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Sanna A, Lambert Y, Jimeno Maroto I, Galindo MS, Plessis L, Bardon T, Carboni C, Bordalo J, Hiwat H, Cairo H, Musset L, Lazrek Y, Pelleau S, White M, Suárez Mutis M, Vreden S, Douine M. CUREMA project: a further step towards malaria elimination among hard-to-reach and mobile populations. Malar J 2024; 23:271. [PMID: 39256842 PMCID: PMC11385508 DOI: 10.1186/s12936-024-05040-8] [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: 03/13/2024] [Accepted: 07/09/2024] [Indexed: 09/12/2024] Open
Abstract
BACKGROUND In most countries engaged on the last mile towards malaria elimination, residual transmission mainly persists among vulnerable populations represented by isolated and mobile (often cross-border) communities. These populations are sometimes involved in informal or even illegal activities. In regions with Plasmodium vivax transmission, the specific biology of this parasite poses additional difficulties related to the need for a radical treatment against hypnozoites to prevent relapses. Among hard-to-reach communities, case management, a pillar of elimination strategy, is deficient: acute malaria attacks often occur in remote areas, where there is limited access to care, and drugs acquired outside formal healthcare are often inadequately used for treatment, which typically does not include radical treatment against P. vivax. For these reasons, P. vivax circulation among these communities represents one of the main challenges for malaria elimination in many non-African countries. The objective of this article is to describe the protocol of the CUREMA study, which aims to meet the challenge of targeting malaria in hard-to-reach populations with a focus on P. vivax. RESULTS CUREMA is a multi-centre, international public health intervention research project. The study population is represented by persons involved in artisanal and small-scale gold mining who are active and mobile in the Guiana Shield, deep inside the Amazon Forest. The CUREMA project includes a complex intervention composed of a package of actions: (1) health education activities; (2) targeted administration of treatment against P. vivax after screening against G6PD deficiency to asymptomatic persons considered at risk of silently carrying the parasite; (3) distribution of a self-testing and self-treatment kit (malakit) associated with user training for self-management of malaria symptoms occurring while in extreme isolation. These actions are offered by community health workers at settlements and neighbourhoods (often cross-border) that represent transit and logistic bases of gold miners. The study relies on hybrid design, aiming to evaluate both the effectiveness of the intervention on malaria transmission with a pre/post quasi-experimental design, and its implementation with a mixed methods approach. CONCLUSIONS The purpose of this study is to experiment an intervention that addresses both Plasmodium falciparum and P. vivax malaria elimination in a mobile and isolated population and to produce results that can be transferred to many contexts facing the same challenges around the world.
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Affiliation(s)
- Alice Sanna
- French West Indies-French Guiana Center for Clinical Investigation (CIC Inserm 1424), Department of Research, Innovation, and Public Health, Cayenne Hospital, Cayenne, French Guiana, France.
| | - Yann Lambert
- French West Indies-French Guiana Center for Clinical Investigation (CIC Inserm 1424), Department of Research, Innovation, and Public Health, Cayenne Hospital, Cayenne, French Guiana, France
| | - Irene Jimeno Maroto
- French West Indies-French Guiana Center for Clinical Investigation (CIC Inserm 1424), Department of Research, Innovation, and Public Health, Cayenne Hospital, Cayenne, French Guiana, France
| | - Muriel Suzanne Galindo
- French West Indies-French Guiana Center for Clinical Investigation (CIC Inserm 1424), Department of Research, Innovation, and Public Health, Cayenne Hospital, Cayenne, French Guiana, France
| | - Lorraine Plessis
- French West Indies-French Guiana Center for Clinical Investigation (CIC Inserm 1424), Department of Research, Innovation, and Public Health, Cayenne Hospital, Cayenne, French Guiana, France
| | - Teddy Bardon
- French West Indies-French Guiana Center for Clinical Investigation (CIC Inserm 1424), Department of Research, Innovation, and Public Health, Cayenne Hospital, Cayenne, French Guiana, France
| | - Carlotta Carboni
- French West Indies-French Guiana Center for Clinical Investigation (CIC Inserm 1424), Department of Research, Innovation, and Public Health, Cayenne Hospital, Cayenne, French Guiana, France
| | - Jane Bordalo
- Associação Desenvolvimento, Prevenção, Acompanhamento e Cooperação de Fronteiras (DPAC), Oiapoque, Brazil
| | - Helene Hiwat
- National Malaria Programme, Ministry of Health, Paramaribo, Suriname
| | - Hedley Cairo
- National Malaria Programme, Ministry of Health, Paramaribo, Suriname
| | - Lise Musset
- Laboratoire de Parasitologie, Institut Pasteur de la Guyane, Centre National de Référence du Paludisme, Cayenne, French Guiana, France
| | - Yassamine Lazrek
- Laboratoire de Parasitologie, Institut Pasteur de la Guyane, Centre National de Référence du Paludisme, Cayenne, French Guiana, France
| | - Stéphane Pelleau
- Infectious Disease Epidemiology and Analytics, Institut Pasteur, Université Paris Cité, Paris, France
| | - Michael White
- Infectious Disease Epidemiology and Analytics, Institut Pasteur, Université Paris Cité, Paris, France
| | - Martha Suárez Mutis
- Laboratory of Parasitic Diseases, Graduate Program in Tropical Medicine, Instituto Oswaldo Cruz, Fiocruz, Rio de Janeiro, Brazil
| | - Stephen Vreden
- Foundation for the Advancement of Scientific Research in Suriname (SWOS), Paramaribo, Suriname
| | - Maylis Douine
- French West Indies-French Guiana Center for Clinical Investigation (CIC Inserm 1424), Department of Research, Innovation, and Public Health, Cayenne Hospital, Cayenne, French Guiana, France
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Bradley L, Yewhalaw D, Hemming-Schroeder E, Embury P, Lee MC, Zemene E, Degefa T, King C, Kazura J, Yan G, Dent A. Determination of Plasmodium vivax and Plasmodium falciparum Malaria Exposure in Two Ethiopian Communities and Its Relationship to Duffy Expression. Am J Trop Med Hyg 2023; 109:1028-1035. [PMID: 37918005 PMCID: PMC10622468 DOI: 10.4269/ajtmh.22-0644] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Accepted: 07/16/2023] [Indexed: 11/04/2023] Open
Abstract
Despite historical dogma that Duffy blood group negativity of human erythrocytes confers resistance to Plasmodium vivax blood stage infection, cases of P. vivax malaria and asymptomatic blood stage infection (subclinical malaria) have recently been well documented in Duffy-negative individuals throughout Africa. However, the impact of Duffy negativity on the development of naturally acquired immunity to P. vivax remains poorly understood. We examined antibody reactivity to P. vivax and P. falciparum antigens at two field sites in Ethiopia and assessed Duffy gene expression by polymerase chain reaction amplification and sequencing of the GATA-1 transcription factor-binding site of the Duffy antigen receptor for chemokines (DARC) gene promotor region that is associated with silencing of erythroid cell transcription and absent protein expression. Antibodies to three of the four P. vivax blood stage antigens examined, RBP2b, EBP2, and DBPIISal-1, were significantly lower (P < 0.001) in Duffy-negative individuals relative to Duffy-positive individuals. In stark contrast, no clear pattern was found across Duffy-negative and Duffy-positive genotypes for P. falciparum antibodies. We conclude that lack of erythroid Duffy expression is associated with reduced serologic responses, indicative of less naturally acquired immunity and less cumulative exposure to blood stage P. vivax parasites relative to Duffy positive individuals living in the same communities.
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Affiliation(s)
- Lauren Bradley
- Department of Ecology and Evolutionary Biology, School of Biological Sciences, University of California, Irvine, California
| | - Delenasaw Yewhalaw
- Department of Medical Laboratory Sciences and Pathology, College of Health Sciences, Jimma University, Jimma, Ethiopia
- Tropical and Infectious Diseases Research Center, Jimma University, Jimma, Ethiopia
| | | | - Paula Embury
- Center for Global Health and Disease, Case Western Reserve University, Cleveland, Ohio
| | - Ming-Chieh Lee
- Program in Public Health, College of Health Sciences, University of California, Irvine, California
| | - Endalew Zemene
- Tropical and Infectious Diseases Research Center, Jimma University, Jimma, Ethiopia
| | - Teshome Degefa
- School of Medical Laboratory Sciences, Faculty of Health Sciences, Jimma University, Jimma, Ethiopia
| | - Christopher King
- Center for Global Health and Disease, Case Western Reserve University, Cleveland, Ohio
| | - James Kazura
- Center for Global Health and Disease, Case Western Reserve University, Cleveland, Ohio
| | - Guiyun Yan
- Department of Ecology and Evolutionary Biology, School of Biological Sciences, University of California, Irvine, California
- Program in Public Health, College of Health Sciences, University of California, Irvine, California
| | - Arlene Dent
- Center for Global Health and Disease, Case Western Reserve University, Cleveland, Ohio
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Tedijanto C, Solomon AW, Martin DL, Nash SD, Keenan JD, Lietman TM, Lammie PJ, Aiemjoy K, Amza A, Aragie S, Arzika AM, Callahan EK, Carolan S, Dawed AA, Goodhew EB, Gwyn S, Hammou J, Kadri B, Kalua K, Maliki R, Nassirou B, Seife F, Tadesse Z, West SK, Wittberg DM, Zeru Tadege T, Arnold BF. Monitoring transmission intensity of trachoma with serology. Nat Commun 2023; 14:3269. [PMID: 37277341 PMCID: PMC10241377 DOI: 10.1038/s41467-023-38940-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Accepted: 05/22/2023] [Indexed: 06/07/2023] Open
Abstract
Trachoma, caused by ocular Chlamydia trachomatis infection, is targeted for global elimination as a public health problem by 2030. To provide evidence for use of antibodies to monitor C. trachomatis transmission, we collated IgG responses to Pgp3 antigen, PCR positivity, and clinical observations from 19,811 children aged 1-9 years in 14 populations. We demonstrate that age-seroprevalence curves consistently shift along a gradient of transmission intensity: rising steeply in populations with high levels of infection and active trachoma and becoming flat in populations near elimination. Seroprevalence (range: 0-54%) and seroconversion rates (range: 0-15 per 100 person-years) correlate with PCR prevalence (r: 0.87, 95% CI: 0.57, 0.97). A seroprevalence threshold of 13.5% (seroconversion rate 2.75 per 100 person-years) identifies clusters with any PCR-identified infection at high sensitivity ( >90%) and moderate specificity (69-75%). Antibody responses in young children provide a robust, generalizable approach to monitor population progress toward and beyond trachoma elimination.
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Affiliation(s)
- Christine Tedijanto
- Francis I. Proctor Foundation, University of California San Francisco, San Francisco, CA, 94158, USA
| | - Anthony W Solomon
- Global Neglected Tropical Diseases Programme, World Health Organization, Geneva, Switzerland
| | - Diana L Martin
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, 30329, USA
| | | | - Jeremy D Keenan
- Francis I. Proctor Foundation, University of California San Francisco, San Francisco, CA, 94158, USA
- Department of Ophthalmology, University of California San Francisco, San Francisco, CA, 94158, USA
| | - Thomas M Lietman
- Francis I. Proctor Foundation, University of California San Francisco, San Francisco, CA, 94158, USA
- Department of Ophthalmology, University of California San Francisco, San Francisco, CA, 94158, USA
- Institute for Global Health Sciences, University of California San Francisco, San Francisco, CA, 94143, USA
- Department of Epidemiology and Biostatistics, University of California San Francisco, San Francisco, CA, 94143, USA
| | - Patrick J Lammie
- Neglected Tropical Diseases Support Center, Task Force for Global Health, Atlanta, GA, 30030, USA
| | - Kristen Aiemjoy
- Division of Epidemiology, Department of Public Health Sciences, University of California Davis School of Medicine, Davis, CA, USA
| | - Abdou Amza
- Programme National de Santé Oculaire, Niamey, Niger
- Programme National de Lutte Contre la Cecité, Niamey, Niger
| | - Solomon Aragie
- Francis I. Proctor Foundation, University of California San Francisco, San Francisco, CA, 94158, USA
- The Carter Center Ethiopia, Addis Ababa, Ethiopia
- Infection Biology, Addis Ababa University, Addis Ababa, Ethiopia
| | | | | | - Sydney Carolan
- Francis I. Proctor Foundation, University of California San Francisco, San Francisco, CA, 94158, USA
| | | | - E Brook Goodhew
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, 30329, USA
| | - Sarah Gwyn
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, 30329, USA
| | - Jaouad Hammou
- Service of Ocular and Otological Diseases, Epidemiology and Disease Control Directorate, Ministry of Health, Rabat, Morocco
| | - Boubacar Kadri
- Programme National de Santé Oculaire, Niamey, Niger
- Programme National de Lutte Contre la Cecité, Niamey, Niger
| | - Khumbo Kalua
- Blantyre Institute for Community Outreach, Blantyre, Malawi
| | | | - Beido Nassirou
- Programme National de Santé Oculaire, Niamey, Niger
- Programme National de Lutte Contre la Cecité, Niamey, Niger
| | - Fikre Seife
- Federal Ministry of Health, Addis Ababa, Ethiopia
| | | | - Sheila K West
- Johns Hopkins School of Medicine, Dana Center for Preventive Ophthalmology, Wilmer Eye Institute, Baltimore, MD, USA
| | - Dionna M Wittberg
- Francis I. Proctor Foundation, University of California San Francisco, San Francisco, CA, 94158, USA
| | | | - Benjamin F Arnold
- Francis I. Proctor Foundation, University of California San Francisco, San Francisco, CA, 94158, USA.
- Department of Ophthalmology, University of California San Francisco, San Francisco, CA, 94158, USA.
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Tedijanto C, Solomon AW, Martin DL, Nash SD, Keenan JD, Lietman TM, Lammie PJ, Aiemjoy K, Amza A, Aragie S, Arzika AM, Callahan EK, Carolan S, Dawed AA, Goodhew EB, Gwyn S, Hammou J, Kadri B, Kalua K, Maliki R, Nassirou B, Seife F, Tadesse Z, West SK, Wittberg DM, Zeru T, Arnold BF. Monitoring transmission intensity of trachoma with serology. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2023:2023.02.13.23285881. [PMID: 36824972 PMCID: PMC9949201 DOI: 10.1101/2023.02.13.23285881] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
Trachoma, caused by ocular Chlamydia trachomatis infection, is targeted for global elimination as a public health problem by 2030. To provide evidence for use of antibodies to monitor C. trachomatis transmission, we collated IgG responses to Pgp3 antigen, PCR positivity, and clinical observations from 19,811 children aged 1- 9 years in 14 populations. We demonstrate that age-seroprevalence curves consistently shift along a gradient of transmission intensity: rising steeply in populations with high levels of infection and active trachoma and becoming flat in populations near elimination. Seroprevalence (range: 0-54%) and seroconversion rates (range: 0-15 per 100 person-years) correlate with PCR prevalence (r: 0.87, 95% CI: 0.57, 0.97). A seroprevalence threshold of 13.5% (seroconversion rate 2.75 per 100 person-years) identifies clusters with any PCR-identified infection at high sensitivity (>90%) and moderate specificity (69-75%). Antibody responses in young children provide a robust, generalizable approach to monitor population progress toward and beyond trachoma elimination.
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Affiliation(s)
- Christine Tedijanto
- Francis I. Proctor Foundation, University of California San Francisco, San Francisco, CA, USA, 94158
| | - Anthony W. Solomon
- Global Neglected Tropical Diseases Programme, World Health Organization, Geneva, Switzerland
| | - Diana L. Martin
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, USA 30329
| | | | - Jeremy D. Keenan
- Francis I. Proctor Foundation, University of California San Francisco, San Francisco, CA, USA, 94158
- Department of Ophthalmology, University of California San Francisco, San Francisco, CA, USA, 94158
| | - Thomas M. Lietman
- Francis I. Proctor Foundation, University of California San Francisco, San Francisco, CA, USA, 94158
- Department of Ophthalmology, University of California San Francisco, San Francisco, CA, USA, 94158
- Institute for Global Health Sciences, University of California San Francisco, San Francisco, CA 94143
- Department of Epidemiology and Biostatistics, University of California San Francisco, San Francisco, CA 94143
| | - Patrick J. Lammie
- Neglected Tropical Diseases Support Center, Task Force for Global Health, Atlanta, GA, USA, 30030
| | - Kristen Aiemjoy
- Division of Epidemiology, Department of Public Health Sciences, University of California Davis School of Medicine, Davis, CA, USA
| | - Abdou Amza
- Programme National de Santé Oculaire, Niamey, Niger
- Programme National de Lutte Contre la Cecité, Niamey, Niger
| | - Solomon Aragie
- Francis I. Proctor Foundation, University of California San Francisco, San Francisco, CA, USA, 94158
- The Carter Center Ethiopia, Addis Ababa, Ethiopia
- Infection Biology, Addis Ababa University, Addis Ababa, Ethiopia
| | | | | | - Sydney Carolan
- Francis I. Proctor Foundation, University of California San Francisco, San Francisco, CA, USA, 94158
| | | | - E. Brook Goodhew
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, USA 30329
| | - Sarah Gwyn
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, USA 30329
| | - Jaouad Hammou
- Service of Ocular and Otological Diseases, Epidemiology and Disease Control Directorate, Ministry of Health, Morocco
| | - Boubacar Kadri
- Programme National de Santé Oculaire, Niamey, Niger
- Programme National de Lutte Contre la Cecité, Niamey, Niger
| | - Khumbo Kalua
- Blantyre Institute for Community Outreach, Malawi
| | | | - Beido Nassirou
- Programme National de Santé Oculaire, Niamey, Niger
- Programme National de Lutte Contre la Cecité, Niamey, Niger
| | - Fikre Seife
- Federal Ministry of Health, Addis Ababa, Ethiopia
| | | | - Sheila K. West
- Johns Hopkins School of Medicine, Dana Center for Preventive Ophthalmology, Wilmer Eye Institute, Baltimore MD USA
| | - Dionna M. Wittberg
- Francis I. Proctor Foundation, University of California San Francisco, San Francisco, CA, USA, 94158
| | - Taye Zeru
- Amhara Public Health Institute, Bahir-Dar, Ethiopia
| | - Benjamin F. Arnold
- Francis I. Proctor Foundation, University of California San Francisco, San Francisco, CA, USA, 94158
- Department of Ophthalmology, University of California San Francisco, San Francisco, CA, USA, 94158
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Identification of factors associated with residual malaria transmission using school-based serological surveys in settings pursuing elimination. Malar J 2022; 21:242. [PMID: 35989358 PMCID: PMC9392911 DOI: 10.1186/s12936-022-04260-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Accepted: 08/09/2022] [Indexed: 12/05/2022] Open
Abstract
Background Targeted research on residual malaria transmission is important to improve strategies in settings pursuing elimination, where transmission reductions prove challenging. This study aimed to detect and characterize spatial heterogeneity and factors associated with Plasmodium falciparum infections and exposure, P. falciparum apical membrane antigen 1 (PfAMA1) antibody (Ab) response, in the Central Highlands of Madagascar (CHL). Methods From May to July 2014, a cross-sectional school-based survey was carried out in 182 fokontany (villages) within 7 health districts of the CHL. Rapid diagnostic tests (RDTs) and a bead-based immunoassay including PfAMA1 antigen biomarker were used to estimate malaria prevalence and seroprevalence, respectively. Local Moran’s I index was used to detect spatial “hotspots”. Remotely sensed environmental data—temperature, vegetation indices, land covers, and elevation—were used in multivariable mixed-effects logistic regression models to characterize factors associated with malaria infection and cumulative exposure. Results Among 6,293 school-children ages 2–14 years surveyed, RDT prevalence was low at 0.8% (95% CI 0.6–1.1%), while PfAMA1 Ab seroprevalence was 7.0% (95% CI 6.4–7.7%). Hotspots of PfAMA1 Ab seroprevalence were observed in two districts (Ankazobe and Mandoto). Seroprevalence increased for children living > 5 km from a health centre (adjusted odds ratio (OR) = 1.6, 95% CI 1.2–2.2), and for those experiencing a fever episode in the previous 2 weeks (OR 1.7, 95% CI 1.2–2.4), but decreased at higher elevation (for each 100-m increase, OR = 0.7, 95% CI 0.6–0.8). A clear age pattern was observed whereby children 9–10 years old had an OR of 1.8 (95% CI 1.2–2.4), children 11–12 years an OR of 3.7 (95% CI 2.8–5.0), and children 13–14 years an OR of 5.7 (95% CI 4.0–8.0) for seropositivity, compared with younger children (2–8 years). Conclusion The use of serology in this study provided a better understanding of malaria hotspots and associated factors, revealing a pattern of higher transmission linked to geographical barriers in health care access. The integration of antibody-assays into existing surveillance activities could improve exposure assessment, and may help to monitor the effectiveness of malaria control efforts and adapt elimination interventions. Supplementary Information The online version contains supplementary material available at 10.1186/s12936-022-04260-0.
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Dias MHF, Guimarães LFF, Barcelos MG, Moreira EUM, do Nascimento MFA, de Souza TN, Pires CV, Monteiro TAF, Middeldorp JM, Soares IS, Fontes CJF, Ntumngia FB, Adams JH, Kano FS, Carvalho LH. Impact of Epstein-Barr virus co-infection on natural acquired Plasmodium vivax antibody response. PLoS Negl Trop Dis 2022; 16:e0010305. [PMID: 35921373 PMCID: PMC9377613 DOI: 10.1371/journal.pntd.0010305] [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: 03/04/2022] [Revised: 08/15/2022] [Accepted: 07/22/2022] [Indexed: 11/18/2022] Open
Abstract
Background
The simultaneous infection of Plasmodium falciparum and Epstein-Barr virus (EBV) could promote the development of the aggressive endemic Burkitt’s Lymphoma (eBL) in children living in P. falciparum holoendemic areas. While it is well-established that eBL is not related to other human malaria parasites, the impact of EBV infection on the generation of human malaria immunity remains largely unexplored. Considering that this highly prevalent herpesvirus establishes a lifelong persistent infection on B-cells with possible influence on malaria immunity, we hypothesized that EBV co-infection could have impact on the naturally acquired antibody responses to P. vivax, the most widespread human malaria parasite.
Methodology/Principal findings
The study design involved three cross-sectional surveys at six-month intervals (baseline, 6 and 12 months) among long-term P. vivax exposed individuals living in the Amazon rainforest. The approach focused on a group of malaria-exposed individuals whose EBV-DNA (amplification of balf-5 gene) was persistently detected in the peripheral blood (PersVDNA, n = 27), and an age-matched malaria-exposed group whose EBV-DNA could never be detected during the follow-up (NegVDNA, n = 29). During the follow-up period, the serological detection of EBV antibodies to lytic/ latent viral antigens showed that IgG antibodies to viral capsid antigen (VCA-p18) were significantly different between groups (PersVDNA > NegVDNA). A panel of blood-stage P. vivax antigens covering a wide range of immunogenicity confirmed that in general PersVDNA group showed low levels of antibodies as compared with NegVDNA. Interestingly, more significant differences were observed to a novel DBPII immunogen, named DEKnull-2, which has been associated with long-term neutralizing antibody response. Differences between groups were less pronounced with blood-stage antigens (such as MSP1-19) whose levels can fluctuate according to malaria transmission.
Conclusions/Significance
In a proof-of-concept study we provide evidence that a persistent detection of EBV-DNA in peripheral blood of adults in a P. vivax semi-immune population may impact the long-term immune response to major malaria vaccine candidates.
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Affiliation(s)
| | | | | | | | | | - Taís N. de Souza
- Instituto René Rachou/FIOCRUZ Minas, Belo Horizonte, Minas Gerais, Brazil
| | - Camilla V. Pires
- Center for Global Health and Infectious Diseases Research, Department of Global Health, College of Public Health, University of South Florida, Tampa, Florida, United States of America
| | - Talita A. F. Monteiro
- Instituto Evandro Chagas, Secretaria de Vigilância em Saúde, Ministério da Saúde (IEC/SVS/MS), Belém, Pará, Brazil
| | - Jaap M. Middeldorp
- Department of Pathology, Free University Medical Center, Amsterdam, The Netherlands
| | - Irene S. Soares
- Faculdade de Ciências Farmacêuticas, Universidade de São Paulo (USP), São Paulo, Brazil
| | - Cor J. F. Fontes
- Julio Müller School Hospital, Faculdade de Medicina, Universidade Federal de Mato Grosso, Cuiabá, Mato Grosso, Brazil
| | - Francis B. Ntumngia
- Center for Global Health and Infectious Diseases Research, Department of Global Health, College of Public Health, University of South Florida, Tampa, Florida, United States of America
| | - John H. Adams
- Center for Global Health and Infectious Diseases Research, Department of Global Health, College of Public Health, University of South Florida, Tampa, Florida, United States of America
| | - Flora S. Kano
- Instituto René Rachou/FIOCRUZ Minas, Belo Horizonte, Minas Gerais, Brazil
| | - Luzia H. Carvalho
- Instituto René Rachou/FIOCRUZ Minas, Belo Horizonte, Minas Gerais, Brazil
- * E-mail:
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Tomar SJ, Alagarasu K, More A, Nadkarni M, Bachal R, Bote M, Patil J, Venkatesh V, Parashar D, Tandale BV. Decadal Change in Seroprevalence of Chikungunya Virus Infection in Pune City, India. Viruses 2022; 14:v14050998. [PMID: 35632740 PMCID: PMC9144945 DOI: 10.3390/v14050998] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 05/04/2022] [Accepted: 05/06/2022] [Indexed: 02/01/2023] Open
Abstract
Chikungunya virus (CHIKV) is an arthropod-borne virus capable of causing large outbreaks. We aimed to determine the decadal change in the extent of chikungunya virus infection from 2009 to 2019. We implemented a prospective cross-sectional survey in Pune City using a 30-cluster approach with probability-proportion-to-size (PPS) sampling, with blood samples collected from 1654 participants in early 2019. The study also included an additional 799 blood samples from an earlier serosurvey in late 2009. The samples were tested by an in-house anti-CHIKV IgG ELISA assay. The overall seroprevalence in 2019 was 53.2% (95% CI 50.7−55.6) as against 8.5% (95% CI 6.5−10.4) in 2009. A fivefold increase in seroprevalence was observed in a decade (p < 0.00001). The seroprevalence increased significantly with age; however, it did not differ between genders. Modeling of age-stratified seroprevalence data from 2019 coincided with a recent outbreak in 2016 followed by the low-level circulation. The mean estimated force of infection during the outbreak was 35.8% (95% CI 2.9−41.2), and it was 1.2% after the outbreak. To conclude, the study reports a fivefold increase in the seroprevalence of chikungunya infection over a decade in Pune City. The modeling approach considering intermittent outbreaks with continuous low-level circulation was a better fit and coincided with a recent outbreak reported in 2016. Community engagement and effective vector control measures are needed to avert future chikungunya outbreaks.
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Affiliation(s)
- Shilpa Jagatram Tomar
- Epidemiology Group, ICMR-National Institute of Virology, Pune 411021, India; (S.J.T.); (V.V.)
| | - Kalichamy Alagarasu
- Dengue and Chikungunya Group, ICMR-National Institute of Virology, Pune 411001, India; (K.A.); (A.M.); (M.N.); (R.B.); (M.B.); (J.P.)
| | - Ashwini More
- Dengue and Chikungunya Group, ICMR-National Institute of Virology, Pune 411001, India; (K.A.); (A.M.); (M.N.); (R.B.); (M.B.); (J.P.)
| | - Manasi Nadkarni
- Dengue and Chikungunya Group, ICMR-National Institute of Virology, Pune 411001, India; (K.A.); (A.M.); (M.N.); (R.B.); (M.B.); (J.P.)
| | - Rupali Bachal
- Dengue and Chikungunya Group, ICMR-National Institute of Virology, Pune 411001, India; (K.A.); (A.M.); (M.N.); (R.B.); (M.B.); (J.P.)
| | - Minal Bote
- Dengue and Chikungunya Group, ICMR-National Institute of Virology, Pune 411001, India; (K.A.); (A.M.); (M.N.); (R.B.); (M.B.); (J.P.)
| | - Jayashri Patil
- Dengue and Chikungunya Group, ICMR-National Institute of Virology, Pune 411001, India; (K.A.); (A.M.); (M.N.); (R.B.); (M.B.); (J.P.)
| | - Vasanthy Venkatesh
- Epidemiology Group, ICMR-National Institute of Virology, Pune 411021, India; (S.J.T.); (V.V.)
| | - Deepti Parashar
- Dengue and Chikungunya Group, ICMR-National Institute of Virology, Pune 411001, India; (K.A.); (A.M.); (M.N.); (R.B.); (M.B.); (J.P.)
- Correspondence: (D.P.); (B.V.T.)
| | - Babasaheb Vishwanath Tandale
- Epidemiology Group, ICMR-National Institute of Virology, Pune 411021, India; (S.J.T.); (V.V.)
- Correspondence: (D.P.); (B.V.T.)
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8
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Distinct kinetics of antibodies to 111 Plasmodium falciparum proteins identifies markers of recent malaria exposure. Nat Commun 2022; 13:331. [PMID: 35039519 PMCID: PMC8764098 DOI: 10.1038/s41467-021-27863-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2020] [Accepted: 12/15/2021] [Indexed: 11/09/2022] Open
Abstract
Strengthening malaria surveillance is a key intervention needed to reduce the global disease burden. Reliable serological markers of recent malaria exposure could improve current surveillance methods by allowing for accurate estimates of infection incidence from limited data. We studied the IgG antibody response to 111 Plasmodium falciparum proteins in 65 adult travellers followed longitudinally after a natural malaria infection in complete absence of re-exposure. We identified a combination of five serological markers that detect exposure within the previous three months with >80% sensitivity and specificity. Using mathematical modelling, we examined the antibody kinetics and determined that responses informative of recent exposure display several distinct characteristics: rapid initial boosting and decay, less inter-individual variation in response kinetics, and minimal persistence over time. Such serological exposure markers could be incorporated into routine malaria surveillance to guide efforts for malaria control and elimination. Serological markers of recent Plasmodium falciparum infection could be useful to estimate incidence. Here, the authors identify a combination of five serological markers to detect exposure to infection within the previous three months with >80% sensitivity and specificity.
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9
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Willen L, Milton P, Hamley JID, Walker M, Osei-Atweneboana MY, Volf P, Basáñez MG, Courtenay O. Demographic patterns of human antibody levels to Simulium damnosum s.l. saliva in onchocerciasis-endemic areas: An indicator of exposure to vector bites. PLoS Negl Trop Dis 2022; 16:e0010108. [PMID: 35020729 PMCID: PMC8789114 DOI: 10.1371/journal.pntd.0010108] [Citation(s) in RCA: 4] [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: 09/30/2021] [Revised: 01/25/2022] [Accepted: 12/17/2021] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND In onchocerciasis endemic areas in Africa, heterogenous biting rates by blackfly vectors on humans are assumed to partially explain age- and sex-dependent infection patterns with Onchocerca volvulus. To underpin these assumptions and further improve predictions made by onchocerciasis transmission models, demographic patterns in antibody responses to salivary antigens of Simulium damnosum s.l. are evaluated as a measure of blackfly exposure. METHODOLOGY/PRINCIPAL FINDINGS Recently developed IgG and IgM anti-saliva immunoassays for S. damnosum s.l. were applied to blood samples collected from residents in four onchocerciasis endemic villages in Ghana. Demographic patterns in antibody levels according to village, sex and age were explored by fitting generalized linear models. Antibody levels varied between villages but showed consistent patterns with age and sex. Both IgG and IgM responses declined with increasing age. IgG responses were generally lower in males than in females and exhibited a steeper decline in adult males than in adult females. No sex-specific difference was observed in IgM responses. CONCLUSIONS/SIGNIFICANCE The decline in age-specific antibody patterns suggested development of immunotolerance or desensitization to blackfly saliva antigen in response to persistent exposure. The variation between sexes, and between adults and youngsters may reflect differences in behaviour influencing cumulative exposure. These measures of antibody acquisition and decay could be incorporated into onchocerciasis transmission models towards informing onchocerciasis control, elimination, and surveillance.
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Affiliation(s)
- Laura Willen
- Department of Parasitology, Faculty of Science, Charles University, Prague, Czech Republic
- Centre for the Evaluation of Vaccinations, Vaccine and Infectious Disease Institute, University of Antwerp, Wilrijk, Belgium
- * E-mail: (LW); (OC)
| | - Philip Milton
- MRC Centre for Global Infectious Disease Analysis and London Centre for Neglected Tropical Disease Research, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, London, United Kingdom
| | - Jonathan I. D. Hamley
- MRC Centre for Global Infectious Disease Analysis and London Centre for Neglected Tropical Disease Research, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, London, United Kingdom
| | - Martin Walker
- London Centre for Neglected Tropical Disease Research and Department of Pathobiology and Population Sciences, Royal Veterinary College, Hatfield, United Kingdom
| | | | - Petr Volf
- Department of Parasitology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Maria-Gloria Basáñez
- MRC Centre for Global Infectious Disease Analysis and London Centre for Neglected Tropical Disease Research, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, London, United Kingdom
| | - Orin Courtenay
- Zeeman Institute for Systems Biology & Infectious Disease Epidemiology Research and School of Life Sciences, University of Warwick, Coventry, United Kingdom
- * E-mail: (LW); (OC)
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10
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Oseno B, Marura F, Ogwang R, Muturi M, Njunge J, Nkumama I, Mwakesi R, Mwai K, Rono MK, Mwakubambanya R, Osier F, Tuju J. Characterization of Anopheles gambiae D7 salivary proteins as markers of human-mosquito bite contact. Parasit Vectors 2022; 15:11. [PMID: 34996508 PMCID: PMC8742437 DOI: 10.1186/s13071-021-05130-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 12/11/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Malaria is transmitted when infected Anopheles mosquitoes take a blood meal. During this process, the mosquitoes inject a cocktail of bioactive proteins that elicit antibody responses in humans and could be used as biomarkers of exposure to mosquito bites. This study evaluated the utility of IgG responses to members of the Anopheles gambiae D7 protein family as serological markers of human-vector contact. METHODS The D7L2, D7r1, D7r2, D7r3, D7r4 and SG6 salivary proteins from An. gambiae were expressed as recombinant antigens in Escherichia coli. Antibody responses to the salivary proteins were compared in Europeans with no prior exposure to malaria and lifelong residents of Junju in Kenya and Kitgum in Uganda where the intensity of malaria transmission is moderate and high, respectively. In addition, to evaluate the feasibility of using anti-D7 IgG responses as a tool to evaluate the impact of vector control interventions, we compared responses between individuals using insecticide-treated bednets to those who did not in Junju, Kenya where bednet data were available. RESULTS We show that both the long and short forms of the D7 salivary gland antigens elicit a strong antibody response in humans. IgG responses against the D7 antigens reflected the transmission intensities of the three study areas, with the highest to lowest responses observed in Kitgum (northern Uganda), Junju (Kenya) and malaria-naïve Europeans, respectively. Specifically, the long form D7L2 induced an IgG antibody response that increased with age and that was lower in individuals who slept under a bednet, indicating its potential as a serological tool for estimating human-vector contact and monitoring the effectiveness of vector control interventions. CONCLUSIONS This study reveals that D7L2 salivary antigen has great potential as a biomarker of exposure to mosquito bites and as a tool for assessing the efficacy of vector control strategies such as bednet use.
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Affiliation(s)
- Brenda Oseno
- KEMRI-Wellcome Trust Research Programme CGMRC, P.O. Box 230-80108, Kilifi, Kenya.,Egerton University, P.O. Box 536-20115, Nakuru, Kenya
| | - Faith Marura
- KEMRI-Wellcome Trust Research Programme CGMRC, P.O. Box 230-80108, Kilifi, Kenya
| | - Rodney Ogwang
- KEMRI-Wellcome Trust Research Programme CGMRC, P.O. Box 230-80108, Kilifi, Kenya
| | - Martha Muturi
- KEMRI-Wellcome Trust Research Programme CGMRC, P.O. Box 230-80108, Kilifi, Kenya
| | - James Njunge
- KEMRI-Wellcome Trust Research Programme CGMRC, P.O. Box 230-80108, Kilifi, Kenya
| | - Irene Nkumama
- KEMRI-Wellcome Trust Research Programme CGMRC, P.O. Box 230-80108, Kilifi, Kenya.,Heidelberg University Hospital, Neuenheimer Feld, 672 69120, Heidelberg, Germany
| | - Robert Mwakesi
- KEMRI-Wellcome Trust Research Programme CGMRC, P.O. Box 230-80108, Kilifi, Kenya
| | - Kennedy Mwai
- KEMRI-Wellcome Trust Research Programme CGMRC, P.O. Box 230-80108, Kilifi, Kenya.,School of Public Health, University of the Witwatersrand, 1 Jan Smuts Avenue, Braamfontein 2000, Johannesburg, South Africa
| | - Martin K Rono
- KEMRI-Wellcome Trust Research Programme CGMRC, P.O. Box 230-80108, Kilifi, Kenya.,Pwani University, P.O. Box 195-80108, Kilifi, Kenya
| | | | - Faith Osier
- KEMRI-Wellcome Trust Research Programme CGMRC, P.O. Box 230-80108, Kilifi, Kenya.,Pwani University, P.O. Box 195-80108, Kilifi, Kenya.,Heidelberg University Hospital, Neuenheimer Feld, 672 69120, Heidelberg, Germany
| | - James Tuju
- KEMRI-Wellcome Trust Research Programme CGMRC, P.O. Box 230-80108, Kilifi, Kenya. .,Pwani University, P.O. Box 195-80108, Kilifi, Kenya.
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11
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Kyomuhangi I, Giorgi E. A threshold-free approach with age-dependency for estimating malaria seroprevalence. Malar J 2022; 21:1. [PMID: 34980109 PMCID: PMC8725324 DOI: 10.1186/s12936-021-04022-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 12/12/2021] [Indexed: 11/21/2022] Open
Abstract
Background In malaria serology analysis, the standard approach to obtain seroprevalence, i.e the proportion of seropositive individuals in a population, is based on a threshold which is used to classify individuals as seropositive or seronegative. The choice of this threshold is often arbitrary and is based on methods that ignore the age-dependency of the antibody distribution. Methods Using cross-sectional antibody data from the Western Kenyan Highlands, this paper introduces a novel approach that has three main advantages over the current threshold-based approach: it avoids the use of thresholds; it accounts for the age dependency of malaria antibodies; and it allows us to propagate the uncertainty from the classification of individuals into seropositive and seronegative when estimating seroprevalence. The reversible catalytic model is used as an example for illustrating how to propagate this uncertainty into the parameter estimates of the model. Results This paper finds that accounting for age-dependency leads to a better fit to the data than the standard approach which uses a single threshold across all ages. Additionally, the paper also finds that the proposed threshold-free approach is more robust against the selection of different age-groups when estimating seroprevalence. Conclusion The novel threshold-free approach presented in this paper provides a statistically principled and more objective approach to estimating malaria seroprevalence. The introduced statistical framework also provides a means to compare results across studies which may use different age ranges for the estimation of seroprevalence. Supplementary Information The online version contains supplementary material available at 10.1186/s12936-021-04022-4.
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Affiliation(s)
- Irene Kyomuhangi
- CHICAS, Lancaster University, Sir John Fisher Drive, Lancaster, UK.
| | - Emanuele Giorgi
- CHICAS, Lancaster University, Sir John Fisher Drive, Lancaster, UK
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12
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Kearney EA, Agius PA, Chaumeau V, Cutts JC, Simpson JA, Fowkes FJI. Anopheles salivary antigens as serological biomarkers of vector exposure and malaria transmission: A systematic review with multilevel modelling. eLife 2021; 10:e73080. [PMID: 34939933 PMCID: PMC8860437 DOI: 10.7554/elife.73080] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Accepted: 12/21/2021] [Indexed: 12/25/2022] Open
Abstract
Background Entomological surveillance for malaria is inherently resource-intensive and produces crude population-level measures of vector exposure which are insensitive in low-transmission settings. Antibodies against Anopheles salivary proteins measured at the individual level may serve as proxy biomarkers for vector exposure and malaria transmission, but their relationship is yet to be quantified. Methods A systematic review of studies measuring antibodies against Anopheles salivary antigens (PROSPERO: CRD42020185449). Multilevel modelling (to account for multiple study-specific observations [level 1], nested within study [level 2], and study nested within country [level 3]) estimated associations between seroprevalence with Anopheles human biting rate (HBR) and malaria transmission measures. Results From 3981 studies identified in literature searches, 42 studies across 16 countries were included contributing 393 study-specific observations of anti-Anopheles salivary antibodies determined in 42,764 samples. A positive association between HBR (log transformed) and seroprevalence was found; overall a twofold (100% relative) increase in HBR was associated with a 23% increase in odds of seropositivity (OR: 1.23, 95% CI: 1.10-1.37; p<0.001). The association between HBR and Anopheles salivary antibodies was strongest with concordant, rather than discordant, Anopheles species. Seroprevalence was also significantly positively associated with established epidemiological measures of malaria transmission: entomological inoculation rate, Plasmodium spp. prevalence, and malarial endemicity class. Conclusions Anopheles salivary antibody biomarkers can serve as a proxy measure for HBR and malaria transmission, and could monitor malaria receptivity of a population to sustain malaria transmission. Validation of Anopheles species-specific biomarkers is important given the global heterogeneity in the distribution of Anopheles species. Salivary biomarkers have the potential to transform surveillance by replacing impractical, inaccurate entomological investigations, especially in areas progressing towards malaria elimination. Funding Australian National Health and Medical Research Council, Wellcome Trust.
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Affiliation(s)
- Ellen A Kearney
- The McFarlane Burnet Institute of Medical Research and Public HealthMelbourneAustralia
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of MelbourneMelbourneAustralia
| | - Paul A Agius
- The McFarlane Burnet Institute of Medical Research and Public HealthMelbourneAustralia
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of MelbourneMelbourneAustralia
- Department of Epidemiology and Preventive Medicine, Monash UniversityMelbourneAustralia
| | - Victor Chaumeau
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol UniversityMae SotThailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of OxfordOxfordUnited Kingdom
| | - Julia C Cutts
- The McFarlane Burnet Institute of Medical Research and Public HealthMelbourneAustralia
- Department of Medicine at the Doherty Institute, The University of MelbourneMelbourneAustralia
| | - Julie A Simpson
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of MelbourneMelbourneAustralia
| | - Freya JI Fowkes
- The McFarlane Burnet Institute of Medical Research and Public HealthMelbourneAustralia
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of MelbourneMelbourneAustralia
- Department of Epidemiology and Preventive Medicine, Monash UniversityMelbourneAustralia
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13
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Senyonjo L, Addy J, Martin DL, Agyemang D, Yeboah-Manu D, Gwyn S, Marfo B, Asante-Poku A, Aboe A, Mensah E, Solomon AW, Bailey RL. Surveillance for peri-elimination trachoma recrudescence: Exploratory studies in Ghana. PLoS Negl Trop Dis 2021; 15:e0009744. [PMID: 34543293 PMCID: PMC8519445 DOI: 10.1371/journal.pntd.0009744] [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: 05/19/2021] [Revised: 10/15/2021] [Accepted: 08/18/2021] [Indexed: 11/26/2022] Open
Abstract
Introduction To date, eleven countries have been validated as having eliminated trachoma as a public health problem, including Ghana in 2018. Surveillance for recrudescence is needed both pre- and post-validation but evidence-based guidance on appropriate strategies is lacking. We explored two potential surveillance strategies in Ghana. Methodology/principal findings Amongst randomly-selected communities enrolled in pre-validation on-going surveillance between 2011 and 2015, eight were identified as having had trachomatous-inflammation follicular (TF) prevalence ≥5% in children aged 1–9 years between 2012 and 2014. These eight were re-visited in 2015 and 2016 and neighbouring communities were also added (“TF trigger” investigations). Resident children aged 1–9 years were then examined for trachoma and had a conjunctival swab to test for Chlamydia trachomatis (Ct) and a dried blood spot (DBS) taken to test for anti-Pgp3 antibodies. These investigations identified at least one community with evidence of probable recent Ct ocular transmission. However, the approach likely lacks sufficient spatio-temporal power to be reliable. A post-validation surveillance strategy was also evaluated, this reviewed the ocular Ct infection and anti-Pgp3 seroprevalence data from the TF trigger investigations and from the pre-validation surveillance surveys in 2015 and 2016. Three communities identified as having ocular Ct infection >0% and anti-Pgp3 seroprevalence ≥15.0% were identified, and along with three linked communities, were followed-up as part of the surveillance strategy. An additional three communities with a seroprevalence ≥25.0% but no Ct infection were also followed up (“antibody and infection trigger” investigations). DBS were taken from all residents aged ≥1 year and ocular swabs from all children aged 1–9 years. There was evidence of transmission in the group of communities visited in one district (Zabzugu-Tatale). There was no or little evidence of continued transmission in other districts, suggesting previous infection identified was transient or potentially not true ocular Ct infection. Conclusions/significance There is evidence of heterogeneity in Ct transmission dynamics in northern Ghana, even 10 years after wide-scale MDA has stopped. There is added value in monitoring Ct infection and anti-Ct antibodies, using these indicators to interrogate past or present surveillance strategies. This can result in a deeper understanding of transmission dynamics and inform new post-validation surveillance strategies. Opportunities should be explored for integrating PCR and serological-based markers into surveys conducted in trachoma elimination settings. The goal for trachoma programmes is elimination of trachoma as a public health problem. This means that ongoing low-level eye-to-eye transmission of the causative bacterium, Chlamydia trachomatis (Ct), is acceptable. Countries need to implement a suitable surveillance system to identify any return to higher transmission levels. The best methodology for doing this is not known. We first explored the approach used by Ghana in its standard programme, which involved monitoring a limited number of randomly selected communities for evidence of active (inflammatory) trachoma visible in children’s eyes on examination by trained observers. Although this strategy led to identification of at least one community that had probably had recent Ct transmission, the approach is unlikely to consistently identify places where return to higher levels of transmission is a risk. We also explored using information on infection (detected in eye swabs) and antibodies to Ct (detected in the blood) to identify communities at risk. We found evidence of both persistent eye-to-eye Ct transmission and areas where infection was transient and has now gone away. We conclude that the use of infection and antibody data for surveillance of trachoma appears promising.
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Affiliation(s)
- Laura Senyonjo
- Research Team, Sightsavers, Haywards Heath, United Kingdom
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, United Kingdom
- * E-mail:
| | - James Addy
- Eye Health Department, Ghana Health Service, Accra, Ghana
| | - Diana L. Martin
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, United States of America
| | | | - Dorothy Yeboah-Manu
- Bacteriology Department, Noguchi Memorial Institute for Medical Research, Accra, Ghana
| | - Sarah Gwyn
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, United States of America
| | - Benjamin Marfo
- Neglected Tropical Diseases Division, Ghana Health Service, Accra, Ghana
| | - Adwoa Asante-Poku
- Bacteriology Department, Noguchi Memorial Institute for Medical Research, Accra, Ghana
| | | | | | - Anthony W. Solomon
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Robin L. Bailey
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, United Kingdom
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14
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Milne G, Webster JP, Walker M. Toward Improving Interventions Against Toxoplasmosis by Identifying Routes of Transmission Using Sporozoite-specific Serological Tools. Clin Infect Dis 2021; 71:e686-e693. [PMID: 32280956 PMCID: PMC7744992 DOI: 10.1093/cid/ciaa428] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Accepted: 04/10/2020] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Horizontal transmission of Toxoplasma gondii occurs primarily via ingestion of environmental oocysts or consumption of undercooked/raw meat containing cyst-stage bradyzoites. The relative importance of these 2 transmission routes remains unclear. Oocyst infection can be distinguished from bradyzoite infection by identification of immunoglobulin G (IgG) antibodies against T. gondii embryogenesis-related protein (TgERP). These antibodies are, however, thought to persist for only 6-8 months in human sera, limiting the use of TgERP serology to only those patients recently exposed to T. gondii. Yet recent serological survey data indicate a more sustained persistence of anti-TgERP antibodies. Elucidating the duration of anti-TgERP IgG will help to determine whether TgERP serology has epidemiological utility for quantifying the relative importance of different routes of T. gondii transmission. METHODS We developed a serocatalytic mathematical model to capture the change in seroprevalence of non-stage-specific IgG and anti-TgERP IgG antibodies with human age. The model was fitted to published datasets collected in an endemic region of Brazil to estimate the duration of anti-TgERP IgG antibodies, accounting for variable age-force of infection profiles and uncertainty in the diagnostic performance of TgERP serology. RESULTS We found that anti-TgERP IgG persists for substantially longer than previously recognized, with estimates ranging from 8.3 to 41.1 years. The Brazilian datasets were consistent with oocysts being the predominant transmission route in these settings. CONCLUSIONS The longer than previously recognized duration of anti-TgERP antibodies indicates that anti-TgERP serology could be a useful tool for delineating T. gondii transmission routes in human populations. TgERP serology may therefore be an important epidemiological tool for informing the design of tailored, setting-specific public health information campaigns and interventions.
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Affiliation(s)
- Gregory Milne
- Department of Pathobiology and Population Sciences, Royal Veterinary College, University of London, Hertfordshire, United Kingdom.,London Centre for Neglected Tropical Disease Research, Imperial College London Faculty of Medicine, St Mary's Hospital Campus, London, United Kingdom
| | - Joanne P Webster
- Department of Pathobiology and Population Sciences, Royal Veterinary College, University of London, Hertfordshire, United Kingdom.,London Centre for Neglected Tropical Disease Research, Imperial College London Faculty of Medicine, St Mary's Hospital Campus, London, United Kingdom
| | - Martin Walker
- Department of Pathobiology and Population Sciences, Royal Veterinary College, University of London, Hertfordshire, United Kingdom.,London Centre for Neglected Tropical Disease Research, Imperial College London Faculty of Medicine, St Mary's Hospital Campus, London, United Kingdom
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15
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Abstract
Serology data are an increasingly important tool in malaria surveillance, especially in low transmission settings where the estimation of parasite-based indicators is often problematic. Existing methods rely on the use of thresholds to identify seropositive individuals and estimate transmission intensity, while making assumptions about the temporal dynamics of malaria transmission that are rarely questioned. Here, we present a novel threshold-free approach for the analysis of malaria serology data which avoids dichotomization of continuous antibody measurements and allows us to model changes in the antibody distribution across age in a more flexible way. The proposed unified mechanistic model combines the properties of reversible catalytic and antibody acquisition models, and allows for temporally varying boosting and seroconversion rates. Additionally, as an alternative to the unified mechanistic model, we also propose an empirical approach to analysis where modelling of the age-dependency is informed by the data rather than biological assumptions. Using serology data from Western Kenya, we demonstrate both the usefulness and limitations of the novel modelling framework.
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16
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McCaffery JN, Singh B, Nace D, Moreno A, Udhayakumar V, Rogier E. Natural infections with different Plasmodium species induce antibodies reactive to a chimeric Plasmodium vivax recombinant protein. Malar J 2021; 20:86. [PMID: 33579292 PMCID: PMC7880512 DOI: 10.1186/s12936-021-03626-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 02/04/2021] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND As malaria incidence and transmission in a region decreases, it becomes increasingly difficult to identify areas of active transmission. Improved methods for identifying and monitoring foci of active malaria transmission are needed in areas of low parasite prevalence in order to achieve malaria elimination. Serological assays can provide population-level infection history to inform elimination campaigns. METHODS A bead-based multiplex antibody detection assay was used to evaluate a chimeric Plasmodium vivax MSP1 protein (PvRMC-MSP1), designed to be broadly immunogenic for use in vaccine studies, to act as a pan-malaria serological tool based on its ability to capture IgG in plasma samples obtained from naturally exposed individuals. Samples from 236 US travellers with PCR confirmed infection status from all four major Plasmodium species infecting humans, Plasmodium falciparum (n = 181), Plasmodium vivax (n = 38), Plasmodium malariae (n = 4), and Plasmodium ovale (n = 13) were tested for IgG capture using PvRMC-MSP1 as well as the four recombinant MSP1-19 kD isoforms representative of these Plasmodium species. RESULTS Regardless of infecting Plasmodium species, a large proportion of plasma samples from infected US travellers provided a high assay signal to the PvRMC-MSP1 chimeric protein, with 115 high responders out of 236 samples assessed (48.7%). When grouped by active infection, 38.7% P. falciparum-, 92.1% of P. vivax-, 75.0% P. malariae-, and 53.4% of P. ovale-infected individuals displayed high assay signals in response to PvRMC-MSP1. It was also determined that plasma from P. vivax-infected individuals produced increased assay signals in response to the PvRMC-MSP1 chimera as compared to the recombinant PvMSP1 for 89.5% (34 out of 38) of individuals. PvRMC-MSP1 also showed improved ability to capture IgG antibodies from P. falciparum-infected individuals when compared to the capture by recombinant PvMSP1, with high assay signals observed for 38.7% of P. falciparum-infected travellers in response to PvRMC-MSP1 IgG capture compared to just 1.1% who were high responders to capture by the recombinant PvMSP1 protein. CONCLUSIONS These results support further study of designed antigens as an approach for increasing sensitivity or broadening binding capacity to improve existing serological tools for determining population-level exposure to Plasmodium species. Including both broad-reacting and Plasmodium species-specific antigen-coated beads in an assay panel could provide a nuanced view of population-level exposure histories, an extensive IgG profile, and detailed seroestimates. A more sensitive serological tool for detection of P. vivax exposure would aid malaria elimination campaigns in co-endemic areas and regions where P. vivax is the dominant parasite.
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Affiliation(s)
- Jessica N McCaffery
- Emory Vaccine Center, Yerkes National Primate Research Center, Emory University, 954 Gatewood Road, Atlanta, GA, 30329, USA
| | - Balwan Singh
- Malaria Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, 30329, USA
| | - Douglas Nace
- Malaria Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, 30329, USA
| | - Alberto Moreno
- Emory Vaccine Center, Yerkes National Primate Research Center, Emory University, 954 Gatewood Road, Atlanta, GA, 30329, USA
- Division of Infectious Diseases, Department of Medicine, Emory University, 69 Jesse Hill, Jr. Drive, Atlanta, SEGA, 30303, USA
| | - Venkatachalam Udhayakumar
- Malaria Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, 30329, USA
| | - Eric Rogier
- Malaria Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, 30329, USA.
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17
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Antibody Dynamics for Plasmodium vivax Malaria: A Mathematical Model. Bull Math Biol 2021; 83:6. [PMID: 33387082 DOI: 10.1007/s11538-020-00837-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 11/13/2020] [Indexed: 10/22/2022]
Abstract
Malaria is a mosquito-borne disease that, despite intensive control and mitigation initiatives, continues to pose an enormous public health burden. Plasmodium vivax is one of the principal causes of malaria in humans. Antibodies, which play a fundamental role in the host response to P. vivax, are acquired through exposure to the parasite. Here, we introduce a stochastic, within-host model of antibody responses to P. vivax for an individual in a general transmission setting. We begin by developing an epidemiological framework accounting for P. vivax infections resulting from new mosquito bites (primary infections), as well as the activation of dormant-liver stages known as hypnozoites (relapses). By constructing an infinite server queue, we obtain analytic results for the distribution of relapses in a general transmission setting. We then consider a simple model of antibody kinetics, whereby antibodies are boosted with each infection, but are subject to decay over time. By embedding this model for antibody kinetics in the epidemiological framework using a generalised shot noise process, we derive analytic expressions governing the distribution of antibody levels for a single individual in a general transmission setting. Our work provides a means to explore exposure-dependent antibody dynamics for P. vivax, with the potential to address key questions in the context of serological surveillance and acquired immunity.
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18
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Wu L, Mwesigwa J, Affara M, Bah M, Correa S, Hall T, Singh SK, Beeson JG, Tetteh KKA, Kleinschmidt I, D’Alessandro U, Drakeley C. Sero-epidemiological evaluation of malaria transmission in The Gambia before and after mass drug administration. BMC Med 2020; 18:331. [PMID: 33183292 PMCID: PMC7664049 DOI: 10.1186/s12916-020-01785-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2020] [Accepted: 09/16/2020] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND As The Gambia aims to achieve malaria elimination by 2030, serological assays are a useful surveillance tool to monitor trends in malaria incidence and evaluate community-based interventions. METHODS Within a mass drug administration (MDA) study in The Gambia, where reduced malaria infection and clinical disease were observed after the intervention, a serological sub-study was conducted in four study villages. Spatio-temporal variation in transmission was measured with a panel of recombinant Pf antigens on a multiplexed bead-based assay. Village-level antibody levels were quantified as under-15 sero-prevalence, sero-conversion rates, and age-adjusted antibody acquisition rates. Antibody levels prior to MDA were assessed for association with persistent malaria infection after community chemoprophylaxis. RESULTS Seasonal changes in antibodies to Etramp5.Ag1 were observed in children under 15 years in two transmission settings-the West Coast and Upper River Regions (4.32% and 31.30% Pf prevalence, respectively). At the end of the malaria season, short-lived antibody responses to Etramp5.Ag1, GEXP18, HSP40.Ag1, EBA175 RIII-V, and Rh2.2030 were lower amongst 1-15 year olds in the West Coast compared to the Upper River, reflecting known differences in transmission. Prior to MDA, individuals in the top 50th percentile of antibody levels had two-fold higher odds of clinical malaria during the transmission season, consistent with previous findings from the Malaria Transmission Dynamics Study, where individuals infected before the implementation of MDA had two-fold higher odds of re-infection post-MDA. CONCLUSIONS Serological markers can serve dual functions as indicators of malaria exposure and incidence. By monitoring age-specific sero-prevalence, the magnitude of age-stratified antibody levels, or identifying groups of individuals with above-average antibody responses, these antigens have the potential to complement conventional malaria surveillance tools. Further studies, particularly cluster randomised trials, can help establish standardised serological protocols to reliably measure transmission across endemic settings.
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Affiliation(s)
- Lindsey Wu
- Faculty of Infectious Tropical Diseases, Department of Infection Biology, London School of Hygiene and Tropical Medicine (LSHTM), London, WC1E 7HT UK
| | - Julia Mwesigwa
- Medical Research Council Unit The Gambia at London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Muna Affara
- Bernhard Nocht Institute for Tropical Medicine (BNITM), Arusha, Tanzania
| | - Mamadou Bah
- Medical Research Council Unit The Gambia at London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Simon Correa
- Medical Research Council Unit The Gambia at London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Tom Hall
- St. George’s University of London (SGUL), London, SW17 0RE UK
| | - Susheel K. Singh
- Department for Congenital Disorders, Statens Serum Institut, Copenhagen, Denmark
- Centre for Medical Parasitology at Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - James G. Beeson
- Burnet Institute, Melbourne, Victoria 3004 Australia
- Central Clinical School, Monash University, Melbourne, Victoria Australia
- Department of Medicine, University of Melbourne, Melbourne, Victoria Australia
| | - Kevin K. A. Tetteh
- Faculty of Infectious Tropical Diseases, Department of Infection Biology, London School of Hygiene and Tropical Medicine (LSHTM), London, WC1E 7HT UK
| | - Immo Kleinschmidt
- Faculty of Epidemiology and Population Health, Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine (LSHTM), London, WC1E 7HT UK
- School of Pathology, Wits Institute for Malaria Research, Faculty of Health Science, University of Witwatersrand, Johannesburg, South Africa
| | - Umberto D’Alessandro
- Medical Research Council Unit The Gambia at London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Chris Drakeley
- Faculty of Infectious Tropical Diseases, Department of Infection Biology, London School of Hygiene and Tropical Medicine (LSHTM), London, WC1E 7HT UK
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19
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Ondigo BN, Hamre KES, Frosch AEP, Ayodo G, White MT, John CC. Antibody Profiles to P. falciparum Antigens Over Time Characterize Acute and Long-Term Malaria Exposure in an Area of Low and Unstable Transmission. Am J Trop Med Hyg 2020; 103:2189-2197. [PMID: 33124539 DOI: 10.4269/ajtmh.19-0480] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Prevalence and levels of antibodies to multiple Plasmodium falciparum antigens show promise as tools for estimating malaria exposure. In a highland area of Kenya with unstable transmission, we assessed the presence and levels of antibodies to 12 pre-erythrocytic and blood-stage P. falciparum antigens by multiplex cytometric bead assay or ELISA in 604 individuals in August 2007, with follow-up testing in this cohort in April 2008, April 2009, and May 2010. Four hundred individuals were tested at all four time points. During this period, the only substantial malaria incidence occurred from April to August 2009. Antibody prevalence in adults was high at all time points (> 70%) for apical membrane antigen 1, erythrocyte-binding antigen 175, erythrocyte-binding protein-2, glutamate rich protein (GLURP)-R2, merozoite surface protein (MSP) 1 (19), MSP-1 (42), and liver-stage antigen-1; moderate (30-70%) for GLURP-R0, MSP-3, and thrombospondin-related adhesive protein; and low (< 30%) for SE and circumsporozoite protein (CSP). Changes in community-wide malaria exposure were best reflected in decreasing antibody levels overtime for highly immunogenic antigens, and in antibody seroprevalence overtime for the less-immunogenic antigens. Over the 3 years, antibody levels to all antigens except CSP and schizont extract (SE) decreased in an age-dependent manner. Prevalence and levels of antibodies to all antigens except CSP and SE increased with age. Increases in antibody prevalence and levels to CSP and SE coincided with increases in community-wide malaria incidence. Antibody levels to multiple P. falciparum antigens decrease in the absence of consistent transmission. Multiplex assays that assess both the presence and level of antibodies to multiple pre-erythrocytic and blood-stage P. falciparum antigens may provide the most useful estimates of past and recent malaria transmission in areas of unstable transmission and could be useful tools in malaria control and elimination campaigns.
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Affiliation(s)
- Bartholomew N Ondigo
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health (NIH), Bethesda, Maryland.,Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya.,Department of Biochemistry and Molecular Biology, Egerton University, Nakuru, Kenya
| | - Karen E S Hamre
- CDC Foundation, Atlanta, Georgia.,Division of Epidemiology and Community Health, University of Minnesota, Minneapolis, Minnesota.,Division of Global Pediatrics, University of Minnesota, Minneapolis, Minnesota
| | - Anne E P Frosch
- Hennepin Healthcare Research Institute, Minneapolis, Minnesota.,Department of Medicine, University of Minnesota, Minneapolis, Minnesota
| | - George Ayodo
- School of Health Sciences, Jaramogi Oginga Odinga University of Science and Technology, Siaya, Kenya.,Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Michael T White
- Department of Parasites and Insect Vectors, Institut Pasteur, Paris, France
| | - Chandy C John
- Division of Global Pediatrics, University of Minnesota, Minneapolis, Minnesota.,Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya.,Ryan White Center for Pediatric Infectious Diseases and Global Health, Indiana University School of Medicine, Indianapolis, Indiana
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20
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Wu L, Mwesigwa J, Affara M, Bah M, Correa S, Hall T, Singh SK, Beeson JG, Tetteh KKA, Kleinschmidt I, D'Alessandro U, Drakeley C. Antibody responses to a suite of novel serological markers for malaria surveillance demonstrate strong correlation with clinical and parasitological infection across seasons and transmission settings in The Gambia. BMC Med 2020; 18:304. [PMID: 32972398 PMCID: PMC7517687 DOI: 10.1186/s12916-020-01724-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 07/30/2020] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND As malaria transmission declines, sensitive diagnostics are needed to evaluate interventions and monitor transmission. Serological assays measuring malaria antibody responses offer a cost-effective detection method to supplement existing surveillance tools. METHODS A prospective cohort study was conducted from 2013 to 2015 in 12 villages across five administrative regions in The Gambia. Serological analysis included samples from the West Coast Region at the start and end of the season (July and December 2013) and from the Upper River Region in July and December 2013 and April and December 2014. Antigen-specific antibody responses to eight Plasmodium falciparum (P. falciparum) antigens-Etramp5.Ag1, GEXP18, HSP40.Ag1, Rh2.2030, EBA175 RIII-V, PfMSP119, PfAMA1, and PfGLURP.R2-were quantified using a multiplexed bead-based assay. The association between antibody responses and clinical and parasitological endpoints was estimated at the individual, household, and population level. RESULTS Strong associations were observed between clinical malaria and concurrent sero-positivity to Etramp5.Ag1 (aOR 4.60 95% CI 2.98-7.12), PfMSP119 (aOR 4.09 95% CI 2.60-6.44), PfAMA1 (aOR 2.32 95% CI 1.40-3.85), and PfGLURP.R2 (aOR 3.12, 95% CI 2.92-4.95), while asymptomatic infection was associated with sero-positivity to all antigens. Village-level sero-prevalence amongst children 2-10 years against Etramp5.Ag1, HSP40.Ag1, and PfMSP119 showed the highest correlations with clinical and P. falciparum infection incidence rates. For all antigens, there were increased odds of asymptomatic P. falciparum infection in subjects residing in a compound with greater than 50% sero-prevalence, with a 2- to 3-fold increase in odds of infection associated with Etramp5.Ag1, GEXP18, Rh2.2030, PfMSP119, and PfAMA1. For individuals residing in sero-positive compounds, the odds of clinical malaria were reduced, suggesting a protective effect. CONCLUSIONS At low transmission, long-lived antibody responses could indicate foci of malaria transmission that have been ongoing for several seasons or years. In settings where sub-patent infections are prevalent and fluctuate below the detection limit of polymerase chain reaction (PCR), the presence of short-lived antibodies may indicate recent infectivity, particularly in the dry season when clinical cases are rare. Serological responses may reflect a persistent reservoir of infection, warranting community-targeted interventions if individuals are not clinically apparent but have the potential to transmit. Therefore, serological surveillance at the individual and household level may be used to target interventions where there are foci of asymptomatically infected individuals, such as by measuring the magnitude of age-stratified antibody levels or identifying areas with clustering of above-average antibody responses across a diverse range of serological markers.
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Affiliation(s)
- Lindsey Wu
- Faculty of Infectious Tropical Diseases, Department of Infection Biology, London School of Hygiene and Tropical Medicine (LSHTM), London, WC1E 7HT, UK.
| | - Julia Mwesigwa
- Medical Research Council Unit The Gambia at London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Muna Affara
- Bernhard Nocht Institute for Tropical Medicine (BNITM), Arusha, Tanzania
| | - Mamadou Bah
- Medical Research Council Unit The Gambia at London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Simon Correa
- Medical Research Council Unit The Gambia at London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Tom Hall
- St. George's University of London (SGUL), London, UK
| | - Susheel K Singh
- Department for Congenital Disorders, Statens Serum Institut, Copenhagen, Denmark.,Centre for Medical Parasitology at Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - James G Beeson
- Burnet Institute, Melbourne, Australia.,Central Clinical School, Monash University, Melbourne, Victoria, Australia.,Department of Medicine, University of Melbourne, Melbourne, Victoria, Australia
| | - Kevin K A Tetteh
- Faculty of Infectious Tropical Diseases, Department of Infection Biology, London School of Hygiene and Tropical Medicine (LSHTM), London, WC1E 7HT, UK
| | - Immo Kleinschmidt
- Faculty of Epidemiology and Population Health, Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine (LSHTM), London, WC1E 7HT, UK.,School of Pathology, Wits Institute for Malaria Research, Faculty of Health Science, University of Witwatersrand, Johannesburg, South Africa
| | - Umberto D'Alessandro
- Medical Research Council Unit The Gambia at London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Chris Drakeley
- Faculty of Infectious Tropical Diseases, Department of Infection Biology, London School of Hygiene and Tropical Medicine (LSHTM), London, WC1E 7HT, UK
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21
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Buezo Montero S, Gabrieli P, Montarsi F, Borean A, Capelli S, De Silvestro G, Forneris F, Pombi M, Breda A, Capelli G, Arcà B. IgG Antibody Responses to the Aedes albopictus 34k2 Salivary Protein as Novel Candidate Marker of Human Exposure to the Tiger Mosquito. Front Cell Infect Microbiol 2020; 10:377. [PMID: 32850479 PMCID: PMC7405501 DOI: 10.3389/fcimb.2020.00377] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Accepted: 06/18/2020] [Indexed: 01/01/2023] Open
Abstract
Mosquitoes of the Aedes genus transmit arboviruses of great importance to human health as dengue, chikungunya, Zika and yellow fever. The tiger mosquito Aedes albopictus can play an important role as arboviral vector, especially when Aedes aegypti is absent or present at low levels. Remarkably, the rapid worldwide spreading of the tiger mosquito is expanding the risk of arboviral transmission also to temperate areas, and the autochthonous cases of chikungunya, dengue and Zika in Europe emphasize the need for improved monitoring and control. Proteomic and transcriptomic studies on blood feeding arthropod salivary proteins paved the way toward the exploitation of genus-specific mosquito salivary proteins for the development of novel tools to evaluate human exposure to mosquito bites. We previously found that the culicine-specific 34k2 salivary protein from Ae. albopictus (al34k2) evokes specific IgG responses in experimentally exposed mice, and provided preliminary evidence of its immunogenicity to humans. In this study we measured IgG responses to al34k2 and to Ae. albopictus salivary gland protein extracts (SGE) in individuals naturally exposed to the tiger mosquito. Sera were collected in two areas of Northeast Italy (Padova and Belluno) during two different time periods: at the end of the low- and shortly after the high-density mosquito seasons. Anti-SGE and anti-al34k2 IgG levels increased after the summer period of exposure to mosquito bites and were higher in Padova as compared to Belluno. An age-dependent decrease of anti-saliva IgG responses was found especially in Padova, an area with at least 25 years history of Ae. albopictus colonization. Moreover, a weak correlation between anti-saliva IgG levels and individual perception of mosquito bites by study participants was found. Finally, determination of anti-al34k2 IgG1 and IgG4 levels indicated a large predominance of IgG1 antibodies. Overall, this study provides a convincing indication that antibody responses to al34k2 may be regarded as a reliable candidate marker to detect temporal and/or spatial variation of human exposure to Ae. albopictus; a serological tool of this kind may prove useful both for epidemiological studies and to estimate the effectiveness of anti-vectorial measures.
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Affiliation(s)
- Sara Buezo Montero
- Division of Parasitology, Department of Public Health and Infectious Diseases, Sapienza University of Rome, Rome, Italy
| | - Paolo Gabrieli
- Department of Biology and Biotechnology "L. Spallanzani", University of Pavia, Pavia, Italy
| | - Fabrizio Montarsi
- Laboratory of Parasitology, Istituto Zooprofilattico Sperimentale delle Venezie, Legnaro, Italy
| | - Alessio Borean
- Department of Immunohematology and Transfusion Medicine, San Martino Hospital, Belluno, Italy
| | - Stefano Capelli
- Department of Immunohematology and Transfusion Medicine, San Martino Hospital, Belluno, Italy
| | | | - Federico Forneris
- Department of Biology and Biotechnology "L. Spallanzani", University of Pavia, Pavia, Italy
| | - Marco Pombi
- Division of Parasitology, Department of Public Health and Infectious Diseases, Sapienza University of Rome, Rome, Italy
| | - Antonio Breda
- Coordinamento Regionale Attività Trasfusionali (CRAT), Padova, Italy
| | - Gioia Capelli
- Laboratory of Parasitology, Istituto Zooprofilattico Sperimentale delle Venezie, Legnaro, Italy
| | - Bruno Arcà
- Division of Parasitology, Department of Public Health and Infectious Diseases, Sapienza University of Rome, Rome, Italy
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22
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Imported Malaria in Countries where Malaria Is Not Endemic: a Comparison of Semi-immune and Nonimmune Travelers. Clin Microbiol Rev 2020; 33:33/2/e00104-19. [PMID: 32161068 DOI: 10.1128/cmr.00104-19] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The continuous increase in long-distance travel and recent large migratory movements have changed the epidemiological characteristics of imported malaria in countries where malaria is not endemic (here termed non-malaria-endemic countries). While malaria was primarily imported to nonendemic countries by returning travelers, the proportion of immigrants from malaria-endemic regions and travelers visiting friends and relatives (VFRs) in malaria-endemic countries has continued to increase. VFRs and immigrants from malaria-endemic countries now make up the majority of malaria patients in many nonendemic countries. Importantly, this group is characterized by various degrees of semi-immunity to malaria, resulting from repeated exposure to infection and a gradual decline of protection as a result of prolonged residence in non-malaria-endemic regions. Most studies indicate an effect of naturally acquired immunity in VFRs, leading to differences in the parasitological features, clinical manifestation, and odds for severe malaria and clinical complications between immune VFRs and nonimmune returning travelers. There are no valid data indicating evidence for differing algorithms for chemoprophylaxis or antimalarial treatment in semi-immune versus nonimmune malaria patients. So far, no robust biomarkers exist that properly reflect anti-parasite or clinical immunity. Until they are found, researchers should rigorously stratify their study results using surrogate markers, such as duration of time spent outside a malaria-endemic country.
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23
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Odhiambo G, Bergmann-Leitner E, Maraka M, Wanjala CNL, Duncan E, Waitumbi J, Andagalu B, Jura WGZO, Dutta S, Angov E, Ogutu BR, Kamau E, Ochiel D. Correlation Between Malaria-Specific Antibody Profiles and Responses to Artemisinin Combination Therapy for Treatment of Uncomplicated Malaria in Western Kenya. J Infect Dis 2020; 219:1969-1979. [PMID: 30649381 DOI: 10.1093/infdis/jiz027] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Accepted: 01/11/2019] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND The impact of preexisting immunity on the efficacy of artemisinin combination therapy must be examined to monitor resistance, and for implementation of new treatment strategies. METHODS Serum samples obtained from a clinical trial in Western Kenya randomized to receive artemether-lumefantrine (AL) or artesunate-mefloquine (ASMQ) were screened for total immunoglobulin G against preerythrocytic and erythrocytic antigens. The association and correlation between different variables, and impact of preexisting immunity on parasite slope half-life (t½) was determined. RESULTS There was no significant difference in t½, but the number of individuals with lag phase was significantly higher in the AL than in the ASMQ arm (29 vs 13, respectively; P < .01). Circumsporozoite protein-specific antibodies correlate positively with t½ (AL, P = .03; ASMQ, P = .09), but negatively with clearance rate in both study arms (AL, P = .16; ASMQ, P = .02). The t½ correlated negatively with age in ASMQ group. When stratified based on t½, the antibody titers against circumsporozoite protein and merozoite surface protein 1 were significantly higher in participants who cleared parasites rapidly in the AL group (P = .01 and P = .02, respectively). CONCLUSION Data presented here define immunoprofiles associated with distinct responses to 2 different antimalarial drugs, revealing impact of preexisting immunity on the efficacy of artemisinin combination therapy regimens in a malaria-holoendemic area. CLINICAL TRIALS REGISTRATION NCT01976780.
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Affiliation(s)
- Geoffrey Odhiambo
- Department of Emerging and Infectious Diseases, United States Army Medical Research Directorate-Africa, Kenya Medical Research Institute/Walter Reed Project , Kisumu.,Maseno University School of Physical and Biological Sciences Zoology Department, Maseno, Kenya
| | - Elke Bergmann-Leitner
- Malaria Vaccine Branch, Walter Reed Army Institute of Research, Silver Spring, Maryland
| | - Moureen Maraka
- Department of Emerging and Infectious Diseases, United States Army Medical Research Directorate-Africa, Kenya Medical Research Institute/Walter Reed Project , Kisumu
| | - Christine N L Wanjala
- Department of Emerging and Infectious Diseases, United States Army Medical Research Directorate-Africa, Kenya Medical Research Institute/Walter Reed Project , Kisumu.,Maseno University School of Physical and Biological Sciences Zoology Department, Maseno, Kenya
| | - Elizabeth Duncan
- Malaria Vaccine Branch, Walter Reed Army Institute of Research, Silver Spring, Maryland
| | - John Waitumbi
- Department of Emerging and Infectious Diseases, United States Army Medical Research Directorate-Africa, Kenya Medical Research Institute/Walter Reed Project , Kisumu
| | - Ben Andagalu
- Department of Emerging and Infectious Diseases, United States Army Medical Research Directorate-Africa, Kenya Medical Research Institute/Walter Reed Project , Kisumu
| | - Walter G Z O Jura
- Maseno University School of Physical and Biological Sciences Zoology Department, Maseno, Kenya
| | - Sheetij Dutta
- Malaria Vaccine Branch, Walter Reed Army Institute of Research, Silver Spring, Maryland
| | - Evelina Angov
- Malaria Vaccine Branch, Walter Reed Army Institute of Research, Silver Spring, Maryland
| | - Bernhards R Ogutu
- Department of Emerging and Infectious Diseases, United States Army Medical Research Directorate-Africa, Kenya Medical Research Institute/Walter Reed Project , Kisumu.,Kenya Medical Research Institute, Nairobi
| | - Edwin Kamau
- Department of Emerging and Infectious Diseases, United States Army Medical Research Directorate-Africa, Kenya Medical Research Institute/Walter Reed Project , Kisumu.,Malaria Vaccine Branch, Walter Reed Army Institute of Research, Silver Spring, Maryland
| | - Daniel Ochiel
- Department of Emerging and Infectious Diseases, United States Army Medical Research Directorate-Africa, Kenya Medical Research Institute/Walter Reed Project , Kisumu.,Maseno University School of Physical and Biological Sciences Zoology Department, Maseno, Kenya
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24
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Müller-Sienerth N, Shilts J, Kadir KA, Yman V, Homann MV, Asghar M, Ngasala B, Singh B, Färnert A, Wright GJ. A panel of recombinant proteins from human-infective Plasmodium species for serological surveillance. Malar J 2020; 19:31. [PMID: 31952523 PMCID: PMC6969409 DOI: 10.1186/s12936-020-3111-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Accepted: 01/08/2020] [Indexed: 12/20/2022] Open
Abstract
Background Malaria remains a global health problem and accurate surveillance of Plasmodium parasites that are responsible for this disease is required to guide the most effective distribution of control measures. Serological surveillance will be particularly important in areas of low or periodic transmission because patient antibody responses can provide a measure of historical exposure. While methods for detecting host antibody responses to Plasmodium falciparum and Plasmodium vivax are well established, development of serological assays for Plasmodium knowlesi, Plasmodium ovale and Plasmodium malariae have been inhibited by a lack of immunodiagnostic candidates due to the limited availability of genomic information. Methods Using the recently completed genome sequences from P. malariae, P. ovale and P. knowlesi, a set of 33 candidate cell surface and secreted blood-stage antigens was selected and expressed in a recombinant form using a mammalian expression system. These proteins were added to an existing panel of antigens from P. falciparum and P. vivax and the immunoreactivity of IgG, IgM and IgA immunoglobulins from individuals diagnosed with infections to each of the five different Plasmodium species was evaluated by ELISA. Logistic regression modelling was used to quantify the ability of the responses to determine prior exposure to the different Plasmodium species. Results Using sera from European travellers with diagnosed Plasmodium infections, antigens showing species-specific immunoreactivity were identified to select a panel of 22 proteins from five Plasmodium species for serological profiling. The immunoreactivity to the antigens in the panel of sera taken from travellers and individuals living in malaria-endemic regions with diagnosed infections showed moderate power to predict infections by each species, including P. ovale, P. malariae and P. knowlesi. Using a larger set of patient samples and logistic regression modelling it was shown that exposure to P. knowlesi could be accurately detected (AUC = 91%) using an antigen panel consisting of the P. knowlesi orthologues of MSP10, P12 and P38. Conclusions Using the recent availability of genome sequences to all human-infective Plasmodium spp. parasites and a method of expressing Plasmodium proteins in a secreted functional form, an antigen panel has been compiled that will be useful to determine exposure to these parasites.
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Affiliation(s)
| | - Jarrod Shilts
- Cell Surface Signalling Laboratory, Wellcome Sanger Institute, Cambridge, UK
| | - Khamisah Abdul Kadir
- Malaria Research Centre, Universiti Malaysia Sarawak, Kota Samarahan, Sarawak, Malaysia
| | - Victor Yman
- Division of Infectious Diseases, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden
| | - Manijeh Vafa Homann
- Division of Infectious Diseases, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden
| | - Muhammad Asghar
- Division of Infectious Diseases, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden
| | - Billy Ngasala
- Department of Parasitology and Medical Entomology, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania.,Department of Women's and Children's Health, International Maternal and Child Health (IMCH), Uppsala University, Uppsala, Sweden
| | - Balbir Singh
- Malaria Research Centre, Universiti Malaysia Sarawak, Kota Samarahan, Sarawak, Malaysia
| | - Anna Färnert
- Division of Infectious Diseases, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden.,Department of Infectious Diseases, Karolinska University Hospital, Stockholm, Sweden
| | - Gavin J Wright
- Cell Surface Signalling Laboratory, Wellcome Sanger Institute, Cambridge, UK.
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25
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Greenhouse B, Smith DL, Rodríguez-Barraquer I, Mueller I, Drakeley CJ. Taking Sharper Pictures of Malaria with CAMERAs: Combined Antibodies to Measure Exposure Recency Assays. Am J Trop Med Hyg 2019; 99:1120-1127. [PMID: 30298804 PMCID: PMC6221205 DOI: 10.4269/ajtmh.18-0303] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Antibodies directed against malaria parasites are easy and inexpensive to measure but remain an underused surveillance tool because of a lack of consensus on what to measure and how to interpret results. High-throughput screening of antibodies from well-characterized cohorts offers a means to substantially improve existing assays by rationally choosing the most informative sets of responses and analytical methods. Recent data suggest that high-resolution information on malaria exposure can be obtained from a small number of samples by measuring a handful of properly chosen antibody responses. In this review, we discuss how standardized multi-antibody assays can be developed and efficiently integrated into existing surveillance activities, with potential to greatly augment the breadth and quality of information available to direct and monitor malaria control and elimination efforts.
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Affiliation(s)
- Bryan Greenhouse
- Department of Medicine, University of California, San Francisco, San Francisco, California.,Chan Zuckerberg Biohub, San Francisco, California
| | - David L Smith
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, Washington
| | | | - Ivo Mueller
- Institute Pasteur, Paris, France.,Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
| | - Chris J Drakeley
- London School of Hygiene & Tropical Medicine, London, United Kingdom
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26
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Antigenicity and immune correlate assessment of seven Plasmodium falciparum antigens in a longitudinal infant cohort from northern Ghana. Sci Rep 2019; 9:8621. [PMID: 31197225 PMCID: PMC6565625 DOI: 10.1038/s41598-019-45092-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Accepted: 05/30/2019] [Indexed: 11/23/2022] Open
Abstract
The current global malaria control and elimination agenda requires development of additional effective disease intervention tools. Discovery and characterization of relevant parasite antigens is important for the development of new diagnostics and transmission monitoring tools and for subunit vaccine development. This study assessed the natural antibody response profile of seven novel Plasmodium falciparum pre-erythrocytic antigens and their potential association with protection against clinical malaria. Antigen-specific antibody levels in plasma collected at six time points from a longitudinal cohort of one-to-five year old children resident in a seasonal malaria transmission area of northern Ghana were assessed by ELISA. Antibody levels were compared between parasite-positive and parasite-negative individuals and the association of antibody levels with malaria risk assessed using a regression model. Plasma antibody levels against five of the seven antigens were significantly higher in parasite-positive children compared to parasite-negative children, especially during low transmission periods. None of the antigen-specific antibodies showed an association with protection against clinical malaria. The study identified five of the seven antigens as markers of exposure to malaria, and these will have relevance for the development of disease diagnostic and monitoring tools. The vaccine potential of these antigens requires further assessment.
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27
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Yman V, Wandell G, Mutemi DD, Miglar A, Asghar M, Hammar U, Karlsson M, Lind I, Nordfjell C, Rooth I, Ngasala B, Homann MV, Färnert A. Persistent transmission of Plasmodium malariae and Plasmodium ovale species in an area of declining Plasmodium falciparum transmission in eastern Tanzania. PLoS Negl Trop Dis 2019; 13:e0007414. [PMID: 31136585 PMCID: PMC6555537 DOI: 10.1371/journal.pntd.0007414] [Citation(s) in RCA: 82] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Revised: 06/07/2019] [Accepted: 04/26/2019] [Indexed: 11/18/2022] Open
Abstract
A reduction in the global burden of malaria over the past two decades has encouraged efforts for regional malaria elimination. Despite the need to target all Plasmodium species, current focus is mainly directed towards Plasmodium falciparum, and to a lesser extent P. vivax. There is a substantial lack of data on both global and local transmission patterns of the neglected malaria parasites P. malariae and P. ovale spp. We used a species-specific real-time PCR assay targeting the Plasmodium 18s rRNA gene to evaluate temporal trends in the prevalence of all human malaria parasites over a 22-year period in a rural village in Tanzania.We tested 2897 blood samples collected in five cross-sectional surveys conducted between 1994 and 2016. Infections with P. falciparum, P. malariae, and P. ovale spp. were detected throughout the study period, while P. vivax was not detected. Between 1994 and 2010, we found a more than 90% reduction in the odds of infection with all detected species. The odds of P. falciparum infection was further reduced in 2016, while the odds of P. malariae and P. ovale spp. infection increased 2- and 6-fold, respectively, compared to 2010. In 2016, non-falciparum species occurred more often as mono-infections. The results demonstrate the persistent transmission of P. ovale spp., and to a lesser extent P. malariae despite a continued decline in P. falciparum transmission. This illustrates that the transmission patterns of the non-falciparum species do not necessarily follow those of P. falciparum, stressing the need for attention towards non-falciparum malaria in Africa. Malaria elimination will require a better understanding of the epidemiology of P. malariae and P. ovale spp. and improved tools for monitoring the transmission of all Plasmodium species, with a particular focus towards identifying asymptomatic carriers of infection and designing appropriate interventions to enhance malaria control. The reduction in the global burden of malaria has encouraged efforts for elimination. Attempts to control and monitor transmission have mainly focused on the predominant malaria parasites Plasmodium falciparum and P. vivax. However, eliminating malaria requires the elimination of all human malaria parasites and limited interest has been directed towards estimating the disease burden attributable to the neglected malaria parasites P. ovale spp. and P. malariae. The authors used molecular methods to analyse 2897 blood samples collected in five cross-sectional surveys over a period of 22 years, and described the transmission patterns of all human malaria parasites in a Tanzanian village. They demonstrate a persistent transmission of P. malariae and P. ovale spp. despite a substantial reduction in transmission of P. falciparum, highlighting the need for more attention towards non-falciparum malaria. The authors discuss the implications of these findings in the context of current efforts for regional malaria elimination.
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Affiliation(s)
- Victor Yman
- Division of Infectious Diseases, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden
| | - Grace Wandell
- Division of Infectious Diseases, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden.,Department of Otolaryngology, University of Washington Medical Center, Seattle, Washington, United States of America
| | - Doreen D Mutemi
- Division of Infectious Diseases, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden.,Department of Parasitology and Medical Entomology, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania
| | - Aurelie Miglar
- Division of Infectious Diseases, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden
| | - Muhammad Asghar
- Division of Infectious Diseases, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden
| | - Ulf Hammar
- Unit of Biostatistics, Department of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Mattias Karlsson
- Division of Infectious Diseases, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden
| | - Ingrid Lind
- Division of Infectious Diseases, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden
| | - Cleis Nordfjell
- Division of Infectious Diseases, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden
| | - Ingegerd Rooth
- Division of Infectious Diseases, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden
| | - Billy Ngasala
- Department of Parasitology and Medical Entomology, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania.,Department of Women's and Children's Health, International Maternal and Child Health (IMCH), Uppsala University, Uppsala, Sweden
| | - Manijeh Vafa Homann
- Division of Infectious Diseases, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden
| | - Anna Färnert
- Division of Infectious Diseases, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden.,Department of Infectious Diseases, Karolinska University Hospital, Stockholm, Sweden
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28
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Yman V, White MT, Asghar M, Sundling C, Sondén K, Draper SJ, Osier FHA, Färnert A. Antibody responses to merozoite antigens after natural Plasmodium falciparum infection: kinetics and longevity in absence of re-exposure. BMC Med 2019; 17:22. [PMID: 30696449 PMCID: PMC6352425 DOI: 10.1186/s12916-019-1255-3] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Accepted: 01/08/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Antibodies against merozoite antigens are key components of malaria immunity. The naturally acquired antibody response to these antigens is generally considered short-lived; however, the underlying mechanisms remain unclear. Prospective studies of travellers with different levels of prior exposure, returning to malaria-free countries with Plasmodium infection, offer a unique opportunity to investigate the kinetics and composition of the antibody response after natural infection. METHODS Adults diagnosed with P. falciparum malaria in Stockholm, Sweden (20 likely malaria naïve and 41 with repeated previous exposure during residency in sub-Saharan Africa) were sampled at diagnosis and 10 days and 1, 3, 6, and 12 months after treatment. Total and subclass-specific IgG responses to P. falciparum merozoite antigens (AMA-1, MSP-119, MSP-2, MSP-3, and RH5) and tetanus toxoid were measured by multiplex bead-based immunoassays and ELISA. Mathematical modelling was used to estimate the exposure-dependent longevity of antibodies and antibody-secreting cells (ASCs). RESULTS A majority of individuals mounted detectable antibody responses towards P. falciparum merozoite antigens at diagnosis; however, the magnitude and breadth were greater in individuals with prior exposure. In both exposure groups, antibody levels increased rapidly for 2 weeks and decayed thereafter. Previously exposed individuals maintained two- to ninefold greater antibody levels throughout the 1-year follow-up. The half-lives of malaria-specific long-lived ASCs, responsible for maintaining circulating antibodies, ranged from 1.8 to 3.7 years for merozoite antigens and were considerably short compared to tetanus-specific ASCs. Primary infected individuals did acquire a long-lived component of the antibody response; however, the total proportion of long-lived ASCs generated in response to infection was estimated not to exceed 10%. In contrast, previously exposed individuals maintained substantially larger numbers of long-lived ASCs (10-56% of total ASCs). CONCLUSION The short-lived nature of the naturally acquired antibody response, to all tested merozoite antigens, following primary malaria infection can be attributed to a combination of a poor acquisition and short half-life of long-lived ASCs. Greater longevity is acquired with repeated infections and can be explained by the maintenance of larger numbers of long-lived ASCs. These insights advance our understanding of naturally acquired malaria immunity and will guide strategies for further development of both vaccines and serological tools to monitor exposure.
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Affiliation(s)
- Victor Yman
- Division of Infectious Diseases, Department of Medicine Solna, Karolinska Institutet, Karolinska University Hospital, 171 76, Stockholm, Sweden.
| | - Michael T White
- Department of Parasites and Insect Vectors, Institut Pasteur, 25-28 Rue du Dr Roux, 75015, Paris, France
| | - Muhammad Asghar
- Division of Infectious Diseases, Department of Medicine Solna, Karolinska Institutet, Karolinska University Hospital, 171 76, Stockholm, Sweden
| | - Christopher Sundling
- Division of Infectious Diseases, Department of Medicine Solna, Karolinska Institutet, Karolinska University Hospital, 171 76, Stockholm, Sweden
| | - Klara Sondén
- Division of Infectious Diseases, Department of Medicine Solna, Karolinska Institutet, Karolinska University Hospital, 171 76, Stockholm, Sweden
- Department of Infectious Diseases, Karolinska University Hospital, 171 76, Stockholm, Sweden
| | - Simon J Draper
- Jenner Institute, University of Oxford, Oxford, OX3 7DQ, UK
| | - Faith H A Osier
- Kenya Medical Research Institute - Wellcome Trust Research Program, Centre for Geographic Medicine Research-Coast, PO Box 230-80108, Kilifi, Kenya
- Centre for Infectious Diseases, Parasitology, Heidelberg University Hospital, Im Neuenheimer Feld 324, 69120, Heidelberg, Germany
| | - Anna Färnert
- Division of Infectious Diseases, Department of Medicine Solna, Karolinska Institutet, Karolinska University Hospital, 171 76, Stockholm, Sweden
- Department of Infectious Diseases, Karolinska University Hospital, 171 76, Stockholm, Sweden
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29
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Pinsent A, Solomon AW, Bailey RL, Bid R, Cama A, Dean D, Goodhew B, Gwyn SE, Jack KR, Kandel RP, Kama M, Massae P, Macleod C, Mabey DCW, Migchelsen S, Müller A, Sandi F, Sokana O, Taoaba R, Tekeraoi R, Martin DL, White MT. The utility of serology for elimination surveillance of trachoma. Nat Commun 2018; 9:5444. [PMID: 30575720 PMCID: PMC6303365 DOI: 10.1038/s41467-018-07852-0] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Accepted: 11/27/2018] [Indexed: 11/24/2022] Open
Abstract
Robust surveillance methods are needed for trachoma control and recrudescence monitoring, but existing methods have limitations. Here, we analyse data from nine trachoma-endemic populations and provide operational thresholds for interpretation of serological data in low-transmission and post-elimination settings. Analyses with sero-catalytic and antibody acquisition models provide insights into transmission history within each population. To accurately estimate sero-conversion rates (SCR) for trachoma in populations with high-seroprevalence in adults, the model accounts for secondary exposure to Chlamydia trachomatis due to urogenital infection. We estimate the population half-life of sero-reversion for anti-Pgp3 antibodies to be 26 (95% credible interval (CrI): 21–34) years. We show SCRs below 0.015 (95% confidence interval (CI): 0.0–0.049) per year correspond to a prevalence of trachomatous inflammation—follicular below 5%, the current threshold for elimination of active trachoma as a public health problem. As global trachoma prevalence declines, we may need cross-sectional serological survey data to inform programmatic decisions. Robust surveillance methods are needed for trachoma control and recrudescence monitoring, but existing methods have limitations. Here, Pinsent et al. analyse data from nine trachoma-endemic populations and provide operational thresholds for interpretation of serological data in low transmission and post-elimination settings.
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Affiliation(s)
- Amy Pinsent
- Department of Public Health and Preventative Medicine, Monash University, Melbourne, VIC, 3004, Australia. .,Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, WC1E 7HT, UK.
| | - Anthony W Solomon
- Department of Control of Neglected Tropical Diseases, World Health Organization, 1211, Geneva 27, Switzerland.,Clinical Research Department, London School of Hygiene & Tropical Medicine, London, WC1E 7HT, UK
| | - Robin L Bailey
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, WC1E 7HT, UK
| | - Rhiannon Bid
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, WC1E 7HT, UK
| | - Anaseini Cama
- International Agency for the Prevention of Blindness, Western Pacific Region, Suva, Fiji.,The Fred Hollows Foundation, Level 2, 61 Dunning Ave, Rosebury, NSW, 2018, Australia
| | - Deborah Dean
- UCSF Benioff Children's Hospital Oakland Research Institute, 5700 Martin Luther King Jr Way, Oakland, CA, 94609, USA
| | - Brook Goodhew
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, GA, 30333, USA
| | - Sarah E Gwyn
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, GA, 30333, USA
| | - Kelvin R Jack
- Eyecare Department, Ministry of Health, Honiara, Solomon Islands
| | | | - Mike Kama
- Department of Communicable Diseases, Ministry of Health, Suva, Fiji
| | - Patrick Massae
- Department of Ophthalmology, Kilimanjaro Christian Medical Centre, Moshi, Tanzania
| | - Colin Macleod
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, WC1E 7HT, UK.,Sightsavers, 35 Perrymount Road, Haywards Heath, RH16 6NG, UK
| | - David C W Mabey
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, WC1E 7HT, UK
| | - Stephanie Migchelsen
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, WC1E 7HT, UK
| | - Andreas Müller
- Centre for Eye Research Australia, Level 7/32 Gisborne St, East Melbourne, VIC, 3002, Australia
| | - Frank Sandi
- Department of Ophthalmology, Kilimanjaro Christian Medical Centre, Moshi, Tanzania.,The University of Dodoma, Dodoma, Tanzania
| | - Oliver Sokana
- Eyecare Department, Ministry of Health, Honiara, Solomon Islands
| | - Raebwebwe Taoaba
- Eye Department, Ministry of Health and Medical Services, South Tarawa, Kiribati
| | - Rabebe Tekeraoi
- Eye Department, Ministry of Health and Medical Services, South Tarawa, Kiribati
| | - Diana L Martin
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, GA, 30333, USA
| | - Michael T White
- Malaria: Parasites & Hosts, Department of Parasites and Insect Vectors, Institut Pasteur, 25-28 Rue du Dr Roux, 75015, Paris, France
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30
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Pires CV, Alves JRS, Lima BAS, Paula RB, Costa HL, Torres LM, Sousa TN, Soares IS, Sanchez BAM, Fontes CJF, Ntumngia FB, Adams JH, Kano FS, Carvalho LH. Blood-stage Plasmodium vivax antibody dynamics in a low transmission setting: A nine year follow-up study in the Amazon region. PLoS One 2018; 13:e0207244. [PMID: 30419071 PMCID: PMC6231651 DOI: 10.1371/journal.pone.0207244] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Accepted: 10/26/2018] [Indexed: 11/23/2022] Open
Abstract
Plasmodium vivax remains a global health problem and its ability to cause relapses and subpatent infections challenge control and elimination strategies. Even in low malaria transmission settings, such as the Amazon basin, where progress in malaria control has caused a remarkable reduction in case incidence, a recent increase in P. vivax transmission demonstrates the continued vulnerability of P.vivax-exposed populations. As part of a search for complementary approaches to P.vivax surveillance in areas in which adults are the majority of the exposed-population, here we evaluated the potential of serological markers covering a wide range of immunogenicity to estimate malaria transmission trends. For this, antibodies against leading P. vivax blood-stage vaccine candidates were assessed during a 9 year follow-up study among adults exposed to unstable malaria transmission in the Amazon rainforest. Circulating antibody levels against immunogenic P. vivax proteins, such as the Apical Membrane Antigen-1, were a sensitive measure of recent P. vivax exposure, while antibodies against less immunogenic proteins were indicative of naturally-acquired immunity, including the novel engineered Duffy binding protein II immunogen (DEKnull-2). Our results suggest that the robustness of serology to estimate trends in P.vivax malaria transmission will depend on the immunological background of the study population, and that for adult populations exposed to unstable P.vivax malaria transmission, the local heterogeneity of antibody responses should be considered when considering use of serological surveillance.
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Affiliation(s)
- Camilla V. Pires
- Instituto René Rachou/FIOCRUZ, Belo Horizonte, Minas Gerais, Brazil
| | | | | | - Ruth B. Paula
- Instituto René Rachou/FIOCRUZ, Belo Horizonte, Minas Gerais, Brazil
| | - Helena L. Costa
- Instituto René Rachou/FIOCRUZ, Belo Horizonte, Minas Gerais, Brazil
| | | | - Taís N. Sousa
- Instituto René Rachou/FIOCRUZ, Belo Horizonte, Minas Gerais, Brazil
| | - Irene S. Soares
- Departamento de Análises Clínicas e Toxicológicas, Faculdade de Ciências Farmacêuticas, Universidade de São Paulo, São Paulo, SP, Brazil
| | - Bruno A. M. Sanchez
- Instituto de Ciências da Saúde, Universidade Federal de Mato Grosso, Campus Sinop, Sinop, Mato Grosso, Brazil
| | - Cor J. F. Fontes
- Hospital Júlio Muller, Universidade Federal de Mato Grosso, Cuiabá, Mato Grosso, Brazil
| | - Francis B. Ntumngia
- Center for Global Health and Infectious Diseases Research, Department of Global Health, College of Public Health, University of South Florida, Tampa, Florida, United States of America
| | - John H. Adams
- Center for Global Health and Infectious Diseases Research, Department of Global Health, College of Public Health, University of South Florida, Tampa, Florida, United States of America
| | - Flora S. Kano
- Instituto René Rachou/FIOCRUZ, Belo Horizonte, Minas Gerais, Brazil
- * E-mail: (LHC); (FSK)
| | - Luzia H. Carvalho
- Instituto René Rachou/FIOCRUZ, Belo Horizonte, Minas Gerais, Brazil
- * E-mail: (LHC); (FSK)
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31
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Weber GE, White MT, Babakhanyan A, Sumba PO, Vulule J, Ely D, John C, Angov E, Lanar D, Dutta S, Narum DL, Horii T, Cowman A, Beeson J, Smith J, Kazura JW, Dent AE. Sero-catalytic and Antibody Acquisition Models to Estimate Differing Malaria Transmission Intensities in Western Kenya. Sci Rep 2017; 7:16821. [PMID: 29203846 PMCID: PMC5715086 DOI: 10.1038/s41598-017-17084-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Accepted: 11/21/2017] [Indexed: 12/19/2022] Open
Abstract
We sought to identify a subset of Plasmodium falciparum antibody targets that would inform monitoring efforts needed to eliminate malaria in high transmission settings. IgG antibodies to 28 recombinant Pf antigens were measured in residents of two communities in western Kenya examined in 2003 and 2013, when the respective prevalence of asymptomatic parasitemia among children was 81 and 15 percent by microscopy. Annual seroconversion rates based on a sero-catalytic model that dichotomised antibody values to negative versus positive showed that rates were higher in 2003 than 2013 for 1 pre-erythrocytic and 7 blood-stage antigens. Antibody acquisition models that considered antibody levels as continuous variables showed that age-related antibody levels to Circumsporozoite Protein and 10 merozoite proteins increased at different rates with age in 2003 versus 2013. Both models found that antibodies to 5 proteins of the Merozoite Surface Protein 1 complex were differentially acquired between the cohorts, and that changes in antibody levels to Apical Membrane Antigen 1 suggested a decrease in transmission that occurred ~10 years before 2013. Further studies evaluating antibodies to this subset of Pf antigens as biomarkers of malaria exposure and naturally acquired immunity are warranted in endemic settings where transmission has been reduced but persists.
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Affiliation(s)
- Grace E Weber
- Center for Global Health and Diseases, Case Western Reserve University, Cleveland, OH, USA.,Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | | | - Anna Babakhanyan
- Center for Global Health and Diseases, Case Western Reserve University, Cleveland, OH, USA
| | | | - John Vulule
- Kenya Medical Research Institute, Kisumu, Kenya
| | - Dylan Ely
- Center for Global Health and Diseases, Case Western Reserve University, Cleveland, OH, USA
| | - Chandy John
- Department of Pediatrics, Riley Hospital, Indiana University, Indianapolis, IN, USA
| | - Evelina Angov
- Malaria Vaccine Branch, Walter Reed Army Institute of Research, Silver Spring, MD, USA
| | - David Lanar
- Malaria Vaccine Branch, Walter Reed Army Institute of Research, Silver Spring, MD, USA
| | - Sheetij Dutta
- Malaria Vaccine Branch, Walter Reed Army Institute of Research, Silver Spring, MD, USA
| | - David L Narum
- Laboratory of Malaria Immunology and Vaccinology, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
| | - Toshihiro Horii
- Department of Molecular Protozoology, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan
| | - Alan Cowman
- Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia
| | | | - Joseph Smith
- Center for Infectious Disease Research, Seattle, WA, USA
| | - James W Kazura
- Center for Global Health and Diseases, Case Western Reserve University, Cleveland, OH, USA.
| | - Arlene E Dent
- Center for Global Health and Diseases, Case Western Reserve University, Cleveland, OH, USA.,Department of Pediatrics, Rainbow Babies and Children's Hospital, Cleveland, OH, USA
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32
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Migchelsen SJ, Sepúlveda N, Martin DL, Cooley G, Gwyn S, Pickering H, Joof H, Makalo P, Bailey R, Burr SE, Mabey DCW, Solomon AW, Roberts CH. Serology reflects a decline in the prevalence of trachoma in two regions of The Gambia. Sci Rep 2017; 7:15040. [PMID: 29118442 PMCID: PMC5678181 DOI: 10.1038/s41598-017-15056-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Accepted: 10/16/2017] [Indexed: 11/09/2022] Open
Abstract
Trachoma is caused by Chlamydia trachomatis (Ct). It is targeted for global elimination as a public health problem. In 2014, a population-based cross-sectional study was performed in two previously trachoma-endemic areas of The Gambia. Participants of all ages from Lower River Region (LRR) (N = 1028) and Upper River Region (URR) (N = 840) underwent examination for trachoma and had blood collected for detection of antibodies against the Ct antigen Pgp3, by ELISA. Overall, 30 (1.6%) individuals had active trachoma; the prevalence in children aged 1-9 years was 3.4% (25/742) with no statistically significant difference in prevalence between the regions. There was a significant difference in overall seroprevalence by region: 26.2% in LRR and 17.1% in URR (p < 0.0001). In children 1-9 years old, seroprevalence was 4.4% in LRR and 3.9% in URR. Reversible catalytic models using information on age-specific seroprevalence demonstrated a decrease in the transmission of Ct infection in both regions, possibly reflecting the impact of improved access to water, health and sanitation as well as mass drug administration campaigns. Serological testing for antibodies to Ct antigens is potentially useful for trachoma programmes, but consideration should be given to the co-endemicity of sexually transmitted Ct infections.
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Affiliation(s)
- Stephanie J Migchelsen
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, United Kingdom.
| | - Nuno Sepúlveda
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, United Kingdom
- Centro de Estatística e Aplicações, Faculdade de Ciências, Universidade de Lisboa, Lisboa, Portugal
| | - Diana L Martin
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Gretchen Cooley
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Sarah Gwyn
- IHRC, Inc., Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Harry Pickering
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Hassan Joof
- Disease Control and Elimination Theme, Medical Research Council, The Gambia Unit, Fajara, The Gambia
| | - Pateh Makalo
- Disease Control and Elimination Theme, Medical Research Council, The Gambia Unit, Fajara, The Gambia
| | - Robin Bailey
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Sarah E Burr
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, United Kingdom
- Disease Control and Elimination Theme, Medical Research Council, The Gambia Unit, Fajara, The Gambia
| | - David C W Mabey
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Anthony W Solomon
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Chrissy H Roberts
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, United Kingdom
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33
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malERA: An updated research agenda for characterising the reservoir and measuring transmission in malaria elimination and eradication. PLoS Med 2017; 14:e1002452. [PMID: 29190279 PMCID: PMC5708619 DOI: 10.1371/journal.pmed.1002452] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
This paper summarises key advances in defining the infectious reservoir for malaria and the measurement of transmission for research and programmatic use since the Malaria Eradication Research Agenda (malERA) publication in 2011. Rapid and effective progress towards elimination requires an improved understanding of the sources of transmission as well as those at risk of infection. Characterising the transmission reservoir in different settings will enable the most appropriate choice, delivery, and evaluation of interventions. Since 2011, progress has been made in a number of areas. The extent of submicroscopic and asymptomatic infections is better understood, as are the biological parameters governing transmission of sexual stage parasites. Limitations of existing transmission measures have been documented, and proof-of-concept has been established for new innovative serological and molecular methods to better characterise transmission. Finally, there now exists a concerted effort towards the use of ensemble datasets across the spectrum of metrics, from passive and active sources, to develop more accurate risk maps of transmission. These can be used to better target interventions and effectively monitor progress toward elimination. The success of interventions depends not only on the level of endemicity but also on how rapidly or recently an area has undergone changes in transmission. Improved understanding of the biology of mosquito-human and human-mosquito transmission is needed particularly in low-endemic settings, where heterogeneity of infection is pronounced and local vector ecology is variable. New and improved measures of transmission need to be operationally feasible for the malaria programmes. Outputs from these research priorities should allow the development of a set of approaches (applicable to both research and control programmes) that address the unique challenges of measuring and monitoring transmission in near-elimination settings and defining the absence of transmission.
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Niass O, Saint-Pierre P, Niang M, Diop F, Diouf B, Faye MM, Sarr FD, Faye J, Diagne N, Sokhna C, Trape JF, Perraut R, Tall A, Diongue AK, Toure Balde A. Modelling dynamic change of malaria transmission in holoendemic setting (Dielmo, Senegal) using longitudinal measures of antibody prevalence to Plasmodium falciparum crude schizonts extract. Malar J 2017; 16:409. [PMID: 29020949 PMCID: PMC5637097 DOI: 10.1186/s12936-017-2052-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Accepted: 10/04/2017] [Indexed: 11/25/2022] Open
Abstract
Background Evaluation of local Plasmodium falciparum malaria transmission has been investigated previously using the reversible catalytic model based on prevalence of antibody responses to single antigen to estimate seroconversion rates. High correlations were observed between seroconversion rates and entomological inoculation rates (EIR). However, in this model, the effects of malaria control interventions and clinical episodes on serological measurements were not assessed. This study monitors the use of antibody responses to P. falciparum crude extracts for assessing malaria transmission, compares seroconversion rates estimated from longitudinal data to those derived from cross-sectional surveys and investigates the effects of malaria control interventions on these measures in an area of declining malaria transmission. In addition, the validity of this model was evaluated by comparison with the alternative model. Methods Five cross-sectional surveys were carried out at the end of the wet season in Dielmo, a malaria-endemic Senegalese rural area in 2000, 2002, 2008, 2010 and 2012. Antibodies against schizonts crude extract of a local P. falciparum strain adapted to culture (Pf 07/03) were measured by ELISA. Age-specific seroprevalence model was used both for cross-sectional surveys and longitudinal data (combined data of all surveys). Results A total of 1504 plasma samples obtained through several years follow-up of 350 subjects was used in this study. Seroconversion rates based on P. falciparum schizonts crude extract were estimated for each cross-sectional survey and were found strongly correlated with EIR. High variability between SCRs from cross-sectional and longitudinal surveys was observed. In longitudinal studies, the alternative catalytic reversible model adjusted better with serological data than the catalytic model. Clinical malaria attacks and malaria control interventions were found to have significant effect on seroconversion. Discussion The results of the study suggested that crude extract was a good serological tool that could be used to assess the level of malaria exposure in areas where malaria transmission is declining. However, additional parameters such as clinical malaria and malaria control interventions must be taken into account for determining serological measurements for more accuracy in transmission assessment. Electronic supplementary material The online version of this article (doi:10.1186/s12936-017-2052-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Oumy Niass
- Immunology Unit, Institut Pasteur Dakar, 36 Avenue Pasteur, BP 220, Dakar, Senegal.,Laboratoire d'étude et de Recherche en Statistique et Développement, Université Gaston Berger, BP 237, Saint-Louis, Senegal
| | | | - Makhtar Niang
- Immunology Unit, Institut Pasteur Dakar, 36 Avenue Pasteur, BP 220, Dakar, Senegal
| | - Fode Diop
- Immunology Unit, Institut Pasteur Dakar, 36 Avenue Pasteur, BP 220, Dakar, Senegal
| | - Babacar Diouf
- Immunology Unit, Institut Pasteur Dakar, 36 Avenue Pasteur, BP 220, Dakar, Senegal
| | - Michel Matar Faye
- Immunology Unit, Institut Pasteur Dakar, 36 Avenue Pasteur, BP 220, Dakar, Senegal
| | - Fatoumata Diène Sarr
- Epidemiology of Infectious Diseases Unit, Institut Pasteur Dakar, 36 Avenue Pasteur, BP 220, Dakar, Senegal
| | - Joseph Faye
- Epidemiology of Infectious Diseases Unit, Institut Pasteur Dakar, 36 Avenue Pasteur, BP 220, Dakar, Senegal
| | - Nafissatou Diagne
- Institut de Recherche pour le Développement, BP 1386, Dakar, Senegal
| | - Cheikh Sokhna
- Institut de Recherche pour le Développement, BP 1386, Dakar, Senegal
| | | | - Ronald Perraut
- Immunology Unit, Institut Pasteur Dakar, 36 Avenue Pasteur, BP 220, Dakar, Senegal
| | - Adama Tall
- Epidemiology of Infectious Diseases Unit, Institut Pasteur Dakar, 36 Avenue Pasteur, BP 220, Dakar, Senegal
| | - Abdou Kâ Diongue
- Laboratoire d'étude et de Recherche en Statistique et Développement, Université Gaston Berger, BP 237, Saint-Louis, Senegal
| | - Aïssatou Toure Balde
- Immunology Unit, Institut Pasteur Dakar, 36 Avenue Pasteur, BP 220, Dakar, Senegal.
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Simmons RA, Mboera L, Miranda ML, Morris A, Stresman G, Turner EL, Kramer R, Drakeley C, O'Meara WP. A longitudinal cohort study of malaria exposure and changing serostatus in a malaria endemic area of rural Tanzania. Malar J 2017; 16:309. [PMID: 28764717 PMCID: PMC5539976 DOI: 10.1186/s12936-017-1945-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Accepted: 07/18/2017] [Indexed: 01/16/2023] Open
Abstract
Background Measurements of anti-malarial antibodies are increasingly used as a proxy of transmission intensity. Most serological surveys are based on the use of cross-sectional data that, when age-stratified, approximates historical patterns of transmission within a population. Comparatively few studies leverage longitudinal data to explicitly relate individual infection events with subsequent antibody responses. Methods The occurrence of seroconversion and seroreversion events for two Plasmodium falciparum asexual stage antigens (MSP-1 and AMA-1) was examined using three annual measurements of 691 individuals from a cohort of individuals in a malaria-endemic area of rural east-central Tanzania. Mixed-effect logistic regression models were employed to determine factors associated with changes in serostatus over time. Results While the expected population-level relationship between seroprevalence and disease incidence was observed, on an individual level the relationship between individual infections and the antibody response was complex. MSP-1 antibody responses were more dynamic in response to the occurrence and resolution of infection events than AMA-1, while the latter was more correlated with consecutive infections. The MSP-1 antibody response to an observed infection seemed to decay faster over time than the corresponding AMA-1 response. Surprisingly, there was no evidence of an age effect on the occurrence of a conversion or reversion event. Conclusions While the population-level results concur with previously published sero-epidemiological surveys, the individual-level results highlight the more complex relationship between detected infections and antibody dynamics than can be analysed using cross-sectional data. The longitudinal analysis of serological data may provide a powerful tool for teasing apart the complex relationship between infection events and the corresponding immune response, thereby improving the ability to rapidly assess the success or failure of malaria control programmes.
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Affiliation(s)
- Ryan A Simmons
- Department of Biostatistics and Bioinformatics, Duke University Medical Center, 2721, Durham, NC, 27701, USA. .,Duke Global Health Institute, Duke University, 310 Trent Drive, Durham, NC, 27701, USA.
| | - Leonard Mboera
- National Institute for Medical Research, 3 Barack Obama Drive, P.O. Box 9653, 11101, Dar es Salaam, United Republic of Tanzania
| | | | - Alison Morris
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Gillian Stresman
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Elizabeth L Turner
- Department of Biostatistics and Bioinformatics, Duke University Medical Center, 2721, Durham, NC, 27701, USA.,Duke Global Health Institute, Duke University, 310 Trent Drive, Durham, NC, 27701, USA
| | - Randall Kramer
- Duke Global Health Institute, Duke University, 310 Trent Drive, Durham, NC, 27701, USA
| | - Chris Drakeley
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Wendy P O'Meara
- Duke Global Health Institute, Duke University, 310 Trent Drive, Durham, NC, 27701, USA
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Arnold BF, van der Laan MJ, Hubbard AE, Steel C, Kubofcik J, Hamlin KL, Moss DM, Nutman TB, Priest JW, Lammie PJ. Measuring changes in transmission of neglected tropical diseases, malaria, and enteric pathogens from quantitative antibody levels. PLoS Negl Trop Dis 2017; 11:e0005616. [PMID: 28542223 PMCID: PMC5453600 DOI: 10.1371/journal.pntd.0005616] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Revised: 06/01/2017] [Accepted: 05/01/2017] [Indexed: 12/01/2022] Open
Abstract
BACKGROUND Serological antibody levels are a sensitive marker of pathogen exposure, and advances in multiplex assays have created enormous potential for large-scale, integrated infectious disease surveillance. Most methods to analyze antibody measurements reduce quantitative antibody levels to seropositive and seronegative groups, but this can be difficult for many pathogens and may provide lower resolution information than quantitative levels. Analysis methods have predominantly maintained a single disease focus, yet integrated surveillance platforms would benefit from methodologies that work across diverse pathogens included in multiplex assays. METHODS/PRINCIPAL FINDINGS We developed an approach to measure changes in transmission from quantitative antibody levels that can be applied to diverse pathogens of global importance. We compared age-dependent immunoglobulin G curves in repeated cross-sectional surveys between populations with differences in transmission for multiple pathogens, including: lymphatic filariasis (Wuchereria bancrofti) measured before and after mass drug administration on Mauke, Cook Islands, malaria (Plasmodium falciparum) before and after a combined insecticide and mass drug administration intervention in the Garki project, Nigeria, and enteric protozoans (Cryptosporidium parvum, Giardia intestinalis, Entamoeba histolytica), bacteria (enterotoxigenic Escherichia coli, Salmonella spp.), and viruses (norovirus groups I and II) in children living in Haiti and the USA. Age-dependent antibody curves fit with ensemble machine learning followed a characteristic shape across pathogens that aligned with predictions from basic mechanisms of humoral immunity. Differences in pathogen transmission led to shifts in fitted antibody curves that were remarkably consistent across pathogens, assays, and populations. Mean antibody levels correlated strongly with traditional measures of transmission intensity, such as the entomological inoculation rate for P. falciparum (Spearman's rho = 0.75). In both high- and low transmission settings, mean antibody curves revealed changes in population mean antibody levels that were masked by seroprevalence measures because changes took place above or below the seropositivity cutoff. CONCLUSIONS/SIGNIFICANCE Age-dependent antibody curves and summary means provided a robust and sensitive measure of changes in transmission, with greatest sensitivity among young children. The method generalizes to pathogens that can be measured in high-throughput, multiplex serological assays, and scales to surveillance activities that require high spatiotemporal resolution. Our results suggest quantitative antibody levels will be particularly useful to measure differences in exposure for pathogens that elicit a transient antibody response or for monitoring populations with very high- or very low transmission, when seroprevalence is less informative. The approach represents a new opportunity to conduct integrated serological surveillance for neglected tropical diseases, malaria, and other infectious diseases with well-defined antigen targets.
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Affiliation(s)
- Benjamin F. Arnold
- School of Public Health, University of California, Berkeley, Berkeley, California, United States of America
| | - Mark J. van der Laan
- School of Public Health, University of California, Berkeley, Berkeley, California, United States of America
| | - Alan E. Hubbard
- School of Public Health, University of California, Berkeley, Berkeley, California, United States of America
| | - Cathy Steel
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Joseph Kubofcik
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Katy L. Hamlin
- Division of Parasitic Diseases and Malaria, United States Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Delynn M. Moss
- Division of Foodborne, Waterborne, and Environmental Diseases, United States Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Thomas B. Nutman
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Jeffrey W. Priest
- Division of Foodborne, Waterborne, and Environmental Diseases, United States Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Patrick J. Lammie
- Division of Parasitic Diseases and Malaria, United States Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
- Neglected Tropical Diseases Support Center, Task Force for Global Health, Decatur, Georgia, United States of America
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Longley RJ, França CT, White MT, Kumpitak C, Sa-Angchai P, Gruszczyk J, Hostetler JB, Yadava A, King CL, Fairhurst RM, Rayner JC, Tham WH, Nguitragool W, Sattabongkot J, Mueller I. Asymptomatic Plasmodium vivax infections induce robust IgG responses to multiple blood-stage proteins in a low-transmission region of western Thailand. Malar J 2017; 16:178. [PMID: 28454546 PMCID: PMC5410030 DOI: 10.1186/s12936-017-1826-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2017] [Accepted: 04/19/2017] [Indexed: 11/11/2022] Open
Abstract
Background Thailand is aiming to eliminate malaria by the year 2024. Plasmodium vivax has now become the dominant species causing malaria within the country, and a high proportion of infections are asymptomatic. A better understanding of antibody dynamics to P. vivax antigens in a low-transmission setting, where acquired immune responses are poorly characterized, will be pivotal for developing new strategies for elimination, such as improved surveillance methods and vaccines. The objective of this study was to characterize total IgG antibody levels to 11 key P. vivax proteins in a village of western Thailand. Methods Plasma samples from 546 volunteers enrolled in a cross-sectional survey conducted in 2012 in Kanchanaburi Province were utilized. Total IgG levels to 11 different proteins known or predicted to be involved in reticulocyte binding or invasion (ARP, GAMA, P41, P12, PVX_081550, and five members of the PvRBP family), as well as the leading pre-erythrocytic vaccine candidate (CSP) were measured using a multiplexed bead-based assay. Associations between IgG levels and infection status, age, and spatial location were explored. Results Individuals from a low-transmission region of western Thailand reacted to all 11 P. vivax recombinant proteins. Significantly greater IgG levels were observed in the presence of a current P. vivax infection, despite all infected individuals being asymptomatic. IgG levels were also higher in adults (18 years and older) than in children. For most of the proteins, higher IgG levels were observed in individuals living closer to the Myanmar border and further away from local health services. Conclusions Robust IgG responses were observed to most proteins and IgG levels correlated with surrogates of exposure, suggesting these antigens may serve as potential biomarkers of exposure, immunity, or both. Electronic supplementary material The online version of this article (doi:10.1186/s12936-017-1826-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Rhea J Longley
- Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia.,Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Department of Medical Biology, University of Melbourne, Melbourne, Australia
| | - Camila T França
- Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia.,Department of Medical Biology, University of Melbourne, Melbourne, Australia
| | - Michael T White
- Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia.,Imperial College, London, UK
| | - Chalermpon Kumpitak
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Patiwat Sa-Angchai
- Department of Tropical Hygiene, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Jakub Gruszczyk
- Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
| | - Jessica B Hostetler
- Malaria Programme, Wellcome Trust Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, UK.,Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Anjali Yadava
- Malaria Vaccine Branch, United States Military Malaria Research Program, Walter Reed Army Institute of Research, Silver Spring, MD, USA
| | - Christopher L King
- Center for Global Health and Diseases, Case Western Reserve University, Cleveland, OH, USA
| | - Rick M Fairhurst
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Julian C Rayner
- Malaria Programme, Wellcome Trust Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, UK
| | - Wai-Hong Tham
- Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia.,Department of Medical Biology, University of Melbourne, Melbourne, Australia
| | - Wang Nguitragool
- Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Jetsumon Sattabongkot
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Ivo Mueller
- Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia. .,Department of Medical Biology, University of Melbourne, Melbourne, Australia. .,ISGlobal, Barcelona Institute for Global Health, Hospital Clínic-Universitat de Barcelona, 08036, Barcelona, Spain. .,Institut Pasteur, Paris, France.
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Arcà B, Lombardo F, Struchiner CJ, Ribeiro JMC. Anopheline salivary protein genes and gene families: an evolutionary overview after the whole genome sequence of sixteen Anopheles species. BMC Genomics 2017; 18:153. [PMID: 28193177 PMCID: PMC5307786 DOI: 10.1186/s12864-017-3579-8] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Accepted: 02/09/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Mosquito saliva is a complex cocktail whose pharmacological properties play an essential role in blood feeding by counteracting host physiological response to tissue injury. Moreover, vector borne pathogens are transmitted to vertebrates and exposed to their immune system in the context of mosquito saliva which, in virtue of its immunomodulatory properties, can modify the local environment at the feeding site and eventually affect pathogen transmission. In addition, the host antibody response to salivary proteins may be used to assess human exposure to mosquito vectors. Even though the role of quite a few mosquito salivary proteins has been clarified in the last decade, we still completely ignore the physiological role of many of them as well as the extent of their involvement in the complex interactions taking place between the mosquito vectors, the pathogens they transmit and the vertebrate host. The recent release of the genomes of 16 Anopheles species offered the opportunity to get insights into function and evolution of salivary protein families in anopheline mosquitoes. RESULTS Orthologues of fifty three Anopheles gambiae salivary proteins were retrieved and annotated from 18 additional anopheline species belonging to the three subgenera Cellia, Anopheles, and Nyssorhynchus. Our analysis included 824 full-length salivary proteins from 24 different families and allowed the identification of 79 novel salivary genes and re-annotation of 379 wrong predictions. The comparative, structural and phylogenetic analyses yielded an unprecedented view of the anopheline salivary repertoires and of their evolution over 100 million years of anopheline radiation shedding light on mechanisms and evolutionary forces that contributed shaping the anopheline sialomes. CONCLUSIONS We provide here a comprehensive description, classification and evolutionary overview of the main anopheline salivary protein families and identify two novel candidate markers of human exposure to malaria vectors worldwide. This anopheline sialome catalogue, which is easily accessible as hyperlinked spreadsheet, is expected to be useful to the vector biology community and to improve the capacity to gain a deeper understanding of mosquito salivary proteins facilitating their possible exploitation for epidemiological and/or pathogen-vector-host interaction studies.
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Affiliation(s)
- Bruno Arcà
- Department of Public Health and Infectious Diseases - Division of Parasitology, Sapienza University, Piazzale Aldo Moro 5, 00185, Rome, Italy.
| | - Fabrizio Lombardo
- Department of Public Health and Infectious Diseases - Division of Parasitology, Sapienza University, Piazzale Aldo Moro 5, 00185, Rome, Italy
| | - Claudio J Struchiner
- Fundação Oswaldo Cruz, Avenida Brasil, 4365, Rio de Janeiro, Brazil.,Instituto de Medicina Social, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, Brazil
| | - José M C Ribeiro
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, 12735 Twinbrook Parkway, Rockville, MD, 20852, USA
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Seroprevalence of Antibodies against Plasmodium falciparum Sporozoite Antigens as Predictive Disease Transmission Markers in an Area of Ghana with Seasonal Malaria Transmission. PLoS One 2016; 11:e0167175. [PMID: 27875594 PMCID: PMC5119834 DOI: 10.1371/journal.pone.0167175] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Accepted: 11/09/2016] [Indexed: 12/04/2022] Open
Abstract
Introduction As an increasing number of malaria-endemic countries approach the disease elimination phase, sustenance of control efforts and effective monitoring are necessary to ensure success. Mathematical models that estimate anti-parasite antibody seroconversion rates are gaining relevance as more sensitive transmission intensity estimation tools. Models however estimate yearly seroconversion and seroreversion rates and usually predict long term changes in transmission, occurring years before the time of sampling. Another challenge is the identification of appropriate antigen targets since specific antibody levels must directly reflect changes in transmission patterns. We therefore investigated the potential of antibodies to sporozoite and blood stage antigens for detecting short term differences in malaria transmission in two communities in Northern Ghana with marked, seasonal transmission. Methods Cross-sectional surveys were conducted during the rainy and dry seasons in two communities, one in close proximity to an irrigation dam and the other at least 20 Km away from the dam. Antibodies against the sporozoite-specific antigens circumsporozoite protein (CSP) and Cell traversal for ookinetes and sporozoites (CelTOS) and the classical blood stage antigen apical membrane antigen 1 (AMA1) were measured by indirect ELISA. Antibody levels and seroprevalence were compared between surveys and between study communities. Antibody seroprevalence data were fitted to a modified reversible catalytic model to estimate the seroconversion and seroreversion rates. Results Changes in sporozoite-specific antibody levels and seroprevalence directly reflected differences in parasite prevalence between the rainy and dry seasons and hence the extent of malaria transmission. Seroconversion rate estimates from modelled seroprevalence data did not however support the above observation. Conclusions The data confirms the potential utility of sporozoite-specific antigens as useful markers for monitoring short term/seasonal changes in malaria transmission. It may however be essential to update models to allow for assessment of seasonal changes in malaria transmission, which usually occur within four to six months.
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Kerkhof K, Sluydts V, Willen L, Kim S, Canier L, Heng S, Tsuboi T, Sochantha T, Sovannaroth S, Ménard D, Coosemans M, Durnez L. Serological markers to measure recent changes in malaria at population level in Cambodia. Malar J 2016; 15:529. [PMID: 27809852 PMCID: PMC5096337 DOI: 10.1186/s12936-016-1576-z] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2016] [Accepted: 10/27/2016] [Indexed: 11/10/2022] Open
Abstract
Background Serological markers for exposure to different Plasmodium species have recently been used in multiplex immunoassays based on the Luminex technology. However, interpretation of the assay results requires consideration of the half-life of specific antibodies against these markers. Therefore, the aim of the present study was to document the half-life of malaria specific serological makers, as well as assessing the sensitivity of these markers to pick up recent changes in malaria exposure. Methods A recently developed multiplex immunoassay was used to measure the intensity of antibody (Ab) responses against 19 different Plasmodium specific antigens, covering different human malaria parasites and two vector saliva antigens. Therefore, 8439 blood samples from five cross-sectional surveys in Ratanakiri, Cambodia, were analysed. These involve a random selection from two selected surveys, and an additional set of blood samples of individuals that were randomly re-sampled three, four or five times. A generalized estimating equation model and linear regression models were fitted on log transformed antibody intensity data. Results Results showed that most (17/21) Ab-responses are higher in PCR positive than PCR negative individuals. Furthermore, these antibody-responses follow the same upward trend within each age group. Estimation of the half-lives showed differences between serological markers that reflect short- (seasonal) and long-term (year round) transmission trends. Ab levels declined significantly together with a decrease of PCR prevalence in a group of malaria endemic villages. Conclusion For Plasmodium falciparum, antibodies against LSA3.RE, GLURP and Pf.GLURP.R2 are most likely to be a reflexion of recent (range from 6 to 8 months) exposure in the Mekong Subregion. PvEBP is the only Plasmodium vivax Ag responding reasonably well, in spite of an estimated Ab half-life of more than 1 year. The use of Ab intensity data rather dichotomizing the continuous Ab-titre data (positive vs negative) will lead to an improved approach for serological surveillance. Electronic supplementary material The online version of this article (doi:10.1186/s12936-016-1576-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Karen Kerkhof
- Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium. .,Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium.
| | - Vincent Sluydts
- Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium.,Department of Biology, University of Antwerp, Antwerp, Belgium
| | - Laura Willen
- Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium.,Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium
| | - Saorin Kim
- Molecular Epidemiology Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | - Lydie Canier
- Molecular Epidemiology Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | - Somony Heng
- National Centre for Parasitology, Entomology and Malaria Control, Phnom Penh, Cambodia
| | - Takafumi Tsuboi
- Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Japan
| | - Tho Sochantha
- National Centre for Parasitology, Entomology and Malaria Control, Phnom Penh, Cambodia
| | - Siv Sovannaroth
- National Centre for Parasitology, Entomology and Malaria Control, Phnom Penh, Cambodia
| | - Didier Ménard
- Molecular Epidemiology Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | - Marc Coosemans
- Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium.,Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium
| | - Lies Durnez
- Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium.
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Mapping Malaria Risk in Low Transmission Settings: Challenges and Opportunities. Trends Parasitol 2016; 32:635-645. [PMID: 27238200 DOI: 10.1016/j.pt.2016.05.001] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2016] [Revised: 04/29/2016] [Accepted: 05/02/2016] [Indexed: 11/24/2022]
Abstract
As malaria transmission declines, it becomes increasingly focal and prone to outbreaks. Understanding and predicting patterns of transmission risk becomes an important component of an effective elimination campaign, allowing limited resources for control and elimination to be targeted cost-effectively. Malaria risk mapping in low transmission settings is associated with some unique challenges. This article reviews the main challenges and opportunities related to risk mapping in low transmission areas including recent advancements in risk mapping low transmission malaria, relevant metrics, and statistical approaches and risk mapping in post-elimination settings.
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Sluydts V, Durnez L, Heng S, Gryseels C, Canier L, Kim S, Van Roey K, Kerkhof K, Khim N, Mao S, Uk S, Sovannaroth S, Grietens KP, Sochantha T, Menard D, Coosemans M. Efficacy of topical mosquito repellent (picaridin) plus long-lasting insecticidal nets versus long-lasting insecticidal nets alone for control of malaria: a cluster randomised controlled trial. THE LANCET. INFECTIOUS DISEASES 2016; 16:1169-1177. [PMID: 27371977 DOI: 10.1016/s1473-3099(16)30148-7] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Revised: 05/19/2016] [Accepted: 05/26/2016] [Indexed: 11/30/2022]
Abstract
BACKGROUND Although effective topical repellents provide personal protection against malaria, whether mass use of topical repellents in addition to long-lasting insecticidal nets can contribute to a further decline of malaria is not known, particularly in areas where outdoor transmission occurs. We aimed to assess the epidemiological efficacy of a highly effective topical repellent in addition to long-lasting insecticidal nets in reducing malaria prevalence in this setting. METHODS A cluster randomised controlled trial was done in the 117 most endemic villages in Ratanakiri province, Cambodia, to assess the efficacy of topical repellents in addition to long-lasting insecticidal nets in controlling malaria in a low-endemic setting. We did a pre-trial assessment of village accessibility and excluded four villages because of their inaccessibility during the rainy season. Another 25 villages were grouped because of their proximity to each other, resulting in 98 study clusters (comprising either a single village or multiple neighbouring villages). Clusters were randomly assigned (1:1) to either a control (long-lasting insecticidal nets) or intervention (long-lasting insecticidal nets plus topical repellent) study group after a restricted randomisation. All clusters received one long-lasting insecticidal net per individual, whereas those in the intervention group also received safe and effective topical repellents (picaridin KBR3023, SC Johnson, Racine, WI, USA), along with instruction and promotion of its daily use. Cross-sectional surveys of 65 randomly selected individuals per cluster were done at the beginning and end of the malaria transmission season in 2012 and 2013. The primary outcome was Plasmodium species-specific prevalence in participants obtained by real-time PCR, assessed in the intention-to-treat population. Complete safety analysis data will be published seperately; any ad-hoc adverse events are reported here. This trial is registered with ClinicalTrials.gov, number NCT01663831. FINDINGS Of the 98 clusters that villages were split into, 49 were assigned to the control group and 49 were assigned to the intervention group. Despite having a successful distribution system, the daily use of repellents was suboptimum. No post-intervention differences in PCR plasmodium prevalence were observed between study groups in 2012 (4·91% in the control group vs 4·86% in the intervention group; adjusted odds ratio [aOR] 1·01 [95% CI 0·60-1·70]; p=0·975) or in 2013 (2·96% in the control group vs 3·85% in the intervention group; aOR 1·31 [0·81-2·11]; p=0·266). Similar results were obtained according to Plasmodium species (1·33% of participants in the intervention group vs 1·10% in the intervention group were infected with Plasmodium falciparum; aOR 0·83 [0·44-1·56]; p=0·561; and 1·85% in the control group vs 2·67% in the intervention group were infected with Plasmodium vivax; aOR 1·51 [0·88-2·57]; p=0·133). 41 adverse event notifications from nine villages were received, of which 33 were classified as adverse reactions (11 of these 33 were cases of repellent abuse through oral ingestion, either accidental or not). All participants with adverse reactions fully recovered and 17 were advised to permanently stop using the repellent. INTERPRETATION Mass distribution of highly effective topical repellents in resource-sufficient conditions did not contribute to a further decline in malaria endemicity in a pre-elimination setting in the Greater Mekong subregion. Daily compliance and appropriate use of the repellents remains the main obstacle. FUNDING Bill & Melinda Gates Foundation.
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Affiliation(s)
- Vincent Sluydts
- Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium; Department of Biology, University of Antwerp, Belgium
| | - Lies Durnez
- Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium
| | - Somony Heng
- Department of Biomedical Sciences, University of Antwerp, Belgium; National Center for Parasitology, Entomology and Malaria Control, Phnom Penh, Cambodia
| | - Charlotte Gryseels
- Department of Public Health, Institute of Tropical Medicine, Antwerp, Belgium; Amsterdam Institute of Social Science Research, University of Amsterdam, Amsterdam, Netherlands
| | - Lydie Canier
- Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | - Saorin Kim
- Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | - Karel Van Roey
- Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium
| | - Karen Kerkhof
- Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium
| | - Nimol Khim
- Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | - Sokny Mao
- National Center for Parasitology, Entomology and Malaria Control, Phnom Penh, Cambodia
| | - Sambunny Uk
- National Center for Parasitology, Entomology and Malaria Control, Phnom Penh, Cambodia
| | - Siv Sovannaroth
- National Center for Parasitology, Entomology and Malaria Control, Phnom Penh, Cambodia
| | - Koen Peeters Grietens
- Department of Public Health, Institute of Tropical Medicine, Antwerp, Belgium; School of Tropical Medicine and Global Health, Nagasaki University, Nagasaki, Japan; Partners for Applied Social Sciences, PASS-international, Tessenderlo, Belgium
| | - Tho Sochantha
- National Center for Parasitology, Entomology and Malaria Control, Phnom Penh, Cambodia
| | | | - Marc Coosemans
- Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium; Department of Biomedical Sciences, University of Antwerp, Belgium.
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Golden A, Faulx D, Kalnoky M, Stevens E, Yokobe L, Peck R, Karabou P, Banla M, Rao R, Adade K, Gantin RG, Komlan K, Soboslay PT, de Los Santos T, Domingo GJ. Analysis of age-dependent trends in Ov16 IgG4 seroprevalence to onchocerciasis. Parasit Vectors 2016; 9:338. [PMID: 27296630 PMCID: PMC4907250 DOI: 10.1186/s13071-016-1623-1] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 06/02/2016] [Indexed: 11/30/2022] Open
Abstract
Background Diagnostics provide a means to measure progress toward disease elimination. Many countries in Africa are approaching elimination of onchocerciasis after successful implementation of mass drug administration programs as well as vector control. An understanding of how markers for infection such as skin snip microfilaria and Onchocerca volvulus-specific seroconversion perform in near-elimination settings informs how to best use these markers. Methods All-age participants from 35 villages in Togo were surveyed in 2013 and 2014 for skin snip Onchocerca volvulus microfilaria and IgG4 antibody response by enzyme-linked immunosorbent assay (ELISA) to the Onchocerca volvulus-specific antigen Ov16. A Gaussian mixture model applying the expectation-maximization (EM) algorithm was used to determine seropositivity from Ov16 ELISA data. For a subset of participants (n = 434), polymerase chain reaction (PCR) was performed on the skin snips taken during surveillance. Results Within the 2,005 participants for which there was Ov16 ELISA data, O. volvulus microfilaremia prevalence and Ov16 seroprevalence were, 2.5 and 19.7 %, respectively, in the total population, and 1.6 and 3.6 % in children under 11. In the subset of 434 specimens for which ELISA, PCR, and microscopy data were generated, it was found that in children under 11 years of age, the anti-Ov16 IgG4 antibody response demonstrate a sensitivity and specificity of 80 and 97 %, respectively, against active infections as determined by combined PCR and microscopy on skin snips. Further analysis was performed in 34 of the 35 villages surveyed. These villages were stratified by all-age seroprevalence into three clusters: < 15 %; 15–20 %; and > 20 %. Age-dependence of seroprevalence for each cluster was best reflected by a two-phase force-of-infection (FOI) catalytic model. In all clusters, the lower of the two phases of FOI was associated with a younger age group, as reflected by the seroconversion rates for each phase. The age at which transition from lower to higher seroconversion, between the two phases of FOI, was found to be highest (older) for the cluster of villages with < 15 % seroprevalence and lowest (younger) for the cluster with the highest all-age seroprevalence. Conclusions The anti-Ov16 IgG4 antibody response is an accurate marker for active infection in children under 11 years of age in this population. Applying Ov16 surveillance to a broader age range provides additional valuable information for understanding progression toward elimination and can inform where targeted augmented interventions may be needed. Clustering of villages by all-age sero-surveillance allowed application of a biphasic FOI model to differentiate seroconversion rates for different age groups within the village cluster categories. Electronic supplementary material The online version of this article (doi:10.1186/s13071-016-1623-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | - Dunia Faulx
- Diagnostics Global Program, PATH, Seattle, WA, USA
| | | | - Eric Stevens
- Diagnostics Global Program, PATH, Seattle, WA, USA
| | | | - Roger Peck
- Diagnostics Global Program, PATH, Seattle, WA, USA
| | | | - Méba Banla
- Onchocerciasis Reference Laboratory, National Institute of Hygiene, Sokodé, Togo
| | | | - Kangi Adade
- National Onchocerciasis Control Programme, Kara, Togo
| | - Richard G Gantin
- Onchocerciasis Reference Laboratory, National Institute of Hygiene, Sokodé, Togo
| | - Kossi Komlan
- Onchocerciasis Reference Laboratory, National Institute of Hygiene, Sokodé, Togo
| | - Peter T Soboslay
- Onchocerciasis Reference Laboratory, National Institute of Hygiene, Sokodé, Togo.,Institute of Tropical Medicine, University Clinics of Tübingen, Tübingen, Germany
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44
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França CT, Hostetler JB, Sharma S, White MT, Lin E, Kiniboro B, Waltmann A, Darcy AW, Li Wai Suen CSN, Siba P, King CL, Rayner JC, Fairhurst RM, Mueller I. An Antibody Screen of a Plasmodium vivax Antigen Library Identifies Novel Merozoite Proteins Associated with Clinical Protection. PLoS Negl Trop Dis 2016; 10:e0004639. [PMID: 27182597 PMCID: PMC4868274 DOI: 10.1371/journal.pntd.0004639] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2015] [Accepted: 03/29/2016] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Elimination of Plasmodium vivax malaria would be greatly facilitated by the development of an effective vaccine. A comprehensive and systematic characterization of antibodies to P. vivax antigens in exposed populations is useful in guiding rational vaccine design. METHODOLOGY/PRINCIPAL FINDINGS In this study, we investigated antibodies to a large library of P. vivax entire ectodomain merozoite proteins in 2 Asia-Pacific populations, analysing the relationship of antibody levels with markers of current and cumulative malaria exposure, and socioeconomic and clinical indicators. 29 antigenic targets of natural immunity were identified. Of these, 12 highly-immunogenic proteins were strongly associated with age and thus cumulative lifetime exposure in Solomon Islanders (P<0.001-0.027). A subset of 6 proteins, selected on the basis of immunogenicity and expression levels, were used to examine antibody levels in plasma samples from a population of young Papua New Guinean children with well-characterized individual differences in exposure. This analysis identified a strong association between reduced risk of clinical disease and antibody levels to P12, P41, and a novel hypothetical protein that has not previously been studied, PVX_081550 (IRR 0.46-0.74; P<0.001-0.041). CONCLUSION/SIGNIFICANCE These data emphasize the benefits of an unbiased screening approach in identifying novel vaccine candidate antigens. Functional studies are now required to establish whether PVX_081550 is a key component of the naturally-acquired protective immune response, a biomarker of immune status, or both.
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Affiliation(s)
- Camila T. França
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
- Department of Medical Biology, University of Melbourne, Melbourne, Australia
| | - Jessica B. Hostetler
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
- Malaria Programme, Wellcome Trust Sanger Institute, Hinxton, United Kingdom
| | - Sumana Sharma
- Malaria Programme, Wellcome Trust Sanger Institute, Hinxton, United Kingdom
| | - Michael T. White
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
- Center for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
| | - Enmoore Lin
- Vector Borne Diseases Unit, PNG Institute of Medical Research, Madang, Papua New Guinea
| | - Benson Kiniboro
- Vector Borne Diseases Unit, PNG Institute of Medical Research, Madang, Papua New Guinea
| | - Andreea Waltmann
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
- Department of Medical Biology, University of Melbourne, Melbourne, Australia
| | - Andrew W. Darcy
- National Health Training & Research Institute, Ministry of Health, Honiara, Solomon Islands
| | - Connie S. N. Li Wai Suen
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
- Department of Medical Biology, University of Melbourne, Melbourne, Australia
| | - Peter Siba
- Vector Borne Diseases Unit, PNG Institute of Medical Research, Madang, Papua New Guinea
| | - Christopher L. King
- Center for Global Health & Diseases, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Julian C. Rayner
- Malaria Programme, Wellcome Trust Sanger Institute, Hinxton, United Kingdom
- * E-mail: (JCR); (RMF); (IM)
| | - Rick M. Fairhurst
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail: (JCR); (RMF); (IM)
| | - Ivo Mueller
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
- Department of Medical Biology, University of Melbourne, Melbourne, Australia
- ISGlobal, Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clínic, Universitat de Barcelona, Barcelona, Spain
- * E-mail: (JCR); (RMF); (IM)
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