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Amoah AGB, Sagoe KW, Quakyi IA, Ayettey Anie HNG, Ayettey-Adamafio MNB, Ayettey Brew RNA, Newman-Nartey M, Nartey NO, Brightson KTC, Kessie G, Ayettey AS, Konotey-Ahulu FID. Further observations on hydrogen peroxide antisepsis and COVID-19 cases among healthcare workers and inpatients. J Hosp Infect 2022; 126:103-108. [PMID: 35594985 PMCID: PMC9113766 DOI: 10.1016/j.jhin.2022.05.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Revised: 04/28/2022] [Accepted: 05/08/2022] [Indexed: 11/29/2022]
Abstract
Background The use of prophylactic antisepsis to protect against coronavirus disease 2019 (COVID-19) has been suggested. This study investigated hydrogen peroxide antisepsis (HPA) at two hospitals in Ghana. Methods Cases of COVID-19 among healthcare workers (HCWs) using hydrogen peroxide (HP-HCWs) or not using hydrogen peroxide (NHP-HCWs), vaccinated or unvaccinated, were recorded at Shai-Osudoku Hospital (SODH), Dodowa, and Mount Olives Hospital (MOH), Techiman, between May 2020 and December 2021. The effect of HPA in all inpatients at MOH was also observed. Permutation tests were used to determine P values. Findings At SODH, there were 62 (13.5%) cases of COVID-19 among 458 NHP-HCWs but no cases among eight HP-HCWs (P=0.622) from May to December 2020. Between January and March 2021, 10 (2.7%) of 372 NHP-HCWs had COVID-19, but there were no cases among 94 HP-HCWs (P=0.206). At MOH, prior to HPA, 17 (20.2%) of 84 HCWs and five (1.4%) of 370 inpatients had COVID-19 in July 2020. From August 2020 to March 2021, two of 54 (3.7%) HCWs who stopped HPA had COVID-19; none of 32 NHP-HCWs contracted COVID-19. At SODH, none of 23 unvaccinated HP-HCWs and 35 (64%) of 55 unvaccinated NHP-HCWs had COVID-19 from April to December 2021 (P<0.0001). None of 34 vaccinated HP-HCWs and 53 (13.6%) of 390 vaccinated NHP-HCWs had COVID-19 (P=0.015). No inpatients on prophylactic HPA (total 7736) contracted COVID-19. Conclusion Regular, daily HPA protects HCWs from COVID-19, and curtails nosocomial spread of SARS-CoV-2.
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Affiliation(s)
- A G B Amoah
- Department of Medicine and Therapeutics, University of Ghana Medical School, College of Health Sciences, University of Ghana, Legon, Ghana
| | - K W Sagoe
- Department of Medical Microbiology, University of Ghana Medical School, College of Health Sciences, University of Ghana, Legon, Ghana.
| | - I A Quakyi
- Department of Biological Environmental and Occupational Health Sciences, School of Public Health, College of Health Sciences, University of Ghana, Legon, Ghana
| | - H N G Ayettey Anie
- National Radiotherapy Oncology and Nuclear Medicine Centre, Korle Bu Teaching Hospital, Accra, Ghana
| | - M N B Ayettey-Adamafio
- Department of Dental/Oral and Maxillofacial Surgery, Korle Bu Teaching Hospital, Korle Bu, Accra, Ghana
| | - R N A Ayettey Brew
- Department of Obstetrics and Gynaecology, Holy Family Hospital, Techiman, Bono East Region, Ghana
| | - M Newman-Nartey
- Department of Orthodontics and Pedodontics, University of Ghana Dental School, College of Health Sciences, University of Ghana, Legon, Ghana
| | - N O Nartey
- Department of Oral Pathology and Oral Medicine, University of Ghana Dental School, College of Health Sciences, University of Ghana, Legon, Ghana
| | | | - G Kessie
- Mount Olives Hospital, Techiman, Bono East Region, Ghana
| | - A S Ayettey
- Department of Anatomy, University of Ghana Medical School, College of Health Sciences, University of Ghana, Legon, Ghana
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2
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Amoah GB, Quakyi IA, Sagoe KW, Ayettey-Anie HNG, Ayettey-Adamafio MNB, Ayettey Brew RNA, Newman-Nartey M, Nartey NO, Brightson KTC, Kessie G, Ayettey AS, Konotey-Ahulu FID. Re: Oral antiseptics against coronavirus: in-vitro and clinical evidence. J Hosp Infect 2021; 118:108-109. [PMID: 34487774 PMCID: PMC8414839 DOI: 10.1016/j.jhin.2021.08.024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 08/29/2021] [Indexed: 02/07/2023]
Affiliation(s)
- G B Amoah
- University of Ghana Medical School, College of Health Sciences, University of Ghana, Legon, Ghana
| | - I A Quakyi
- School of Public Health, College of Health Sciences, University of Ghana, Legon, Ghana
| | - K W Sagoe
- Department of Medical Microbiology, University of Ghana Medical School, College of Health Sciences, University of Ghana, Legon, Ghana.
| | - H N G Ayettey-Anie
- National Radiotherapy Oncology and Nuclear Medicine Centre, Korle Bu Teaching Hospital, Accra, Ghana
| | | | - R N A Ayettey Brew
- Department of Obstetrics and Gynecology, Korle Bu Teaching Hospital, Accra, Ghana
| | - M Newman-Nartey
- University of Ghana Dental School, College of Health Sciences, University of Ghana, Ghana
| | - N O Nartey
- University of Ghana Dental School, College of Health Sciences, University of Ghana, Ghana
| | | | - G Kessie
- Mount Olives Hospital (MO), Techiman, Bono East Region, Ghana
| | - A S Ayettey
- University of Ghana Medical School, College of Health Sciences, University of Ghana, Legon, Ghana
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3
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Acquah AA, D'Souza C, Martin BJ, Arko-Mensah J, Basu N, Quakyi IA, Robins TG, Fobil JN. Comparison of ergonomic risk factors and work-related musculoskeletal disorders among dismantler and burners of electronic waste in Agbogbloshie, Accra Ghana. Proc Hum Factors Ergon Soc Annu Meet 2021; 65:715-719. [PMID: 35115743 PMCID: PMC8809478 DOI: 10.1177/1071181321651256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Rudimentary methods for electronic waste (e-waste) recycling employed in developing countries are a source of work-related musculoskeletal disorders (WRMSDs). A summarized comparison of WRMSDs and preliminary exposure assessment among e-waste dismantlers (D) and burners (B) in Agbogbloshie, Ghana is presented. A cross-sectional study was conducted to investigate WRMSDs and associated risk factors using the Cornell Musculoskeletal Discomfort Questionnaire and a newly developed ergonomic assessment tool. Results indicated higher WRMSDs prevalence in the lower back (68% D vs. 52% B; p = 0.172), shoulder (41% D vs. 29% B; p = 0.279) and upper arm (33% D vs 5% B; p = 0.010). Moderate to severe trunk flexion, high force exertion, repetition and vibration were prevalent risk factors among workers and were significantly higher in dismantlers than burners (p ≤ 0.001). Detailed ergonomic studies investigating the relationship between physical exposures and WRMSDs are needed to provide a deeper understanding of WRMSD causation in e-waste workers and more particularly in unstructured, unregulated work.
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Affiliation(s)
- Augustine A Acquah
- Department of Biological Environmental and Occupational Health Sciences, School of Public Health, University of Ghana, Accra, Ghana
| | - Clive D'Souza
- Center for Ergonomics, Department of Industrial and Operations Engineering, University of Michigan, Ann Arbor, USA
| | - Bernard J Martin
- Center for Ergonomics, Department of Industrial and Operations Engineering, University of Michigan, Ann Arbor, USA
| | - John Arko-Mensah
- Department of Biological Environmental and Occupational Health Sciences, School of Public Health, University of Ghana, Accra, Ghana
| | - Niladri Basu
- Faculty of Agricultural and Environmental Sciences, McGill University, Montréal, QC, Canada
| | - Isabella A Quakyi
- Department of Biological Environmental and Occupational Health Sciences, School of Public Health, University of Ghana, Accra, Ghana
| | - Thomas G Robins
- Environmental Health Sciences, School of Public Health, University of Michigan, Ann Arbor, USA
| | - Julius N Fobil
- Department of Biological Environmental and Occupational Health Sciences, School of Public Health, University of Ghana, Accra, Ghana
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4
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Tripathi AK, Oakley MS, Verma N, Mlambo G, Zheng H, Meredith SM, Essuman E, Puri A, Skelton RA, Takeda K, Majam V, Quakyi IA, Locke E, Morin M, Miura K, Long CA, Kumar S. Plasmodium falciparum Pf77 and male development gene 1 as vaccine antigens that induce potent transmission-reducing antibodies. Sci Transl Med 2021; 13:eabg2112. [PMID: 34108248 PMCID: PMC11018285 DOI: 10.1126/scitranslmed.abg2112] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Accepted: 04/22/2021] [Indexed: 12/14/2022]
Abstract
Malaria vaccines that disrupt the Plasmodium life cycle in mosquitoes and reduce parasite transmission in endemic areas are termed transmission-blocking vaccines (TBVs). Despite decades of research, there are only a few Plasmodium falciparum antigens that indisputably and reproducibly demonstrate transmission-blocking immunity. So far, only two TBV candidates have advanced to phase 1/2 clinical testing with limited success. By applying an unbiased transcriptomics-based approach, we have identified Pf77 and male development gene 1 (PfMDV-1) as two P. falciparum TBV antigens that, upon immunization, induced antibodies that caused reductions in oocyst counts in Anopheles mosquito midguts in a standard membrane feeding assay. In-depth studies were performed to characterize the genetic diversity of, stage-specific expression by, and natural immunity to these two molecules to evaluate their suitability as TBV candidates. Pf77 and PfMDV-1 display limited antigenic polymorphism, are pan-developmentally expressed within the parasite, and induce naturally occurring antibodies in Ghanaian adults, which raises the prospect of natural boosting of vaccine-induced immune response in endemic regions. Together, these biological properties suggest that Pf77 and PfMDV-1 may warrant further investigation as TBV candidates.
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Affiliation(s)
- Abhai K Tripathi
- Molecular Microbiology and Immunology, Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA
| | - Miranda S Oakley
- Laboratory of Emerging Pathogens, Division of Emerging and Transfusion Transmitted Diseases, Office of Blood Research and Review, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, MD 20993, USA
| | - Nitin Verma
- Laboratory of Emerging Pathogens, Division of Emerging and Transfusion Transmitted Diseases, Office of Blood Research and Review, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, MD 20993, USA
| | - Godfree Mlambo
- Molecular Microbiology and Immunology, Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA
| | - Hong Zheng
- Laboratory of Emerging Pathogens, Division of Emerging and Transfusion Transmitted Diseases, Office of Blood Research and Review, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, MD 20993, USA
| | - Scott M Meredith
- Laboratory of Emerging Pathogens, Division of Emerging and Transfusion Transmitted Diseases, Office of Blood Research and Review, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, MD 20993, USA
| | - Edward Essuman
- Laboratory of Emerging Pathogens, Division of Emerging and Transfusion Transmitted Diseases, Office of Blood Research and Review, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, MD 20993, USA
| | - Ankit Puri
- Laboratory of Emerging Pathogens, Division of Emerging and Transfusion Transmitted Diseases, Office of Blood Research and Review, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, MD 20993, USA
| | - Richard A Skelton
- Laboratory of Emerging Pathogens, Division of Emerging and Transfusion Transmitted Diseases, Office of Blood Research and Review, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, MD 20993, USA
| | - Kazuyo Takeda
- Division of Bacterial, Parasitic, and Allergenic Products, Office of Vaccines Research and Review, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, MD 20993, USA
| | - Victoria Majam
- Laboratory of Emerging Pathogens, Division of Emerging and Transfusion Transmitted Diseases, Office of Blood Research and Review, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, MD 20993, USA
| | | | - Emily Locke
- PATH-Malaria Vaccine Initiative, Washington, DC 20001, USA
| | | | - Kazutoyo Miura
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD 20852, USA
| | - Carole A Long
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD 20852, USA
| | - Sanjai Kumar
- Laboratory of Emerging Pathogens, Division of Emerging and Transfusion Transmitted Diseases, Office of Blood Research and Review, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, MD 20993, USA.
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Acquah AA, D'Souza C, Martin BJ, Arko-Mensah J, Botwe PK, Tettey P, Dwomoh D, Nti AA, Kwarteng L, Takyi S, Quakyi IA, Robins TG, Fobil JN. A PRELIMINARY ASSESSMENT OF PHYSICAL WORK EXPOSURES AMONG ELECTRONIC WASTE WORKERS AT AGBOGBLOSHIE, ACCRA GHANA. Int J Ind Ergon 2021; 82:103096. [PMID: 33767518 PMCID: PMC7986988 DOI: 10.1016/j.ergon.2021.103096] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Occupational exposure associated with unstructured, informal e-waste recycling has received very limited attention. This study aimed to quantify the occupational physical exposures among informal e-waste workers at the largest e-waste site in Africa. A cross-sectional field survey of 163 male e-waste workers was conducted using a self-report occupational physical activity questionnaire, along with direct work observations, and pedometer estimates of walking activity for a subset of workers (n = 42). Results indicated significant differences in self-reported 7-day work exposures among the three main e-waste job categories, namely, collectors (n = 70), dismantlers (n = 73) and burners (n = 20). Prolonged walking, sitting and standing on five or more days in the workweek was frequently reported by collectors (87%), dismantlers (82%) and burners (60%), respectively. Nearly 90% of collectors and burners and 60% of dismantlers reported lifting and carrying on five or more days in the workweek. The exposure combinations identified suggest a risk for musculoskeletal disorders (MSDs). Findings call attention to the need for research examining potential associations between physical exposures and MSDs affecting e-waste workers in Agbogbloshie. The high exposure variability both between and within workers has implications for future exposure assessments conducted in unregulated, informal work settings.
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Affiliation(s)
- Augustine A. Acquah
- Department of Biological Environmental and Occupational Health Sciences, School of Public Health, University of Ghana, Accra, Ghana
- Corresponding Author: Augustine A. Acquah, Department of Biological, Environmental and Occupational Health Sciences, P.O. Box LG 13, School of Public Health, CHS, University of Ghana;
| | - Clive D'Souza
- Center for Ergonomics, Department of Industrial and Operations Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Bernard J. Martin
- Center for Ergonomics, Department of Industrial and Operations Engineering, University of Michigan, Ann Arbor, MI, USA
| | - John Arko-Mensah
- Department of Biological Environmental and Occupational Health Sciences, School of Public Health, University of Ghana, Accra, Ghana
| | - Paul K. Botwe
- Department of Biological Environmental and Occupational Health Sciences, School of Public Health, University of Ghana, Accra, Ghana
| | - Prudence Tettey
- Department of Biological Environmental and Occupational Health Sciences, School of Public Health, University of Ghana, Accra, Ghana
| | - Duah Dwomoh
- Department of Biological Environmental and Occupational Health Sciences, School of Public Health, University of Ghana, Accra, Ghana
| | - Afua Amoabeng Nti
- Department of Biological Environmental and Occupational Health Sciences, School of Public Health, University of Ghana, Accra, Ghana
| | - Lawrencia Kwarteng
- Department of Biological Environmental and Occupational Health Sciences, School of Public Health, University of Ghana, Accra, Ghana
| | - Sylvia Takyi
- Department of Biological Environmental and Occupational Health Sciences, School of Public Health, University of Ghana, Accra, Ghana
| | - Isabella A. Quakyi
- Department of Biological Environmental and Occupational Health Sciences, School of Public Health, University of Ghana, Accra, Ghana
| | - Thomas G. Robins
- Environmental Health Sciences, School of Public Health, University of Michigan, Ann Arbor, MI, USA
| | - Julius N. Fobil
- Department of Biological Environmental and Occupational Health Sciences, School of Public Health, University of Ghana, Accra, Ghana
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6
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Acquah AA, D’Souza C, Martin BJ, Arko-Mensah J, Dwomoh D, Nti AAA, Kwarteng L, Takyi SA, Basu N, Quakyi IA, Robins TG, Fobil JN. Musculoskeletal Disorder Symptoms among Workers at an Informal Electronic-Waste Recycling Site in Agbogbloshie, Ghana. Int J Environ Res Public Health 2021; 18:2055. [PMID: 33669889 PMCID: PMC7923259 DOI: 10.3390/ijerph18042055] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/05/2020] [Revised: 02/12/2021] [Accepted: 02/13/2021] [Indexed: 11/16/2022]
Abstract
Informal recycling of electrical and electronic waste (e-waste) has myriad environmental and occupational health consequences, though information about the chronic musculoskeletal health effects on workers is limited. The aim of this study was to examine the prevalence and intensity of self-reported musculoskeletal disorder (MSD) symptoms among e-waste workers at Agbogbloshie in Ghana-the largest informal e-waste dumpsite in West Africa-relative to workers not engaged in e-waste recycling. A standardized musculoskeletal discomfort questionnaire was administered to 176 e-waste workers (73 collectors, 82 dismantlers, and 21 burners) and 41 workers in a reference group. The number of body parts with musculoskeletal discomfort were 1.62 and 1.39 times higher for collectors and dismantlers than burners, respectively. A 1-week discomfort prevalence was highest for collectors (91.8%) followed by dismantlers (89%), burners (81%), and the reference group (70.7%). The discomfort prevalence for e-waste workers was highest in the lower back (65.9%), shoulders (37.5%), and knees (37.5%). Whole-body pain scores (mean ± SE) were higher for collectors (83.7 ± 10.6) than dismantlers (45.5 ± 7.6), burners (34.0 ± 9.1), and the reference group (26.4 ± 5.9). Differences in prevalence, location, and intensity of MSD symptoms by the e-waste job category suggest specific work-related morbidity. Symptom prevalence and intensity call attention to the high risk for MSDs and work disability among informal e-waste workers, particularly collectors and dismantlers.
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Affiliation(s)
- Augustine A. Acquah
- Department of Biological Environmental and Occupational Health Sciences, School of Public Health, University of Ghana, Accra 00233, Ghana; (J.A.-M.); (D.D.); (A.A.A.N.); (L.K.); (S.A.T.); (I.A.Q.); (J.N.F.)
| | - Clive D’Souza
- Center for Ergonomics, Department of Industrial and Operations Engineering, University of Michigan, Ann Arbor, MI 48109-2117, USA; (C.D.); (B.J.M.)
| | - Bernard J. Martin
- Center for Ergonomics, Department of Industrial and Operations Engineering, University of Michigan, Ann Arbor, MI 48109-2117, USA; (C.D.); (B.J.M.)
| | - John Arko-Mensah
- Department of Biological Environmental and Occupational Health Sciences, School of Public Health, University of Ghana, Accra 00233, Ghana; (J.A.-M.); (D.D.); (A.A.A.N.); (L.K.); (S.A.T.); (I.A.Q.); (J.N.F.)
| | - Duah Dwomoh
- Department of Biological Environmental and Occupational Health Sciences, School of Public Health, University of Ghana, Accra 00233, Ghana; (J.A.-M.); (D.D.); (A.A.A.N.); (L.K.); (S.A.T.); (I.A.Q.); (J.N.F.)
| | - Afua Asabea Amoabeng Nti
- Department of Biological Environmental and Occupational Health Sciences, School of Public Health, University of Ghana, Accra 00233, Ghana; (J.A.-M.); (D.D.); (A.A.A.N.); (L.K.); (S.A.T.); (I.A.Q.); (J.N.F.)
| | - Lawrencia Kwarteng
- Department of Biological Environmental and Occupational Health Sciences, School of Public Health, University of Ghana, Accra 00233, Ghana; (J.A.-M.); (D.D.); (A.A.A.N.); (L.K.); (S.A.T.); (I.A.Q.); (J.N.F.)
| | - Sylvia A. Takyi
- Department of Biological Environmental and Occupational Health Sciences, School of Public Health, University of Ghana, Accra 00233, Ghana; (J.A.-M.); (D.D.); (A.A.A.N.); (L.K.); (S.A.T.); (I.A.Q.); (J.N.F.)
| | - Niladri Basu
- Faculty of Agricultural and Environmental Sciences, McGill University, Montréal, QC H9X 3V9, Canada;
| | - Isabella A. Quakyi
- Department of Biological Environmental and Occupational Health Sciences, School of Public Health, University of Ghana, Accra 00233, Ghana; (J.A.-M.); (D.D.); (A.A.A.N.); (L.K.); (S.A.T.); (I.A.Q.); (J.N.F.)
| | - Thomas G. Robins
- Department of Environmental Health Sciences, School of Public Health, University of Michigan, Ann Arbor, MI 48109-2029, USA;
| | - Julius N. Fobil
- Department of Biological Environmental and Occupational Health Sciences, School of Public Health, University of Ghana, Accra 00233, Ghana; (J.A.-M.); (D.D.); (A.A.A.N.); (L.K.); (S.A.T.); (I.A.Q.); (J.N.F.)
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7
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Acquah AA, D'Souza C, Martin B, Arko-Mensah J, Nti AA, Kwarteng L, Takyi S, Botwe PK, Tettey P, Dwomoh D, Quakyi IA, Robins TG, Fobil JN. Development of an observation-based tool for ergonomic exposure assessment in informal electronic waste recycling and other unregulated non-repetitive work. ACTA ACUST UNITED AC 2021; 64:905-909. [PMID: 33731982 DOI: 10.1177/1071181320641216] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Most existing ergonomic assessment tools are intended for routine work. Time- and cost-efficient observational tools for ergonomic assessment of unregulated work are lacking. This paper presents the development of an observation-based tool designed to investigate ergonomic exposures among informal electronic waste workers that could be applied to other unregulated jobs/tasks. Real time coding of observation is used to estimate the relative duration, intensity, and frequency of exposure to key work postures, forceful exertions, movements, contact stress and vibration. Time spent in manual material handling activities such as carrying, lifting and pushing/pulling of working carts are also estimated. A preliminary study conducted with 6 e-waste workers showed that the tool can easily be used with minimal training and good inter-observer agreement (i.e., 89% to 100%) for most risk factors assessed. This new assessment tool provides effective and flexible options for quantifying ergonomic exposures among workers engaged in unregulated, highly variable work.
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Affiliation(s)
- Augustine A Acquah
- Department of Biological Environmental and Occupational Health Sciences, School of Public Health, University of Ghana, Accra, Ghana
| | - Clive D'Souza
- Center for Ergonomics, Department of Industrial and Operations Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Bernard Martin
- Center for Ergonomics, Department of Industrial and Operations Engineering, University of Michigan, Ann Arbor, MI, USA
| | - John Arko-Mensah
- Department of Biological Environmental and Occupational Health Sciences, School of Public Health, University of Ghana, Accra, Ghana
| | - Afua Asabea Nti
- Department of Biological Environmental and Occupational Health Sciences, School of Public Health, University of Ghana, Accra, Ghana
| | - Lawrencia Kwarteng
- Department of Biological Environmental and Occupational Health Sciences, School of Public Health, University of Ghana, Accra, Ghana
| | - Sylvia Takyi
- Department of Biological Environmental and Occupational Health Sciences, School of Public Health, University of Ghana, Accra, Ghana
| | - Paul K Botwe
- Department of Biological Environmental and Occupational Health Sciences, School of Public Health, University of Ghana, Accra, Ghana
| | - Prudence Tettey
- Department of Biological Environmental and Occupational Health Sciences, School of Public Health, University of Ghana, Accra, Ghana
| | - Duah Dwomoh
- Department of Biological Environmental and Occupational Health Sciences, School of Public Health, University of Ghana, Accra, Ghana
| | - Isabella A Quakyi
- Department of Biological Environmental and Occupational Health Sciences, School of Public Health, University of Ghana, Accra, Ghana
| | - Thomas G Robins
- Environmental Health Sciences, School of Public Health, University of Michigan, Ann Arbor, MI, USA
| | - Julius N Fobil
- Department of Biological Environmental and Occupational Health Sciences, School of Public Health, University of Ghana, Accra, Ghana
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8
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Acquah AA, D'Souza C, Martin B, Arko-Mensah J, Nti AA, Kwarteng L, Takyi S, Quakyi IA, Robins TG, Fobil JN. Processes and Challenges associated with informal electronic waste recycling at Agbogbloshie, a suburb of Accra, Ghana. ACTA ACUST UNITED AC 2019; 63:938-942. [PMID: 33664560 DOI: 10.1177/1071181319631219] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Electronic waste (e-waste) is a worldwide problem with regards to its increasing rate in the global waste stream. Its recycling is known to be associated with adverse health outcomes. The recycling site at Agbogbloshie is a major e-waste recycling hub which presents enormous health threats to the residents in this community as a result of exposure to complex mixtures of chemicals associated with the poor work methods employed. This paper describes the processes involved in e-waste recycling at Agbogbloshie and discusses some of the associated health and psychosocial challenges. Direct field observations and in-depth interviews of eight e-waste workers were conducted from November, 2017 to December, 2017. Results from a thematic analysis of obtained data suggest that inappropriate recycling methods, financial constraints, and the high physical demands of e-waste recycling work were associated with adverse musculoskeletal health conditions among the workers. A more systematic ergonomic study is currently being undertaken to quantify the associations between physical work exposures and worker musculoskeletal health among e-waste workers in Agbogbloshie. Further studies are needed that focus on locally adapted ergonomic interventions for effective recycling of e-waste and reducing the health risk to workers.
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Affiliation(s)
- Augustine A Acquah
- Department of Biological Environmental and Occupational Health Sciences, School of Public Health, University of Ghana, Accra, Ghana
| | - Clive D'Souza
- Center for Ergonomics, Department of Industrial and Operations Engineering, University of Michigan, Ann Arbor, USA
| | - Bernard Martin
- Center for Ergonomics, Department of Industrial and Operations Engineering, University of Michigan, Ann Arbor, USA
| | - John Arko-Mensah
- Department of Biological Environmental and Occupational Health Sciences, School of Public Health, University of Ghana, Accra, Ghana
| | - Afua Amoabeng Nti
- Department of Biological Environmental and Occupational Health Sciences, School of Public Health, University of Ghana, Accra, Ghana
| | - Lawrencia Kwarteng
- Department of Biological Environmental and Occupational Health Sciences, School of Public Health, University of Ghana, Accra, Ghana
| | - Sylvia Takyi
- Department of Biological Environmental and Occupational Health Sciences, School of Public Health, University of Ghana, Accra, Ghana
| | - Isabella A Quakyi
- Department of Biological Environmental and Occupational Health Sciences, School of Public Health, University of Ghana, Accra, Ghana
| | - Thomas G Robins
- Environmental Health Sciences, School of Public Health, University of Michigan, Ann Arbor, USA
| | - Julius N Fobil
- Department of Biological Environmental and Occupational Health Sciences, School of Public Health, University of Ghana, Accra, Ghana
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Grabias B, Essuman E, Quakyi IA, Kumar S. Sensitive real-time PCR detection of Plasmodium falciparum parasites in whole blood by erythrocyte membrane protein 1 gene amplification. Malar J 2019; 18:116. [PMID: 30940128 PMCID: PMC6444846 DOI: 10.1186/s12936-019-2743-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Accepted: 03/21/2019] [Indexed: 01/13/2023] Open
Abstract
Background Malaria remains a global public health problem responsible for 445,000 deaths in 2016. While microscopy remains the mainstay of malaria diagnosis, highly sensitive molecular methods for detection of low-grade sub-microscopic infections are needed for surveillance studies and identifying asymptomatic reservoirs of malaria transmission. Methods The Plasmodium falciparum genome sequence was analysed to identify high copy number genes that improve P. falciparum parasite detection in blood by RT-PCR. Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1)-specific primers were evaluated for P. falciparum detection in hospital-based microscopically positive dried blood spots and field-acquired whole blood from asymptomatic individuals from Ghana. Results PfEMP1 outperformed the Pf18S sequence for amplification-based P. falciparum detection. PfEMP1 primers exhibited sevenfold higher sensitivity compared to Pf18S primers for parasite genomic DNA. Probit analysis established a 95% detection threshold of 9.3 parasites/mL for PfEMP1 compared to 98.2 parasites/mL for Pf18S primers. The PfEMP1 primers also demonstrated superior clinical sensitivity, identifying 100% (20/20) of dried blood spot samples and 70% (69/98) of asymptomatic individuals as positive versus 55% (11/20) and 54% (53/98), respectively, for Pf18S amplification. Conclusions These results establish PfEMP1 as a novel amplification target for highly sensitive detection of both acute infections from filter paper samples and submicroscopic asymptomatic low-grade infections.
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Affiliation(s)
- Bryan Grabias
- Laboratory of Emerging Pathogens, Division of Emerging and Transfusion Transmitted Diseases, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, MD, 20993, USA
| | - Edward Essuman
- Laboratory of Emerging Pathogens, Division of Emerging and Transfusion Transmitted Diseases, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, MD, 20993, USA
| | - Isabella A Quakyi
- Department of Biological Environmental and Occupational Health Sciences, School of Public Health, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Sanjai Kumar
- Laboratory of Emerging Pathogens, Division of Emerging and Transfusion Transmitted Diseases, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, MD, 20993, USA. .,Laboratory of Emerging Pathogens, Division of Emerging and Transfusion Transmitted Diseases, Center for Biologics Evaluation and Research, Food and Drug Administration, 10903 New Hampshire Ave. Building 52-72 Rm 5304, Silver Spring, MD, 20993, USA.
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Quakyi IA, Adjei GO, Sullivan DJ, Laar A, Stephens JK, Owusu R, Winch P, Sakyi KS, Coleman N, Krampa FD, Essuman E, Aubyn VNA, Boateng IA, Borteih BB, Vanotoo L, Tuakli J, Addison E, Bart-Plange C, Sorvor F, Adjei AA. Diagnostic capacity, and predictive values of rapid diagnostic tests for accurate diagnosis of Plasmodium falciparum in febrile children in Asante-Akim, Ghana. Malar J 2018; 17:468. [PMID: 30547795 PMCID: PMC6295071 DOI: 10.1186/s12936-018-2613-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2018] [Accepted: 12/05/2018] [Indexed: 12/04/2022] Open
Abstract
Background This study seeks to compare the performance of HRP2 (First Response) and pLDH/HRP2 (Combo) RDTs for falciparum malaria against microscopy and PCR in acutely ill febrile children at presentation and follow-up. Methods This is an interventional study that recruited children < 5 years who reported to health facilities with a history of fever within the past 72 h or a documented axillary temperature of 37.5 °C. Using a longitudinal approach, recruitment and follow-up of participants was done between January and May 2012. Based on results of HRP2-RDT screening, the children were grouped into one of the following three categories: (1) tested positive for malaria using RDT and received anti-malarial treatment (group 1, n = 85); (2) tested negative for malaria using RDT and were given anti-malarial treatment by the admitting physician (group 2, n = 74); or, (3) tested negative for malaria using RDT and did not receive any anti-malarial treatment (group 3, n = 101). Independent microscopy, PCR and Combo-RDT tests were done for each sample on day 0 and all follow-up days. Results Mean age of the study participants was 22 months and females accounted for nearly 50%. At the time of diagnosis, the mean body temperature was 37.9 °C (range 35–40.1 °C). Microscopic parasite density ranged between 300 and 99,500 parasites/µL. With microscopy as gold standard, the sensitivity of HRP2 and Combo-RDTs were 95.1 and 96.3%, respectively. The sensitivities, specificities and predictive values for RDTs were relatively higher in microscopy-defined malaria cases than in PCR positive-defined cases. On day 0, participants who initially tested negative for HRP2 were positive by microscopy (n = 2), Combo (n = 1) and PCR (n = 17). On days 1 and 2, five of the children in this group (initially HRP2-negative) tested positive by PCR alone. On day 28, four patients who were originally HRP2-negative tested positive for microscopy (n = 2), Combo (n = 2) and PCR (n = 4). Conclusion The HRP2/pLDH RDTs showed comparable diagnostic accuracy in children presenting with an acute febrile illness to health facilities in a hard-to-reach rural area in Ghana. Nevertheless, discordant results recorded on day 0 and follow-up visits using the recommended RDTs means improved malaria diagnostic capability in malaria-endemic regions is necessary.
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Affiliation(s)
- Isabella A Quakyi
- Department of Biological, Environmental and Occupational Health Sciences, School of Public Health, College of Health Sciences, University of Ghana, Legon, Accra, Ghana
| | - George O Adjei
- Centre for Tropical Clinical Pharmacology and Therapeutics, School of Medicine and Dentistry, University of Ghana, Accra, Ghana
| | - David J Sullivan
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe St, Baltimore, MD, 21205, USA
| | - Amos Laar
- Department of Population, Family, and Reproductive Health, School of Public Health, University of Ghana, Legon, Accra, Ghana
| | - Judith K Stephens
- Department of Biological, Environmental and Occupational Health Sciences, School of Public Health, College of Health Sciences, University of Ghana, Legon, Accra, Ghana
| | - Richmond Owusu
- Department of Health Policy, Planning and Management, School of Public Health, University of Ghana, Legon, Accra, Ghana
| | - Peter Winch
- Department of International Health, Social and Behavioural Interventions Program, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe St, Baltimore, MD, 21205, USA
| | - Kwame S Sakyi
- Department of Public and Environmental Wellness, Oakland University, 3101 Human Health Building, 433 Meadow Brook Rd, Rochester, MI, 48309-4452, USA
| | - Nathaniel Coleman
- Department of Biological, Environmental and Occupational Health Sciences, School of Public Health, College of Health Sciences, University of Ghana, Legon, Accra, Ghana
| | - Francis D Krampa
- Department of Biochemistry, Cell and Molecular Biology, University of Ghana, Legon, Accra, Ghana
| | - Edward Essuman
- Department of Biological, Environmental and Occupational Health Sciences, School of Public Health, College of Health Sciences, University of Ghana, Legon, Accra, Ghana
| | - Vivian N A Aubyn
- National Malaria Control Programme, Ministry of Health, Accra, Ghana
| | - Isaac A Boateng
- Asante-Akim Central Municipal Health Directorate, Ghana Health Services, Konongo, Ghana
| | - Bernard B Borteih
- Department of Biological, Environmental and Occupational Health Sciences, School of Public Health, College of Health Sciences, University of Ghana, Legon, Accra, Ghana
| | - Linda Vanotoo
- Regional Health Directorate, Ghana Health Services, Accra, Ghana
| | | | | | | | - Felix Sorvor
- Department of Biological, Environmental and Occupational Health Sciences, School of Public Health, College of Health Sciences, University of Ghana, Legon, Accra, Ghana
| | - Andrew A Adjei
- Worldwide Universities Network, University of Ghana, P.O. Box LG 13, Legon, Accra, Ghana.
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Lamptey H, Ofori MF, Kusi KA, Adu B, Owusu-Yeboa E, Kyei-Baafour E, Arku AT, Bosomprah S, Alifrangis M, Quakyi IA. The prevalence of submicroscopic Plasmodium falciparum gametocyte carriage and multiplicity of infection in children, pregnant women and adults in a low malaria transmission area in Southern Ghana. Malar J 2018; 17:331. [PMID: 30223841 PMCID: PMC6142636 DOI: 10.1186/s12936-018-2479-y] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Accepted: 09/10/2018] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND The gametocyte stage of Plasmodium falciparum is considered an important target for disrupting malaria transmission. Indications are that various demographic groups, such as children and pregnant women may differ in risk of harbouring gametocytes, which may be crucial for targeted control. In this study, the relationship between the prevalence and multiplicity of P. falciparum, asexual parasite infections and gametocytaemia was assessed in three different demographic groups in an area of southern Ghana with low malaria endemicity. Levels of antibody responses to Pfs230 were also assessed as a proxy for the presence of gametocytes. METHODS The study involved multiple cross-sectional sampling of children (N = 184, aged 2-15 years), male and non-pregnant female adults (N = 154, aged 16-65 years) and pregnant women (N = 125, aged 18-45 years) from Asutsuare in the Shai Osudoku District of Greater Accra Region in Ghana. Asexual parasitaemia was detected by microscopy and PCR, and gametocytaemia was assessed by Pfs25-real time PCR. Multiclonal P. falciparum infections were estimated by msp2 genotyping and an indirect ELISA was used to measure plasma IgG antibodies to Pfs230 antigen. RESULTS Overall, children and pregnant women had higher prevalence of submicroscopic gametocytes (39.5% and 29.7%, respectively) compared to adults (17.4%). Multiplicity of infection observed amongst children (3.1) and pregnant women (3.9) were found to be significantly higher (P = 0.006) compared with adults (2.7). Risk of gametocyte carriage was higher in individuals infected with P. falciparum having both Pfmsp2 3D7 and FC27 parasite types (OR = 5.92, 95% CI 1.56-22.54, P = 0.009) compared with those infected with only 3D7 or FC27 parasite types. In agreement with the parasite prevalence data, anti-Pfs230 antibody levels were lower in gametocyte positive adults (β = - 0.57, 95% CI - 0.81, - 0.34, P < 0.001) compared to children. CONCLUSIONS These findings suggest that children and pregnant women are particularly important as P. falciparum submicroscopic gametocyte reservoirs and represent important focus groups for control interventions. The number of clones increased in individuals carrying gametocytes compared to those who did not carry gametocytes. The higher anti-gametocyte antibody levels in children suggests recent exposure and may be a marker of gametocyte carriage.
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Affiliation(s)
- Helena Lamptey
- Immunology Department, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana.
| | - Michael Fokuo Ofori
- Immunology Department, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Kwadwo Asamoah Kusi
- Immunology Department, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Bright Adu
- Immunology Department, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Eunice Owusu-Yeboa
- Immunology Department, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Eric Kyei-Baafour
- Immunology Department, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Andrea Twumwaa Arku
- Immunology Department, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Samuel Bosomprah
- Department of Biostatistics, School of Public Health, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Michael Alifrangis
- Centre for Medical Parasitology, Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
- Department of Infectious Disease, National University Hospital (Rigshospitalet), Copenhagen, Denmark
| | - Isabella A Quakyi
- Department of Biological, Environmental and Occupational Health Sciences, School of Public Health, College of Health Sciences, University of Ghana, Legon, Ghana
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Quakyi IA, Adjei GO, Sullivan DJ, Stephens JK, Laar A, Ama Aubyn VN, Owusu R, Sakyi KS, Coleman N, Krampa FD, Vanotoo L, Tuakli J, Bortei BB, Essuman E, Sorvor F, Boateng IA, Bart-Plange C, Addison EA, Winch P, Adjei AA. Targeted community based interventions improved malaria management competencies in rural Ghana. Glob Health Res Policy 2017; 2:29. [PMID: 29202097 PMCID: PMC5683319 DOI: 10.1186/s41256-017-0048-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Accepted: 08/08/2017] [Indexed: 11/10/2022] Open
Abstract
Background Malaria is one of the most challenging public health concerns in the developing world. To address its impact in endemic regions, several interventions are implemented by stakeholders. The Affordable Medicine Facility-malaria (AMFm) is an example of such interventions. Its activities include communication interventions to enhance the knowledge of caregivers of children under five years, licensed chemical sellers (LCS) and prescribers on malaria management with artemisinin-based combination therapy (ACT). This study was conducted to evaluate the effectiveness of the AMFm activities on malaria among targeted groups in two rural communities in Ghana. Methods A communication intervention study was conducted in the Asante-Akim North and South Districts of Ghana. Repeated cross-sectional pre and post surveys were deployed. Relevant malaria messages were designed and used to develop the information, education and communication (IEC) tools for the intervention. With the aid of posters and flipcharts developed by our study, community health workers (CHWs), prescribers, and licenced chemical sellers provided proper counselling to clients on malaria management. Trained CHWs and community based volunteers educated caregivers of children under five years on malaria management at their homes and at public gatherings such as churches, mosques, schools. Chi-square tests and logistic regression were run to determine associations and control for demographic differences respectively. Results There was significantly high exposure to malaria/ACT interventions in the intervention district than in the comparison district (OR = 16.02; 95% CI = 7.88–32.55) and same for malaria/ACT-related knowledge (OR = 3.63; 95% CI = 2.52–5.23). The participants in the intervention district were also more knowledgeable about correct administration of dispersible drug for children <5 years than their counterparts in the unexposed district. Conclusion Our data show that targeted interventions improve malaria based competences in rural community settings. The availability of subsidized ACTs and the intensity of the communication campaigns contributed to the AMFm-related awareness, improved knowledge on malaria/ACTs and management practices.
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Affiliation(s)
- Isabella A Quakyi
- Department of Biological, Environmental and Occupational Health Sciences, School of Public Health, College of Health Sciences, University of Ghana, P.O. Box LG 13, Legon, Accra, Ghana
| | - George O Adjei
- Office of Research, Innovation and Development, University of Ghana, Legon, Accra, Ghana
| | - David J Sullivan
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe St, Baltimore, MD 21205 USA
| | - Judith K Stephens
- Department of Biological, Environmental and Occupational Health Sciences, School of Public Health, College of Health Sciences, University of Ghana, P.O. Box LG 13, Legon, Accra, Ghana
| | - Amos Laar
- Department of Population, Family, and Reproductive Health, School of Public Health, University of Ghana, Legon, Accra, Ghana
| | | | - Richmond Owusu
- Department of Health Policy, Planning and Management, School of Public Health, University of Ghana, Legon, Accra, Ghana
| | - Kwame S Sakyi
- Department of International Health, Social and Behavioural Interventions Program, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe St, Baltimore, MD 21205 USA
| | - Nathaniel Coleman
- Department of Biological, Environmental and Occupational Health Sciences, School of Public Health, College of Health Sciences, University of Ghana, P.O. Box LG 13, Legon, Accra, Ghana
| | - Francis D Krampa
- Department of Biochemistry, Cell and Molecular Biology, University of Ghana, Legon, Accra, Ghana
| | - Linda Vanotoo
- Regional Health Directorate, Ghana Health Services, Accra, Ghana
| | | | - Bernard B Bortei
- Department of Biological, Environmental and Occupational Health Sciences, School of Public Health, College of Health Sciences, University of Ghana, P.O. Box LG 13, Legon, Accra, Ghana
| | - Edward Essuman
- Department of Biological, Environmental and Occupational Health Sciences, School of Public Health, College of Health Sciences, University of Ghana, P.O. Box LG 13, Legon, Accra, Ghana
| | - Felix Sorvor
- Department of Biological, Environmental and Occupational Health Sciences, School of Public Health, College of Health Sciences, University of Ghana, P.O. Box LG 13, Legon, Accra, Ghana
| | - Isaac A Boateng
- Asante-Akim Central Municipal Health Directorate, Ghana Health Services, Konongo, Ghana
| | - Constance Bart-Plange
- Department of Biochemistry, Cell and Molecular Biology, University of Ghana, Legon, Accra, Ghana
| | - Ebenezer A Addison
- Kpone Katamanso District Health Directorate, Ghana Health Services, Kpone, Tema, Ghana
| | - Peter Winch
- Department of International Health, Social and Behavioural Interventions Program, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe St, Baltimore, MD 21205 USA
| | - Andrew A Adjei
- Worldwide Universities Network, University of Ghana, P.O. Box LG 13, Legon, Accra, Ghana
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Stephens JK, Kyei-Baafour E, Dickson EK, Ofori JK, Ofori MF, Wilson ML, Quakyi IA, Akanmori BD. Effect of IPTp on Plasmodium falciparum antibody levels among pregnant women and their babies in a sub-urban coastal area in Ghana. Malar J 2017; 16:224. [PMID: 28549426 PMCID: PMC5446726 DOI: 10.1186/s12936-017-1857-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2017] [Accepted: 05/12/2017] [Indexed: 12/31/2022] Open
Abstract
Background Women exposed to Plasmodium infection develop antibodies and become semi-immune. This immunity is suppressed during pregnancy making both the pregnant woman and the foetus vulnerable to the adverse effects of malaria, particularly by Plasmodium falciparum. Intermittent preventive treatment of malaria in pregnancy (IPTp) with Sulfadoxine–pyrimethamine (SP) tablets is one of the current interventions to mitigate the effects of malaria on both the pregnant woman and the unborn child. The extent to which IPTp may interfere with the acquisition of protective immunity against pregnancy-associated malaria (PAM) is undefined in Ghana. Methods Three-hundred-and-twenty pregnant women were randomly enrolled at the antenatal clinic (ANC) in Madina, Accra. Venous blood samples were obtained at first ANC registration and at 4-week intervals (post-IPTp administration). Placental and cord blood samples were obtained at delivery and the infants were followed monthly for 6 months after birth. Anti-IgG and IgM antibodies against a crude antigen preparation and the glutamate-rich protein (GLURP) of P. falciparum were quantified by the enzyme-linked immunosorbent assay (ELISA). Results There was a general decline in the trend of mean concentrations of all the antibodies from enrolment to delivery. The levels of antibodies in cord blood and placenta were well correlated. Children did not show clinical signs of malaria at 6 months after birth. Conclusions IgG against both crude antigen and GLURP were present in placenta and cord blood and it is therefore concluded that there is a trend of declining antibody from enrolment to delivery and IPTp-SP may have reduced malaria exposure, however, this does not impact on the transfer of antibodies to the foetus in utero. The levels of maternal and cord blood antibodies at delivery showed no adverse implications on malaria among the children at 6 months. However, the quantum and quality of the antibody transferred needs further investigation to ensure that the infants are protected from severe episodes of malaria.
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Affiliation(s)
- Judith K Stephens
- Biological, Environmental and Occupational and Health Sciences Department, School of Public Health, College of Health Sciences, University of Ghana, P. O. Box LG 13, Legon, Accra, Ghana.
| | - Eric Kyei-Baafour
- Immunology Department Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, P. O. Box LG 581, Legon, Accra, Ghana
| | - Emmanuel K Dickson
- Immunology Department Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, P. O. Box LG 581, Legon, Accra, Ghana
| | - Jones K Ofori
- Biological, Environmental and Occupational and Health Sciences Department, School of Public Health, College of Health Sciences, University of Ghana, P. O. Box LG 13, Legon, Accra, Ghana
| | - Michael F Ofori
- Immunology Department Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, P. O. Box LG 581, Legon, Accra, Ghana
| | - Mark L Wilson
- Department of Epidemiology, School of Public Health, The University of Michigan, 109 Observatory Street, Ann Arbor, MI, 48109-2029, USA
| | - Isabella A Quakyi
- Biological, Environmental and Occupational and Health Sciences Department, School of Public Health, College of Health Sciences, University of Ghana, P. O. Box LG 13, Legon, Accra, Ghana
| | - Bartholomew D Akanmori
- Immunology Department Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, P. O. Box LG 581, Legon, Accra, Ghana.,Vaccine Research and Development, Immunization and Vaccines Development Cluster, Office of the Regional Director, WHO Regional Office for Africa, P. O. Box 06, Djoue, Brazzaville, Congo
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Taylor DW, Bobbili N, Khadka VS, Quakyi IA, Leke RGF. Individuals living in a malaria-endemic area of Cameroon do not have an acquired antibody response to Plasmodium falciparum histidine-rich protein 2. Malar J 2017; 16:58. [PMID: 28148260 PMCID: PMC5286799 DOI: 10.1186/s12936-017-1704-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Accepted: 01/19/2017] [Indexed: 12/02/2022] Open
Abstract
Background Diagnosis of Plasmodium falciparum is often based on detection of histidine-rich protein 2 (HRP2) in blood. Most HRP2-based assays have high sensitivity and specificity; however, authors have suggested that antibodies (Ab) to HRP2 could reduce assay sensitivity. This study sought to characterize the antibody response to HRP2 with respect to prevalence, class, subclass, affinity, and age distribution in Cameroonian children and adults residing in an area with high P. falciparum transmission. Methods Plasma samples from 181 Cameroonian children and adults who had been repeatedly exposed to P. falciparum and 112 samples from American adults who had never been exposed were tested for IgG Ab to HRP2. For comparison, Ab to the merozoite antigens MSP1, MSP2, MSP3 and the pregnancy-associated antigen VAR2CSA were measured using a multiplex bead-based assay. In addition, 81 plasma samples from slide-positive individuals were screened for IgM Ab to HRP2. Results As expected, children and adults had IgG Ab to MSP1, MSP2 and MSP3, antibody levels increased with age, and only women of child-bearing age had Ab to VAR2CSA; however, no convincing evidence was found that these individuals had an acquired antibody response to HRP2. That is, using two sources of recombinant HRP2, identical results were obtained when plasma from 110 Cameroonian adults and 112 US adults were screened for IgG Ab. Further studies showed that antibody prevalence and levels did not increase with age in Cameroonians between ages 5 and >80 years. Although a few samples from slide-positive Cameroonians had IgM values slightly above the American cut-off, it was unclear if the individuals had a true IgM response to HRP2 or if the values were due to non-specific binding from elevated immunoglobulin levels associated with infection. Data from prediction models showed a paucity of Class II T cell epitopes in HRP2. Conclusions These data support the conclusion that most individuals in malaria-endemic areas do not produce an acquired humoral response to HRP2. The absence of Ab helps explain why HRP2-based assays are able to detect nanogram amounts of HRP2 and why HRP2 continues to circulate for a long time after parasite clearance.
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Affiliation(s)
- Diane Wallace Taylor
- Department of Tropical Medicine, Medical Microbiology and Pharmacology, John A. Burns School of Medicine, University of Hawaii at Manoa, 561 Ilalo Street, Honolulu, HI, 96813, USA.
| | - Naveen Bobbili
- Department of Tropical Medicine, Medical Microbiology and Pharmacology, John A. Burns School of Medicine, University of Hawaii at Manoa, 561 Ilalo Street, Honolulu, HI, 96813, USA
| | - Vedbar S Khadka
- Office of Biostatistics & Quantitative Health Sciences, John A. Burns School of Medicine, University of Hawaii at Manoa, 561 Ilalo Street, Honolulu, HI, 96813, USA
| | - Isabella A Quakyi
- Department of Biological, Environmental and Occupational Health Sciences, School of Public Health, College of Health Sciences, University of Ghana, Legon, P.O. Box LG 13, Accra, Ghana
| | - Rose G F Leke
- Faculty of Medicine and Biomedical Sciences, Biotechnology Center, University of Yaoundé I, Yaoundé, Cameroon
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Alnasser Y, Ferradas C, Clark T, Calderon M, Gurbillon A, Gamboa D, McKakpo US, Quakyi IA, Bosompem KM, Sullivan DJ, Vinetz JM, Gilman RH. Correction: Colorimetric Detection of Plasmodium vivax in Urine Using MSP10 Oligonucleotides and Gold Nanoparticles. PLoS Negl Trop Dis 2016; 10:e0005143. [PMID: 27828953 PMCID: PMC5102355 DOI: 10.1371/journal.pntd.0005143] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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Alnasser Y, Ferradas C, Clark T, Calderon M, Gurbillon A, Gamboa D, McKakpo US, Quakyi IA, Bosompem KM, Sullivan DJ, Vinetz JM, Gilman RH. Colorimetric Detection of Plasmodium vivax in Urine Using MSP10 Oligonucleotides and Gold Nanoparticles. PLoS Negl Trop Dis 2016; 10:e0005029. [PMID: 27706158 PMCID: PMC5051960 DOI: 10.1371/journal.pntd.0005029] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2016] [Accepted: 09/09/2016] [Indexed: 11/19/2022] Open
Abstract
Plasmodium vivax is the most prevalent cause of human malaria in the world and can lead to severe disease with high potential for relapse. Its genetic and geographic diversities make it challenging to control. P. vivax is understudied and to achieve control of malaria in endemic areas, a rapid, accurate, and simple diagnostic tool is necessary. In this pilot study, we found that a colorimetric system using AuNPs and MSP10 DNA detection in urine can provide fast, easy, and inexpensive identification of P. vivax. The test exhibited promising sensitivity (84%), high specificity (97%), and only mild cross-reactivity with P. falciparum (21%). It is simple to use, with a visible color change that negates the need for a spectrometer, making it suitable for use in austere conditions. Using urine eliminates the need for finger-prick, increasing both the safety profile and patient acceptance of this model.
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Affiliation(s)
- Yossef Alnasser
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America
- Universidad Peruana Cayetano Heredia, Lima, Peru
- King Saud University, Riyadh, Saudi Arabia
| | | | - Taryn Clark
- Universidad Peruana Cayetano Heredia, Lima, Peru
- Section of Emergency Medicine, Department of Medicine, Louisiana State University Health Sciences Center, New Orleans, Louisiana, United States of America
| | | | | | | | - Uri S. McKakpo
- School of Public Health and Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Accra, Ghana
| | - Isabella A. Quakyi
- School of Public Health and Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Accra, Ghana
| | - Kwabena M. Bosompem
- School of Public Health and Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Accra, Ghana
| | - David J. Sullivan
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | - Joseph M. Vinetz
- Universidad Peruana Cayetano Heredia, Lima, Peru
- University of California San Diego, San Diego, California, United States of America
| | - Robert H. Gilman
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America
- Universidad Peruana Cayetano Heredia, Lima, Peru
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Markakpo US, Bosompem KM, Dzodzomenyo M, Danso-Appiah A, Essuman EE, Anyan WK, Suzuki M, Stephens JK, Anim-Baidoo I, Asmah RH, Ofori MF, Madjitey P, Danquah JB, Frempong NA, Kwofie KD, Amoa-Bosompem M, Sullivan D, Fobil JN, Quakyi IA. Minimising invasiveness in diagnostics: developing a rapid urine-based monoclonal antibody dipstick test for malaria. Trop Med Int Health 2016; 21:1263-1271. [PMID: 27546068 DOI: 10.1111/tmi.12744] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
OBJECTIVE To generate monoclonal antibodies (MAbs) for developing a rapid malaria diagnostic urine-based assay (RUBDA), using Plasmodium-infected human urinary antigens. METHODS Plasmodium-infected human urinary (PAgHU) and cultured parasite (CPfAg) antigens were used to generate mouse MAbs. The reactivity and accuracy of the MAbs produced were then evaluated using microplate ELISA, SDS-PAGE, Western blotting assay, microscopy and immunochromatographic tests. RESULTS Ninety-six MAb clones were generated, of which 68.8% reacted to both PAgHU and CPfAg, 31.3% reacted to PAgHU only, and none reacted to CPfAg only. One promising MAb (UCP4W7) reacted in WBA, to both PAgHU and CPfAg, but not to Plasmodium-negative human urine and blood, Schistosoma haematobium and S. mansoni antigens nor measles and poliomyelitis vaccines. CONCLUSION MAb UCP4W7 seems promising for diagnosing Plasmodium infection. Urine is a reliable biomarker source for developing non-invasive malaria diagnostic tests. SDS-PAGE and MAb-based WBA appear explorable in assays for detecting different levels of Plasmodium parasitaemia.
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Affiliation(s)
- Uri S Markakpo
- School of Public Health, University of Ghana, Legon, Ghana. .,Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana.
| | - Kwabena M Bosompem
- Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana
| | | | | | | | - William K Anyan
- Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana
| | - Mitsuko Suzuki
- Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana.,Section of Environmental Parasitology, Tokyo Medical and Dental University, Tokyo, Japan
| | | | - Isaac Anim-Baidoo
- School of Allied Health Sciences, University of Ghana, Korlebu, Ghana
| | - Richard H Asmah
- School of Allied Health Sciences, University of Ghana, Korlebu, Ghana
| | - Michael F Ofori
- Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana
| | | | | | - Naa Adjeley Frempong
- Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana
| | - Kofi D Kwofie
- Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana
| | | | - David Sullivan
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Julius N Fobil
- School of Public Health, University of Ghana, Legon, Ghana
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Adjei AA, Winch P, Laar A, Sullivan DJ, Sakyi KS, Stephens JK, Adjei GO, Boateng IA, Aubyn VNA, Kubio C, Tuakli J, Vanotoo L, Bortei BB, Amo-Addae M, Sorvor F, Coleman N, Dalglish S, Owusu R, Gebreyesus T, Essuman E, Greene R, Ankomah E, Houston K, Bart-Plange C, Salamat S, Addison EA, Quakyi IA. Insights into the Affordable Medicines Facility-malaria in Ghana: the role of caregivers and licensed chemical sellers in four regions. Malar J 2016; 15:263. [PMID: 27160685 PMCID: PMC4862058 DOI: 10.1186/s12936-016-1307-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 04/23/2016] [Indexed: 12/03/2022] Open
Abstract
Background The Affordable Medicine Facility-malaria (AMFm) was an innovative global financing mechanism for the provision of quality-assured artemisinin-based combination therapy (ACT) across both the private and public health sectors in eight countries in sub-Saharan Africa. This study evaluated the effectiveness of AMFm subsidies in increasing access to ACT in Ghana and documented malaria management practices at the household and community levels during the implementation of the AMFm. Methods This study, conducted in four regions in Ghana between January, 2011 to December, 2012, employed cross-sectional mixed-methods design that included qualitative and quantitative elements, specifically household surveys, focus group discussions (FGD) and in-depth interviews. Results The study indicated high ACT availability, adequate provider knowledge and reasonably low quality-assured ACT use in the study areas, all of which are a reflection of a high market share of ACT in these hard-to-reach areas of the country. Adequate recognition of childhood malaria symptoms by licensed chemical seller (LCS) attendants was observed. A preference by caregivers for LCS over health facilities for seeking treatment solutions to childhood malaria was found. Conclusions Artemisinin-based combination therapy with the AMFm logo was accessible and affordable for most people seeking treatment from health facilities and LCS shops in rural areas. Caregivers and LCS were seen to play key roles in the health of the community especially with children under 5 years of age.
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Affiliation(s)
- Andrew A Adjei
- Office of Research, Innovation and Development, University of Ghana, Legon, Accra, Ghana
| | - Peter Winch
- Department of International Health, Social and Behavioural Interventions Program, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe St, Baltimore, MD, 21205, USA
| | - Amos Laar
- Department of Population, Family, and Reproductive Health, School of Public Health, University of Ghana, Legon, Accra, Ghana
| | - David J Sullivan
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe St, Baltimore, MD, 21205, USA
| | - Kwame S Sakyi
- Department of International Health, Social and Behavioural Interventions Program, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe St, Baltimore, MD, 21205, USA
| | - Judith K Stephens
- Department of Biological, Environmental and Occupational Health Sciences, School of Public Health, College of Health Sciences, University of Ghana, P.O. Box LG 13, Legon, Accra, Ghana
| | - George O Adjei
- Centre for Tropical, Clinical, Pharmacology and Therapeutics, School of Medicine and Dentistry, College of Health Sciences, University of Ghana, Legon, Accra, Ghana
| | - Isaac A Boateng
- Ashanti Akim Central Municipal Health Directorate, Ghana Health Services, Konongo, Ghana
| | | | | | | | - Linda Vanotoo
- Regional Health Directorate, Ghana Health Services, Accra, Ghana
| | - Bernard B Bortei
- Department of Biological, Environmental and Occupational Health Sciences, School of Public Health, College of Health Sciences, University of Ghana, P.O. Box LG 13, Legon, Accra, Ghana
| | - Maame Amo-Addae
- Shama District Health Directorate, Ghana Health Services, Shama, Ghana
| | - Felix Sorvor
- Department of Biological, Environmental and Occupational Health Sciences, School of Public Health, College of Health Sciences, University of Ghana, P.O. Box LG 13, Legon, Accra, Ghana
| | - Nathaniel Coleman
- Department of Biological, Environmental and Occupational Health Sciences, School of Public Health, College of Health Sciences, University of Ghana, P.O. Box LG 13, Legon, Accra, Ghana
| | - Sarah Dalglish
- Department of International Health, Social and Behavioural Interventions Program, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe St, Baltimore, MD, 21205, USA
| | - Richmond Owusu
- Department of Biological, Environmental and Occupational Health Sciences, School of Public Health, College of Health Sciences, University of Ghana, P.O. Box LG 13, Legon, Accra, Ghana
| | - Tsega Gebreyesus
- Department of International Health, Social and Behavioural Interventions Program, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe St, Baltimore, MD, 21205, USA
| | - Edward Essuman
- Department of Biological, Environmental and Occupational Health Sciences, School of Public Health, College of Health Sciences, University of Ghana, P.O. Box LG 13, Legon, Accra, Ghana
| | - Rebecca Greene
- Department of Paediatrics, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Ezekiel Ankomah
- Department of Biological, Environmental and Occupational Health Sciences, School of Public Health, College of Health Sciences, University of Ghana, P.O. Box LG 13, Legon, Accra, Ghana
| | - Kiely Houston
- Department of International Health, Social and Behavioural Interventions Program, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe St, Baltimore, MD, 21205, USA
| | | | - Samuel Salamat
- Department of Biological, Environmental and Occupational Health Sciences, School of Public Health, College of Health Sciences, University of Ghana, P.O. Box LG 13, Legon, Accra, Ghana
| | - Ebenezer A Addison
- Kpone Katamanso District Health Directorate, Ghana Health Services, Kpone, Tema, Ghana
| | - Isabella A Quakyi
- Department of Biological, Environmental and Occupational Health Sciences, School of Public Health, College of Health Sciences, University of Ghana, P.O. Box LG 13, Legon, Accra, Ghana.
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Laar AK, Grant FE, Addo Y, Soyiri I, Nkansah B, Abugri J, Laar AS, Ampofo WK, Tuakli JM, Quakyi IA. Predictors of fetal anemia and cord blood malaria parasitemia among newborns of HIV-positive mothers. BMC Res Notes 2013; 6:350. [PMID: 24007344 PMCID: PMC3844504 DOI: 10.1186/1756-0500-6-350] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Accepted: 08/30/2013] [Indexed: 12/02/2022] Open
Abstract
Background Malaria and HIV infections during pregnancy can individually or jointly unleash or confound pregnancy outcomes. Two of the probable outcomes are fetal anemia and cord blood malaria parasitemia. We determined clinical and demographic factors associated with fetal anemia and cord blood malaria parasitemia in newborns of HIV-positive women from two districts in Ghana. Results We enrolled 1,154 antenatal attendees (443 HIV-positive and 711 HIV-negative) of which 66% were prospectively followed up at delivery. Maternal malaria parasitemia, and anemia rates among HIV+ participants at enrolment were 20.3% and 78.7% respectively, and 12.8% and 51.6% among HIV- participants. Multivariate linear and logistic regression models were used to study associations. Prevalence of fetal anemia (cord hemoglobin level < 12.5 g/dL) and cord parasitemia (presence of P. falciparum in cord blood at delivery) were 57.3% and 24.4% respectively. Factors found to be associated with fetal anemia were maternal malaria parasitemia and maternal anemia. Infant cord hemoglobin status at delivery was positively and significantly associated with maternal hemoglobin and gestational age whilst female gender of infant was negatively associated with cord hemoglobin status. Maternal malaria parasitemia status at recruitment and female gender of infant were positively associated with infant cord malaria parasitemia status. Conclusions Our data show that newborns of women infected with HIV and/or malaria are at increased risk of anemia and also cord blood malaria parasitemia. Prevention of malaria infection during pregnancy may reduce the incidence of both adverse perinatal outcomes.
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Affiliation(s)
- Amos K Laar
- Department of Population, Family, & Reproductive Health, School of Public Health, College of Health Sciences, University of Ghana, Box LG 13, Legon, Accra, Ghana.
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Tchouassi DP, Quakyi IA, Addison EA, Bosompem KM, Wilson MD, Appawu MA, Brown CA, Boakye DA. Characterization of malaria transmission by vector populations for improved interventions during the dry season in the Kpone-on-Sea area of coastal Ghana. Parasit Vectors 2012; 5:212. [PMID: 23013551 PMCID: PMC3495633 DOI: 10.1186/1756-3305-5-212] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2012] [Accepted: 09/13/2012] [Indexed: 11/17/2022] Open
Abstract
Background Malaria is a major public health problem in Ghana. We present a site-specific entomological study of malaria vectors and transmission indices as part of an effort to develop a site for the testing of improved control strategies including possible vaccine trials. Methods Pyrethrum spray catches (PSC), and indoor and outdoor human landing collections of adult female anopheline mosquitoes were carried out over a six-month period (November 2005 - April 2006) at Kpone-on-Sea, a fishing village in southern Ghana. These were morphologically identified to species level and sibling species of the Anopheles gambiae complex further characterized by the polymerase chain reaction (PCR). Enzyme-linked immunosorbent assay was used to detect Plasmodium falciparum mosquito infectivity and host blood meal sources. Parity rate was examined based on dilatation of ovarian tracheoles following dissection. Results Of the 1233 Anopheles mosquitoes collected, An. gambiae s.l. was predominant (99.5%), followed by An. funestus (0.4%) and An. pharoensis (0.1%). All An. gambiae s.l. examined (480) were identified as An. gambiae s.s. with a majority of M molecular form (98.2%) and only 1.8% S form with no record of M/S hybrid. A significantly higher proportion of anophelines were observed outdoors relative to indoors (χ2 = 159.34, df = 1, p < 0.0000). Only An. gambiae M molecular form contributed to transmission with a high degree of anthropophily, parity rate and an estimated entomological inoculation rate (EIR) of 62.1 infective bites/person/year. The Majority of the infective bites occurred outdoors after 09.00 pm reaching peaks between 12.00-01.00 am and 03.00-04.00 am. Conclusion Anopheles gambiae M molecular form is responsible for maintaining the status quo of malaria in the surveyed site during the study period. The findings provide a baseline for evidence-based planning and implementation of improved malaria interventions. The plasticity observed in biting patterns especially the combined outdoor and early biting behavior of the vector may undermine the success of insecticide-based strategies using insecticide treated nets (ITN) and indoor residual spray (IRS). As such, novel or improved vector interventions should be informed by the local malaria epidemiology data as it relates to vector behavior.
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Mahajan B, Zheng H, Pham PT, Sedegah MY, Majam VF, Akolkar N, Rios M, Ankrah I, Madjitey P, Amoah G, Addison E, Quakyi IA, Kumar S. Polymerase chain reaction-based tests for pan-species and species-specific detection of human Plasmodium parasites. Transfusion 2012. [PMID: 22320188 DOI: 10.1111/j.1537-2995.2011.03541] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BACKGROUND There is still a need to improve the sensitivity of polymerase chain reaction (PCR) tests for malaria to detect submicroscopic asexual stage Plasmodium infections during the early phase and chronic, asymptomatic phase of infection when the parasite burden is very low. STUDY DESIGN AND METHODS The inhibitory effect of hemoglobin (Hb) on PCR limits the volume of blood that can be used in the PCR-based detection of intraerythrocytic Plasmodium parasites. We lysed red blood cells with saponin to reduce the Hb concentration in extracted nucleic acid and, as a result, significantly increased the volume of blood that can be tested by PCR. The analytical sensitivity of the PCR was determined using whole blood spiked with ring-stage Plasmodium falciparum parasites, and its clinical sensitivity by testing blood film-positive and blood film-negative samples from individuals living in an endemic area in Ghana. RESULTS We have developed a pan-Plasmodium PCR that detects all five human Plasmodium species with the highest analytical sensitivity of two P. falciparum parasites/mL of whole blood and species-specific PCR tests that distinguished between the five human Plasmodium species. Pan-Plasmodium PCR detected 78 of 78 (100%) blood film-positive and 19 of 101 (18.81%) blood film-negative samples from asymptomatic individuals living in Ghana. Pan-Plasmodium PCR was equally sensitive with samples collected as anticoagulated whole blood and clotted blood and in blood collected by finger stick into capillaries. CONCLUSION We have developed PCR tests with the highest reported sensitivity to date for pan-Plasmodium diagnosis and species-specific diagnosis and detected blood film-negative asymptomatic infections in individuals living in malaria-endemic countries.
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Affiliation(s)
- Babita Mahajan
- Laboratory of Emerging Pathogens, Division of Emerging and Transfusion Transmitted Diseases, Office of Blood Research and Review, Center for Biologics Evaluation and Research, US Food and Drug Administration, Rockville, Maryland 20852, USA
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Mahajan B, Zheng H, Pham PT, Sedegah MY, Majam VF, Akolkar N, Rios M, Ankrah I, Madjitey P, Amoah G, Addison E, Quakyi IA, Kumar S. Polymerase chain reaction-based tests for pan-species and species-specific detection of human Plasmodium parasites. Transfusion 2012; 52:1949-56. [DOI: 10.1111/j.1537-2995.2011.03541.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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Howard CT, McKakpo US, Semba RD, Quakyi IA, Sullivan D, Addison EA, Sun K, Bosompem KM. Relationship of Hepcidin with Parasitemia and Anemia among Patients with Uncomplicated Plasmodium falciparum Malaria in Ghana. Am J Trop Med Hyg 2007. [DOI: 10.4269/ajtmh.2007.77.623] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Howard CT, McKakpo US, Quakyi IA, Bosompem KM, Addison EA, Sun K, Sullivan D, Semba RD. Relationship of hepcidin with parasitemia and anemia among patients with uncomplicated Plasmodium falciparum malaria in Ghana. Am J Trop Med Hyg 2007; 77:623-626. [PMID: 17978060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2023] Open
Abstract
The pathogenesis of malarial anemia is incompletely understood. Hepcidin, a recently discovered peptide hormone, is a major regulator of iron metabolism and is thought to play a central role in the anemia of chronic inflammation. The specific aim of the study was to characterize the association between urinary hepcidin, hemoglobin, and parasitemia in 199 patients presenting for evaluation of Plasmodium falciparum malaria in Ghana. Urinary hepcidin was semi-quantitatively assessed using surface-enhanced laser desorption/ionization time-of-flight mass spectrometry. Urinary hepcidin (intensity/mmol creatinine) was associated with log parasitemia in 86 children (beta = 0.086, standard error [SE] = 0.035, P < 0.017), 31 pregnant women (beta = 0.218, SE = 0.085, P < 0.016), and 82 adults (beta = 0.184, SE =0.043, P < 0.0001). Urinary hepcidin was not significantly associated with hemoglobin or anemia. Urinary hepcidin is more strongly associated with parasitemia than hemoglobin or anemia among patients with acute P. falciparum malaria in Ghana.
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Affiliation(s)
- Caitlin T Howard
- Johns Hopkins Medical Institutions, Baltimore, Maryland 21205, USA
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Johnson AH, Leke RGF, Mendell NR, Shon D, Suh YJ, Bomba-Nkolo D, Tchinda V, Kouontchou S, Thuita LW, van der Wel AM, Thomas A, Stowers A, Saul A, Zhou A, Taylor DW, Quakyi IA. Human leukocyte antigen class II alleles influence levels of antibodies to the Plasmodium falciparum asexual-stage apical membrane antigen 1 but not to merozoite surface antigen 2 and merozoite surface protein 1. Infect Immun 2004; 72:2762-71. [PMID: 15102786 PMCID: PMC387839 DOI: 10.1128/iai.72.5.2762-2771.2004] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The apical membrane antigen 1 (AMA1), merozoite surface antigen 2 (MSA2), and merozoite surface protein 1 (MSP1) are asexual-stage proteins currently being evaluated for inclusion in a vaccine for Plasmodium falciparum. Accordingly, it is important to understand factors that control antibody responses to these antigens. Antibody levels in plasma from residents of Etoa, Cameroon, between the ages of 5 and 70 years, were determined using recombinant AMA1, MSA2, and the N-terminal region of MSP1 (MSP1-190L). In addition, antibody responses to four variants of the C-terminal region of MSP1 (MSP1(19)) were assessed. Results showed that all individuals produced antibodies to AMA1, MSA2, and MSP1-190L; however, a proportion of individuals never produced antibodies to the MSP1(19) variants, although the percentage of nonresponders decreased with age. The influence of age and human leukocyte antigen (HLA)-DRB1/DQB1 alleles on antibody levels was evaluated using two-way analysis of variance. Age was correlated with levels of antibodies to AMA1 and MSP1(19) but not with levels of antibodies to MSA2 and MSP1-190L. No association was found between a single HLA allele and levels of antibodies to MSA2, MSP1-190L, or any of the MSP1(19) variants. However, individuals positive for DRB1*1201 had higher levels of antibodies to the variant of recombinant AMA1 tested than did individuals of all other HLA types. Since the effect was seen across all age groups, HLA influenced the level but not the rate of antibody acquisition. This association for AMA1, combined with the previously reported association between HLA class II alleles and levels of antibodies to rhoptry-associated protein 1 (RAP1) and RAP2, indicates that HLA influences the levels of antibodies to three of the five vaccine candidate antigens that we have evaluated.
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Affiliation(s)
- Armead H Johnson
- Departments of Pediatrics, Georgetown University, Washington, DC 20057, USA.
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Quakyi IA, Ahlers JD. Assessing CD4+ helper T-lymphocyte responses by lymphoproliferation. Methods Mol Med 2003; 72:369-83. [PMID: 12125133 DOI: 10.1385/1-59259-271-6:369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
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Ryan JR, Davé K, Collins KM, Hochberg L, Sattabongkot J, Coleman RE, Dunton RF, Bangs MJ, Mbogo CM, Cooper RD, Schoeler GB, Rubio-Palis Y, Magris M, Romer LI, Padilla N, Quakyi IA, Bigoga J, Leke RG, Akinpelu O, Evans B, Walsey M, Patterson P, Wirtz RA, Chan AST. Extensive multiple test centre evaluation of the VecTest malaria antigen panel assay. Med Vet Entomol 2002; 16:321-327. [PMID: 12243234 DOI: 10.1046/j.1365-2915.2002.00368.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
To determine which species and populations of Anopheles transmit malaria in any given situation, immunological assays for malaria sporozoite antigen can replace traditional microscopical examination of freshly dissected Anopheles. We developed a wicking assay for use with mosquitoes that identifies the presence or absence of specific peptide epitopes of circumsporozoite (CS) protein of Plasmodium falciparum and two strains of Plasmodium vivax (variants 210 and 247). The resulting assay (VecTest Malaria) is a rapid, one-step procedure using a 'dipstick' test strip capable of detecting and distinguishing between P. falciparum and P. vivax infections in mosquitoes. The objective of the present study was to test the efficacy, sensitivity, stability and field-user acceptability of this wicking dipstick assay. In collaboration with 16 test centres world-wide, we evaluated more than 40 000 units of this assay, comparing it to the standard CS ELISA. The 'VecTest Malaria' was found to show 92% sensitivity and 98.1% specificity, with 97.8% accuracy overall. In accelerated storage tests, the dipsticks remained stable for > 15 weeks in dry conditions up to 45 degrees C and in humid conditions up to 37 degrees C. Evidently, this quick and easy dipstick test performs at an acceptable level of reliability and offers practical advantages for field workers needing to make rapid surveys of malaria vectors.
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Affiliation(s)
- J R Ryan
- Department of Entomology, Walter Reed Army Institute of Research, Silver Spring, MD 20910-7500, USA.
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Ellis JM, Hoyer RJ, Costello CN, Mshana RN, Quakyi IA, Mshana MN, Diaby B, Traore M, Johnson AH, Hurley CK. HLA-B allele frequencies in Côte d'Ivoire defined by direct DNA sequencing: identification of HLA-B*1405, B*4410, and B*5302. Tissue Antigens 2001; 57:339-43. [PMID: 11380943 DOI: 10.1034/j.1399-0039.2001.057004339.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Direct automated DNA sequencing was used to analyze exons 2 and 3 of HLA-B alleles present in forty-four unrelated individuals residing in the village of Adiopodoume, Côte d'Ivoire (Ivory Coast). Of the 23 HLA-B alleles observed, the most frequently detected allele was HLA-B*5301 (22.7%), which is believed to confer resistance to severe Plasmodium falciparum malaria. B*4501 (9.1%), B*1503 (8.0%), B*0705 (5.7%), B*1510 (5.7%) and B*3501 (5.7%) occurred frequently in the population. A second allele of B53 was identified; B*5302 contains a single amino acid variation at residue 171 (Y-->H). Two additional novel alleles, B* 1405 (a single amino acid variant of B*1402) and B*4410 (a five amino acid variant of B*4403) were characterized.
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Affiliation(s)
- J M Ellis
- Department of Microbiology and Immunology, Georgetown University Medical Center, Washington, DC, USA
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Quakyi IA, Ndoutse L, Ngu J, Lohoue J, Fogako J, Befidi-Mengue R, Harun LT, Eno A, Walker-Abbey A, Folefack A, Alake G, Taylor DW, Tchinda V, Megnekou R, Ndountse L, Tietche F, Wansi E, Leke RG, Titanji V, Leke R, Sama G, Manga L, Johnson AH, Mvondo JL, Nyonglema P, Djokam R, Bomba-Nkolo C, Tsafack M, Hickey MA, Bigoga J, Bomba-Nkolo D, Kouontchou S, Meli J, Njeungue E, Metenou S, Same-Ekobo A. The epidemiology of Plasmodium falciparum malaria in two Cameroonian villages: Simbok and Etoa. Am J Trop Med Hyg 2000. [DOI: 10.4269/ajtmh.2000.63.222] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Quakyi IA, Leke RG, Befidi-Mengue R, Tsafack M, Bomba-Nkolo D, Manga L, Tchinda V, Njeungue E, Kouontchou S, Fogako J, Nyonglema P, Harun LT, Djokam R, Sama G, Eno A, Megnekou R, Metenou S, Ndountse L, Same-Ekobo A, Alake G, Meli J, Ngu J, Tietche F, Lohoue J, Mvondo JL, Wansi E, Leke R, Folefack A, Bigoga J, Bomba-Nkolo C, Titanji V, Walker-Abbey A, Hickey MA, Johnson AH, Taylor DW, Ndoutse L. The epidemiology of Plasmodium falciparum malaria in two Cameroonian villages: Simbok and Etoa. Am J Trop Med Hyg 2000; 63:222-30. [PMID: 11421368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2023] Open
Abstract
In support of ongoing immunologic studies on immunity to Plasmodium falciparum, demographic, entomologic, parasitologic, and clinical studies were conducted in two Cameroonian villages located 3 km apart. Simbok (population = 907) has pools of water present year round that provide breeding sites for Anopheles gambiae, whereas Etoa (population = 485) has swampy areas that dry up annually in which A. funestus breed. Results showed that individuals in Simbok receive an estimated 1.9 and 1.2 infectious bites per night in the wet and dry season, respectively, whereas individuals in Etoa receive 2.4 and 0.4 infectious bites per night, respectively. Although transmission patterns differ, the rate of acquisition of immunity to malaria appears to be similar in both villages. A prevalence of 50-75% was found in children < 10 years old, variable levels in children 11-15 years old, and 31% in adults. Thus, as reported in other parts of Africa, individuals exposed to continuous transmission of P. falciparum slowly acquired significant, but not complete, immunity.
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Affiliation(s)
- I A Quakyi
- Department of Biology, Reiss Science Center, Georgetown University, Washington, District of Columbia 20057, USA
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Parra M, Hui G, Johnson AH, Berzofsky JA, Roberts T, Quakyi IA, Taylor DW. Characterization of conserved T- and B-cell epitopes in Plasmodium falciparum major merozoite surface protein 1. Infect Immun 2000; 68:2685-91. [PMID: 10768960 PMCID: PMC97475 DOI: 10.1128/iai.68.5.2685-2691.2000] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Vaccines for P. falciparum will need to contain both T- and B-cell epitopes. Conserved epitopes are the most desirable, but they are often poorly immunogenic. The major merozoite surface protein 1 (MSP-1) is currently a leading vaccine candidate antigen. In this study, six peptides from conserved or partly conserved regions of MSP-1 were evaluated for immunogenicity in B10 congenic mice. Following immunization with the peptides, murine T cells were tested for the ability to proliferate in vitro and antibody responses to MSP-1 were evaluated in vivo. The results showed that one highly conserved sequence (MSP-1#1, VTHESYQELVKKLEALEDAV; located at amino acid positions 20 to 39) and one partly conserved sequence (MSP-1#23, GLFHKEKMILNEEEITTKGA; located at positions 44 to 63) contained both T- and B-cell epitopes. Immunization of mice with these peptides resulted in T-cell proliferation and enhanced production of antibody to MSP-1 upon exposure to merozoites. MSP-1#1 stimulated T-cell responses in three of the six strains of mice evaluated, whereas MSP-1#23 was immunogenic in only one strain. Immunization with the other four peptides resulted in T-cell responses to the peptides, but none of the resulting peptide-specific T cells recognized native MSP-1. These results demonstrate that two sequences located in the N terminus of MSP-1 can induce T- and B-cell responses following immunization in a murine model. Clearly, these sequences merit further consideration for inclusion in a vaccine for malaria.
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Affiliation(s)
- M Parra
- Departments of Biology, Georgetown University, Washington, DC 20057, USA.
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Johnson A, Leke R, Harun L, Ginsberg C, Ngogang J, Stowers A, Saul A, Quakyi IA. Interaction of HLA and age on levels of antibody to Plasmodium falciparum rhoptry-associated proteins 1 and 2. Infect Immun 2000; 68:2231-6. [PMID: 10722624 PMCID: PMC97408 DOI: 10.1128/iai.68.4.2231-2236.2000] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Plasmodium falciparum rhoptry-associated proteins 1 and 2 (RAP1 and RAP2) are candidate antigens for a subunit malaria vaccine. The design of the study, which looks at the acquisition of immunity to malaria from childhood to old age, has allowed us to document the interaction of HLA and age on levels of antibody to specific malarial antigens. Antibodies reach maximum levels to RAP1 after the age of 15 but to RAP2 only after the age of 30. The effect of HLA-DRB1 and -DQB1 and age on levels of antibody to rRAP1 and rRAP2 was analyzed with a multiple regression model in which all HLA alleles and age were independent variables. DQB1*0301 and -*03032 showed an age-dependent association with levels of antibody to rRAP1, being significant in children 5 to 15 years (P < 0.001) but not in individuals over 15 years of age. DRB1*03011 showed an age-dependent association with antibody levels to rRAP2; however, this association was in adults over the age of 30 years (P < 0.01) but not in individuals under the age of 30 years. No associations were detected between DRB1 alleles and RAP1 antibody levels or between DQB1 alleles and RAP2 antibody levels. Thus, not only the HLA allele but also the age at which an interaction is manifested varies for different malarial antigens. The interaction may influence either the rate of acquisition of antibody or the final level of antibody acquired by adults.
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Affiliation(s)
- A Johnson
- Pediatrics, Georgetown University, Washington, D.C., USA.
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33
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Quakyi IA, Miller LH, Good MF, Ahlers JD, Isaacs SN, Nunberg JH, Houghten RA, Keister DB, Coligan JE, Moss B. Synthetic peptides from P. falciparum sexual stage 25-kDa protein induce antibodies that react with the native protein: the role of IL-2 and conformational structure on immunogenicity of Pfs25. Pept Res 1995; 8:335-44. [PMID: 8838417] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
To identify B-cell epitopes of the Plasmodium falciparum 25-kDa ookinete protein, Pfs25, 41 overlapping synthetic peptides spanning the entire length of the protein were used individually to immunize CAF1 (F1 hybrid of BALB/c female and A/J male) mice. Antipeptide sera were tested for reactivity to live intact zygote/early ookinete (post-fertilization stage) by immunofluorescence, and by Western blot analysis under nonreducing and reducing conditions, immunoprecipitation of 35S-cysteine-labeled antigen, and ELISA using a vaccinia recombinant Pfs25 antigen. Fourteen B-cell epitopes were identified. These peptides were immunogenic only when administered with high-dose recombinant interleukin-2. Antibodies to 11 peptides recognized only the native conformational structure, one peptide induced antibodies that recognized both reduced and native protein, and two other peptides, after primary immunization, made antibodies to denatured Pfs25, but after boosting the antibodies reacted to both denatured and native Pfs25. Anti-sera to peptides in the first (peptide 7) and fourth (peptide 34) epidermal growth factor-like domains of Pfs25 reacted most strongly with zygotes/ookinetes by immunofluorescence assay. The antibodies elicited by immunization with peptide 34 suppressed infectivity of the parasite to mosquitoes. We further observed that the secondary structure of Pfs25 may be important for immunogenicity because monoclonal antibodies (MAbs) 1C7 and 1D2, both transmission-blocking MAbs, protected enzyme cleavage sites in Pfs25 from proteolysis, suggesting that discontinuous segments of Pfs25 may come together to form immunogenic epitopic sites. Thus, definition of B- and T-cell epitopes may be required to construct a Pfs25 vaccine for optimum immunogenicity.
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Affiliation(s)
- I A Quakyi
- Georgetown University, Washington, DC, USA
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34
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Quakyi IA, Currier J, Fell A, Taylor DW, Roberts T, Houghten RA, England RD, Berzofsky JA, Miller LH, Good MF. Analysis of human T cell clones specific for conserved peptide sequences within malaria proteins. Paucity of clones responsive to intact parasites. The Journal of Immunology 1994. [DOI: 10.4049/jimmunol.153.5.2082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Abstract
T cells are thought to be of central importance in malaria immunity. Peptides copying malaria protein sequences often stimulate human CD4+ T cells and it was thought that they represented T cell epitopes present in the parasite and may thus have particular relevance to malaria vaccine development. To verify whether synthetic peptides representing highly conserved regions of parasite Ags may contribute to a malaria vaccine, we searched the data bank for conserved regions of Plasmodium falciparum malaria proteins that were not homologous to known self (human) proteins. We synthesized 24 such peptides representing 11 of the cloned and sequenced malaria asexual stage Ags, which were predicted by algorithms to represent T cell epitopes, and 6 peptides not predicted to be T cell epitopes and used these to generate T cell clones from individuals with an extensive previous history of malaria exposure. The T cell clones responded vigorously to many peptides but only a single clone, specific for a peptide within merozoite surface protein-1, 20-39, VTHESYQELVKKLEALEDAV, and not previously defined to be a T cell epitope responded to malaria parasites by proliferation and secretion of IFN-gamma. This epitope was not revealed by studying parasite-induced T cell lines and is thus subdominant. The clone was able to significantly inhibit parasite growth in vitro. The final step in the inhibition of parasite growth appears to be nonspecific because other activated clones (not specific for malaria sequences) can inhibit parasite growth. Our data suggest that few conserved peptides within malaria parasites can be processed from the intact parasite. However, such peptides that can be processed from malaria parasites may be expected to stimulate parasite-specific T cells that could inhibit parasite growth and as such may be lead candidates for a vaccine aimed at inducing cellular immunity to malaria.
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Affiliation(s)
- I A Quakyi
- Malaria and Arbovirus Unit, Queensland Institute of Medical Research, Brisbane, Australia
| | - J Currier
- Malaria and Arbovirus Unit, Queensland Institute of Medical Research, Brisbane, Australia
| | - A Fell
- Malaria and Arbovirus Unit, Queensland Institute of Medical Research, Brisbane, Australia
| | - D W Taylor
- Malaria and Arbovirus Unit, Queensland Institute of Medical Research, Brisbane, Australia
| | - T Roberts
- Malaria and Arbovirus Unit, Queensland Institute of Medical Research, Brisbane, Australia
| | - R A Houghten
- Malaria and Arbovirus Unit, Queensland Institute of Medical Research, Brisbane, Australia
| | - R D England
- Malaria and Arbovirus Unit, Queensland Institute of Medical Research, Brisbane, Australia
| | - J A Berzofsky
- Malaria and Arbovirus Unit, Queensland Institute of Medical Research, Brisbane, Australia
| | - L H Miller
- Malaria and Arbovirus Unit, Queensland Institute of Medical Research, Brisbane, Australia
| | - M F Good
- Malaria and Arbovirus Unit, Queensland Institute of Medical Research, Brisbane, Australia
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35
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Quakyi IA, Currier J, Fell A, Taylor DW, Roberts T, Houghten RA, England RD, Berzofsky JA, Miller LH, Good MF. Analysis of human T cell clones specific for conserved peptide sequences within malaria proteins. Paucity of clones responsive to intact parasites. J Immunol 1994; 153:2082-92. [PMID: 8051413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
T cells are thought to be of central importance in malaria immunity. Peptides copying malaria protein sequences often stimulate human CD4+ T cells and it was thought that they represented T cell epitopes present in the parasite and may thus have particular relevance to malaria vaccine development. To verify whether synthetic peptides representing highly conserved regions of parasite Ags may contribute to a malaria vaccine, we searched the data bank for conserved regions of Plasmodium falciparum malaria proteins that were not homologous to known self (human) proteins. We synthesized 24 such peptides representing 11 of the cloned and sequenced malaria asexual stage Ags, which were predicted by algorithms to represent T cell epitopes, and 6 peptides not predicted to be T cell epitopes and used these to generate T cell clones from individuals with an extensive previous history of malaria exposure. The T cell clones responded vigorously to many peptides but only a single clone, specific for a peptide within merozoite surface protein-1, 20-39, VTHESYQELVKKLEALEDAV, and not previously defined to be a T cell epitope responded to malaria parasites by proliferation and secretion of IFN-gamma. This epitope was not revealed by studying parasite-induced T cell lines and is thus subdominant. The clone was able to significantly inhibit parasite growth in vitro. The final step in the inhibition of parasite growth appears to be nonspecific because other activated clones (not specific for malaria sequences) can inhibit parasite growth. Our data suggest that few conserved peptides within malaria parasites can be processed from the intact parasite. However, such peptides that can be processed from malaria parasites may be expected to stimulate parasite-specific T cells that could inhibit parasite growth and as such may be lead candidates for a vaccine aimed at inducing cellular immunity to malaria.
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Affiliation(s)
- I A Quakyi
- Malaria and Arbovirus Unit, Queensland Institute of Medical Research, Brisbane, Australia
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36
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Quakyi IA, Taylor DW, Johnson AH, Allotey JB, Berzofsky JA, Miller LH, Good MF. Development of a malaria T-cell vaccine for blood stage immunity. Scand J Immunol Suppl 1992; 11:9-16. [PMID: 1381110 DOI: 10.1111/j.1365-3083.1992.tb01611.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
We have defined a strategy for the development of a T-cell vaccine for blood stage immunity, taking into consideration the central role of T cells and MHC restriction in malaria immune responses. We have used the AMPHI computer algorithm to identify putative T-cell epitopes from conserved regions of 11 Plasmodium falciparum asexual stage proteins. Ten of the eleven proteins are currently candidates for vaccine development. Using this algorithm we selected 22 putative T-cell epitope peptides and 8 control peptides. These peptides were used to test the T-cell responses of three defined populations of Caucasians who have (1) recovered from P. falciparum malaria, (2) been exposed, but never clinically infected, (3) never been exposed or infected. Preliminary analysis of our data shows population differences in T-cell responses to putative T-cell epitope peptides. Ultimately, these studies will help to identify those T epitopes that can be incorporated into a T-cell vaccine for protective immunity.
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Affiliation(s)
- I A Quakyi
- Department of Biology, Georgetown University, Washington DC 20057-1028
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37
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Leke RG, Ndansi R, Southerland NJ, Quakyi IA, Taylor DW. Identification of anti-Plasmodium falciparum antibodies in human breast milk. Scand J Immunol Suppl 1992; 11:17-22. [PMID: 1514035 DOI: 10.1111/j.1365-3083.1992.tb01612.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Malarial infections are rarely observed in neonates. It has been postulated that some immunity may be passively transferred during nursing, but anti-malarial antibodies (Abs) have not been detected in human milk. In this study, milk samples, collected 2-14 days after parturition from women at the Central Maternity Hospital, Yaounde, were evaluated for total IgG and IgA antibody levels by radial diffusion, protein composition by SDS-PAGE, anti-malarial antibodies using an isotype-specific immunofluorescence assay, and the ability to immunoprecipitate Plasmodium falciparum antigens metabolically labelled with 35S-methionine. Results showed that anti-P. falciparum antibodies were present in breast milk, and that paired milk and serum samples from individual women contained Abs that recognized similar malarial antigens.
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Affiliation(s)
- R G Leke
- University Centre for Health Sciences, University of Yaounde, Cameroun
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38
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Barr PJ, Green KM, Gibson HL, Bathurst IC, Quakyi IA, Kaslow DC. Recombinant Pfs25 protein of Plasmodium falciparum elicits malaria transmission-blocking immunity in experimental animals. J Exp Med 1991; 174:1203-8. [PMID: 1940798 PMCID: PMC2118997 DOI: 10.1084/jem.174.5.1203] [Citation(s) in RCA: 169] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Pfs25 is a sexual stage antigen of Plasmodium falciparum that is expressed on the surface of zygote and ookinete forms of the parasite. Monoclonal antibodies directed against native Pfs25 can block completely the development of P. falciparum oocysts in the midgut of the mosquito vector. Thus, this 25-kD protein is a potential vaccine candidate for eliciting transmission-blocking immunity in inhabitants of malaria endemic regions. We have synthesized, by secretion from yeast, a polypeptide analogue of Pfs25 that reacts with conformation-dependent monoclonal antibodies, and elicits transmission-blocking antibodies when used to immunize mice and monkeys in conjunction with a muramyl tripeptide adjuvant. Our results suggest the further evaluation of recombinant DNA-derived Pfs25 in transmission-blocking vaccination studies in humans.
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Affiliation(s)
- P J Barr
- Chiron Corporation, Emeryville, California 94608
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39
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Rodriguez-del Valle M, Quakyi IA, Amuesi J, Quaye JT, Nkrumah FK, Taylor DW. Detection of antigens and antibodies in the urine of humans with Plasmodium falciparum malaria. J Clin Microbiol 1991; 29:1236-42. [PMID: 1864942 PMCID: PMC269976 DOI: 10.1128/jcm.29.6.1236-1242.1991] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Humans infected with Plasmodium falciparum frequently have elevated levels of proteins in their urine, but it is unclear if any of these proteins are parasite antigens or antimalarial antibodies. To resolve this question, urine samples from malaria patients and controls living in Thailand and Ghana were evaluated. Urine samples from 85% of the patients had elevated protein levels and contained proteins with Mrs ranging from less than 29,000 to greater than 224,000 as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Antisera were produced against urine from infected and control subjects. Antisera raised against infected, but not control, urine were positive by indirect immunofluorescence on P. falciparum parasites and immunoprecipitated approximately 12 unique bands from extracts of parasites metabolically labeled with 35S-methionine. These data suggest that a variety of P. falciparum antigens are released into urine during acute infection. It is also likely that anti-P. falciparum antibodies are present in the urine of malaria patients because samples from these patients, but not controls, were positive in indirect immunofluorescence assays and immunoprecipitated at least 19 P. falciparum antigens from extracts of metabolically labeled parasites. The detection of malarial antigens and antibodies in urine may lead to a new approach for the diagnosis of malaria.
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40
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Kaslow DC, Isaacs SN, Quakyi IA, Gwadz RW, Moss B, Keister DB. Induction of Plasmodium falciparum transmission-blocking antibodies by recombinant vaccinia virus. Science 1991; 252:1310-3. [PMID: 1925544 DOI: 10.1126/science.1925544] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Many candidate antigens of malaria vaccines have limited immunological recognition. One exception is Pfs25, a cysteine-rich, 25-kilodalton sexual stage surface protein of Plasmodium falciparum. Pfs25 is a target of monoclonal antibodies that block transmission of malaria from vertebrate host to mosquito vector. The surface of mammalian cells infected with a recombinant vaccinia virus that expressed Pfs25 specifically bound transmission-blocking monoclonal antibodies. Furthermore, major histocompatibility complex-disparate congenic mouse strains immunized with recombinant Pfs25 elicited transmission-blocking antibodies, demonstrating that the capacity to develop transmission-blocking antibodies is not genetically restricted in mice. Live recombinant viruses may provide an inexpensive, easily administered alternative to subunit vaccines prepared from purified recombinant proteins to block transmission of malaria in developing countries.
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Affiliation(s)
- D C Kaslow
- Malaria Section, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892
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41
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Carter R, Graves PM, Keister DB, Quakyi IA. Properties of epitopes of Pfs 48/45, a target of transmission blocking monoclonal antibodies, on gametes of different isolates of Plasmodium falciparum. Parasite Immunol 1990; 12:587-603. [PMID: 1707506 DOI: 10.1111/j.1365-3024.1990.tb00990.x] [Citation(s) in RCA: 96] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
We have studied the properties of epitopes on Plasmodium falciparum gamete surface protein Pfs 48/45, a target antigen of malaria transmission blocking antibodies. Using a two site immunoradiometric assay we have defined three spacially separate, non-repeated, epitope regions on the peptides representing this antigen. Epitope region I is a target of monoclonal antibodies (MoAbs) which strongly suppress infectivity of gametocytes of P. falciparum to mosquitoes; the effect is complement independent and is mediated as effectively by the monovalent Fab fragments as by intact MoAb. Epitope region II consists of two spacially close subregions, IIa and IIb; variant forms of epitopes IIa and IIb occurred in different isolates of P. falciparum. Epitope region III also showed slight structural modification between isolates. MoAbs against regions II or III were relatively ineffective in suppressing gametocyte infectivity compared to MoAbs against region I. However, certain combinations of MoAbs against regions II and III together acted synergistically to suppress infectivity to mosquitoes. All these epitopes failed to react with MoAb when the antigen was presented in reduced form. A fourth epitope, however, was identified which reacted strongly with MoAb when the antigen was presented in reduced form. The MoAb against this epitope had no effect on the infectivity of gametocytes of P. falciparum to mosquitoes.
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Affiliation(s)
- R Carter
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892
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42
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Good MF, Kumar S, De Groot AS, Weiss WR, Quakyi IA, Dontfraid F, Smith GE, Cochran M, Berzofsky JA, Miller LH. Evidence implicating MHC genes in the immunological nonresponsiveness to the Plasmodium falciparum CS protein. Bull World Health Organ 1990; 68 Suppl:80-4. [PMID: 1709836 PMCID: PMC2393035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The circumsporozoite (CS) protein is a major candidate vaccine antigen for the sporozoite stage of malaria. Both cytotoxic T cells (CTL) and antibody specific for the CS protein are thought to be important in protection. By examining the immune response in mice and humans we have shown that genes mapping to the major histocompatibility complex (MHC) are important for immune responsiveness. F1 mice between high antibody responders and low antibody responders are high antibody responders, suggesting that in this model immune suppressor genes do not control the immune response. Using synthetic peptides to map epitopes for CTL and helper T cells (which are important for the antibody response) we have shown that the T-cell epitopes are located in the polymorphic region of the protein, and we hypothesize that T cells have indeed selected the variation observed in the CS protein. The success of subunit vaccines will depend on the pattern of variation in different geographical locations, the ability to construct multivalent vaccines containing different variant epitopes from this protein, and on the existence of other sporozoite and liver-stage proteins involved in protection.
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Affiliation(s)
- M F Good
- Laboratory of Parasitic Diseases, N.I.A.I.D., National Institutes of Health, Bethesda, MD
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43
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Quakyi IA, Otoo LN, Pombo D, Sugars LY, Menon A, De Groot AS, Johnson A, Alling D, Miller LH, Good MF. Differential non-responsiveness in humans of candidate Plasmodium falciparum vaccine antigens. Am J Trop Med Hyg 1989; 41:125-34. [PMID: 2672834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Synthetic subunit vaccines to sporozoites, merozoites, and gametes are being developed for malaria. The vaccine strategy assumes that the population to be immunized will respond favorably to these vaccine antigens. Using sera of 35 adults and 50 children from the The Gambia, West Africa, where Plasmodium falciparum is highly endemic, we examined the humoral immune response to candidate malaria vaccine antigens from sporozoites, merozoites, and gametes. We observed widespread restricted immunogenicity to defined parasite antigens in children and adults. HLA typing of adult lymphocytes demonstrated a marked diversity in HLA haplotypes in this population. Our results and those from our studies in mice suggest that genetic factors may partly explain the immunological non-responsiveness. This may necessitate re-evaluation of the malaria vaccine strategy.
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Affiliation(s)
- I A Quakyi
- National Institutes of Health, Bethesda, Maryland
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44
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Quakyi IA, Menon A, Good MF, Pombo D, Otoo LN, Miller LH, Alling D, Johnson A, DeGroot AS, Sugars LY. Differential non-Responsiveness in Humans of Candidate Plasmodium Falciparum Vaccine Antigens. Am J Trop Med Hyg 1989. [DOI: 10.4269/ajtmh.1989.41.125] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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45
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de Groot AS, Johnson AH, Maloy WL, Quakyi IA, Riley EM, Menon A, Banks SM, Berzofsky JA, Good MF. Human T cell recognition of polymorphic epitopes from malaria circumsporozoite protein. The Journal of Immunology 1989. [DOI: 10.4049/jimmunol.142.11.4000] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Abstract
Lymphocytes obtained from forty individuals living in a malaria endemic area of West Africa were tested for in vitro proliferative responses to peptides representing variant regions of the immunodominant T cell domain of the circumsporozoite protein (amino acids 326 to 345, referred to as Th2R, and 361 to 380, referred to as Th3R) from three distinct strains of Plasmodium falciparum. A total of 83% of the individuals responded to at least one of the six peptides tested, confirming that these epitopes are immunodominant. A much greater number of individuals than expected by chance (32% of the responders to Th2R and 27% of the responders to Th3R) reacted to all three of the variant peptides for that epitope, indicating interdependency of the T cell responses, suggestive of cross-reactivity. Nevertheless, some subjects' T cells were clearly able to distinguish each variant peptide from the others. Using EBV transformed B cells, lymphocytes from 10 of the individuals were HLA typed. In this small group, HLA DRw13 was associated with a positive response to any of the peptides, whereas there was a negative association between DQw3 and response to any of the peptides. These results, although limited by the small sample size, suggest that recognition of T epitopes may be Ir gene linked. Our findings suggest that it may be possible to broaden the immunogenicity of an anti-sporozoite malaria vaccine.
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Affiliation(s)
- A S de Groot
- Laboratory of Parasitic Diseases, National Institutes of Allergy and Infectious Disease, Bethesda, MD 20892
| | - A H Johnson
- Laboratory of Parasitic Diseases, National Institutes of Allergy and Infectious Disease, Bethesda, MD 20892
| | - W L Maloy
- Laboratory of Parasitic Diseases, National Institutes of Allergy and Infectious Disease, Bethesda, MD 20892
| | - I A Quakyi
- Laboratory of Parasitic Diseases, National Institutes of Allergy and Infectious Disease, Bethesda, MD 20892
| | - E M Riley
- Laboratory of Parasitic Diseases, National Institutes of Allergy and Infectious Disease, Bethesda, MD 20892
| | - A Menon
- Laboratory of Parasitic Diseases, National Institutes of Allergy and Infectious Disease, Bethesda, MD 20892
| | - S M Banks
- Laboratory of Parasitic Diseases, National Institutes of Allergy and Infectious Disease, Bethesda, MD 20892
| | - J A Berzofsky
- Laboratory of Parasitic Diseases, National Institutes of Allergy and Infectious Disease, Bethesda, MD 20892
| | - M F Good
- Laboratory of Parasitic Diseases, National Institutes of Allergy and Infectious Disease, Bethesda, MD 20892
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de Groot AS, Johnson AH, Maloy WL, Quakyi IA, Riley EM, Menon A, Banks SM, Berzofsky JA, Good MF. Human T cell recognition of polymorphic epitopes from malaria circumsporozoite protein. J Immunol 1989; 142:4000-5. [PMID: 2469729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Lymphocytes obtained from forty individuals living in a malaria endemic area of West Africa were tested for in vitro proliferative responses to peptides representing variant regions of the immunodominant T cell domain of the circumsporozoite protein (amino acids 326 to 345, referred to as Th2R, and 361 to 380, referred to as Th3R) from three distinct strains of Plasmodium falciparum. A total of 83% of the individuals responded to at least one of the six peptides tested, confirming that these epitopes are immunodominant. A much greater number of individuals than expected by chance (32% of the responders to Th2R and 27% of the responders to Th3R) reacted to all three of the variant peptides for that epitope, indicating interdependency of the T cell responses, suggestive of cross-reactivity. Nevertheless, some subjects' T cells were clearly able to distinguish each variant peptide from the others. Using EBV transformed B cells, lymphocytes from 10 of the individuals were HLA typed. In this small group, HLA DRw13 was associated with a positive response to any of the peptides, whereas there was a negative association between DQw3 and response to any of the peptides. These results, although limited by the small sample size, suggest that recognition of T epitopes may be Ir gene linked. Our findings suggest that it may be possible to broaden the immunogenicity of an anti-sporozoite malaria vaccine.
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Affiliation(s)
- A S de Groot
- Laboratory of Parasitic Diseases, National Institutes of Allergy and Infectious Disease, Bethesda, MD 20892
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Quakyi IA, Matsumoto Y, Carter R, Udomsangpetch R, Sjolander A, Berzins K, Perlmann P, Aikawa M, Miller LH. Movement of a falciparum malaria protein through the erythrocyte cytoplasm to the erythrocyte membrane is associated with lysis of the erythrocyte and release of gametes. Infect Immun 1989; 57:833-9. [PMID: 2645212 PMCID: PMC313185 DOI: 10.1128/iai.57.3.833-839.1989] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Erythrocytes containing mature gametocytes of Plasmodium falciparum circulate in the blood until they are ingested by a mosquito, an event that triggers gametogenesis and lysis of the infected erythrocyte. It was previously shown that a parasite protein (Pf155/RESA) accumulates in the erythrocyte cytoplasm next to the parasitophorous vacuolar membrane (S. Uni, A. Masuda, M. J. Stewart, R. Nussenzweig, and M. Aikawa, Am. J. Trop. Med. Hyg., 36:481-488, 1987). Using a monoclonal antibody to Pf155/RESA and rabbit sera to two different repeat peptides of Pf155/RESA, we have studied the location of Pf155/RESA after induction of gametogenesis. Five minutes after triggering gametogenesis, the parasitophorous membrane no longer surrounded the parasite, bringing the parasite membrane in contact with the erythrocyte cytoplasm. Clear spaces appeared throughout the hemoglobin-rich host cytoplasm; Pf155/RESA was now localized in the cytoplasm directly surrounding the spaces. No membrane existed between the spaces and the erythrocyte cytoplasm. The spaces with surrounding Pf155/RESA protein extended to the erythrocyte membrane. After lysis of the erythrocyte membrane (15 min after triggering gametogenesis), the protein was distributed along the erythrocyte membrane and throughout the space between the gamete and the erythrocyte membrane. The mechanism by which Pf155/RESA remained aggregated around the spaces and its role in erythrocyte lysis are unknown. It is of interest that the parasite appeared to use the same molecule during invasion of erythrocytes and during release of gametes from infected erythrocytes.
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Affiliation(s)
- I A Quakyi
- Malaria Section, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland 20892
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Affiliation(s)
- D C Kaslow
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, MD 20892
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Carter R, Graves PM, Quakyi IA, Good MF. Restricted or absent immune responses in human populations to Plasmodium falciparum gamete antigens that are targets of malaria transmission-blocking antibodies. J Exp Med 1989; 169:135-47. [PMID: 2642527 PMCID: PMC2189199 DOI: 10.1084/jem.169.1.135] [Citation(s) in RCA: 87] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
We have studied the antibodies to sexual stage antigens of Plasmodium falciparum in human sera from Papua New Guinea where intense transmission of P. falciparum occurs as well as the less prevalent P. malariae and P. vivax. In extracts of gametes of P. falciparum we have studied the reactivity of serum antibodies with antigens labeled with 125I on the surface of the gametes as well as intracellular gamete antigens. A prominent 27-kD sexual stage-specific intracellular protein was recognized more or less in proportion to the general antibody response to gamete proteins. The response to the gamete surface proteins, however, was quite unrepresentative of the general antibody response to the intracellular gamete proteins. No antibodies were detected against Pfs25, a 21-kD protein expressed on zygotes and ookinetes of P. falciparum and known to be a sensitive target of malaria transmission-blocking antibodies. The antibody response to two other target antigens of transmission-blocking antibodies on the surface of gametes of P. falciparum, a 230- and a 48- and 45-kD protein doublet, was very variable and independent of the response to the internal protein antigens. Several possibilities are discussed that may account for the variable response to these gamete surface antigens in individuals with otherwise good antibody responses to internal sexual stage proteins. Among these is the possibility that there is MHC restriction of the immune response to the gamete surface antigens in the human population. This interpretation accords well with evidence for MHC-restricted immune response to the same P. falciparum gamete surface antigens in studies with H-2 congenic mice (24).
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Affiliation(s)
- R Carter
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland 20892
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Dontfraid F, Cochran MA, Pombo D, Knell JD, Quakyi IA, Kumar S, Houghten RA, Berzofsky JA, Miller LH, Good MF. Human and murine CD4 T cell epitopes map to the same region of the malaria circumsporozoite protein: limited immunogenicity of sporozoites and circumsporozoite protein. Mol Biol Med 1988; 5:185-96. [PMID: 2468986] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The circumsporozoite (CS) protein is a candidate vaccine antigen for the sporozoite stage in the life cycle of the malaria parasite. Using CS protein purified from recombinant baculovirus-infected cells and a panel of H-2 congenic mice, we are able to demonstrate that this protein is poorly immunogenic in terms of antibody production as a result of Ir gene control. The immune response to the protein is also restricted following immunization with a CS-recombinant vaccinia virus or with sporozoites. Using a panel of overlapping peptides spanning the entire protein, we are able to show that the high responder mice recognize helper T cell epitopes from the same region of the protein as do humans. This region, however, is the polymorphic segment of the protein, which has implications for vaccine development. However, the close overlap of human and murine T cell epitopes demonstrates that murine models may be very useful in epitope mapping and vaccine development for human pathogens. The T cell antigenic regions of this protein fulfil the predictive requirements for the amphipathic helicity algorithm.
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Affiliation(s)
- F Dontfraid
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, MD 20892
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