hamtandi Magloire Natama
- Department of Biomedical Sciences, Institute of Tropical Medicine, 2000, Antwerp, Belgium. .,Unité de Recherche Clinique de Nanoro, Institut de Recherche en Sciences de la Santé, Nanoro, BP 218, Burkina Faso. .,Department of Biomedical Sciences, University of Antwerp, 2610, Antwerp, Belgium.
| | - Eduard Rovira-Vallbona
- Department of Biomedical Sciences, Institute of Tropical Medicine, 2000, Antwerp, Belgium
| | - M Athanase Somé
- Unité de Recherche Clinique de Nanoro, Institut de Recherche en Sciences de la Santé, Nanoro, BP 218, Burkina Faso
| | - Serge Henri Zango
- Unité de Recherche Clinique de Nanoro, Institut de Recherche en Sciences de la Santé, Nanoro, BP 218, Burkina Faso.,Centre Muraz, Bobo Dioulasso, BP 390, Burkina Faso
| | - Hermann Sorgho
- Unité de Recherche Clinique de Nanoro, Institut de Recherche en Sciences de la Santé, Nanoro, BP 218, Burkina Faso
| | - Pieter Guetens
- Department of Biomedical Sciences, Institute of Tropical Medicine, 2000, Antwerp, Belgium
| | - Maminata Coulibaly-Traoré
- Unité de Recherche Clinique de Nanoro, Institut de Recherche en Sciences de la Santé, Nanoro, BP 218, Burkina Faso
| | - Innocent Valea
- Unité de Recherche Clinique de Nanoro, Institut de Recherche en Sciences de la Santé, Nanoro, BP 218, Burkina Faso
| | - Petra F Mens
- Department of Medical Microbiology-Parasitology Unit, Academic Medical Centre, 1105 AZ, Amsterdam, The Netherlands
| | - Henk D F H Schallig
- Department of Medical Microbiology-Parasitology Unit, Academic Medical Centre, 1105 AZ, Amsterdam, The Netherlands
| | - Luc Kestens
- Department of Biomedical Sciences, Institute of Tropical Medicine, 2000, Antwerp, Belgium.,Department of Biomedical Sciences, University of Antwerp, 2610, Antwerp, Belgium
| | - Halidou Tinto
- Unité de Recherche Clinique de Nanoro, Institut de Recherche en Sciences de la Santé, Nanoro, BP 218, Burkina Faso.,Centre Muraz, Bobo Dioulasso, BP 390, Burkina Faso
| | - Anna Rosanas-Urgell
- Department of Biomedical Sciences, Institute of Tropical Medicine, 2000, Antwerp, Belgium
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14
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Mechanism of splenic cell death and host mortality in a Plasmodium yoelii malaria model. Sci Rep 2017; 7:10438. [PMID: 28874800 PMCID: PMC5585408 DOI: 10.1038/s41598-017-10776-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Accepted: 08/14/2017] [Indexed: 12/14/2022] Open
Abstract
Malaria is a fatal disease that displays a spectrum of symptoms and severity, which are determined by complex host-parasite interactions. It has been difficult to study the effects of parasite strains on disease severity in human infections, but the mechanisms leading to specific disease phenotypes can be investigated using strains of rodent malaria parasites that cause different disease symptoms in inbred mice. Using a unique mouse malaria model, here we investigated the mechanisms of splenic cell death and their relationship to control of parasitemia and host mortality. C57BL/6 mice infected with Plasmodium yoelii nigeriensis N67C display high levels of pro-inflammatory cytokines and chemokines (IL-6, IFN-γ, TNF-α, CXCL1, and CCL2) and extensive splenic damage with dramatic reduction of splenic cell populations. These disease phenotypes were rescued in RAG2−/−, IFN-γ−/−, or T cell depleted mice, suggesting IFN-γ and T cell mediated disease mechanisms. Additionally, apoptosis was one of the major pathways involved in splenic cell death, which coincides with the peaks of pro-inflammatory cytokines. Our results demonstrate the critical roles of T cells and IFN-γ in mediating splenic cell apoptosis, parasitemia control, and host lethality and thus may provide important insights for preventing/reducing morbidity associated with severe malaria in humans.
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15
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Nash SD, Prevots DR, Kabyemela E, Khasa YP, Lee KL, Fried M, Duffy PE. A Malaria-Resistant Phenotype with Immunological Correlates in a Tanzanian Birth Cohort Exposed to Intense Malaria Transmission. Am J Trop Med Hyg 2017; 96:1190-1196. [PMID: 28500801 DOI: 10.4269/ajtmh.16-0554] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
AbstractMalaria incidence is highly heterogeneous even in areas of high transmission, although no conclusive evidence exists that innate or naturally acquired resistance can prevent infection over an extended period of time. This longitudinal study examined immunoparasitological evidence for a malaria-resistant phenotype in which children do not develop malaria despite an extended period of exposure to parasites. Within a birth cohort followed from 2002 to 2006 in Muheza, Tanzania, an area of intense transmission, children (N = 687) provided blood smears biweekly during infancy and monthly thereafter. Maternal and childhood characteristics were obtained, cord-blood cytokines were measured, and antibody responses were assayed as measures of stage-specific exposure. Sixty-three (9.2%) children had no blood smear-positive slides over 2 years of follow-up (range: 1-3.5 years) and were identified as malaria resistant. Malaria-resistant children were similar to other children with respect to completeness of follow-up and all maternal and childhood characteristics except residence area. Antibody seroprevalence was similar for two sporozoite antigens, but malaria-resistant children had a lower antibody seroprevalence to merozoite antigens merozoite surface protein 1 (5.4% versus 30.2%; P < 0.0001) and apical membrane antigen 1 (7.2% versus 33.3%; P < 0.0001). Malaria-resistant children had higher cytokine levels in cord blood, particularly interleukin-1β. In summary, a subset of children living in an area of intense transmission was exposed to malaria parasites, but never developed patent parasitemia; this phenotype was associated with a distinct cytokine profile at birth and antibody profile during infancy. Further research with malaria-resistant children may identify mechanisms for naturally acquired immunity.
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Affiliation(s)
- Scott D Nash
- Epidemiology Unit, Laboratory of Clinical Infectious Diseases, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland.,Laboratory of Malaria Immunology and Vaccinology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland
| | - D Rebecca Prevots
- Epidemiology Unit, Laboratory of Clinical Infectious Diseases, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland
| | | | - Yogender P Khasa
- Department of Microbiology, University of Delhi South Campus, New Delhi, India
| | - Kun-Lin Lee
- Laboratory of Malaria Immunology and Vaccinology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland
| | - Michal Fried
- Laboratory of Malaria Immunology and Vaccinology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland
| | - Patrick E Duffy
- Laboratory of Malaria Immunology and Vaccinology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland
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16
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Murungi LM, Sondén K, Odera D, Oduor LB, Guleid F, Nkumama IN, Otiende M, Kangoye DT, Fegan G, Färnert A, Marsh K, Osier FHA. Cord blood IgG and the risk of severe Plasmodium falciparum malaria in the first year of life. Int J Parasitol 2016; 47:153-162. [PMID: 27890694 PMCID: PMC5297353 DOI: 10.1016/j.ijpara.2016.09.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2016] [Revised: 08/31/2016] [Accepted: 09/03/2016] [Indexed: 01/18/2023]
Abstract
Severe malaria episodes are rare during the first few months of life. The rate of decay of cord blood IgG is inversely proportional to the starting concentration. Antibody dependent respiratory burst mediated by cord IgG protects from severe malaria during the first 6 months of infancy.
Young infants are less susceptible to severe episodes of malaria but the targets and mechanisms of protection are not clear. Cord blood antibodies may play an important role in mediating protection but many studies have examined their association with the outcome of infection or non-severe malaria. Here, we investigated whether cord blood IgG to Plasmodium falciparum merozoite antigens and antibody-mediated effector functions were associated with reduced odds of developing severe malaria at different time points during the first year of life. We conducted a case-control study of well-defined severe falciparum malaria nested within a longitudinal birth cohort of Kenyan children. We measured cord blood total IgG levels against five recombinant merozoite antigens and antibody function in the growth inhibition activity and neutrophil antibody-dependent respiratory burst assays. We also assessed the decay of maternal antibodies during the first 6 months of life. The mean antibody half-life range was 2.51 months (95% confidence interval (CI): 2.19–2.92) to 4.91 months (95% CI: 4.47–6.07). The rate of decline of maternal antibodies was inversely proportional to the starting concentration. The functional assay of antibody-dependent respiratory burst activity predicted significantly reduced odds of developing severe malaria during the first 6 months of life (Odds ratio (OR) 0.07, 95% CI: 0.007–0.74, P = 0.007). Identification of the targets of antibodies mediating antibody-dependent respiratory burst activity could contribute to the development of malaria vaccines that protect against severe episodes of malaria in early infancy.
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Affiliation(s)
- Linda M Murungi
- Kenya Medical Research Institute, Centre for Geographic Medicine Research, Coast, P.O. Box 230-80108, Kilifi, Kenya.
| | - Klara Sondén
- Unit of Infectious Diseases, Department of Medicine, Solna, Karolinska Institutet, SE-171 76 Stockholm, Sweden
| | - Dennis Odera
- Kenya Medical Research Institute, Centre for Geographic Medicine Research, Coast, P.O. Box 230-80108, Kilifi, Kenya
| | - Loureen B Oduor
- Kenya Medical Research Institute, Centre for Geographic Medicine Research, Coast, P.O. Box 230-80108, Kilifi, Kenya
| | - Fatuma Guleid
- Kenya Medical Research Institute, Centre for Geographic Medicine Research, Coast, P.O. Box 230-80108, Kilifi, Kenya
| | - Irene N Nkumama
- Kenya Medical Research Institute, Centre for Geographic Medicine Research, Coast, P.O. Box 230-80108, Kilifi, Kenya
| | - Mark Otiende
- Kenya Medical Research Institute, Centre for Geographic Medicine Research, Coast, P.O. Box 230-80108, Kilifi, Kenya
| | - David T Kangoye
- Kenya Medical Research Institute, Centre for Geographic Medicine Research, Coast, P.O. Box 230-80108, Kilifi, Kenya; Centre National de Recherche et de Formation sur le Paludisme (CNRFP), 01 BP 2208, Ouagadougou 01, Burkina Faso
| | - Greg Fegan
- Kenya Medical Research Institute, Centre for Geographic Medicine Research, Coast, P.O. Box 230-80108, Kilifi, Kenya
| | - Anna Färnert
- Unit of Infectious Diseases, Department of Medicine, Solna, Karolinska Institutet, SE-171 76 Stockholm, Sweden; Department of Infectious Diseases, Karolinska University Hospital, Stockholm, Sweden
| | - Kevin Marsh
- Kenya Medical Research Institute, Centre for Geographic Medicine Research, Coast, P.O. Box 230-80108, Kilifi, Kenya; African Academy of Sciences, P.O. Box 24916-00502, Nairobi, Kenya; Nuffield Department of Medicine, Centre for Clinical Vaccinology and Tropical Medicine, University of Oxford, Churchill Hospital, Oxford, United Kingdom
| | - Faith H A Osier
- Kenya Medical Research Institute, Centre for Geographic Medicine Research, Coast, P.O. Box 230-80108, Kilifi, Kenya
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Ndyomugyenyi R, Magnussen P, Brabin BJ. Chloroquine prophylaxis, iron/folic-acid supplementation or case management of malaria attacks in primigravidae in western Uganda: effects on congenital malaria and infant haemoglobin concentrations. ANNALS OF TROPICAL MEDICINE AND PARASITOLOGY 2016. [DOI: 10.1080/00034983.2000.11813600] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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Prevalence and diagnostics of congenital malaria in rural Burundi, a cross-sectional study. Malar J 2016; 15:443. [PMID: 27577552 PMCID: PMC5006417 DOI: 10.1186/s12936-016-1478-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Accepted: 08/10/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Congenital malaria, defined as the presence of asexual forms of malaria parasites in the peripheral blood during the first 7 days of life, remains a neglected area of research. Knowledge gaps exist about prevalence and management of malaria in this age group. The objective of this study was to evaluate the prevalence of congenital malaria and the validity of a rapid diagnostic test (RDT) for its diagnosis in rural Burundi. METHODS A cross-sectional study was conducted in a meso-endemic malaria context in Burundi among 290 mothers, and their newborns (n = 303), who delivered at the maternity departments of Kirundo and Mukenke Hospitals during March and April 2014. Peripheral blood samples were collected from all mothers/newborns pairs in order to examine the presence of malaria parasites with two RDT (SD-Bioline HRP2 and Carestart pan-pLDH) and a blood slide. In addition, quantitative real-time polymerase chain reaction (PCR) was performed from the newborn peripheral sample. Frequencies and proportions were calculated for categorical variables. Sensitivity and specificity were calculated with a 95 % confidence interval (CI). RESULTS None of the newborns were found positive by PCR (0/303; 95 % CI 0.0-1.3). The prevalence in newborns born from microscopy-positive mothers was 0 % (0/44; 95 % CI 0.0-8.0). Two newborns were positive with SD-Bioline HRP2 (0.7 %, 95 % CI 0.2-2.4) but none with Carestart pan-pLDH or microscopy. Sensitivity of the diagnostic tests could not be evaluated as no congenital malaria was detected. Specificity of SD-Bioline HRP2, Carestart pan-pLDH and microscopy to detect congenital malaria was 99.3 % (95 % CI 97.6-99.8), 100.0 % (95 % CI 98.3-100.0) and 100.0 % (95 % CI 98.8-100.0), respectively. CONCLUSION In Burundi or the Central African region, no recent prevalence studies for congenital malaria have been carried out. This study found that the prevalence of congenital malaria in two hospitals in Kirundo province is zero. RDT showed to have an excellent specificity and, therefore, can be used to rule out congenital malaria: the risk of overtreatment is low. However, as no cases of congenital malaria were detected, the study was not able to draw conclusions about the sensitivity of the RDT, nor about risk factors for congenital malaria. Further studies evaluating the sensitivity of RDT for diagnosis of congenital malaria are needed.
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Abstract
Malaria is one of the most serious infectious diseases with most of the severe disease
caused by Plasmodium falciparum (Pf). Naturally acquired immunity
develops over time after repeated infections and the development of antimalarial
antibodies is thought to play a crucial role. Neonates and young infants are relatively
protected from symptomatic malaria through mechanisms that are poorly understood. The
prevailing paradigm is that maternal antimalarial antibodies transferred to the fetus in
the last trimester of pregnancy protect the infant from early infections. These
antimalarial antibodies wane by approximately 6 months of age leaving the infant
vulnerable to malaria, however direct evidence supporting this epidemiologically based
paradigm is lacking. As infants are the target population for future malaria vaccines,
understanding how they begin to develop immunity to malaria and the gaps in their
responses is key. This review summarizes the antimalarial antibody responses detected in
infants and how they change over time. We focus primarily on Pf antibody responses and
will briefly mention Plasmodium vivax responses in infants.
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Kangoye DT, Mensah VA, Murungi LM, Nkumama I, Nebie I, Marsh K, Cisse B, Bejon P, Osier FHA, Sirima SB. Dynamics and role of antibodies to Plasmodium falciparum merozoite antigens in children living in two settings with differing malaria transmission intensity. Vaccine 2015; 34:160-6. [PMID: 26541134 PMCID: PMC4683095 DOI: 10.1016/j.vaccine.2015.10.058] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Revised: 09/26/2015] [Accepted: 10/12/2015] [Indexed: 11/17/2022]
Abstract
BACKGROUND Young infants have reduced susceptibility to febrile malaria compared with older children, but the mechanism for this remains unclear. There are conflicting data on the role of passively acquired antibodies. Here, we examine antibody titres to merozoite surface antigens in the protection of children in their first two years of life in two settings with differing malaria transmission intensity and compare these titres to previously established protective thresholds. METHODS Two cohorts of children aged four to six weeks were recruited in Banfora, Burkina and Keur Soce, Senegal and followed up for two years. Malaria infections were detected by light microscopic examination of blood smears collected at active and passive case detection visits. The titres of antibodies to the Plasmodium falciparum recombinant merozoite proteins (AMA1-3D7, MSP1-19, MSP2-Dd2, and MSP3-3D7) were measured by enzyme-linked immunosorbent assay at 1-6, 9, 12, 15 and 18 months of age and compared with the protective thresholds established in Kenyan children. RESULTS Antibody titres were below the protective thresholds throughout the study period and we did not find any association with protection against febrile malaria. Antibodies to AMA1 and MSP1-19 appeared to be markers of exposure in the univariate analysis (and so associated with increasing risk) and adjusting for exposure reduced the strength and significance of this association. CONCLUSION The antibody levels we measured are unlikely to be responsible for the apparent protection against febrile malaria seen in young infants. Further work to identify protective antibody responses might include functional assays and a wider range of antigens.
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Affiliation(s)
- David Tiga Kangoye
- Centre National de Recherche et de Formation sur le Paludisme (CNRFP), 01 BP 2208, Ouagadougou 01, Burkina Faso; Kenya Medical Research Institute, Centre for Geographic Medicine Research Coast (KEMRI-CGMRC), P.O. Box 230, Kilifi 80108, Kenya.
| | | | - Linda Muthoni Murungi
- Kenya Medical Research Institute, Centre for Geographic Medicine Research Coast (KEMRI-CGMRC), P.O. Box 230, Kilifi 80108, Kenya
| | - Irene Nkumama
- Kenya Medical Research Institute, Centre for Geographic Medicine Research Coast (KEMRI-CGMRC), P.O. Box 230, Kilifi 80108, Kenya
| | - Issa Nebie
- Centre National de Recherche et de Formation sur le Paludisme (CNRFP), 01 BP 2208, Ouagadougou 01, Burkina Faso
| | - Kevin Marsh
- Kenya Medical Research Institute, Centre for Geographic Medicine Research Coast (KEMRI-CGMRC), P.O. Box 230, Kilifi 80108, Kenya; Nuffield Department of Medicine, Centre for Clinical Vaccinology and Tropical Medicine, University of Oxford, Churchill Hospital, Oxford, United Kingdom
| | - Badara Cisse
- Service de Parasitologie, Université Cheikh Anta Diop (UCAD), BP 5005 UCAD, Dakar, Senegal
| | - Philip Bejon
- Kenya Medical Research Institute, Centre for Geographic Medicine Research Coast (KEMRI-CGMRC), P.O. Box 230, Kilifi 80108, Kenya; Nuffield Department of Medicine, Centre for Clinical Vaccinology and Tropical Medicine, University of Oxford, Churchill Hospital, Oxford, United Kingdom
| | - Faith Hope Among'in Osier
- Kenya Medical Research Institute, Centre for Geographic Medicine Research Coast (KEMRI-CGMRC), P.O. Box 230, Kilifi 80108, Kenya
| | - Sodiomon Bienvenu Sirima
- Centre National de Recherche et de Formation sur le Paludisme (CNRFP), 01 BP 2208, Ouagadougou 01, Burkina Faso
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Augusto DG, Petzl-Erler ML. KIR and HLA under pressure: evidences of coevolution across worldwide populations. Hum Genet 2015; 134:929-40. [PMID: 26099314 DOI: 10.1007/s00439-015-1579-9] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Accepted: 06/15/2015] [Indexed: 01/13/2023]
Abstract
KIR (killer cell immunoglobulin-like receptors) and HLA (human leukocyte antigens) are two distinct gene families with remarkable importance for human immune responses. The recognition of HLA molecules by activating and inhibitory KIR promotes a balance of signals that regulates NK cell function and is especially important for the innate defense against pathogens and early placentation. There is no documented gametic association between these two gene families and no evidence of common regulation. However, due to the critical role of KIR recognition for immunity and reproduction, the possibility of KIR-HLA combinations being under selective pressure is not surprising. In this manuscript, we first summarize the HLA-KIR system, the HLA molecules that are the putative ligands for KIR, and then we review the evidences that suggest these two gene families are coevolving as an integrated system.
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Affiliation(s)
- Danillo G Augusto
- Departamento de Genética, Universidade Federal do Paraná, Caixa Postal 19071, Curitiba, PR, 81531-980, Brazil,
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Muro F, Reyburn R, Reyburn H. Acute respiratory infection and bacteraemia as causes of non-malarial febrile illness in African children: a narrative review. Pneumonia (Nathan) 2015; 6:6-17. [PMID: 26594615 PMCID: PMC4650196 DOI: 10.15172/pneu.2015.6/488] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Accepted: 03/13/2015] [Indexed: 12/16/2022] Open
Abstract
The replacement of "presumptive treatment for malaria" by "test before treat" strategies for the management of febrile illness is raising awareness of the importance of knowing more about the causes of illness in children who are suspected to have malaria but return a negative parasitological test. The most common cause of non-malarial febrile illness (NMFI) in African children is respiratory tract infection. Whilst the bacterial causes of NMFI are well known, the increasing use of sensitive techniques such as polymerase chain reaction (PCR) tests is revealing large numbers of viruses that are potential respiratory pathogens. However, many of these organisms are commonly present in the respiratory tract of healthy children so causality and risk factors for pneumonia remain poorly understood. Infection with a combination of viral and bacterial pathogens is increasingly recognised as important in the pathogenesis of pneumonia. Similarly, blood stream infections with organisms typically grown by aerobic culture are well known but a growing number of organisms that can be identified only by PCR, viral culture, or serology are now recognised to be common pathogens in African children. The high mortality of hospitalised children on the first or second day of admission suggests that, unless results are rapidly available, diagnostic tests to identify specific causes of illness will still be of limited use in guiding the potentially life saving decisions relating to initial treatment of children admitted to district hospitals in Africa with severe febrile illness and a negative test for malaria. Malaria control and the introduction of vaccines against Haemophilus influenzae type b and pneumococcal disease are contributing to improved child survival in Africa. However, increased parasitological testing for malaria is associated with increased use of antibiotics to which resistance is already high.
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Affiliation(s)
- Florid Muro
- Kilimanjaro Christian Medical Centre, Moshi, Tanzania
| | - Rita Reyburn
- Murdoch Children’s Research Institute, Royal Children’s Hospital, Parkville, Victoria Australia
- New Vaccine Evaluation Project, Colonial War Memorial Hospital, Suva, Fiji
| | - Hugh Reyburn
- Department of Disease Control, London School of Hygiene and Tropical Medicine, Keppel St London, WICE7HT UK
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Apinjoh TO, Anchang-Kimbi JK, Mugri RN, Njua-Yafi C, Tata RB, Chi HF, Tangoh DA, Loh BT, Achidi EA. Determinants of infant susceptibility to malaria during the first year of life in South Western cameroon. Open Forum Infect Dis 2015; 2:ofv012. [PMID: 26034763 PMCID: PMC4438893 DOI: 10.1093/ofid/ofv012] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Accepted: 01/22/2015] [Indexed: 12/02/2022] Open
Abstract
Background. Falciparum malaria is an important pediatric infectious disease that frequently affects pregnant women and alters infant morbidity. However, the impact of some prenatal and perinatal risk factors such as season and intermittent preventive treatment during pregnancy (IPTp) on neonatal susceptibility has not been fully elucidated. Methods. A cohort of 415 infants born to women who were positive and negative for malaria was monitored in a longitudinal study in Southwestern Cameroon. The clinical and malaria statuses were assessed throughout, whereas paired maternal-cord and 1-year-old antimalarial antibodies were assayed by enzyme-linked immunosorbent assay. Infant susceptibility to malaria was ascertained after accounting for IPTp and season in the statistical analysis. Results. Malaria prevalence was higher in women (P = .039) who delivered during the rainy season and their infants (P = .030) compared with their dry season counterparts. Infants born to women who were positive for malaria (6.40 ± 2.83 months) were older (P = .028) than their counterparts who were negative for malaria (5.52 ± 2.85 months) when they experienced their first malaria episode. Infants born in September-November (adjusted odds ratio [OR] = 0.31, 95% confidence interval [CI] = 0.13-0.72) and to mothers on 1 or no IPTp-sulfadoxine/pyrimethamine (SP) dose (adjusted OR = 0.51, 95% CI = 0.28-0.91) were protected, whereas those born in the rainy season (adjusted OR = 2.82, 95% CI = 1.21-6.55) were susceptible to malaria. Conclusions. Intermittent preventive treatment during pregnancy and month of birth have important implications for infant susceptibility to malaria, with 2 or more IPTp-SP dosage possibly reducing immunoglobulin M production.
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Affiliation(s)
| | | | - Regina N. Mugri
- Medical Laboratory Science
- Microbiology and Parasitology, University of Buea
| | - Clarisse Njua-Yafi
- Department of Animal Biology and Physiology, University of Yaounde I, Cameroon
| | - Rolland B. Tata
- Medical Laboratory Science
- Microbiology and Parasitology, University of Buea
| | - Hanesh F. Chi
- Medical Laboratory Science
- Microbiology and Parasitology, University of Buea
| | - Delphine A. Tangoh
- Departments of Biochemistry and Molecular Biology
- Medical Laboratory Science
| | | | - Eric A. Achidi
- Departments of Biochemistry and Molecular Biology
- Medical Laboratory Science
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Plasmodium falciparum malaria in children aged 0-2 years: the role of foetal haemoglobin and maternal antibodies to two asexual malaria vaccine candidates (MSP3 and GLURP). PLoS One 2014; 9:e107965. [PMID: 25238160 PMCID: PMC4169582 DOI: 10.1371/journal.pone.0107965] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Accepted: 08/07/2014] [Indexed: 11/20/2022] Open
Abstract
BACKGROUND Children below six months are reported to be less susceptible to clinical malaria. Maternally derived antibodies and foetal haemoglobin are important putative protective factors. We examined antibodies to Plasmodium falciparum merozoite surface protein 3 (MSP3) and glutamate-rich protein (GLURP), in children in their first two years of life in Burkina Faso and their risk of malaria. METHODS A cohort of 140 infants aged between four and six weeks was recruited in a stable transmission area of south-western Burkina Faso and monitored for 24 months by active and passive surveillance. Malaria infections were detected by examining blood smears using light microscopy. Enzyme-linked immunosorbent assay was used to quantify total Immunoglobulin G to Plasmodium falciparum antigens MSP3 and two regions of GLURP (R0 and R2) on blood samples collected at baseline, three, six, nine, 12, 18 and 24 months. Foetal haemoglobin and variant haemoglobin fractions were measured at the baseline visit using high pressure liquid chromatography. RESULTS A total of 79.6% of children experienced one or more episodes of febrile malaria during monitoring. Antibody titres to MSP3 were prospectively associated with an increased risk of malaria while antibody responses to GLURP (R0 and R2) did not alter the risk. Antibody titres to MSP3 were higher among children in areas of high malaria risk. Foetal haemoglobin was associated with delayed first episode of febrile malaria and haemoglobin CC type was associated with reduced incidence of febrile malaria. CONCLUSIONS We did not find any evidence of association between titres of antibodies to MSP3, GLURP-R0 or GLURP-R2 as measured by enzyme-linked immunosorbent assay and early protection against malaria, although anti-MSP3 antibody titres may reflect increased exposure to malaria and therefore greater risk. Foetal haemoglobin was associated with protection against febrile malaria despite the study limitations and its role is therefore worthy further investigation.
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No asymptomatic malaria parasitaemia found among 108 young children at one health facility in Dar es Salaam, Tanzania. Malar J 2013; 12:417. [PMID: 24228811 PMCID: PMC3830543 DOI: 10.1186/1475-2875-12-417] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2013] [Accepted: 11/12/2013] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND Asymptomatic malaria parasitaemia has been reported in areas with high malaria transmission. It may serve as a reservoir for continued transmission, and furthermore complicates diagnostics, as not all individuals with a positive malaria test are necessarily ill due to malaria, although they may present with malaria-like symptoms. Asymptomatic malaria increases with age as immunity to malaria gradually develops. As mortality and morbidity of malaria is higher among younger children it is important to know the prevalence of asymptomatic malaria parasitaemia in this population in order to interpret laboratory results for malaria correctly. METHODS A total of 108 children that had neither been treated for malaria nor had a fever the previous four weeks were recruited consecutively at a maternal and child health clinic (MCHC) in Dar es Salaam, Tanzania. A rapid diagnostic test (RDT) for malaria and dried blood spot (DBS) on filter paper were taken from each child. Social and clinical data were recorded. DNA was extracted from the DBS of study participants by a method using InstaGene™ matrix. PCR targeting the Plasmodium mitochondrial genome was performed on all samples. RESULTS Median age was 4.6 months (range 0.5-38). All the RDTs were negative. PCR was negative for all study subjects. CONCLUSION The study suggests that asymptomatic malaria may not be present in apparently healthy children up to the age of three years in Dar es Salaam, Tanzania. However, because of the small sample size and low median age of the study population, the findings cannot be generalized. Larger studies, including higher age groups, need to be done to clarify whether asymptomatic malaria parasitaemia is present in the general population in the Dar es Salaam area.
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Norman PJ, Hollenbach JA, Nemat-Gorgani N, Guethlein LA, Hilton HG, Pando MJ, Koram KA, Riley EM, Abi-Rached L, Parham P. Co-evolution of human leukocyte antigen (HLA) class I ligands with killer-cell immunoglobulin-like receptors (KIR) in a genetically diverse population of sub-Saharan Africans. PLoS Genet 2013; 9:e1003938. [PMID: 24204327 PMCID: PMC3814319 DOI: 10.1371/journal.pgen.1003938] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2013] [Accepted: 09/16/2013] [Indexed: 02/06/2023] Open
Abstract
Interactions between HLA class I molecules and killer-cell immunoglobulin-like receptors (KIR) control natural killer cell (NK) functions in immunity and reproduction. Encoded by genes on different chromosomes, these polymorphic ligands and receptors correlate highly with disease resistance and susceptibility. Although studied at low-resolution in many populations, high-resolution analysis of combinatorial diversity of HLA class I and KIR is limited to Asian and Amerindian populations with low genetic diversity. At the other end of the spectrum is the West African population investigated here: we studied 235 individuals, including 104 mother-child pairs, from the Ga-Adangbe of Ghana. This population has a rich diversity of 175 KIR variants forming 208 KIR haplotypes, and 81 HLA-A, -B and -C variants forming 190 HLA class I haplotypes. Each individual we studied has a unique compound genotype of HLA class I and KIR, forming 1-14 functional ligand-receptor interactions. Maintaining this exceptionally high polymorphism is balancing selection. The centromeric region of the KIR locus, encoding HLA-C receptors, is highly diverse whereas the telomeric region encoding Bw4-specific KIR3DL1, lacks diversity in Africans. Present in the Ga-Adangbe are high frequencies of Bw4-bearing HLA-B*53:01 and Bw4-lacking HLA-B*35:01, which otherwise are identical. Balancing selection at key residues maintains numerous HLA-B allotypes having and lacking Bw4, and also those of stronger and weaker interaction with LILRB1, a KIR-related receptor. Correspondingly, there is a balance at key residues of KIR3DL1 that modulate its level of cell-surface expression. Thus, capacity to interact with NK cells synergizes with peptide binding diversity to drive HLA-B allele frequency distribution. These features of KIR and HLA are consistent with ongoing co-evolution and selection imposed by a pathogen endemic to West Africa. Because of the prevalence of malaria in the Ga-Adangbe and previous associations of cerebral malaria with HLA-B*53:01 and KIR, Plasmodium falciparum is a candidate pathogen.
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Affiliation(s)
- Paul J. Norman
- Departments of Structural Biology and Microbiology & Immunology, Stanford University School of Medicine, Stanford, California, United States of America
- * E-mail:
| | - Jill A. Hollenbach
- Center for Genetics, Children's Hospital Oakland Research Institute, Oakland, California, United States of America
| | - Neda Nemat-Gorgani
- Departments of Structural Biology and Microbiology & Immunology, Stanford University School of Medicine, Stanford, California, United States of America
| | - Lisbeth A. Guethlein
- Departments of Structural Biology and Microbiology & Immunology, Stanford University School of Medicine, Stanford, California, United States of America
| | - Hugo G. Hilton
- Departments of Structural Biology and Microbiology & Immunology, Stanford University School of Medicine, Stanford, California, United States of America
| | - Marcelo J. Pando
- Department of Pathology, Stanford University School of Medicine, Stanford, California, United States of America
| | - Kwadwo A. Koram
- Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana
| | - Eleanor M. Riley
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Laurent Abi-Rached
- Departments of Structural Biology and Microbiology & Immunology, Stanford University School of Medicine, Stanford, California, United States of America
- Centre National de la Recherche Scientifique, Laboratoire d'Analyse, Topologie, Probabilités - Unité Mixte de Recherche 7353, Equipe ATIP, Aix-Marseille Université, Marseille, France
| | - Peter Parham
- Departments of Structural Biology and Microbiology & Immunology, Stanford University School of Medicine, Stanford, California, United States of America
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Adam I, A-Elbasit IE, Salih I, Elbashir MI. SubmicroscopicPlasmodium falciparuminfections during pregnancy, in an area of Sudan with a low intensity of malaria transmission. ANNALS OF TROPICAL MEDICINE AND PARASITOLOGY 2013; 99:339-44. [PMID: 15949181 DOI: 10.1179/136485905x36244] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
There are few published studies on the burden of malaria during pregnancy from areas of sub-Saharan Africa where the intensity of malarial transmission is low, and few on submicroscopic malarial infections in pregnant women. The present study was conducted in New Halfa, an area of low-intensity transmission in eastern Sudan, between August 2003 and July 2004. The main aims were to assess the prevalences of submicroscopic and multiple Plasmodium falciparum infections in pregnant women (using the P. falciparum merozoite surface protein-2 as a polymorphic marker in PCR-based assays) and to determine the effects of such infections on anaemia during pregnancy. Of the 142 pregnant women who were recruited, only 17 (11.9%) were found smear-positive for P. falciparum by microscopy. The results of the PCR-based assays revealed, however, that 40 (32%) of the 125 smear-negative women had submicroscopic P. falciparum infections. Blood samples from 32 (80%) of those with submicroscopic infections showed only the FC 27 allele (of merozoite surface protein-2), six (15%) showed only the ICI allele, and two (5%) showed both of these alleles. Although the age, parity, gestational age and haemoglobin concentrations of the women with submicroscopic P. falciparum infections were not significantly different from those of the women who were smear- and PCR-negative, such infections may have a significant impact on materno-foetal health.
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Affiliation(s)
- I Adam
- New Halfa Teaching Hospital, Sudan.
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Lundblom K, Murungi L, Nyaga V, Olsson D, Rono J, Osier F, Ogada E, Montgomery S, Scott JAG, Marsh K, Färnert A. Plasmodium falciparum infection patterns since birth and risk of severe malaria: a nested case-control study in children on the coast of Kenya. PLoS One 2013; 8:e56032. [PMID: 23418502 PMCID: PMC3572150 DOI: 10.1371/journal.pone.0056032] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2012] [Accepted: 01/04/2013] [Indexed: 01/27/2023] Open
Abstract
Children in malaria endemic areas acquire immunity to severe malaria faster than to mild malaria. Only a minority of children suffers from severe malaria and it is not known what determines this. The aim of this study was to establish how P. falciparum infections during the first years of life affect the risk of severe malaria. A matched case-control study was nested within a large birth cohort set up to study the immunoepidemiology of pneumococci on the Kenyan coast. Infection patterns in three-monthly blood samples in cohort children admitted to hospital with severe malaria were compared to controls matched on age, residential location and time of sampling. P. falciparum detected at least once from birth conferred an increased risk of severe malaria and particularly if multiclonal infections, as characterized by genotyping of a polymorphic antigen gene, were ever detected. The results show for the first time that children with severe malaria have more infections early in life compared to community controls. These findings provide important insights on the immunity to severe disease, knowledge essential for the development of a vaccine against severe malaria.
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Affiliation(s)
- Klara Lundblom
- Unit of Infectious Diseases, Department of Medicine Solna, Karolinska Institute, Stockholm, Sweden.
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Enweronu-Laryea CC, Adjei GO, Mensah B, Duah N, Quashie NB. Prevalence of congenital malaria in high-risk Ghanaian newborns: a cross-sectional study. Malar J 2013; 12:17. [PMID: 23311646 PMCID: PMC3565937 DOI: 10.1186/1475-2875-12-17] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2012] [Accepted: 12/27/2012] [Indexed: 11/12/2022] Open
Abstract
Background Congenital malaria is defined as malaria parasitaemia in the first week of life. The reported prevalence of congenital malaria in sub-Saharan Africa is variable (0 - 46%). Even though the clinical significance of congenital malaria parasitaemia is uncertain, anti-malarial drugs are empirically prescribed for sick newborns by frontline health care workers. Data on prevalence of congenital malaria in high-risk newborns will inform appropriate drug use and timely referral of sick newborns. Methods Blood samples of untreated newborns less than 1 week of age at the time of referral to Korle Bu Teaching hospital in Accra, Ghana during the peak malaria seasons (April to July) of 2008 and 2010 were examined for malaria parasites by, i) Giemsa-stained thick and thin blood smears for parasite count and species identification, ii) histidine-rich protein- and lactic dehydrogenase-based rapid diagnosis tests, or iii) polymerase chain reaction amplification of the merozoite surface protein 2 gene, for identification of sub-microscopic parasitaemia. Other investigations were also done as clinically indicated. Results In 2008, nine cases of Plasmodium falciparum parasitaemia were diagnosed by microscopy in 405 (2.2%) newborns. All the nine newborns had low parasite densities (≤50 per microlitre). In 2010, there was no case of parasitaemia by either microscopy or rapid diagnosis tests in 522 newborns; however, 56/467 (12%) cases of P. falciparum were detected by polymerase chain reaction. Conclusion Congenital malaria is an uncommon cause of clinical illness in high-risk untreated newborns referred to a tertiary hospital in the first week of life. Empirical anti-malarial drug treatment for sick newborns without laboratory confirmation of parasitaemia is imprudent. Early referral of sick newborns to hospitals with resources and skills for appropriate care is recommended.
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D'Alessandro U, Ubben D, Hamed K, Ceesay SJ, Okebe J, Taal M, Lama EK, Keita M, Koivogui L, Nahum A, Bojang K, Sonko AAJ, Lalya HF, Brabin B. Malaria in infants aged less than six months - is it an area of unmet medical need? Malar J 2012. [PMID: 23198986 PMCID: PMC3529680 DOI: 10.1186/1475-2875-11-400] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Despite the protection provided by several factors, including maternal antibodies, the burden of malaria in young infants may be higher than previously thought. Infants with congenital or neonatal malaria may have a different clinical presentation than older children, and diagnosis may be confused with other neonatal diseases due to an overlap of clinical manifestations. In addition, there is little information on the use of artemisinin-based combination therapy in young infants. There is the need for a more accurate estimate of the parasite prevalence and the incidence of clinical malaria in infants under 6 months old, as well as a better characterization of risk factors, pharmacokinetic profiles, safety and efficacy of currently available anti-malarial treatments, in order to develop evidence-based treatment guidelines for this population.
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31
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Prevention of congenital transmission of malaria in sub-saharan african countries: challenges and implications for health system strengthening. J Trop Med 2011; 2012:648456. [PMID: 21961019 PMCID: PMC3179872 DOI: 10.1155/2012/648456] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2011] [Accepted: 07/27/2011] [Indexed: 11/18/2022] Open
Abstract
Objectives. Review of burden of congenital transmission of malaria, challenges of preventive measures, and implications for health system strengthening in sub-Saharan Africa. Methods. Literature from Pubmed (MEDLINE), Biomed central, Google Scholar, and Cochrane Database were reviewed. Results. The prevalence of congenital malaria in sub-Saharan Africa ranges from 0 to 23%. Diagnosis and existing preventive measures are constantly hindered by weak health systems and sociocultural issues. WHO strategic framework for prevention: intermittent preventive therapy (IPT), insecticide-treated nets (ITNs), and case management of malaria illness and anaemia remain highly promising; though, specific interventions are required to strengthen the health systems in order to improve the effectiveness of these measures. Conclusion. Congenital malaria remains a public health burden in sub-Saharan Africa. Overcoming the challenges of the preventive measures hinges on the ability of national governments and development partners in responding to the weak health systems.
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Abstract
BACKGROUND Each year, malaria threatens 125 million pregnancies, and gestational malaria is responsible for up to 200,000 infant deaths in sub-Saharan Africa. With advancing knowledge of malaria in pregnancy and its impact on newborns, improved preventive and therapeutic interventions are possible. METHODS We reviewed and, by consensus, evaluated published literature relevant to malaria and newborns. Important findings are summarised. RESULTS Pregnant women are more likely than others to be inoculated with and infected by malaria parasites. Poor outcomes are particularly common in primigravid women and their offspring. The placenta is affected through cellular adhesion, cytokine production and mononuclear cell infiltrates. As a result, newborns may have low birthweight owing to intrauterine growth retardation or prematurity. Recent evidence suggests that a subset of these infants is also at higher risk of malaria infections later in life. Preventive strategies to improve maternal and fetal outcomes include intermittent preventive treatment and insecticide-treated bed nets. Asymptomatic malaria infection is not uncommon in newborns, and symptomatic disease occurs. Fever and death are possible during the early days of life, and presentation with a sepsis-like illness can occur during the 1st 2 months of life. Malaria-affected infants face higher than usual risks of infantile anaemia, subsequent malaria infection and death during the 1st year of life. CONCLUSIONS Malaria is common during pregnancy and can have serious consequences for neonatal health. Neonatal morbidity and mortality can be significantly reduced by proper implementation of insecticide-treated nets and intermittent preventive treatment.
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Affiliation(s)
- T K Hartman
- Floating Hospital for Children at Tufts Medical Center, Boston, MA, USA
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33
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Poespoprodjo JR, Fobia W, Kenangalem E, Lampah DA, Hasanuddin A, Warikar N, Sugiarto P, Tjitra E, Anstey NM, Price RN. Vivax malaria: a major cause of morbidity in early infancy. Clin Infect Dis 2009; 48:1704-12. [PMID: 19438395 DOI: 10.1086/599041] [Citation(s) in RCA: 122] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
BACKGROUND In areas where malaria is endemic, infants aged <3 months appear to be relatively protected from symptomatic and severe Plasmodium falciparum malaria, but less is known about the effect of Plasmodium vivax infection in this age group. METHODS To define malaria morbidity in the first year of life in an area where both multidrug-resistant P. falciparum and P. vivax are highly prevalent, data were gathered on all infants attending a referral hospital in Papua, Indonesia, using systematic data forms and hospital computerized records. Additional clinical and laboratory data were prospectively collected from inpatients aged <3 months. RESULTS From April 2004 through April 2008, 4976 infants were admitted to the hospital, of whom 1560 (31%) had malaria, with infection equally attributable to P. falciparum and P. vivax. The case-fatality rate was similar for inpatients with P. falciparum malaria (13 [2.2%] of 599 inpatients died) and P. vivax malaria (6 [1.0%] of 603 died; P= .161), whereas severe malarial anemia was more prevalent among those with P. vivax malaria (193 [32%] of 605 vs. 144 [24%] of 601; P= .025). Of the 187 infants aged <3 months, 102 (56%) had P. vivax malaria, and 55 (30%) had P. falciparum malaria. In these young infants, infection with P. vivax was associated with a greater risk of severe anemia (odds ratio, 2.4; 95% confidence interval, 1.03-5.91; P= .041) and severe thrombocytopenia (odds ratio, 3.3; 95% confidence interval, 1.07-10.6; P= .036) compared with those who have P. falciparum infection. CONCLUSIONS P. vivax malaria is a major cause of morbidity in early infancy. Preventive strategies, early diagnosis, and prompt treatment should be initiated in the perinatal period.
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Affiliation(s)
- Jeanne R Poespoprodjo
- District Health Authority, Menzies School of Health Research, National Institute of Health Research and Development Malaria Research Program, Jakarta, Indonesia
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Emergence of infectious diseases: when hidden pathogens break out. C R Biol 2009; 332:539-47. [PMID: 19520317 DOI: 10.1016/j.crvi.2009.01.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2008] [Accepted: 01/31/2009] [Indexed: 11/23/2022]
Abstract
Our understanding of disease emergence is largely limited by the assumption that disease emergence is the result of increased exposure to pathogenic agents. Pathogen exposure is thought to arise through an increase in the number of interactions between humans and their natural environment, changes in demography and mobility, or through genetic variation in the infectious agents which may alter virulence or ability to infect new host species. The study of new diseases (which are often revealed by unusually severe symptoms or atypical epidemiological patterns) applies the most effort to the research of new pathogens. Here, using examples, we discuss alternative but non-exclusive mechanisms that may either reveal the presence of long-term circulating pathogens or explain changes in their nosologic properties in relation to their pattern of circulation and infection conditions. A better understanding of the ecology of pathogenic organisms and their host populations should help to define more efficient health management strategies.
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Rogerson SJ, Mwapasa V, Meshnick SR. Malaria in Pregnancy: Linking Immunity and Pathogenesis to Prevention. Am J Trop Med Hyg 2007. [DOI: 10.4269/ajtmh.77.6.suppl.14] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Affiliation(s)
- Stephen J. Rogerson
- Department of Medicine (RMH/WH), The University of Melbourne, Royal Melbourne Hospital, Australia; Department of Community Health, College of Medicine, University of Malawi, Blantyre, Malawi; Department of Epidemiology, Microbiology and Immunology, University of North Carolina, Chapel Hill, North Carolina
| | - Victor Mwapasa
- Department of Medicine (RMH/WH), The University of Melbourne, Royal Melbourne Hospital, Australia; Department of Community Health, College of Medicine, University of Malawi, Blantyre, Malawi; Department of Epidemiology, Microbiology and Immunology, University of North Carolina, Chapel Hill, North Carolina
| | - Steven R. Meshnick
- Department of Medicine (RMH/WH), The University of Melbourne, Royal Melbourne Hospital, Australia; Department of Community Health, College of Medicine, University of Malawi, Blantyre, Malawi; Department of Epidemiology, Microbiology and Immunology, University of North Carolina, Chapel Hill, North Carolina
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36
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Fouchet D, Marchandeau S, Bahi-Jaber N, Pontier D. The role of maternal antibodies in the emergence of severe disease as a result of fragmentation. J R Soc Interface 2007; 4:479-89. [PMID: 17251137 PMCID: PMC2373401 DOI: 10.1098/rsif.2006.0189] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2006] [Accepted: 11/06/2006] [Indexed: 11/12/2022] Open
Abstract
Population fragmentation is a major problem for the conservation of mammalian species. Since the spread of an infectious disease is related to the intensity of contacts between individuals, fragmentation destabilizes the way the parasites circulate in their host population. Recently, Zinkernagel has proposed that a reduction in the frequency of infections by a parasite could lead to the emergence of severe forms of the disease, previously avoided because the disease was contracted early in life and attenuated by maternal antibodies. However, it is still unclear whether this change in disease expression increases the global mortality it induces because the disease becomes more severe and also less frequent. Here, we use a mathematical model to link population fragmentation with the hypothesis of Zinkernagel. Firstly, we show that there is a change in the severity of the disease during the fragmentation process, especially at a local scale, suggesting that host population fragmentation could be a widespread mechanism of disease emergence. Secondly, we show that the emergence of the severe form of the disease can lead to a significant increase in its induced mortality. Finally, we determine the types of interactions for which the fragmentation of the host population could be the most dangerous.
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Affiliation(s)
- David Fouchet
- UMR-CNRS 5558, Université Lyon 1, 43 Boulevard du 11 Novembre 1918, Villeurbanne Cedex, France.
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37
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Fouchet D, Marchandeau S, Langlais M, Pontier D. Waning of maternal immunity and the impact of diseases: The example of myxomatosis in natural rabbit populations. J Theor Biol 2006; 242:81-9. [PMID: 16580697 DOI: 10.1016/j.jtbi.2006.02.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2005] [Revised: 01/19/2006] [Accepted: 02/02/2006] [Indexed: 10/24/2022]
Abstract
Myxomatosis is a leporipoxvirus that infects the european rabbit, inducing a high mortality rate. Observations lead us to hypothesize that a rabbit carrying maternal antibodies (or having recovered) can be infected (or re-infected) upon being exposed (or re-exposed) to the virus. Infection will lead to mild disease, boosting host immune protection. Using a modelling approach we show that this phenomenon may lead to a difference of impact of myxomatosis according to its transmission rate. Young are exposed when they still carry maternal antibodies and develop a mild disease in high transmission populations. Our results show that the impact of myxomatosis is generally higher in epidemic situations compared to populations where the virus circulates all the year. As a consequence, waning of acquired immunity and the continuous supply of newborn along the year may reduce the impact of the disease.
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Affiliation(s)
- D Fouchet
- UMR-CNRS 5558, Biométrie et Biologie Evolutive, Université Claude Bernard Lyon 1, 43 Boulevard du 11 Novembre 1918, 69622 Villeurbanne Cedex, France.
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38
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Chandler CIR, Drakeley CJ, Reyburn H, Carneiro I. The effect of altitude on parasite density case definitions for malaria in northeastern Tanzania. Trop Med Int Health 2006; 11:1178-84. [PMID: 16903881 DOI: 10.1111/j.1365-3156.2006.01672.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVES Malaria clinical trials need precise endpoints to measure efficacy. In endemic areas where asymptomatic parasitaemia is common, 'fever plus parasitaemia' may not differentiate between malaria cases and non-cases. Case definitions based on parasite cut-off densities may be more appropriate but may vary with age and transmission intensity. This study examines appropriate case definitions from parasitological surveys conducted over a broad range of transmission intensities, using altitude as a proxy for transmission intensity. METHODS Cross-sectional data collected from 24 villages at different altitudes in an endemic area of northeastern Tanzania were used to calculate malaria-attributable fractions using a modified Poisson regression method. We modelled fever as a function of parasite density and determined the optimum cut-off densities of parasites to cause fever using sensitivity and specificity analyses. RESULTS The optimum cut-off density varied by altitude in children aged under 5 years: a case definition of 4,000 parasites per mul at altitudes <600 m (high transmission intensity) was most appropriate, compared with 1,000 parasites per mul at altitudes >600 m (low transmission intensity). In children aged over 5 years and adults, there was little variation by altitude and a case definition of any parasites plus fever was the most appropriate. CONCLUSIONS Locally appropriate case definitions of malaria should be used for research purposes. In our setting, these varied independently with age and transmission intensity.
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Affiliation(s)
- Clare I R Chandler
- Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK.
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39
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Chelimo K, Ofulla AV, Narum DL, Kazura JW, Lanar DE, John CC. Antibodies to Plasmodium falciparum antigens vary by age and antigen in children in a malaria-holoendemic area of Kenya. Pediatr Infect Dis J 2005; 24:680-4. [PMID: 16094220 DOI: 10.1097/01.inf.0000172151.28851.fd] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Antibodies are important in protection against infection and disease caused by Plasmodium falciparum, but the frequencies of antibodies to multiple P. falciparum antigens in children are not well-characterized. METHODS IgG and IgM antibodies to the vaccine candidate antigens circumsporozoite protein, thrombospondin-related adhesive protein, liver stage antigen-1, apical membrane antigen-1, erythrocyte-binding antigen-175 and merozoite surface protein-1 were measured by enzyme-linked immunosorbent assay in 110 children 0-50 months of age in a malaria holoendemic area of Kenya. RESULTS A similar pattern was seen for IgG antibodies to circumsporozoite protein, thrombospondin-related adhesive protein, apical membrane antigen-1 and erythrocyte-binding antigen-175: high frequencies (70-90%) in children 0-4 months of age; a decrease in children 5-20 months of age (35-71%); and progressive increases in children 21-36 and 37-50 months of age (53-80% and 60-100%, respectively). In contrast, IgG antibodies to liver stage antigen-1 were infrequent in children 0-4 months of age (5%) and increased with age to 64%, and IgG antibody frequencies to merozoite surface protein-1 were similar across age groups (26-52%). IgG antibodies to all antigens were predominantly of the IgG1 and IgG3 subclasses. Frequencies of IgM antibodies to all antigens were low in children 0-4 months of age (0-15%) and increased with age (24-56% in the oldest children). CONCLUSION In children in a malaria-holoendemic area, IgM antibody to all P. falciparum antigens is infrequent in the first 4 months of life but increases with age and increased exposure. The pattern of age-related IgG response frequencies to P. falciparum antigens varies significantly by antigen.
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O'Meara WP, Breman JG, McKenzie FE. The promise and potential challenges of intermittent preventive treatment for malaria in infants (IPTi). Malar J 2005; 4:33. [PMID: 16033653 PMCID: PMC1193983 DOI: 10.1186/1475-2875-4-33] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2005] [Accepted: 07/20/2005] [Indexed: 11/10/2022] Open
Abstract
Intermittent preventive treatment (IPT) administers a full therapeutic course of an anti-malarial drug at predetermined intervals, regardless of infection or disease status. It is recommended by the World Health Organization (WHO) for protecting pregnant women from the adverse effects of malaria (IPTp) and shows great potential as a strategy for reducing illness from malaria during infancy (IPTi). Administered concurrently with standard immunizations, IPTi is expected to reduce the frequency of clinical disease, but to allow blood-stage infections to occur between treatments, thus allowing parasite-specific immunity to develop. While wide deployment of IPTi is being considered, it is important to assess other potential effects. Transmission conditions, drug choice and administration schedule will likely affect the possibility of post-treatment rebound in child morbidity and mortality and the increased spread of parasite drug resistance and should be considered when implementing IPTi.
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Affiliation(s)
- Wendy Prudhomme O'Meara
- Division of Epidemiology and Population Studies, Fogarty International Center, National Institutes of Health, Bethesda, MD 20892 USA
| | - Joel G Breman
- Division of Epidemiology and Population Studies, Fogarty International Center, National Institutes of Health, Bethesda, MD 20892 USA
| | - F Ellis McKenzie
- Division of Epidemiology and Population Studies, Fogarty International Center, National Institutes of Health, Bethesda, MD 20892 USA
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Malhotra I, Mungai P, Muchiri E, Ouma J, Sharma S, Kazura JW, King CL. Distinct Th1- and Th2-Type prenatal cytokine responses to Plasmodium falciparum erythrocyte invasion ligands. Infect Immun 2005; 73:3462-70. [PMID: 15908375 PMCID: PMC1111871 DOI: 10.1128/iai.73.6.3462-3470.2005] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Prenatal immunity to Plasmodium falciparum merozoite proteins involved in erythrocyte invasion may contribute to the partial protection against malaria that is acquired during infancy in areas of stable malaria transmission. We examined newborn and maternal cytokine and antibody responses to merozoite surface protein-1 (MSP-1), ribosomal phosphoprotein P0 (PfP0), and region II of erythrocyte binding antigen-175 (EBA-175) in infant-mother pairs in Kenya. Overall, 82 of 167 (50%), 106 of 176 (60%), and 38 of 84 (45%) cord blood lymphocytes (CBL) from newborns produced one or more cytokines in response to MSP-1, PfP0, and EBA-175, respectively. Newborns of primigravid and/or malaria-infected women were more likely to have antigen-responsive CBL than were newborns of multigravid and/or uninfected women at delivery. Newborn cytokine responses did not match those of their mothers and fell into three distinct categories, Th1 (21 of 55 CBL donors produced only gamma interferon and/or interleukin 2 [IL-2]), Th2 (21 of 55 produced only IL-5 and/or IL-13), and mixed Th1/Th2 (13 of 55). Newborns produced more IL-10 than adults. High and low levels of cord blood IL-12 p70 production induced by anti-CD40 activation were associated with malaria-specific Th1 and Th2 responses, respectively. Antigen-responsive CBL in some newborns were detected only after depletion of IL-10-secreting CD8 cells with enrichment for CD4 cells. These data indicate that prenatal sensitization to blood-stage Plasmodium falciparum occurs frequently in areas where malaria is holoendemic. Modulation of this immunity, possibly by maternal parity and malaria, may affect the acquisition of protective immunity against malaria during infancy.
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Affiliation(s)
- Indu Malhotra
- Center for Global Health and Diseases, Case Western Reserve University, 2103 Cornell Rd., WRC Room 4132, Cleveland, OH 44106-7286, USA
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Mayengue PI, Rieth H, Khattab A, Issifou S, Kremsner PG, Klinkert MQ, Ntoumi F. Submicroscopic Plasmodium falciparum infections and multiplicity of infection in matched peripheral, placental and umbilical cord blood samples from Gabonese women. Trop Med Int Health 2004; 9:949-58. [PMID: 15361107 DOI: 10.1111/j.1365-3156.2004.01294.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Summary In malaria-endemic regions, pregnant women are more susceptible to malarial infections than non-pregnant women. The main objective of this study, which was conducted in the malaria hyperendemic town of Lambaréné (Gabon, Central Africa), was to characterize Plasmodium falciparum infections in peripheral, placental and cord blood from women of different gravidities with submicroscopic infections. Using the P. falciparum merozoite surface protein 2 (MSP 2)* gene as a polymorphic marker in polymerase chain reactions, we analysed genetic diversity and multiplicity of infection in isolates from all three kinds of samples of 184 pregnant women at delivery. We detected infection in 44% of the women who were originally negative by microscopy. Equally important was the finding that the placenta had the highest prevalence of infection (P < 0.001). There was no correlation with gravidity status or age of the patients. The multiplicities of infection in the peripheral and placental blood samples did not differ and single infection was observed in cord blood, independently of the gravidity. The FC27/MSP 2 was the predominant allelic family. The major FC27 alleles detected in the peripheral, placental and cord blood were sequenced and found to be closely related to the published K1 form sequence. Below microscopy level, the placenta remains the most infected organ and this submicroscopic carriage of parasites may contribute to the development and maintenance of immunity to malaria during pregnancy.
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Franks S, Baton L, Tetteh K, Tongren E, Dewin D, Akanmori BD, Koram KA, Ranford-Cartwright L, Riley EM. Genetic diversity and antigenic polymorphism in Plasmodium falciparum: extensive serological cross-reactivity between allelic variants of merozoite surface protein 2. Infect Immun 2003; 71:3485-95. [PMID: 12761133 PMCID: PMC155717 DOI: 10.1128/iai.71.6.3485-3495.2003] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Diversity in the surface antigens of malaria parasites is generally assumed to be a mechanism for immune evasion, but there is little direct evidence that this leads to evasion of protective immunity. Here we show that alleles of the highly polymorphic merozoite surface protein 2 (MSP-2) can be grouped (within the known dimorphic families) into distinct serogroups; variants within a serogroup show extensive serological cross-reactivity. Cross-reactive epitopes are immunodominant, and responses to them may be boosted at the expense of responses to novel epitopes (original antigenic sin). The data imply that immune selection explains only some of the diversity in the msp-2 gene and that MSP-2 vaccines may need to include only a subset of the known variants in order to induce pan-reactive antibodies.
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Affiliation(s)
- Simon Franks
- Institute of Cell, Animal and Population Biology, University of Edinburgh, Edinburgh EH9 3JT, Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London WC1E 7HT, Division of Infection and Immunity, Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow G12 8QQ, United Kingdom, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana
| | - Luke Baton
- Institute of Cell, Animal and Population Biology, University of Edinburgh, Edinburgh EH9 3JT, Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London WC1E 7HT, Division of Infection and Immunity, Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow G12 8QQ, United Kingdom, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana
| | - Kevin Tetteh
- Institute of Cell, Animal and Population Biology, University of Edinburgh, Edinburgh EH9 3JT, Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London WC1E 7HT, Division of Infection and Immunity, Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow G12 8QQ, United Kingdom, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana
| | - Eric Tongren
- Institute of Cell, Animal and Population Biology, University of Edinburgh, Edinburgh EH9 3JT, Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London WC1E 7HT, Division of Infection and Immunity, Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow G12 8QQ, United Kingdom, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana
| | - David Dewin
- Institute of Cell, Animal and Population Biology, University of Edinburgh, Edinburgh EH9 3JT, Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London WC1E 7HT, Division of Infection and Immunity, Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow G12 8QQ, United Kingdom, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana
| | - Bartholomew D. Akanmori
- Institute of Cell, Animal and Population Biology, University of Edinburgh, Edinburgh EH9 3JT, Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London WC1E 7HT, Division of Infection and Immunity, Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow G12 8QQ, United Kingdom, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana
| | - Kojo A. Koram
- Institute of Cell, Animal and Population Biology, University of Edinburgh, Edinburgh EH9 3JT, Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London WC1E 7HT, Division of Infection and Immunity, Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow G12 8QQ, United Kingdom, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana
| | - Lisa Ranford-Cartwright
- Institute of Cell, Animal and Population Biology, University of Edinburgh, Edinburgh EH9 3JT, Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London WC1E 7HT, Division of Infection and Immunity, Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow G12 8QQ, United Kingdom, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana
| | - Eleanor M. Riley
- Institute of Cell, Animal and Population Biology, University of Edinburgh, Edinburgh EH9 3JT, Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London WC1E 7HT, Division of Infection and Immunity, Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow G12 8QQ, United Kingdom, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana
- Corresponding author. Mailing address: Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel St., London WC1E 7HT, United Kingdom. Phone: (44) 207 927 2706. Fax: (44) 207 927 2807. E-mail:
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Mayor A, Saute F, Aponte JJ, Almeda J, Gómez-Olivé FX, Dgedge M, Alonso PL. Plasmodium falciparum multiple infections in Mozambique, its relation to other malariological indices and to prospective risk of malaria morbidity. Trop Med Int Health 2003; 8:3-11. [PMID: 12535242 DOI: 10.1046/j.1365-3156.2003.00968.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We describe the frequency of Plasmodium falciparum clones infecting individuals living in a rural area of southern Mozambique and analyse the relationship between multiplicity of infection, age and other malariometric indices, including prospective risk of clinical malaria. The genotyping was based on the use of restriction fragment length polymorphism-polymerase chain reaction (RFLP-PCR) analysis of P. falciparum merozoite surface protein 2 (msp2). We analysed 826 samples collected during five cross-sectional surveys from residents of Manhiça ranging in age from 4 months to 83 years. We also determined the multiplicity of infection in samples obtained from 6-month-old infants (n = 79) and children <10 years (n = 158) who were then treated and followed prospectively for 1 year or 75 weeks, respectively. Multiplicity of infection did not vary significantly during the first year of life, but increased thereafter, and decreased during adulthood to the levels found in infants. With increasing multiplicity of infection, there was a statistically significant decrease in the risk of submicroscopic infections. There was also a significant correlation between multiplicity of infection and parasite density in infants, children <4 years of age and adults, suggesting that high densities increase the probability of discriminating more clones in complex infections. We found that the relationship between multiple infections and malaria morbidity is age-dependent. In infants, the risk of subsequent episodes of clinical malaria was related to the parasite density but not to baseline multiplicity of infection. In older children, however, the more clones a child carried, the more likely they were to have a clinical malaria episode, and this was true after adjusting for parasite densities. This change in the association between multiplicity and risk of clinical malaria may indicate a shift in the host response to P. falciparum.
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Affiliation(s)
- Alfredo Mayor
- Centro de Investigaçao em Saúde da Manhiça (CISM)/Ministerio de Saúde, Maputo, Mozambique.
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45
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Zhang W, Liu XQ, Xu H, Good MF. Polyspecific malaria antibodies present at the time of infection inhibit the development of immunity to malaria but antibodies specific for the malaria merozoite surface protein, MSP1, facilitate immunity. Parasite Immunol 2002; 24:233-41. [PMID: 12060317 DOI: 10.1046/j.1365-3024.2002.00456.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Serum taken from mice immune to malaria as a result of infection and drug cure, or from mice immunized with a recombinant form of the merozoite surface protein, MSP1, can provide passive protection of recipient mice against the lethal parasite, Plasmodium yoelii YM. However, recipients of MSP1-immune serum go on to develop long-term immunity, whereas recipients of serum from mice naturally immune to malaria rapidly lose their resistance to infection. We demonstrate that 'infection/cure' serum suppresses the development of both antibody and cell-mediated parasite-specific responses in recipients, whereas these develop in recipients of MSP1-specific antibodies. These data have profound implications for our understanding of the development of malaria immunity in babies who passively acquire antibodies from their mothers.
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Affiliation(s)
- Wenbao Zhang
- The Cooperative Research Centre for Vaccine Technology, The Queensland Institute of Medical Research, Royal Brisbane Hospital, Queensland, Australia
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46
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Baruch DI, Gamain B, Barnwell JW, Sullivan JS, Stowers A, Galland GG, Miller LH, Collins WE. Immunization of Aotus monkeys with a functional domain of the Plasmodium falciparum variant antigen induces protection against a lethal parasite line. Proc Natl Acad Sci U S A 2002; 99:3860-5. [PMID: 11904437 PMCID: PMC122614 DOI: 10.1073/pnas.022018399] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Immunity to Plasmodium falciparum in African children has been correlated with antibodies to the P. falciparum erythrocyte membrane protein 1 (PfEMP1) variant gene family expressed on the surface of infected red cells. We immunized Aotus monkeys with a subregion of the Malayan Camp variant antigen (MCvar1) that mediates adhesion to the host receptor CD36 on the endothelial surface and present data that PfEMP1 is an important target for vaccine development. The immunization induced a high level of protection against the homologous strain. Protection correlated with the titer of agglutinating antibodies and occurred despite the expression of variant copies of the gene during recurrent waves of parasitemia. A second challenge with a different P. falciparum strain, to which there was no agglutinating activity, showed no protection but boosted the immune response to this region during the infection. The level of protection and the evidence of boosting during infection encourage further exploration of this concept for malaria vaccine development.
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Affiliation(s)
- Dror I Baruch
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
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47
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Kamwendo DD, Dzinjalamala FK, Snounou G, Kanjala MCC, Mhango CG, Molyneux ME, Rogerson SJ. Plasmodium falciparum: PCR detection and genotyping of isolates from peripheral, placental, and cord blood of pregnant Malawian women and their infants. Trans R Soc Trop Med Hyg 2002; 96:145-9. [PMID: 12055802 DOI: 10.1016/s0035-9203(02)90284-1] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
Abstract
Polymerase chain reaction (PCR) is both a sensitive means of detecting malaria parasitaemia, and a simple tool for identifying genetic differences in parasites infecting human subjects. We compared PCR to microscopy in detection of Plasmodium falciparum infection in peripheral, placental and cord blood samples collected from 131 pregnant Malawian women and their infants in 1997-99. Infections detected by species-specific PCR were genotyped at the merozoite surface protein 1 and 2 loci, and minimum numbers of infecting genotypes determined. PCR was of similar sensitivity to microscopy in detecting peripheral and placental infection, and placental blood PCR was 100% specific compared to placental histology. Cord blood parasitaemia was more frequently detected by PCR than microscopy, 20% versus 6%. Genotype numbers in peripheral blood (mean 2.36; range 1-5), placental blood (mean 2.41; range 1-6) and cord (mean 2.14; range 1-4) were similar. The frequency of detection of each allelic family did not differ between sites. Genotypes from different sites in each patient were compared. In 69% of women, genotypes were detected in peripheral blood and not placenta, or vice versa, suggesting possible differential sequestration of different parasite populations. Cord blood genotypes were usually a subset of those in peripheral and placental blood, but, in some cases, genotypes were found in cord blood that were absent from the mother. Transplacental infection before term, and clearance of maternal infection, is postulated.
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Affiliation(s)
- Deborah D Kamwendo
- Department of Obstetrics and Gynaecology, College of Medicine, University of Malawi, Blantyre, Malawi
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King CL, Malhotra I, Wamachi A, Kioko J, Mungai P, Wahab SA, Koech D, Zimmerman P, Ouma J, Kazura JW. Acquired immune responses to Plasmodium falciparum merozoite surface protein-1 in the human fetus. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2002; 168:356-64. [PMID: 11751981 DOI: 10.4049/jimmunol.168.1.356] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Infants born in areas of stable malaria transmission are relatively protected against severe morbidity and high density Plasmodium falciparum blood-stage infection. This protection may involve prenatal sensitization and immunologic reactivity to malaria surface ligands that participate in invasion of red cells. We examined cord blood T and B cell immunity to P. falciparum merozoite surface protein-1 (MSP-1) in infants born in an area of stable malaria transmission in Kenya. T cell cytokine responses to the C-terminal 19-kDa fragment of MSP-1 (MSP-1(19)) were detected in 24 of 92 (26%) newborns (4-192 IFN-gamma and 3-88 IL-4-secreting cells per 10(6)/cord blood lymphocytes). Peptide epitopes in the N-terminal block 3 region of MSP-1 also drove IFN-gamma and/or IL-13 production. There was no evidence of prenatal T cell sensitization to liver-stage Ag-1. A total of 5 of 86 (6%) newborns had cord blood anti-MSP-1(19) IgM Abs, an Ig isotype that does not cross the placenta and is therefore of fetal origin. The frequency of neonatal B cell sensitization was higher than that indicated by serology alone, as 5 of 27 (18%) cord blood samples contained B cells that produced IgG when stimulated with MSP-1(19) in vitro. Neonatal B cell IgG responses were restricted to the Q-KNG allele of MSP-1(19), the major variant in this endemic area, whereas T cells responded to all four MSP-1(19) alleles evaluated. In utero sensitization to MSP-1 correlated with the presence of malaria parasites in cord blood (chi(2) = 20, p < 0.0001). These data indicate that prenatal sensitization to blood-stage Ags occurs in infants born in malaria endemic areas.
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Affiliation(s)
- Christopher L King
- Division of Geographic Medicine, Department of Medicine, Case Western Reserve University, Harlan Wood Building, 10900 Euclid Avenue, Cleveland, OH 44106, USA.
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49
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Saute F, Menendez C, Mayor A, Aponte J, Gomez-Olive X, Dgedge M, Alonso P. Malaria in pregnancy in rural Mozambique: the role of parity, submicroscopic and multiple Plasmodium falciparum infections. Trop Med Int Health 2002; 7:19-28. [PMID: 11851951 DOI: 10.1046/j.1365-3156.2002.00831.x] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Falciparum malaria affects pregnant women, especially primigravidae, but before malaria control programmes targeted to them can be designed, a description of the frequency and parity pattern of the infection is needed. There is little information on the frequency and effect of submicroscopic malaria infection, as well as on multiplicity of Plasmodium falciparum genotypes in pregnancy. This study aimed to describe the prevalence of malaria parasitaemia and anaemia and their relation to parity and age in pregnant women, during two malaria transmission seasons in a rural area of southern Mozambique. It also tried to assess the frequency and effect on anaemia of submicroscopic and multiple falciparum infections. METHODS A total of 686 pregnant women were enrolled in three cross-sectional community-based surveys during different transmission seasons in rural southern Mozambique. In each survey a questionnaire was administered on previous parity history, the gestational age was assessed, the axillary temperature recorded and both haematocrit and malaria parasitaemia were determined. We used polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) analysis to determine submicroscopic and multiple P. falciparum infections in a subsample of women. FINDINGS A total of 156 women (23%) had microscopic parasitaemia, of which 144 (92%) were asexual forms of P. falciparum. The prevalence of clinical malaria was 18 of 534 (3%), that of anaemia, 382 of 649 (59%). In a multivariate analysis age but not parity was associated with an increased risk of microscopic parasitaemia. Anaemia was associated with microscopic P. falciparum parasitaemia. Both malaria parasitaemia and anaemia were more frequent during the rainy season. Although not statistically significant, submicroscopic infections tended to be more frequent among grand-multiparous pregnant women. Subpatent infections were not associated with increased anaemia. Multiplicity of infection was not associated with either parity, age or anaemia. Likewise, there was no correlation between P. falciparum density and multiplicity of infection. INTERPRETATION We did not observe a clear parity pattern of malaria and anaemia in our study. It is possible although unlikely that selection bias may have influenced these findings; but in which direction is unclear. The importance of locally based research before implementation of public health measures needs to be highlighted. According to our findings, a more cost-effective malaria control approach in this area would be targeting all pregnant women regardless of their parity. This would be also more feasible logistically as it would not rely on accurate ascertainment of parity, something that is not always easy in busy antenatal clinics.
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Affiliation(s)
- Francisco Saute
- Centro de Investigação em Saúde da Manhiça, Instituto Nacional de Saúde, Maputo, Mozambique
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Rhee MS, Akanmori BD, Waterfall M, Riley EM. Changes in cytokine production associated with acquired immunity to Plasmodium falciparum malaria. Clin Exp Immunol 2001; 126:503-10. [PMID: 11737069 PMCID: PMC1906215 DOI: 10.1046/j.1365-2249.2001.01681.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Individuals living in malaria-endemic areas eventually develop clinical immunity to Plasmodium falciparum. That is, they are able to limit blood parasite densities to extremely low levels and fail to show symptoms of infection. As the clinical symptoms of malaria infection are mediated in part by pro-inflammatory cytokines it is not clear whether the acquisition of clinical immunity is due simply to the development of antiparasitic mechanisms or whether the ability to regulate inflammatory cytokine production is also involved. We hypothesize that there is a correlation between risk of developing clinical malaria and the tendency to produce high levels of proinflammatory cytokines in response to malaria infection. In order to test this hypothesis, we have compared the ability of peripheral blood mononuclear cells from malaria-naive and malaria-exposed adult donors to proliferate and to secrete IFN-gamma in response to P. falciparum schizont extract (PfSE). In order to determine how PfSE-induced IFN-gamma production is regulated, we have also measured production of IL-12p40 and IL-10 from PfSE-stimulated PBMC and investigated the role of neutralizing antibody to IL-12 in modulating IFN-gamma production. We find that cells from naive donors produce moderate amounts of IFN-gamma in response to PfSE and that IFN-gamma production is strongly IL-12 dependent. Cells from malaria-exposed donors living in an area of low malaria endemicity produce much higher levels of IFN-gamma and this response is also at least partially IL-12 dependent. In complete contrast, cells from donors living in an area of very high endemicity produce minimal amounts of IFN-gamma. No significant differences were detected between the groups in IL-10 production, suggesting that this cytokine does not play a major role in regulating malaria-induced IFN-gamma production. The data from this study thus strongly support the hypothesis that down-regulation of inflammatory cytokine production may be a component of acquired clinical immunity to malaria but the mechanism by which this is achieved remains to be elucidated.
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Affiliation(s)
- M S Rhee
- Institute of Cell, Animal and Population Biology, Division of Biological Sciences, University of Edinburgh, Edinburgh, UK
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