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The hide and seek of Plasmodium vivax in West Africa: report from a large-scale study in Beninese asymptomatic subjects. Malar J 2016; 15:570. [PMID: 27887647 PMCID: PMC5123334 DOI: 10.1186/s12936-016-1620-z] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Accepted: 11/15/2016] [Indexed: 11/30/2022] Open
Abstract
Background Plasmodium vivax is considered to be absent from western Africa, where the prevalence of Duffy-negative red blood cell phenotype proves to be high. Several studies have, however, detected P. vivax infection cases in this part of Africa, raising the question of what is the actual prevalence of P. vivax in local populations.
Methods The presence of P. vivax was investigated in a large population of healthy blood donors in Benin using microscopy, serology and molecular detection. The seroprevalence was measured with species-specific ELISA using two recombinant P. vivax proteins, namely rPvMSP1 and rPvCSP1. Specific molecular diagnosis of P. vivax infection was carried out using nested-PCR. The performances and cut-off values of both rPvCSP1 and rPvMSP1 ELISA were first assessed using sera from P. vivax-infected patients and from non-exposed subjects. Results Among 1234 Beninese blood donors, no parasites were detected when using microscopy, whereas 28.7% (354/1234) of patients exhibited had antibodies against rPvMSP1, 21.6% (266/1234) against rPvCSP1, and 15.2% (187/1234) against both. Eighty-four samples were selected for nested-PCR analyses, of which 13 were positive for P. vivax nested-PCR and all Duffy negative.
Conclusion The results of the present study highlight an unexpectedly high exposure of Beninese subjects to P. vivax, resulting in sub-microscopic infections. This suggests a probably underestimated and insidious parasite presence in western Africa. While the vaccination campaigns and therapeutic efforts are all focused on Plasmodium falciparum, it is also essential to consider the epidemiological impact of P. vivax. Electronic supplementary material The online version of this article (doi:10.1186/s12936-016-1620-z) contains supplementary material, which is available to authorized users.
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Baird JK. Asia-Pacific malaria is singular, pervasive, diverse and invisible. Int J Parasitol 2016; 47:371-377. [PMID: 27836630 PMCID: PMC5482320 DOI: 10.1016/j.ijpara.2016.06.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Revised: 05/29/2016] [Accepted: 06/01/2016] [Indexed: 12/27/2022]
Abstract
Malaria in the Asia-Pacific region has been targeted for elimination by the year 2030. This article asks the question, "by what means?" in the context of proven technical strategies and tools against key challenges imposed by the distinct character of the Asia-Pacific malaria problem. The misperception of malaria in the Asia-Pacific region as a less serious but otherwise essentially similar problem to African malaria lulls us into rote application of the same tools and strategies. Those now mitigating the harm done by malaria in Africa will not suffice to eliminate malaria in the Asia-Pacific region - these tasks and the problems are fundamentally distinct. This article describes the singular characteristics of Asia-Pacific malaria and the bearing of those upon the technical strategy of malaria elimination. Most of the tools needed for that endeavour do not yet exist and spirited calls for elimination within the next 14years may discourage the patience and investments needed to conceive, optimise and validate them.
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Affiliation(s)
- J Kevin Baird
- Eijkman Oxford Clinical Research Unit, Jakarta, Indonesia; Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom.
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Pava Z, Burdam FH, Handayuni I, Trianty L, Utami RAS, Tirta YK, Kenangalem E, Lampah D, Kusuma A, Wirjanata G, Kho S, Simpson JA, Auburn S, Douglas NM, Noviyanti R, Anstey NM, Poespoprodjo JR, Marfurt J, Price RN. Submicroscopic and Asymptomatic Plasmodium Parasitaemia Associated with Significant Risk of Anaemia in Papua, Indonesia. PLoS One 2016; 11:e0165340. [PMID: 27788243 PMCID: PMC5082812 DOI: 10.1371/journal.pone.0165340] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Accepted: 10/10/2016] [Indexed: 11/19/2022] Open
Abstract
Submicroscopic Plasmodium infections are an important parasite reservoir, but their clinical relevance is poorly defined. A cross-sectional household survey was conducted in southern Papua, Indonesia, using cluster random sampling. Data were recorded using a standardized questionnaire. Blood samples were collected for haemoglobin measurement. Plasmodium parasitaemia was determined by blood film microscopy and PCR. Between April and July 2013, 800 households and 2,830 individuals were surveyed. Peripheral parasitaemia was detected in 37.7% (968/2,567) of individuals, 36.8% (357) of whom were identified by blood film examination. Overall the prevalence of P. falciparum parasitaemia was 15.4% (396/2567) and that of P. vivax 18.3% (471/2567). In parasitaemic individuals, submicroscopic infection was significantly more likely in adults (adjusted odds ratio (AOR): 3.82 [95%CI: 2.49-5.86], p<0.001) compared to children, females (AOR = 1.41 [1.07-1.86], p = 0.013), individuals not sleeping under a bednet (AOR = 1.4 [1.0-1.8], p = 0.035), and being afebrile (AOR = 3.2 [1.49-6.93], p = 0.003). The risk of anaemia (according to WHO guidelines) was 32.8% and significantly increased in those with asymptomatic parasitaemia (AOR 2.9 [95% 2.1-4.0], p = 0.007), and submicroscopic P. falciparum infections (AOR 2.5 [95% 1.7-3.6], p = 0.002). Asymptomatic and submicroscopic infections in this area co-endemic for P. falciparum and P. vivax constitute two thirds of detectable parasitaemia and are associated with a high risk of anaemia. Novel public health strategies are needed to detect and eliminate these parasite reservoirs, for the benefit both of the patient and the community.
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Affiliation(s)
- Zuleima Pava
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, Australia
| | - Faustina H. Burdam
- Mimika District Health Authority, Timika, Papua, Indonesia
- Timika Malaria Research Programme, Papuan Health and Community Development Foundation, Timika, Papua, Indonesia
- Maternal and Child Health and Reproductive Health, Department of Public Health, Faculty of Medicine, Universitas Gadjah Mada, Yogyakarta, Indonesia
| | - Irene Handayuni
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, Australia
| | - Leily Trianty
- Eijkman Institute for Molecular Biology, Jakarta, Indonesia
| | | | | | - Enny Kenangalem
- Mimika District Health Authority, Timika, Papua, Indonesia
- Timika Malaria Research Programme, Papuan Health and Community Development Foundation, Timika, Papua, Indonesia
| | - Daniel Lampah
- Timika Malaria Research Programme, Papuan Health and Community Development Foundation, Timika, Papua, Indonesia
| | - Andreas Kusuma
- Eijkman Institute for Molecular Biology, Jakarta, Indonesia
| | - Grennady Wirjanata
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, Australia
| | - Steven Kho
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, Australia
| | - Julie A. Simpson
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, Australia
| | - Sarah Auburn
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, Australia
| | - Nicholas M. Douglas
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, Australia
- Division of Medicine, Christchurch Hospital, Christchurch, New Zealand
| | | | - Nicholas M. Anstey
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, Australia
| | - Jeanne R. Poespoprodjo
- Mimika District Health Authority, Timika, Papua, Indonesia
- Timika Malaria Research Programme, Papuan Health and Community Development Foundation, Timika, Papua, Indonesia
- Maternal and Child Health and Reproductive Health, Department of Public Health, Faculty of Medicine, Universitas Gadjah Mada, Yogyakarta, Indonesia
| | - Jutta Marfurt
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, Australia
| | - Ric N. Price
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, Australia
- Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, United Kingdom
- * E-mail:
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Motshoge T, Ababio GK, Aleksenko L, Read J, Peloewetse E, Loeto M, Mosweunyane T, Moakofhi K, Ntebele DS, Chihanga S, Motlaleng M, Chinorumba A, Vurayai M, Pernica JM, Paganotti GM, Quaye IK. Molecular evidence of high rates of asymptomatic P. vivax infection and very low P. falciparum malaria in Botswana. BMC Infect Dis 2016; 16:520. [PMID: 27682611 PMCID: PMC5041318 DOI: 10.1186/s12879-016-1857-8] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Accepted: 09/20/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Botswana is one of eight SADC countries targeting malaria elimination by 2018. Through spirited upscaling of control activities and passive surveillance, significant reductions in case incidence of Plasmodium falciparum (0.96 - 0.01) was achieved between 2008 and 2012. As part of the elimination campaign, active detection of asymptomatic Plasmodium species by a highly sensitive method was deemed necessary. This study was carried out to determine asymptomatic Plasmodium species carriage by nested PCR in the country, in 2012. METHOD A cross-sectional study involving 3924 apparently healthy participants were screened for Plasmodium species in 14 districts (5 endemic: Okavango, Ngami, Tutume, Boteti and Bobirwa; and 9 epidemic: North East, Francistown, Serowe-Palapye, Ghanzi, Kweneng West, Kweneng East, Kgatleng, South East, and Good Hope). Venous blood was taken from each participant for a nested PCR detection of Plasmodium species. RESULTS The parasite rates of asymptomatic Plasmodium species detected were as follows: Plasmodium falciparum, 0.16 %; Plasmodium vivax, 4.66 %; Plasmodium malariae, (Pm) 0.16 %; Plasmodium ovale, 0 %, mixed infections (P. falciparum and P. vivax), 0.055 %; and (P. vivax and P. malariae), 0.027 %, (total: 5.062 %). The high proportion of asymptomatic reservoir of P. vivax was clustered in the East, South Eastern and Central districts of the country. There appeared to be a correlation between the occurrence of P. malariae infection with P. vivax infection, with the former only occurring in districts that had substantial P. vivax circulation. The median age among 2-12 year olds for P. vivax infection was 5 years (Mean 5.13 years, interquartile range 3-7 years). The odds of being infected with P. vivax decreased by 7 % for each year increase in age (OR 0.93, 95 % CI 0.87-1.00, p = 0.056). CONCLUSION We have confirmed low parasite rate of asymptomatic Plasmodium species in Botswana, with the exception of P.vivax which was unexpectedly high. This has implication for the elimination campaign so a follow up study is warranted to inform decisions on new strategies that take this evidence into account in the elimination campaign.
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Affiliation(s)
- Thato Motshoge
- Ministry of Health, Gaborone, Botswana.,Biological Sciences Department, University of Botswana, Gaborone, Botswana
| | - Grace K Ababio
- University of Ghana School of Allied Health and Biomedical Sciences, Accra, Ghana
| | - Larysa Aleksenko
- Department of Pathology, University of Namibia School of Medicine, Windhoek, Namibia
| | - John Read
- School of Medicine, University of Botswana, Gaborone, Botswana
| | - Elias Peloewetse
- Biological Sciences Department, University of Botswana, Gaborone, Botswana
| | - Mazhani Loeto
- School of Medicine, University of Botswana, Gaborone, Botswana
| | | | - Kentse Moakofhi
- World Health Organization, Botswana Country Office, Gaborone, Botswana
| | - Davies S Ntebele
- Ministry of Health, National Malaria Control Program, Gaborone, Botswana
| | - Simon Chihanga
- Ministry of Health, National Malaria Control Program, Gaborone, Botswana
| | - Mpho Motlaleng
- Ministry of Health, National Malaria Control Program, Gaborone, Botswana
| | | | - Moses Vurayai
- Ministry of Health, National Malaria Control Program, Gaborone, Botswana
| | - Jeffrey M Pernica
- Division of Infectious Disease, Department of Pediatrics, McMaster University, Hamilton, ON, Canada
| | - Giacomo M Paganotti
- University of Botswana-University of Pennsylvania Partnership, Gaborone, Botswana.,Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Isaac K Quaye
- University of Namibia School of Medicine, Windhoek, PBAG13301, Namibia.
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Vásquez-Jiménez JM, Arévalo-Herrera M, Henao-Giraldo J, Molina-Gómez K, Arce-Plata M, Vallejo AF, Herrera S. Consistent prevalence of asymptomatic infections in malaria endemic populations in Colombia over time. Malar J 2016; 15:70. [PMID: 26852321 PMCID: PMC4744459 DOI: 10.1186/s12936-016-1124-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Accepted: 01/22/2016] [Indexed: 12/25/2022] Open
Abstract
Background Malaria control programmes rely on confirmation of parasite presence in patients’ blood prior to treatment administration. Plasmodium parasites are detected mostly by microscopy or rapid diagnostic test (RDT). Although these methods contribute significantly to malaria control/elimination, they are not suitable for detecting the significant proportion of asymptomatic subjects harbouring low levels of parasitaemia, which endure untreated as potential reservoirs for transmission. Malaria prevalence was assessed in endemic regions of Colombia over a 4-year follow-up. Methods A series of cross-sectional surveys were conducted between 2011 and 2014 in low to moderate malaria transmission sentinel sites (SS) of Tumaco, Buenaventura and Tierralta municipalities of Colombia. A census was performed and a random sample of houses was selected from each SS prior to each survey. Inhabitants were asked to answer a questionnaire on clinical, epidemiological and demographic aspects, and to provide a blood sample for malaria diagnosis using microscopy and quantitative real time polymerase chain reaction (qPCR). Results A total of 3059 blood samples were obtained from all SS, 58.5 % of which were from women and displayed a malaria prevalence ranging from 4 % (95 % CI 3–5 %) to 10 % (95 % CI 8–12 %) in the 4 years’ study period. Almost all malaria cases (n = 220, 97 %) were sub-microscopic and only detectable by qPCR; 90 % of the cases were asymptomatic at the time of blood collection. While Buenaventura and Tierralta had a decreasing tendency during the follow-up, Tumaco had a rise in 2013 and then a decrease in 2014. Plasmodium vivax accounted for the majority (66–100 %) of cases in Tierralta and Buenaventura and for 25–50 % of the cases in Tumaco. Conclusions This study demonstrates an important prevalence of asymptomatic malaria cases not detectable by microscopy, which therefore remain untreated representing a parasite pool for malaria transmission. This demands the introduction of alternative strategies for diagnosis and treatment, especially for areas of low transmission to reduce it to appropriate levels for malaria pre-elimination efforts to start.
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Affiliation(s)
| | - Myriam Arévalo-Herrera
- Caucaseco Scientific Research Center, Cali, Colombia. .,School of Health, Universidad del Valle, Cali, Colombia.
| | | | - Karen Molina-Gómez
- Clinical Trials Unit, Malaria Vaccine and Drug Development Center, Cali, Colombia.
| | - María Arce-Plata
- Data Management Unit, Caucaseco Scientific Research Center, Cali, Colombia.
| | - Andrés F Vallejo
- Molecular Biology Unit, Caucaseco Scientific Research Center, Cali, Colombia.
| | - Sócrates Herrera
- Clinical Trials Unit, Malaria Vaccine and Drug Development Center, Cali, Colombia. .,Caucaseco Scientific Research Center, Cali, Colombia.
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56
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Howes RE, Reiner Jr. RC, Battle KE, Longbottom J, Mappin B, Ordanovich D, Tatem AJ, Drakeley C, Gething PW, Zimmerman PA, Smith DL, Hay SI. Plasmodium vivax Transmission in Africa. PLoS Negl Trop Dis 2015; 9:e0004222. [PMID: 26587988 PMCID: PMC4654493 DOI: 10.1371/journal.pntd.0004222] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Accepted: 10/19/2015] [Indexed: 12/22/2022] Open
Abstract
Malaria in sub-Saharan Africa has historically been almost exclusively attributed to Plasmodium falciparum (Pf). Current diagnostic and surveillance systems in much of sub-Saharan Africa are not designed to identify or report non-Pf human malaria infections accurately, resulting in a dearth of routine epidemiological data about their significance. The high prevalence of Duffy negativity provided a rationale for excluding the possibility of Plasmodium vivax (Pv) transmission. However, review of varied evidence sources including traveller infections, community prevalence surveys, local clinical case reports, entomological and serological studies contradicts this viewpoint. Here, these data reports are weighted in a unified framework to reflect the strength of evidence of indigenous Pv transmission in terms of diagnostic specificity, size of individual reports and corroboration between evidence sources. Direct evidence was reported from 21 of the 47 malaria-endemic countries studied, while 42 countries were attributed with infections of visiting travellers. Overall, moderate to conclusive evidence of transmission was available from 18 countries, distributed across all parts of the continent. Approximately 86.6 million Duffy positive hosts were at risk of infection in Africa in 2015. Analysis of the mechanisms sustaining Pv transmission across this continent of low frequency of susceptible hosts found that reports of Pv prevalence were consistent with transmission being potentially limited to Duffy positive populations. Finally, reports of apparent Duffy-independent transmission are discussed. While Pv is evidently not a major malaria parasite across most of sub-Saharan Africa, the evidence presented here highlights its widespread low-level endemicity. An increased awareness of Pv as a potential malaria parasite, coupled with policy shifts towards species-specific diagnostics and reporting, will allow a robust assessment of the public health significance of Pv, as well as the other neglected non-Pf parasites, which are currently invisible to most public health authorities in Africa, but which can cause severe clinical illness and require specific control interventions.
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Affiliation(s)
- Rosalind E. Howes
- Spatial Ecology and Epidemiology Group, Department of Zoology, University of Oxford, Oxford, United Kingdom
- Center for Global Health and Diseases, Case Western Reserve University, Cleveland, Ohio, United States of America
- * E-mail:
| | - Robert C. Reiner Jr.
- Department of Epidemiology and Biostatistics, School of Public Health, Indiana University, Bloomington, Indiana, United States of America
- Fogarty International Center, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Katherine E. Battle
- Spatial Ecology and Epidemiology Group, Department of Zoology, University of Oxford, Oxford, United Kingdom
| | - Joshua Longbottom
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Bonnie Mappin
- Spatial Ecology and Epidemiology Group, Department of Zoology, University of Oxford, Oxford, United Kingdom
| | - Dariya Ordanovich
- Department of Geography and Environment, University of Southampton, Highfield, Southampton, United Kingdom
| | - Andrew J. Tatem
- Fogarty International Center, National Institutes of Health, Bethesda, Maryland, United States of America
- Department of Geography and Environment, University of Southampton, Highfield, Southampton, United Kingdom
- Flowminder Foundation, Stockholm, Sweden
| | - Chris Drakeley
- Malaria Centre, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Peter W. Gething
- Spatial Ecology and Epidemiology Group, Department of Zoology, University of Oxford, Oxford, United Kingdom
| | - Peter A. Zimmerman
- Center for Global Health and Diseases, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - David L. Smith
- Spatial Ecology and Epidemiology Group, Department of Zoology, University of Oxford, Oxford, United Kingdom
- Fogarty International Center, National Institutes of Health, Bethesda, Maryland, United States of America
- Sanaria Institute for Global Health and Tropical Medicine, Rockville, Maryland, United States of America
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, United States of America
| | - Simon I. Hay
- Fogarty International Center, National Institutes of Health, Bethesda, Maryland, United States of America
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, United States of America
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