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Paul KMM, Simpson SV, Nundu SS, Arima H, Yamamoto T. Genetic diversity of glutamate-rich protein (GLURP) in Plasmodium falciparum isolates from school-age children in Kinshasa, DRC. Parasitol Int 2024; 100:102866. [PMID: 38350548 DOI: 10.1016/j.parint.2024.102866] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 02/08/2024] [Accepted: 02/09/2024] [Indexed: 02/15/2024]
Abstract
Malaria infections in school-age children further make it difficult to control the disease's spread. Moreover, the genetic diversity of glutamate-rich protein, potentially a candidate for vaccine development, has not yet been investigated in the Democratic Republic of Congo. Therefore, we aimed to assess the genetic diversity of the immunodominant C-terminal repetitive region (R2) of Plasmodium falciparum glutamate-rich protein gene (pfglurp) among school-age children living in Kinshasa, DRC. We conducted nested PCR targeting R2 of pfglurp and the amplicon were directly sequenced. We summarized the prevalence of mutations of bases and amino acids and indicated the amino acid repeat sequence in the R2 region by the unit code. We then statistically analyzed whether there was a relationship between the number of mutations in the pfglurp gene and attributes. In 221 samples, haplotype 1 was the most common (n = 137, 61.99%), with the same sequence as the 3D7 strain. Regarding the number of base mutations, it was higher in urban areas than rural areas (p = 0.0363). When genetic neutrality was tested using data from 171 samples of the single strain, Tajima's D was -1.857 (p = 0.0059). In addition, FST as the genetic distance between all attributes was very small and no significant difference was observed. This study clarified the genetic mutation status and relevant patient attributes among School-age children in the DRC. We found that urban areas are more likely to harbour pfglurp mutations. Future research needs to clarify the reason and mechanism involved.
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Affiliation(s)
- Kambale Mathe Mowa Paul
- Department of International Health and Medical Anthropology, Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan; Program for Nurturing Global Leaders in Tropical and Emerging Communicable Diseases, Nagasaki University, Nagasaki, Japan
| | - Shirley V Simpson
- Department of International Health and Medical Anthropology, Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan; Program for Nurturing Global Leaders in Tropical and Emerging Communicable Diseases, Nagasaki University, Nagasaki, Japan
| | - Sabin S Nundu
- Institut National de Recherche Biomédicale, Kinshasa, Democratic Republic of Congo
| | - Hiroaki Arima
- Department of International Health and Medical Anthropology, Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan.
| | - Taro Yamamoto
- Department of International Health and Medical Anthropology, Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan; Program for Nurturing Global Leaders in Tropical and Emerging Communicable Diseases, Nagasaki University, Nagasaki, Japan
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Partey FD, Dowuona JNN, Pobee ANA, Walker MR, Aculley B, Prah DA, Ofori MF, Barfod LK. Atypical memory B cell frequency correlates with antibody breadth and function in malaria immune adults. Sci Rep 2024; 14:4888. [PMID: 38418831 PMCID: PMC10902325 DOI: 10.1038/s41598-024-55206-2] [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: 11/09/2023] [Accepted: 02/21/2024] [Indexed: 03/02/2024] Open
Abstract
Clinical immunity to malaria develops slowly after repeated episodes of infection and antibodies are essential in naturally acquired immunity against malaria. However, chronic exposure to malaria has been linked to perturbation in B-cell homeostasis with the accumulation of atypical memory B cells. It is unclear how perturbations in B cell subsets influence antibody breadth, avidity, and function in individuals naturally exposed to malaria. We show that individuals living in high malaria transmission regions in Ghana have higher Plasmodium falciparum merozoite antigen-specific antibodies and an increased antibody breadth score but lower antibody avidities relative to low transmission regions. The frequency of circulating atypical memory B cells is positively associated with an individual's antibody breadth. In vitro growth inhibition is independent of the ability to bind to free merozoites but associated with the breadth of antibody reactivity in an individual. Taken together, our data shows that repeated malaria episodes hamper the development of high avid antibodies which is compensated for by an increase in antibody breadth. Our results provide evidence to reinforce the idea that in regions with high malaria prevalence, repeated malaria infections lead to the broadening of antibody diversity and the continued presence of atypical memory B cell populations.
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Affiliation(s)
| | | | | | - Melanie Rose Walker
- Centre for Medical Parasitology, Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Belinda Aculley
- Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana
| | - Diana Ahu Prah
- West African Centre for Cell Biology of Infectious Pathogens, University of Ghana, Legon, Ghana
| | - Michael Fokuo Ofori
- Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana
| | - Lea Klingenberg Barfod
- Centre for Medical Parasitology, Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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Seidu Z, Lamptey H, Lopez-Perez M, Whittle NO, Oppong SK, Kyei-Baafour E, Pobee ANA, Adjei GO, Hviid L, Ofori MF. Plasmodium falciparum infection and naturally acquired immunity to malaria antigens among Ghanaian children in northern Ghana. Parasite Epidemiol Control 2023; 22:e00317. [PMID: 37501921 PMCID: PMC10369471 DOI: 10.1016/j.parepi.2023.e00317] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 03/28/2023] [Accepted: 07/18/2023] [Indexed: 07/29/2023] Open
Abstract
Background The surge in malaria cases and deaths in recent years, particularly in Africa, despite the widespread implementation of malaria-control measures could be due to inefficiencies in malaria control and prevention measures in malaria-endemic communities. In this context, this study provides the malaria situation report among children in three Municipalities in Northern Ghana, where Seasonal Malaria Chemotherapy (SMC) is implemented by Ghana Health Service (GHS). Methods A cross-sectional household survey was carried out to assess the malaria knowledge, attitudes, and practices (KAP) and malaria prevalence in 394 households in 13 rural communities in the Kumbugu, Nanton and Tolon Municipalities, Northern Region, Ghana. This was followed by screening for P. falciparum infection with anti-HRP2 RDT and PCR among children 1-17 years in the households. Plasma levels of IgG specific for crude P. falciparum antigen (3D7) and four recombinant malaria antigens (CSP, GLURP, MSP3, and Pfs230) were assessed by ELISA. The malaria and parasitaemia data were converted into frequency and subgroup proportions and disaggregated by study sites and demographic information of the participants. The ELISA data was converted to arbitrary units (AU) and similarly compared across study sites and demographic information. Results The P. falciparum infection rate and frequency of malaria were high in the study areas with significant age-dependent and inter-community differences, which were reflected by differences in plasma levels of P. falciparum-specific IgG. Over 60% of households reported the use of bed nets and indoor insecticide sprays/coils, and 14% mentioned bush clearing around homes (14%) as malaria preventive measures. Community health centres were the preferred place for households (88%) to seek malaria treatment but over-the-counter drug stores were the major source (66%) of their antimalarials. Overall, malaria preventive and treatment practices were sub-optimal. Conclusions P. falciparum infection and malaria are still high in the studied communities, indicating that preventive and control measures against the disease in the region remain inadequate. Efforts to ensure high SMC compliance and to improve preventative and treatment practices thus seem cost-beneficial "low-hanging fruits" in the fight against malaria in the Northern Region of Ghana.
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Affiliation(s)
- Zakaria Seidu
- Immunology Department, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Accra, Ghana
- West Africa Centre for Cell Biology of Infectious Pathogens, Department of Biochemistry, Cell and Molecular Biology, University of Ghana, Accra, Ghana
- Centre for Medical Parasitology at Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
- Department of Biochemistry and Molecular Biology, Faculty of Biosciences, University for Development Studies, Nyankpala, Ghana
| | - Helena Lamptey
- Immunology Department, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Accra, Ghana
| | - Mary Lopez-Perez
- Centre for Medical Parasitology at Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Nora Owusuwaa Whittle
- Immunology Department, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Accra, Ghana
| | - Stephen Kwesi Oppong
- Immunology Department, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Accra, Ghana
| | - Eric Kyei-Baafour
- Immunology Department, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Accra, Ghana
| | - Abigail Naa Adjorkor Pobee
- Immunology Department, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Accra, Ghana
| | - George Obeng Adjei
- Centre for Tropical Clinical Pharmacology and Therapeutics, School of Medicine and Dentistry, College of Health Sciences, University of Ghana, Korle-Bu, Ghana
| | - Lars Hviid
- Centre for Medical Parasitology at Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
- Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark
| | - Michael F. Ofori
- Immunology Department, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Accra, Ghana
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Singh SK, Naghizadeh M, Plieskatt J, Singh S, Theisen M. Cloning and Recombinant Protein Expression in Lactococcus lactis. Methods Mol Biol 2023; 2652:3-20. [PMID: 37093467 DOI: 10.1007/978-1-0716-3147-8_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/25/2023]
Abstract
The Lactococcus lactis, a Gram-positive bacteria, is an ideal expression host for the overproduction of heterologous proteins in a properly folded and functional form. L. lactis has been identified as an efficient cell factory, generally recognized as safe (GRAS), has a long history of safe use in food production, and is known to have probiotic properties. Key desirable features of L. lactis include the following: (1) rapid growth to high cell densities, not requiring aeration which facilitates large-scale fermentation; (2) its Gram-positive nature precludes the presence of contaminating endotoxins; (3) the capacity to secrete stable recombinant protein into the growth medium with few proteases resulting in a properly folded, full-length protein; and (4) the availability of diverse expression vectors facilitating various cloning options. We have previously described production of several recombinant proteins with varying degrees of predicted structural complexities using the L. lactis pH-dependent P170 promoter. The purpose of this chapter is to provide a detailed protocol for facilitating wider application of L. lactis as a reliable platform for expression of heterologous recombinant proteins in soluble form. Here, we present details of the various steps involved such as cloning of the target gene in appropriate expression plasmid vector, determination of the expression levels of the heterologous protein, and initial purification of the expressed soluble recombinant protein of interest.
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Affiliation(s)
- Susheel K Singh
- Biotherapeutic and Vaccine Research Division, ICMR-Regional Medical Research Centre, Bhubaneswar, Odisha, India
| | - Mohammad Naghizadeh
- Department for Congenital Disorders, Statens Serum Institut, Copenhagen, Denmark
- Centre for Medical Parasitology at Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - Jordan Plieskatt
- Department for Congenital Disorders, Statens Serum Institut, Copenhagen, Denmark
| | - Subhash Singh
- Biotherapeutic and Vaccine Research Division, ICMR-Regional Medical Research Centre, Bhubaneswar, Odisha, India
| | - Michael Theisen
- Department for Congenital Disorders, Statens Serum Institut, Copenhagen, Denmark
- Centre for Medical Parasitology at Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
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de Jong RM, Singh SK, Teelen K, van de Vegte-Bolmer M, van Gemert GJ, Stone WJR, Locke E, Plieskatt J, Theisen M, Bousema T, Jore MM. Heterologous Expression and Evaluation of Novel Plasmodium falciparum Transmission Blocking Vaccine Candidates. Front Immunol 2022; 13:909060. [PMID: 35812379 PMCID: PMC9259988 DOI: 10.3389/fimmu.2022.909060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 05/17/2022] [Indexed: 11/27/2022] Open
Abstract
Malaria transmission blocking vaccines (TBV) aim to induce antibodies that can interrupt Plasmodium falciparum development in the mosquito midgut and thereby prevent onward malaria transmission. A limited number of TBV candidates have been identified and only three (Pfs25, Pfs230 and Pfs48/45) have entered clinical testing. While one of these candidates may emerge as a highly potent TBV candidate, it is premature to determine if they will generate sufficiently potent and sustained responses. It is therefore important to explore novel candidate antigens. We recently analyzed sera from naturally exposed individuals and found that the presence and/or intensity of antibodies against 12 novel putative surface expressed gametocyte antigens was associated with transmission reducing activity. In this study, protein fragments of these novel TBV candidates were designed and heterologously expressed in Drosophila melanogaster S2 cells and Lactococcus lactis. Eleven protein fragments, covering seven TBV candidates, were successfully produced. All tested antigens were recognized by antibodies from individuals living in malaria-endemic areas, indicating that native epitopes are present. All antigens induced antigen-specific antibody responses in mice. Two antigens induced antibodies that recognized a native protein in gametocyte extract, and antibodies elicited by four antigens recognized whole gametocytes. In particular, we found that antigen Pf3D7_0305300, a putative transporter, is abundantly expressed on the surface of gametocytes. However, none of the seven novel TBV candidates expressed here induced an antibody response that reduced parasite development in the mosquito midgut as assessed in the standard membrane feeding assay. Altogether, the antigen fragments used in this study did not prove to be promising transmission blocking vaccine constructs, but led to the identification of two gametocyte surface proteins that may provide new leads for studying gametocyte biology.
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Affiliation(s)
- Roos M. de Jong
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, Netherlands
| | - Susheel K. Singh
- Centre for Medical Parasitology at Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
- Department for Congenital Disorders, Statens Serum Institut, Copenhagen, Denmark
| | - Karina Teelen
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, Netherlands
| | | | - Geert-Jan van Gemert
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, Netherlands
| | - Will J. R. Stone
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Emily Locke
- PATH‘s Malaria Vaccine Initiative, Washington, DC, United States
| | - Jordan Plieskatt
- PATH‘s Malaria Vaccine Initiative, Washington, DC, United States
| | - Michael Theisen
- Centre for Medical Parasitology at Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
- Department for Congenital Disorders, Statens Serum Institut, Copenhagen, Denmark
| | - Teun Bousema
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, Netherlands
| | - Matthijs M. Jore
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, Netherlands
- *Correspondence: Matthijs M. Jore,
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Ikegbunam MN, Uba C, Flügge J, Abone H, Ezeagwuna D, Ushie S, Esimone C. Malaria surveillance amongst pregnant women attending antenatal care in private hospitals in Onitsha metropolis, South Eastern Nigeria. MALARIAWORLD JOURNAL 2022; 13:2. [PMID: 35813272 PMCID: PMC9242532] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Background Recent reports suggest that pregnant women living in holoendemic regions of sub-Sahara Africa die in great numbers annually due to malaria disease resulting from their higher susceptibility, reduced immunity and demographic associated factors. This work investigated the prevalence of Plasmodium falciparum in pregnant women attending antenatal care (ANC) in selected private hospitals in Onitsha metropolis South East Nigeria. Methods Venous blood samples were collected from 270 pregnant women during ANC visits between October 2016 and December 2017. A questionnaire was used to collect demographic data, gestational age, knowledge of malaria and preventive measures while clinical presentations and symptoms were extracted from the physician's clerking form. Laboratory diagnosis was done using microscopy. The effect of the demographic variables and other associated factors on prevalence and parasite densities was studied using Chi-square and ANOVA tests. Results The overall P. falciparum prevalence was 42.6%. Prevalence varied with the maternal age, gestational age, preventive measures adopted by the pregnant women and clinical presentations. 27.8 % of the infected women were highly parasitized (>5000 parasites/μl); 67% had a moderate parasite density (1,000-4,999 parasites/μl) and 5.2% showed a low parasite density (1-999 parasites/μl). We observed that 35.2%, 30%, 18.9% and 5.2% of the study cohorts preferred and used treated bed nets, insecticides, windows and door screening and non-treated bed nets respectively as malaria preventive measures. 5.9% did not use any protection. Conclusions The findings of this study revealed high prevalence of malaria among pregnant women living in Onitsha metropolis with high mean parasite densities despite strong adherence to use of sulphadoxine-pyrimethamine (SP) for intermittent preventive treatment in pregnancy (IPTp) and other malaria preventive measures.
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Affiliation(s)
- Moses N. Ikegbunam
- Department of Pharmaceutical Microbiology and Biotechnology, Nnamdi Azikiwe University, Awka, Nigeria,Molecular Research Foundation for Students and Scientists, Nnamdi Azikiwe University, Awka, Nigeria,Institute for Tropical Medicine, Tübingen, Germany,,
| | - Chibuzo Uba
- Department of Pharmaceutical Microbiology and Biotechnology, Nnamdi Azikiwe University, Awka, Nigeria
| | | | - Harrison Abone
- Department of Pharmaceutical Microbiology and Biotechnology, Nnamdi Azikiwe University, Awka, Nigeria
| | - Dorothy Ezeagwuna
- Department of Parasitology and Entomology, Nnamdi Azikiwe University, Awka, Nigeria
| | - Simeon Ushie
- Department of Medical Microbiology and Parasitology, Nnamdi Azikiwe University, Awka, Nigeria
| | - Charles Esimone
- Department of Pharmaceutical Microbiology and Biotechnology, Nnamdi Azikiwe University, Awka, Nigeria,Molecular Research Foundation for Students and Scientists, Nnamdi Azikiwe University, Awka, Nigeria
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Baptista BO, de Souza ABL, Riccio EKP, Bianco-Junior C, Totino PRR, Martins da Silva JH, Theisen M, Singh SK, Amoah LE, Ribeiro-Alves M, Souza RM, Lima-Junior JC, Daniel-Ribeiro CT, Pratt-Riccio LR. Naturally acquired antibody response to a Plasmodium falciparum chimeric vaccine candidate GMZ2.6c and its components (MSP-3, GLURP, and Pfs48/45) in individuals living in Brazilian malaria-endemic areas. Malar J 2022; 21:6. [PMID: 34983540 PMCID: PMC8729018 DOI: 10.1186/s12936-021-04020-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Accepted: 12/09/2021] [Indexed: 12/19/2022] Open
Abstract
Background The GMZ2.6c malaria vaccine candidate is a multi-stage Plasmodium falciparum chimeric protein which contains a fragment of the sexual-stage Pfs48/45-6C protein genetically fused to GMZ2, a fusion protein of GLURP and MSP-3, that has been shown to be well tolerated, safe and immunogenic in clinical trials performed in a malaria-endemic area of Africa. However, there is no data available on the antigenicity or immunogenicity of GMZ2.6c in humans. Considering that circulating parasites can be genetically distinct in different malaria-endemic areas and that host genetic factors can influence the immune response to vaccine antigens, it is important to verify the antigenicity, immunogenicity and the possibility of associated protection in individuals living in malaria-endemic areas with different epidemiological scenarios. Herein, the profile of antibody response against GMZ2.6c and its components (MSP-3, GLURP and Pfs48/45) in residents of the Brazilian Amazon naturally exposed to malaria, in areas with different levels of transmission, was evaluated. Methods This study was performed using serum samples from 352 individuals from Cruzeiro do Sul and Mâncio Lima, in the state of Acre, and Guajará, in the state of Amazonas. Specific IgG, IgM, IgA and IgE antibodies and IgG subclasses were detected by Enzyme-Linked Immunosorbent Assay. Results The results showed that GMZ2.6c protein was widely recognized by naturally acquired antibodies from individuals of the Brazilian endemic areas with different levels of transmission. The higher prevalence of individuals with antibodies against GMZ2.6c when compared to its individual components may suggest an additive effect of GLURP, MSP-3, and Pfs48/45 when inserted in a same construct. Furthermore, naturally malaria-exposed individuals predominantly had IgG1 and IgG3 cytophilic anti-GMZ2.6c antibodies, an important fact considering that the acquisition of anti-malaria protective immunity results from a delicate balance between cytophilic/non-cytophilic antibodies. Interestingly, anti-GMZ2.6c antibodies seem to increase with exposure to malaria infection and may contribute to parasite immunity. Conclusions The data showed that GMZ2.6c protein is widely recognized by naturally acquired antibodies from individuals living in malaria-endemic areas in Brazil and that these may contribute to parasite immunity. These data highlight the importance of GMZ2.6c as a candidate for an anti-malarial vaccine. Supplementary Information The online version contains supplementary material available at 10.1186/s12936-021-04020-6.
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Affiliation(s)
- Barbara Oliveira Baptista
- Laboratório de Pesquisa em Malária, Instituto Oswaldo Cruz (IOC), Fundação Oswaldo Cruz (Fiocruz), Rio de Janeiro, Brazil.,Centro de Pesquisa, Diagnóstico e Treinamento em Malária, Fiocruz, Secretaria de Vigilância em Saúde, Ministério da Saúde, Brazil
| | - Ana Beatriz Lopes de Souza
- Laboratório de Pesquisa em Malária, Instituto Oswaldo Cruz (IOC), Fundação Oswaldo Cruz (Fiocruz), Rio de Janeiro, Brazil.,Centro de Pesquisa, Diagnóstico e Treinamento em Malária, Fiocruz, Secretaria de Vigilância em Saúde, Ministério da Saúde, Brazil
| | - Evelyn Kety Pratt Riccio
- Laboratório de Pesquisa em Malária, Instituto Oswaldo Cruz (IOC), Fundação Oswaldo Cruz (Fiocruz), Rio de Janeiro, Brazil.,Centro de Pesquisa, Diagnóstico e Treinamento em Malária, Fiocruz, Secretaria de Vigilância em Saúde, Ministério da Saúde, Brazil
| | - Cesare Bianco-Junior
- Laboratório de Pesquisa em Malária, Instituto Oswaldo Cruz (IOC), Fundação Oswaldo Cruz (Fiocruz), Rio de Janeiro, Brazil.,Centro de Pesquisa, Diagnóstico e Treinamento em Malária, Fiocruz, Secretaria de Vigilância em Saúde, Ministério da Saúde, Brazil
| | - Paulo Renato Rivas Totino
- Laboratório de Pesquisa em Malária, Instituto Oswaldo Cruz (IOC), Fundação Oswaldo Cruz (Fiocruz), Rio de Janeiro, Brazil.,Centro de Pesquisa, Diagnóstico e Treinamento em Malária, Fiocruz, Secretaria de Vigilância em Saúde, Ministério da Saúde, Brazil
| | | | - Michael Theisen
- Centre for Medical Parasitology at Department of International Health, Immunology and Microbiology, University of Copenhagen and Department of Infectious Diseases, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Susheel Kumar Singh
- Centre for Medical Parasitology at Department of International Health, Immunology and Microbiology, University of Copenhagen and Department of Infectious Diseases, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Linda Eva Amoah
- Immunology Department, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | - Marcelo Ribeiro-Alves
- Laboratório de Pesquisa Clínica em DST e AIDS, Instituto Nacional de Infectologia Evandro Chagas, Fiocruz, Rio de Janeiro, Brazil
| | - Rodrigo Medeiros Souza
- Laboratório de Doenças Infecciosas na Amazônia Ocidental, Universidade Federal do Acre, Acre, Brazil
| | | | - Cláudio Tadeu Daniel-Ribeiro
- Laboratório de Pesquisa em Malária, Instituto Oswaldo Cruz (IOC), Fundação Oswaldo Cruz (Fiocruz), Rio de Janeiro, Brazil.,Centro de Pesquisa, Diagnóstico e Treinamento em Malária, Fiocruz, Secretaria de Vigilância em Saúde, Ministério da Saúde, Brazil
| | - Lilian Rose Pratt-Riccio
- Laboratório de Pesquisa em Malária, Instituto Oswaldo Cruz (IOC), Fundação Oswaldo Cruz (Fiocruz), Rio de Janeiro, Brazil. .,Centro de Pesquisa, Diagnóstico e Treinamento em Malária, Fiocruz, Secretaria de Vigilância em Saúde, Ministério da Saúde, Brazil.
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Quaresima V, Agbenyega T, Oppong B, Awunyo JADA, Adu Adomah P, Enty E, Donato F, Castelli F. Are Malaria Risk Factors Based on Gender? A Mixed-Methods Survey in an Urban Setting in Ghana. Trop Med Infect Dis 2021; 6:161. [PMID: 34564545 PMCID: PMC8482108 DOI: 10.3390/tropicalmed6030161] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 08/27/2021] [Accepted: 08/30/2021] [Indexed: 11/17/2022] Open
Abstract
Malaria still represents one of the most debilitating and deadly diseases in the world. It has been suggested that malaria has different impacts on women and men due to both social and biological factors. A gender perspective is therefore important to understand how to eliminate malaria. This study aimed to investigate malaria from a gender perspective in a non-for-profit private health facility, HopeXchange Medical Centre, based in Kumasi (Ghana). A sequential mixed-methods design, comprising quantitative and qualitative methods, was used. This study found low ownership (40%) and use (19%) of insecticide-treated nets (ITNs). Most malaria cases were women (62%), who were less educated and had more external risk factors associated with infection. Our study reported a trend of preferring malaria self-medication at home, which was practiced mostly by men (43%). Our data suggest that women are more likely to be exposed to malaria infections than men, especially due to their prolonged exposure to mosquito bites during the most dangerous hours. Our study highlighted the need for future malaria control policies to be more focused on social and behavioral aspects and from a gender perspective.
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Affiliation(s)
- Virginia Quaresima
- University Department of Infectious and Tropical Diseases, University of Brescia and ASST Spedali Civili of Brescia, 25123 Brescia, Italy;
- Department of Civil, Environmental, Architectural Engineering and Mathematics (DICATAM), University of Brescia, 25123 Brescia, Italy
- Centro di Ricerca Emato-Oncologica AIL (CREA), Diagnostic Department, ASST Spedali Civili of Brescia, 25123 Brescia, Italy
| | - Tsiri Agbenyega
- Kwame Nkrumah University of Science and Technology (KNUST), Kumasi, Ghana;
- HopeXchange Medical Centre, Kumasi, Ghana; (B.O.); (J.A.D.A.A.); (P.A.A.); (E.E.)
| | - Bismark Oppong
- HopeXchange Medical Centre, Kumasi, Ghana; (B.O.); (J.A.D.A.A.); (P.A.A.); (E.E.)
| | | | - Priscilla Adu Adomah
- HopeXchange Medical Centre, Kumasi, Ghana; (B.O.); (J.A.D.A.A.); (P.A.A.); (E.E.)
| | - Eunice Enty
- HopeXchange Medical Centre, Kumasi, Ghana; (B.O.); (J.A.D.A.A.); (P.A.A.); (E.E.)
| | - Francesco Donato
- University Department of Hygiene, Epidemiology and Public Health, University of Brescia, 25123 Brescia, Italy;
| | - Francesco Castelli
- University Department of Infectious and Tropical Diseases, University of Brescia and ASST Spedali Civili of Brescia, 25123 Brescia, Italy;
- UNESCO Chair ‘Training and Empowering Human Resources for Health Development in Resource-Limited Countries’, University of Brescia, 25123 Brescia, Italy
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9
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Gnangnon B, Duraisingh MT, Buckee CO. Deconstructing the parasite multiplication rate of Plasmodium falciparum. Trends Parasitol 2021; 37:922-932. [PMID: 34119440 DOI: 10.1016/j.pt.2021.05.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2020] [Revised: 05/05/2021] [Accepted: 05/06/2021] [Indexed: 01/22/2023]
Abstract
Epidemiological indicators describing population-level malaria transmission dynamics are widely used to guide policy recommendations. However, the determinants of malaria outcomes within individuals are still poorly understood. This conceptual gap partly reflects the fact that there are few indicators that robustly predict the trajectory of individual infections or clinical outcomes. The parasite multiplication rate (PMR) is a widely used indicator for the Plasmodium intraerythrocytic development cycle (IDC), for example, but its relationship to clinical outcomes is complex. Here, we review its calculation and use in P. falciparum malaria research, as well as the parasite and host factors that impact it. We also provide examples of metrics that can help to link within-host dynamics to malaria clinical outcomes when used alongside the PMR.
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Affiliation(s)
- Bénédicte Gnangnon
- Center for Communicable Diseases Dynamics, Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, USA; Immunology & Infectious Diseases Department, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Manoj T Duraisingh
- Immunology & Infectious Diseases Department, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Caroline O Buckee
- Center for Communicable Diseases Dynamics, Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, USA.
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10
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Amoah LE, Abukari Z, Dawson-Amoah ME, Dieng CC, Lo E, Afrane YA. Population structure and diversity of Plasmodium falciparum in children with asymptomatic malaria living in different ecological zones of Ghana. BMC Infect Dis 2021; 21:439. [PMID: 33985447 PMCID: PMC8120845 DOI: 10.1186/s12879-021-06120-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Accepted: 04/27/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Genetic diversity in Plasmodium falciparum populations can be used to describe the resilience and spatial distribution of the parasite in the midst of intensified intervention efforts. This study used microsatellite analysis to evaluate the genetic diversity and population dynamics of P. falciparum parasites circulating in three ecological zones of Ghana. METHODS A total of 1168 afebrile children aged between 3 to 13 years were recruited from five (5) Primary schools in 3 different ecological zones (Sahel (Tamale and Kumbungu), Forest (Konongo) and Coastal (Ada and Dodowa)) of Ghana. Asymptomatic malaria parasite carriage was determined using microscopy and PCR, whilst fragment analysis of 6 microsatellite loci was used to determine the diversity and population structure of P. falciparum parasites. RESULTS Out of the 1168 samples examined, 16.1 and 39.5% tested positive for P. falciparum by microscopy and nested PCR respectively. The genetic diversity of parasites in the 3 ecological zones was generally high, with an average heterozygosity (He) of 0.804, 0.787 and 0.608 the rainy (peak) season for the Sahel, Forest and Coastal zones respectively. The mean He for the dry (off-peak) season were 0.562, 0.693 and 0.610 for the Sahel, Forest and Coastal zones respectively. Parasites from the Forest zone were more closely related to those from the Sahel than from the Coastal zone, despite the Coastal zone being closer in physical distance to the Forest zone. The fixation indexes among study sites ranged from 0.049 to 0.112 during the rainy season and 0.112 to 0.348 during the dry season. CONCLUSION A large asymptomatic parasite reservoir was found in the school children during both rainy and dry seasons, especially those in the Forest and Sahel savannah zones where parasites were also found to be related compared to those from the Coastal zone. Further studies are recommended to understand why despite the roll out of several malaria interventions in Ghana, high transmission still persist.
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Affiliation(s)
- Linda Eva Amoah
- Department of Immunology, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
- West Africa Center for Cell Biology of Infectious Pathogens, University of Ghana, Accra, Ghana
| | - Zakaria Abukari
- Department of Immunology, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
- Department of Biochemistry and Biotechnology, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Maame Esi Dawson-Amoah
- Department of Medical Microbiology, University of Ghana Medical School, University of Ghana, Accra, Ghana
| | - Cheikh Cambel Dieng
- Department of Biological Sciences, University of North Carolina, Charlotte, NC 28223 USA
| | - Eugenia Lo
- Department of Biological Sciences, University of North Carolina, Charlotte, NC 28223 USA
| | - Yaw Asare Afrane
- Department of Medical Microbiology, University of Ghana Medical School, University of Ghana, Accra, Ghana
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11
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Large Variations in Malaria Parasite Carriage by Afebrile School Children Living in Nearby Communities in the Central Region of Ghana. J Trop Med 2020; 2020:4125109. [PMID: 33029151 PMCID: PMC7528039 DOI: 10.1155/2020/4125109] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 06/25/2020] [Accepted: 09/03/2020] [Indexed: 02/08/2023] Open
Abstract
Background Indicators of successful malaria control interventions include a reduction in the prevalence and densities of malaria parasites contained in both symptomatic and asymptomatic infections as well as a reduction in malaria transmission. Individuals harboring malaria parasites in asymptomatic infections serve as reservoirs for malaria transmission. This study determined the prevalence of asymptomatic malaria parasite carriage in afebrile children attending six different schools in two districts, the Cape Coast Metropolitan Assembly (CCMA) and the Komenda Edina Eguafo Abirem (KEEA) of the Central Region of Ghana. Methods This cross sectional study recruited afebrile children aged between 3 and 15 years old from six randomly selected schools in the Central Region of Ghana. Finger-pricked blood was collected and used to prepare thick and thin blood smears as well as spot a strip of filter paper (Whatman #3). Nested PCR was used to identify Plasmodium falciparum, Plasmodium malariae, Plasmodium ovale, and Plasmodium vivax in DNA extracted from the filter paper spots. The multiplicity of P. falciparum infection was determined using merozoite surface protein 2 genotyping. Results Out of the 528 children sampled, PCR identified 27.1% to harbor Plasmodium parasites in asymptomatic infections, whilst microscopy identified malaria parasites in 10.6% of the children. The overall PCR estimated prevalence of P. falciparum and P. malariae was 26.6% and 1.3%, respectively, with no P. ovale or P. vivax identified by PCR or microscopy. The RDT positivity rate ranged from 55.8% in Simiw to 4.5% in Kuful. Children from the Simiw Basic School accounted for 87.5% of all the asymptomatic infections. The multiplicity of P. falciparum infection was predominantly monoclonal and biclonal. Conclusions The low prevalence of asymptomatic malaria parasite carriage by the children living in the Cape Coast Metropolis suggests that the malaria control interventions in place in CCMA are highly effective and that additional malaria control interventions are required for the KEEA district to reduce the prevalence of asymptomatic malaria parasite carriers. No molecular evidence of P. ovale and P. vivax was identified in the afebrile children sampled from the selected schools.
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12
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Skwarczynski M, Chandrudu S, Rigau-Planella B, Islam MT, Cheong YS, Liu G, Wang X, Toth I, Hussein WM. Progress in the Development of Subunit Vaccines against Malaria. Vaccines (Basel) 2020; 8:vaccines8030373. [PMID: 32664421 PMCID: PMC7563759 DOI: 10.3390/vaccines8030373] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 07/06/2020] [Accepted: 07/07/2020] [Indexed: 12/02/2022] Open
Abstract
Malaria is a life-threatening disease and one of the main causes of morbidity and mortality in the human population. The disease also results in a major socio-economic burden. The rapid spread of malaria epidemics in developing countries is exacerbated by the rise in drug-resistant parasites and insecticide-resistant mosquitoes. At present, malaria research is focused mainly on the development of drugs with increased therapeutic effects against Plasmodium parasites. However, a vaccine against the disease is preferable over treatment to achieve long-term control. Trials to develop a safe and effective immunization protocol for the control of malaria have been occurring for decades, and continue on today; still, no effective vaccines are available on the market. Recently, peptide-based vaccines have become an attractive alternative approach. These vaccines utilize short protein fragments to induce immune responses against malaria parasites. Peptide-based vaccines are safer than traditional vaccines, relatively inexpensive to produce, and can be composed of multiple T- and B-cell epitopes integrated into one antigenic formulation. Various combinations, based on antigen choice, peptide epitope modification and delivery mechanism, have resulted in numerous potential malaria vaccines candidates; these are presently being studied in both preclinical and clinical trials. This review describes the current landscape of peptide-based vaccines, and addresses obstacles and opportunities in the production of malaria vaccines.
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Affiliation(s)
- Mariusz Skwarczynski
- School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, QLD 4072, Australia; (M.S.); (S.C.); (B.R.-P.); (M.T.I.); (Y.S.C.); (G.L.); (X.W.)
| | - Saranya Chandrudu
- School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, QLD 4072, Australia; (M.S.); (S.C.); (B.R.-P.); (M.T.I.); (Y.S.C.); (G.L.); (X.W.)
| | - Berta Rigau-Planella
- School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, QLD 4072, Australia; (M.S.); (S.C.); (B.R.-P.); (M.T.I.); (Y.S.C.); (G.L.); (X.W.)
| | - Md. Tanjir Islam
- School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, QLD 4072, Australia; (M.S.); (S.C.); (B.R.-P.); (M.T.I.); (Y.S.C.); (G.L.); (X.W.)
| | - Yee S. Cheong
- School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, QLD 4072, Australia; (M.S.); (S.C.); (B.R.-P.); (M.T.I.); (Y.S.C.); (G.L.); (X.W.)
| | - Genan Liu
- School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, QLD 4072, Australia; (M.S.); (S.C.); (B.R.-P.); (M.T.I.); (Y.S.C.); (G.L.); (X.W.)
| | - Xiumin Wang
- School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, QLD 4072, Australia; (M.S.); (S.C.); (B.R.-P.); (M.T.I.); (Y.S.C.); (G.L.); (X.W.)
- Gene Engineering Laboratory, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China
- Key Laboratory of Feed Biotechnology, Ministry of Agriculture and Rural Affairs, Beijing 100081, China
| | - Istvan Toth
- School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, QLD 4072, Australia; (M.S.); (S.C.); (B.R.-P.); (M.T.I.); (Y.S.C.); (G.L.); (X.W.)
- School of Pharmacy, Pharmacy Australia Centre of Excellence, The University of Queensland, Woolloongabba, QLD 4072, Australia
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072, Australia
- Correspondence: (I.T.); (W.M.H.)
| | - Waleed M. Hussein
- School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, QLD 4072, Australia; (M.S.); (S.C.); (B.R.-P.); (M.T.I.); (Y.S.C.); (G.L.); (X.W.)
- Correspondence: (I.T.); (W.M.H.)
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13
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Bittencourt NC, da Silva ABIE, Virgili NS, Schappo AP, Gervásio JHDB, Pimenta TS, Kujbida Junior MA, Ventura AMRS, Libonati RMF, Silva-Filho JL, dos Santos HG, Lopes SCP, Lacerda MVG, Machado RLD, Costa FTM, Albrecht L. Plasmodium vivax AMA1: Implications of distinct haplotypes for immune response. PLoS Negl Trop Dis 2020; 14:e0008471. [PMID: 32639964 PMCID: PMC7371208 DOI: 10.1371/journal.pntd.0008471] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Revised: 07/20/2020] [Accepted: 06/10/2020] [Indexed: 02/07/2023] Open
Abstract
In Brazil, Plasmodium vivax infection accounts for around 80% of malaria cases. This infection has a substantial impact on the productivity of the local population as the course of the disease is usually prolonged and the development of acquired immunity in endemic areas takes several years. The recent emergence of drug-resistant strains has intensified research on alternative control methods such as vaccines. There is currently no effective available vaccine against malaria; however, numerous candidates have been studied in the past several years. One of the leading candidates is apical membrane antigen 1 (AMA1). This protein is involved in the invasion of Apicomplexa parasites into host cells, participating in the formation of a moving junction. Understanding how the genetic diversity of an antigen influences the immune response is highly important for vaccine development. In this study, we analyzed the diversity of AMA1 from Brazilian P. vivax isolates and 19 haplotypes of P. vivax were found. Among those sequences, 33 nonsynonymous PvAMA1 amino acid sites were identified, whereas 20 of these sites were determined to be located in predicted B-cell epitopes. Nonsynonymous mutations were evaluated for their influence on the immune recognition of these antigens. Two distinct haplotypes, 5 and 16, were expressed and evaluated for reactivity in individuals from northern Brazil. Both PvAMA1 variants were reactive. Moreover, the IgG antibody response to these two PvAMA1 variants was analyzed in an exposed but noninfected population from a P. vivax endemic area. Interestingly, over 40% of this population had antibodies recognizing both variants. These results have implications for the design of a vaccine based on a polymorphic antigen. Plasmodium vivax is the most abundant Plasmodium species in Brazil. While this species has been neglected for many years, the recent emergence of drug-resistant strains and the absence of a vaccine intensified the efforts for a better control method. Naturally acquired immune response analysis is a useful tool for understanding the antigenicity of Plasmodium proteins and evaluating the potential of a vaccine candidate. In this study, the genetic variability of one of the leading P. vivax vaccine candidates (PvAMA1) was analyzed. Two distinct variants were expressed and the antibody response was evaluated in infected and noninfected individuals in the Brazilian Amazon. This improved understanding of the magnitude and dynamics of the antibody response will contribute to the knowledge of a vaccine candidate and open new perspectives in vivax malaria vaccine development.
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Affiliation(s)
- Najara Carneiro Bittencourt
- Departamento de Genética, Evolução, Microbiologia e Imunologia, Instituto de Biologia, Universidade Estadual de Campinas (UNICAMP), Campinas, SP, Brazil
| | | | - Natália Silveira Virgili
- Departamento de Genética, Evolução, Microbiologia e Imunologia, Instituto de Biologia, Universidade Estadual de Campinas (UNICAMP), Campinas, SP, Brazil
| | - Ana Paula Schappo
- Instituto Carlos Chagas, Fundação Oswaldo Cruz–FIOCRUZ. Curitiba, PR, Brazil
| | | | - Tamirys S. Pimenta
- Núcleo de Medicina Tropical, Universidade Federal do Pará, Belém, PA, Brazil
| | | | | | | | - João Luiz Silva-Filho
- Departamento de Genética, Evolução, Microbiologia e Imunologia, Instituto de Biologia, Universidade Estadual de Campinas (UNICAMP), Campinas, SP, Brazil
| | | | - Stefanie C. P. Lopes
- Fundação de Medicina Tropical Dr. Heitor Vieira Dourado, Gerência de Malária, Manaus, AM, Brazil
- Instituto Leônidas & Maria Deane, FIOCRUZ-AMAZONAS, Manaus, AM, Brazil
| | - Marcus V. G. Lacerda
- Fundação de Medicina Tropical Dr. Heitor Vieira Dourado, Gerência de Malária, Manaus, AM, Brazil
- Instituto Leônidas & Maria Deane, FIOCRUZ-AMAZONAS, Manaus, AM, Brazil
| | - Ricardo L. D. Machado
- Centro de Investigação de Microrganismos, Universidade Federal Fluminense, RJ, Brazil
| | - Fabio T. M. Costa
- Departamento de Genética, Evolução, Microbiologia e Imunologia, Instituto de Biologia, Universidade Estadual de Campinas (UNICAMP), Campinas, SP, Brazil
| | - Letusa Albrecht
- Instituto Carlos Chagas, Fundação Oswaldo Cruz–FIOCRUZ. Curitiba, PR, Brazil
- * E-mail: ,
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14
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Tokplonou L, Nouatin O, Sonon P, M'po G, Glitho S, Agniwo P, Gonzalez-Ortiz D, Tchégninougbo T, Ayitchédji A, Favier B, Donadi EA, Milet J, Luty AJF, Massougbodji A, Garcia A, Ibikounlé M, Courtin D. Schistosoma haematobium infection modulates Plasmodium falciparum parasite density and antimalarial antibody responses. Parasite Immunol 2020; 42:e12702. [PMID: 32020650 DOI: 10.1111/pim.12702] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2019] [Revised: 01/29/2020] [Accepted: 01/31/2020] [Indexed: 12/13/2022]
Abstract
AIMS Schistosomiasis and malaria are endemic in sub-Saharan Africa where Schistosoma haematobium (Sh) and Plasmodium falciparum (Pf) coinfections are thus frequent. We explored the effect of Sh infection on antibody responses directed to Pf merozoite antigens and on malaria susceptibility in Beninese children. METHODS AND RESULTS A total of 268 children were followed during a malaria transmission season. Detection of Pf infection was performed by microscopy and rapid diagnostic tests. Sh infection was determined in urine by microscopy. Antimalarial antibody, cytokine and HLA-G concentrations were quantified by ELISA. The expression of HLA-G receptors by immune cells was assessed by flow cytometry. Children infected by Sh had higher concentrations of IgG1 directed to MSP3 and GLURPR0 , IgG2 directed to GLURPR0 and IgG3 directed to MSP3, GLURPR0 and GLURPR2 and have lower Pf densities than those uninfected by Sh. No difference in cytokine and HLA-G concentrations was observed between Sh egg carriers and non-carriers. CONCLUSION Schistosoma haematobium modulates host immune responses directed to Pf antigens. The absence of immune downregulation usually observed during helminth infections is surprising in our study. We hypothesize that the stage of Sh development could partly explain the immune pathways leading to increased antibody levels that favour better control of Pf parasitemia.
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Affiliation(s)
- Léonidas Tokplonou
- Centre d'Etude et de Recherche sur le Paludisme Associé à la Grossesse et à l'Enfance, Faculté des Sciences de la Santé, Cotonou, Bénin.,UMR 261 MERIT, Université de Paris, Institut de Recherche pour le Développement (IRD), Paris, France.,Département de Zoologie, Faculté des Sciences et Techniques, Université d'Abomey-Calavi, Cotonou, Bénin
| | - Odilon Nouatin
- Centre d'Etude et de Recherche sur le Paludisme Associé à la Grossesse et à l'Enfance, Faculté des Sciences de la Santé, Cotonou, Bénin
| | - Paulin Sonon
- Laboratory of Clinical Immunology, Ribeirão Preto Medicine School, University of São Paulo, São Paulo, Brazil
| | - Grace M'po
- Centre d'Etude et de Recherche sur le Paludisme Associé à la Grossesse et à l'Enfance, Faculté des Sciences de la Santé, Cotonou, Bénin.,Département de Zoologie, Faculté des Sciences et Techniques, Université d'Abomey-Calavi, Cotonou, Bénin
| | - Sonya Glitho
- Centre d'Etude et de Recherche sur le Paludisme Associé à la Grossesse et à l'Enfance, Faculté des Sciences de la Santé, Cotonou, Bénin.,Département de Zoologie, Faculté des Sciences et Techniques, Université d'Abomey-Calavi, Cotonou, Bénin
| | - Privat Agniwo
- Centre d'Etude et de Recherche sur le Paludisme Associé à la Grossesse et à l'Enfance, Faculté des Sciences de la Santé, Cotonou, Bénin.,Département de Zoologie, Faculté des Sciences et Techniques, Université d'Abomey-Calavi, Cotonou, Bénin
| | - Daniel Gonzalez-Ortiz
- UMR 261 MERIT, Université de Paris, Institut de Recherche pour le Développement (IRD), Paris, France
| | | | | | - Benoit Favier
- CEA-Université Paris Sud INSERM U1184, IDMIT Department, IBFJ, DRF, Fontenay-aux-Roses, France
| | - Eduardo A Donadi
- Laboratory of Clinical Immunology, Ribeirão Preto Medicine School, University of São Paulo, São Paulo, Brazil
| | - Jacqueline Milet
- UMR 261 MERIT, Université de Paris, Institut de Recherche pour le Développement (IRD), Paris, France
| | - Adrian J F Luty
- UMR 261 MERIT, Université de Paris, Institut de Recherche pour le Développement (IRD), Paris, France
| | - Achille Massougbodji
- Centre d'Etude et de Recherche sur le Paludisme Associé à la Grossesse et à l'Enfance, Faculté des Sciences de la Santé, Cotonou, Bénin
| | - André Garcia
- UMR 261 MERIT, Université de Paris, Institut de Recherche pour le Développement (IRD), Paris, France
| | - Moudachirou Ibikounlé
- Département de Zoologie, Faculté des Sciences et Techniques, Université d'Abomey-Calavi, Cotonou, Bénin.,Laboratory of Clinical Immunology, Ribeirão Preto Medicine School, University of São Paulo, São Paulo, Brazil
| | - David Courtin
- UMR 261 MERIT, Université de Paris, Institut de Recherche pour le Développement (IRD), Paris, France
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15
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Acquah FK, Lo AC, Akyea-Mensah K, Abagna HB, Faye B, Theisen M, Gyan BA, Amoah LE. Stage-specific Plasmodium falciparum immune responses in afebrile adults and children living in the Greater Accra Region of Ghana. Malar J 2020; 19:64. [PMID: 32041620 PMCID: PMC7011432 DOI: 10.1186/s12936-020-3146-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Accepted: 01/30/2020] [Indexed: 12/02/2022] Open
Abstract
Background Asymptomatic carriage of Plasmodium falciparum is widespread in adults and children living in malaria-endemic countries. This study identified the prevalence of malaria parasites and the corresponding levels of naturally acquired anti-parasite antibody levels in afebrile adults living in two communities in the Greater Accra Region of Ghana. Methods Two cross-sectional studies conducted in January and February 2016 and repeated in July and August 2016 recruited subjects aged between 6 and 75 years from high parasite prevalence (Obom) and low parasite prevalence (Asutsuare) communities. Whole blood (5 ml) was collected from each volunteer, plasma was aliquoted and frozen until needed. An aliquot (10 µl) of the blood was used to prepare thick and thin blood smears, 100 µl was preserved in Trizol and the rest was separated into plasma and blood cells and each stored at − 20 °C until needed. Anti-MSP3 and Pfs230 antibody levels were measured using ELISA. Results Asexual parasite and gametocyte prevalence were higher in Obom than Asutsuare. Antibody (IgG, IgG1, IgG3, IgM) responses against the asexual parasite antigen MSP3 and gametocyte antigen Pfs230 were higher in Obom during the course of the study except for IgM responses against Pfs230, which was higher in Asutsuare than in Obom during the rainy season. Antibody responses in Asutsuare were more significantly associated with age than the responses measured in Obom. Conclusion The pattern of antibody responses measured in people living in the high and low malaria transmission setting was similar. All antibody responses measured against the asexual antigen MSP3 increased, however, IgG and IgG1 responses against gametocyte antigen Pfs230 decreased in moving from the dry to the peak season in both sites. Whilst asexual and gametocyte prevalence was similar between the seasons in the low transmission setting, in the high transmission setting asexual parasite prevalence increased but gametocyte prevalence decreased in the rainy season relative to the dry season.
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Affiliation(s)
- Festus K Acquah
- Immunology Department, Noguchi Memorial Institute for Medical Research (NMIMR), University of Ghana, Accra, Ghana.,West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), University of Ghana, Accra, Ghana
| | - Aminata C Lo
- Immunology Department, Noguchi Memorial Institute for Medical Research (NMIMR), University of Ghana, Accra, Ghana.,Parasitology Department, University Cheikh Anta Diop, Dakar, Senegal
| | - Kwadwo Akyea-Mensah
- Immunology Department, Noguchi Memorial Institute for Medical Research (NMIMR), University of Ghana, Accra, Ghana
| | - Hamza B Abagna
- Immunology Department, Noguchi Memorial Institute for Medical Research (NMIMR), University of Ghana, Accra, Ghana
| | - Babacar Faye
- Parasitology Department, University Cheikh Anta Diop, Dakar, Senegal
| | - Michael Theisen
- Department for Congenital Disorders, Statens Serum Institut, Copenhagen, Denmark.,Centre for Medical Parasitology at Department of International Health, Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - Ben A Gyan
- Immunology Department, Noguchi Memorial Institute for Medical Research (NMIMR), University of Ghana, Accra, Ghana
| | - Linda E Amoah
- Immunology Department, Noguchi Memorial Institute for Medical Research (NMIMR), University of Ghana, Accra, Ghana. .,West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), University of Ghana, Accra, Ghana.
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16
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Amoah LE, Abagna HB, Ayanful-Torgby R, Blankson SO, Aryee NA. Diversity and immune responses against Plasmodium falciparum gametocytes in non-febrile school children living in Southern Ghana. Malar J 2019; 18:265. [PMID: 31370841 PMCID: PMC6676606 DOI: 10.1186/s12936-019-2895-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Accepted: 07/23/2019] [Indexed: 11/22/2022] Open
Abstract
Background Natural exposure to gametocytes can result in the development of immunity against the gametocyte by the host as well as genetic diversity in the gametocyte. This study evaluated the quantity and quality of natural immune responses against a gametocyte antigen, Pfs230 as well as the prevalence and diversity of gametocytes circulating in children living in two communities in southern Ghana. Methods Whole blood (2.5 ml) was collected from 137 non-febrile school children aged between 6 and 12 years old quarterly for a 6-month period. A drop of blood was used to prepare thick and thin blood films for parasite prevalence and density estimation. Subsequently, stored plasma samples were used in ELISAs assays to measure antibody responses and avidity against Pfs230. RNA was extraction from Trizol preserved packed cells and subsequently converted to complementary DNA (cDNA) which was used for reverse transcriptase PCR (RT-PCR) to determine gametocytes prevalence and diversity. Results Gametocyte carriage in the peak season (July) determined by Pfg377 RT-PCR was 49.2% in Obom and 22.2% in Abura, and was higher than that determined by microscopy. Gametocyte diversity was low and predominated by the same allele at both sites. The relative avidity index for antibodies measured in Abura was higher than that recorded in Obom at all time points although Pfs230 IgG concentrations were significantly high (P < 0.0001) in Obom than in Abura at all time points. The IgG responses in Obom were significantly higher than that in Abura during the peak season. Conclusion Naturally induced antibody responses against Pfs230 in children living in both high perennial and low seasonal malaria transmission settings reduced significantly in moving from the peak to the off-peak season. The relative avidity of antibodies against Pfs230 in Abura was significantly higher than those measured in Obom, despite having lower IgG levels. Very limited diversity was identified in the gametocytes circulating in both Obom and Abura. Electronic supplementary material The online version of this article (10.1186/s12936-019-2895-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Linda E Amoah
- Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana. .,West Africa Center for Cell Biology of Infectious Pathogens (WACCBIP), College of Basic and Applied Sciences, University of Ghana, Legon, Ghana.
| | - Hamza B Abagna
- Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana.,Department of Medical Biochemistry, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Ruth Ayanful-Torgby
- Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Samuel O Blankson
- Department of Medical Biochemistry, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Nii A Aryee
- Department of Medical Biochemistry, College of Health Sciences, University of Ghana, Legon, Ghana
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Abukari Z, Okonu R, Nyarko SB, Lo AC, Dieng CC, Salifu SP, Gyan BA, Lo E, Amoah LE. The Diversity, Multiplicity of Infection and Population Structure of P. falciparum Parasites Circulating in Asymptomatic Carriers Living in High and Low Malaria Transmission Settings of Ghana. Genes (Basel) 2019; 10:genes10060434. [PMID: 31181699 PMCID: PMC6628376 DOI: 10.3390/genes10060434] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Revised: 05/31/2019] [Accepted: 06/03/2019] [Indexed: 11/24/2022] Open
Abstract
Background: Diversity in Plasmodium falciparum poses a major threat to malaria control and elimination interventions. This study utilized 12 polymorphic microsatellite (MS) markers and the Msp2 marker to examine diversity, multiplicity of infection (MOI) as well as the population structure of parasites circulating in two sites separated by about 92 km and with varying malaria transmission intensities within the Greater Accra Region of Ghana. Methods: The diversity and MOI of P. falciparum parasites in 160 non-symptomatic volunteers living in Obom (high malaria transmission intensity) and Asutsuare (low malaria transmission intensity) aged between 8 and 60 years was determined using Msp2 genotyping and microsatellite analysis. Results: The prevalence of asymptomatic P. falciparum carriers as well as the parasite density of infections was significantly higher in Obom than in Asutsuare. Samples from Asutsuare and Obom were 100% and 65% clonal, respectively, by Msp2 genotyping but decreased to 50% and 5%, respectively, when determined by MS analysis. The genetic composition of parasites from Obom and Asutsuare were highly distinct, with parasites from Obom being more diverse than those from Asutsuare. Conclusion: Plasmodium falciparum parasites circulating in Obom are genetically more diverse and distinct from those circulating in Asutsuare. The MOI in samples from both Obom and Asutsuare increased when assessed by MS analysis relative to MSP2 genotyping. The TA40 and TA87 loci are useful markers for estimating MOI in high and low parasite prevalence settings.
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Affiliation(s)
- Zakaria Abukari
- Department of Biochemistry and Biotechnology, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana.
- Immunology Department, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana.
| | - Ruth Okonu
- Immunology Department, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana.
| | - Samuel B Nyarko
- School of Medical Sciences, University of Cape Coast, Cape Coast, Ghana.
| | - Aminata C Lo
- Immunology Department, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana.
- Department of Parasitology, University Cheikh Anta Diop, Dakar, Senegal.
| | - Cheikh C Dieng
- Department of Biological Sciences, University of North Carolina at Charlotte, NC 28223, USA.
| | - Samson P Salifu
- Department of Biochemistry and Biotechnology, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana.
| | - Ben A Gyan
- Immunology Department, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana.
| | - Eugenia Lo
- Department of Biological Sciences, University of North Carolina at Charlotte, NC 28223, USA.
| | - Linda E Amoah
- Immunology Department, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana.
- West Africa Center for Cell Biology of Infectious Pathogens, University of Ghana, Accra, Ghana.
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18
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Abstract
The blood stage of the malaria parasite life cycle is responsible for all the clinical symptoms of malaria. During the blood stage, Plasmodium merozoites invade and multiply within host red blood cells (RBCs). Here, we review the progress made, challenges faced, and new strategies available for the development of blood stage malaria vaccines. We discuss our current understanding of immune responses against blood stages and the status of clinical development of various blood stage malaria vaccine candidates. We then discuss possible paths forward to develop effective blood stage malaria vaccines. This includes a discussion of protective immune mechanisms that can be elicited to target blood stage parasites, novel delivery systems, immunoassays and animal models to optimize vaccine candidates in preclinical studies, and use of challenge models to get an early readout of vaccine efficacy.
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19
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Plasmodium genomics: an approach for learning about and ending human malaria. Parasitol Res 2018; 118:1-27. [PMID: 30402656 DOI: 10.1007/s00436-018-6127-9] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Accepted: 10/19/2018] [Indexed: 12/31/2022]
Abstract
Malaria causes high levels of morbidity and mortality in human beings worldwide. According to the World Health Organization (WHO), about half a million people die of this disease each year. Malaria is caused by six species of parasites belonging to the Plasmodium genus: P. falciparum, P. knowlesi, P. vivax, P. malariae, P. ovale curtisi, and P. ovale wallikeri. Currently, malaria is being kept under control with varying levels of elimination success in different countries. The development of new molecular tools as well as the use of next-generation sequencing (NGS) technologies and novel bioinformatic approaches has improved our knowledge of malarial epidemiology, diagnosis, treatment, vaccine development, and surveillance strategies. In this work, the genetics and genomics of human malarias have been analyzed. Since the first P. falciparum genome was sequenced in 2002, various population-level genetic and genomic surveys, together with transcriptomic and proteomic studies, have shown the importance of molecular approaches in supporting malaria elimination.
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20
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Bittencourt NC, Leite JA, Silva ABIE, Pimenta TS, Silva-Filho JL, Cassiano GC, Lopes SCP, Dos-Santos JCK, Bourgard C, Nakaya HI, da Silva Ventura AMR, Lacerda MVG, Ferreira MU, Machado RLD, Albrecht L, Costa FTM. Genetic sequence characterization and naturally acquired immune response to Plasmodium vivax Rhoptry Neck Protein 2 (PvRON2). Malar J 2018; 17:401. [PMID: 30382855 PMCID: PMC6208078 DOI: 10.1186/s12936-018-2543-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Accepted: 10/22/2018] [Indexed: 12/28/2022] Open
Abstract
Background The genetic diversity of malaria antigens often results in allele variant-specific immunity, imposing a great challenge to vaccine development. Rhoptry Neck Protein 2 (PvRON2) is a blood-stage antigen that plays a key role during the erythrocyte invasion of Plasmodium vivax. This study investigates the genetic diversity of PvRON2 and the naturally acquired immune response to P. vivax isolates. Results Here, the genetic diversity of PvRON21828–2080 and the naturally acquired humoral immune response against PvRON21828–2080 in infected and non-infected individuals from a vivax malaria endemic area in Brazil was reported. The diversity analysis of PvRON21828–2080 revealed that the protein is conserved in isolates in Brazil and worldwide. A total of 18 (19%) patients had IgG antibodies to PvRON21828–2080. Additionally, the analysis of the antibody response in individuals who were not acutely infected with malaria, but had been infected with malaria in the past indicated that 32 patients (33%) exhibited an IgG immune response against PvRON2. Conclusions PvRON2 was conserved among the studied isolates. The presence of naturally acquired antibodies to this protein in the absence of the disease suggests that PvRON2 induces a long-term antibody response. These results indicate that PvRON2 is a potential malaria vaccine candidate. Electronic supplementary material The online version of this article (10.1186/s12936-018-2543-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Najara C Bittencourt
- Laboratory of Tropical Diseases-Prof. Dr. Luiz Jacintho da Silva, Department of Genetics, Evolution, Microbiology and Immunology, University of Campinas-UNICAMP, Campinas, SP, Brazil
| | - Juliana A Leite
- Laboratory of Tropical Diseases-Prof. Dr. Luiz Jacintho da Silva, Department of Genetics, Evolution, Microbiology and Immunology, University of Campinas-UNICAMP, Campinas, SP, Brazil
| | | | - Tamirys S Pimenta
- Laboratório de Ensaios Clínicos e Imunogenética em Malária, Instituto Evandro Chagas/SVS/MS, Ananindeua, PA, Brazil
| | - João Luiz Silva-Filho
- Laboratory of Tropical Diseases-Prof. Dr. Luiz Jacintho da Silva, Department of Genetics, Evolution, Microbiology and Immunology, University of Campinas-UNICAMP, Campinas, SP, Brazil
| | - Gustavo C Cassiano
- Laboratory of Tropical Diseases-Prof. Dr. Luiz Jacintho da Silva, Department of Genetics, Evolution, Microbiology and Immunology, University of Campinas-UNICAMP, Campinas, SP, Brazil
| | - Stefanie C P Lopes
- Instituto Leônidas & Maria Deane, Fundação Oswaldo Cruz - FIOCRUZ, Manaus, AM, Brazil.,Fundação de Medicina Tropical-Dr. Heitor Vieira Dourado, Manaus, AM, Brazil
| | - Joao C K Dos-Santos
- Laboratory of Tropical Diseases-Prof. Dr. Luiz Jacintho da Silva, Department of Genetics, Evolution, Microbiology and Immunology, University of Campinas-UNICAMP, Campinas, SP, Brazil
| | - Catarina Bourgard
- Laboratory of Tropical Diseases-Prof. Dr. Luiz Jacintho da Silva, Department of Genetics, Evolution, Microbiology and Immunology, University of Campinas-UNICAMP, Campinas, SP, Brazil
| | - Helder I Nakaya
- School of Pharmaceutical Sciences, University of São Paulo, São Paulo, Brazil
| | | | - Marcus V G Lacerda
- Instituto Leônidas & Maria Deane, Fundação Oswaldo Cruz - FIOCRUZ, Manaus, AM, Brazil.,Fundação de Medicina Tropical-Dr. Heitor Vieira Dourado, Manaus, AM, Brazil
| | - Marcelo U Ferreira
- Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo-USP, São Paulo, Brazil
| | - Ricardo L D Machado
- Laboratório de Ensaios Clínicos e Imunogenética em Malária, Instituto Evandro Chagas/SVS/MS, Ananindeua, PA, Brazil
| | - Letusa Albrecht
- Instituto Carlos Chagas, Fundação Oswaldo Cruz - FIOCRUZ, Curitiba, PR, Brazil.
| | - Fabio T M Costa
- Laboratory of Tropical Diseases-Prof. Dr. Luiz Jacintho da Silva, Department of Genetics, Evolution, Microbiology and Immunology, University of Campinas-UNICAMP, Campinas, SP, Brazil.
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21
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Seasonal variations in Plasmodium falciparum genetic diversity and multiplicity of infection in asymptomatic children living in southern Ghana. BMC Infect Dis 2018; 18:432. [PMID: 30157794 PMCID: PMC6114730 DOI: 10.1186/s12879-018-3350-z] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Accepted: 08/21/2018] [Indexed: 11/11/2022] Open
Abstract
Background Genetic diversity in Plasmodium falciparum (P. falciparum) parasites is a major hurdle to the control of malaria. This study monitored changes in the genetic diversity and the multiplicity of P. falciparum parasite infection in asymptomatic children living in southern Ghana at 3 month intervals between April 2015 and January 2016. Methods Filter paper blood spots (DBS) were collected quarterly from children living in Obom, a community with perennial malaria transmission and Abura, a community with seasonal malaria transmission. Genomic DNA was extracted from the DBS and used in polymerase chain reaction (PCR)-based genotyping of the merozoite surface protein 1 (msp 1) and merozoite surface protein 2 (msp 2) genes. Results Out of a total of 787 samples that were collected from the two study sites, 59.2% (466/787) tested positive for P. falciparum. The msp 1 and msp 2 genes were successfully amplified from 73.8% (344/466) and 82.5% (385/466) of the P. falciparum positive samples respectively. The geometric mean MOI in Abura ranged between 1.17 (95% CI: 1.08–1.28) and 1.48 (95% CI: 1.36–1.60) and was significantly lower (p < 0.01, Dunn’s multiple comparison test) than that determined in Obom, where the geometric mean MOI ranged between 1.82 (95% CI: 1.58–2.08) and 2.50 (95% CI: 2.33–2.678) over the study period. Whilst the msp 1 R033:MAD20:KI allelic family ratio was dynamic, the msp 2 3D7:FC27 allelic family ratio remained relatively stable across the changing seasons in both sites. Conclusions This study shows that seasonal variations in parasite diversity in these communities can be better estimated by msp 1 rather than msp 2 due to the constantly changing relative intra allelic frequencies observed in msp 1 and the fact that the dominance of any msp 2 allele was dependent on the transmission setting but not on the season as opposed to the dominance of any msp 1 allele, which was dependent on both the season and the transmission setting. Electronic supplementary material The online version of this article (10.1186/s12879-018-3350-z) contains supplementary material, which is available to authorized users.
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22
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Zhong D, Koepfli C, Cui L, Yan G. Molecular approaches to determine the multiplicity of Plasmodium infections. Malar J 2018; 17:172. [PMID: 29685152 PMCID: PMC5914063 DOI: 10.1186/s12936-018-2322-5] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Accepted: 04/18/2018] [Indexed: 12/26/2022] Open
Abstract
Multiplicity of infection (MOI), also termed complexity of infection (COI), is defined as the number of genetically distinct parasite strains co-infecting a single host, which is an important indicator of malaria epidemiology. PCR-based genotyping often underestimates MOI. Next generation sequencing technologies provide much more accurate and genome-wide characterization of polyclonal infections. However, complete haplotype characterization of multiclonal infections remains a challenge due to PCR artifacts and sequencing errors, and requires efficient computational tools. In this review, the advantages and limitations of current molecular approaches to determine multiplicity of malaria parasite infection are discussed.
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Affiliation(s)
- Daibin Zhong
- Program in Public Health, University of California, Irvine, CA, 92617, USA.
| | - Cristian Koepfli
- Program in Public Health, University of California, Irvine, CA, 92617, USA
| | - Liwang Cui
- Department of Entomology, Pennsylvania State University, University Park, PA, 16802, USA
| | - Guiyun Yan
- Program in Public Health, University of California, Irvine, CA, 92617, USA.
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23
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Awandare GA, Nyarko PB, Aniweh Y, Ayivor-Djanie R, Stoute JA. Plasmodium falciparum strains spontaneously switch invasion phenotype in suspension culture. Sci Rep 2018; 8:5782. [PMID: 29636510 PMCID: PMC5893586 DOI: 10.1038/s41598-018-24218-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Accepted: 03/28/2018] [Indexed: 01/11/2023] Open
Abstract
The extensive redundancy in the use of invasion ligands by Plasmodium falciparum, and its unique ability to switch between invasion pathways have hampered vaccine development. P. falciparum strains Dd2 and W2mef have been shown to change from sialic acid (SA)-dependent to SA-independent phenotypes when selected on neuraminidase-treated erythrocytes. Following an observation of increasing ability of Dd2 to invade neuraminidase-treated cells when cultured for several weeks, we systematically investigated this phenomenon by comparing invasion phenotypes of Dd2, W2mef and 3D7 strains of P. falciparum that were cultured with gentle shaking (Suspended) or under static (Static) conditions. While Static Dd2 and W2mef remained SA-dependent for the entire duration of the investigation, Suspended parasites spontaneously and progressively switched to SA-independent phenotype from week 2 onwards. Furthermore, returning Suspended cultures to Static conditions led to a gradual reversal to SA-dependent phenotype. The switch to SA-independent phenotype was accompanied by upregulation of the key invasion ligand, reticulocyte-binding homologue 4 (RH4), and the increased invasion was inhibited by antibodies to the RH4 receptor, CR1. Our data demonstrates a novel mechanism for inducing the switching of invasion pathways in P. falciparum parasites and may provide clues for understanding the mechanisms involved.
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Affiliation(s)
- Gordon A Awandare
- West African Centre for Cell Biology of Infectious Pathogens, University of Ghana, Legon, Ghana. .,Department of Biochemistry, Cell and Molecular Biology, University of Ghana, Legon, Ghana.
| | - Prince B Nyarko
- West African Centre for Cell Biology of Infectious Pathogens, University of Ghana, Legon, Ghana
| | - Yaw Aniweh
- West African Centre for Cell Biology of Infectious Pathogens, University of Ghana, Legon, Ghana
| | - Reuben Ayivor-Djanie
- West African Centre for Cell Biology of Infectious Pathogens, University of Ghana, Legon, Ghana.,Department of Biomedical Sciences, University of Health and Allied Sciences, Ho, Ghana
| | - José A Stoute
- Department of Medicine, Pennsylvania State University College of Medicine, Hershey, PA, USA
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24
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Schneider KA. Large and finite sample properties of a maximum-likelihood estimator for multiplicity of infection. PLoS One 2018; 13:e0194148. [PMID: 29630605 PMCID: PMC5890990 DOI: 10.1371/journal.pone.0194148] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2017] [Accepted: 02/26/2018] [Indexed: 12/30/2022] Open
Abstract
Reliable measures of transmission intensities can be incorporated into metrics for monitoring disease-control interventions. Genetic (molecular) measures like multiplicity of infection (MOI) have several advantages compared with traditional measures, e.g., R0. Here, we investigate the properties of a maximum-likelihood approach to estimate MOI and pathogen-lineage frequencies. By verifying regulatory conditions, we prove asymptotical unbiasedness, consistency and efficiency of the estimator. Finite sample properties concerning bias and variance are evaluated over a comprehensive parameter range by a systematic simulation study. Moreover, the estimator's sensitivity to model violations is studied. The estimator performs well for realistic sample sizes and parameter ranges. In particular, the lineage-frequency estimates are almost unbiased independently of sample size. The MOI estimate's bias vanishes with increasing sample size, but might be substantial if sample size is too small. The estimator's variance matrix agrees well with the Cramér-Rao lower bound, even for small sample size. The numerical and analytical results of this study can be used for study design. This is exemplified by a malaria data set from Venezuela. It is shown how the results can be used to determine the necessary sample size to achieve certain performance goals. An implementation of the likelihood method and a simulation algorithm for study design, implemented as an R script, is available as S1 File alongside a documentation (S2 File) and example data (S3 File).
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