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Andrade AO, Santos NAC, Bastos AS, Pontual JDC, Araújo JE, Silva AMV, Martinez LN, Lima AA, Aguiar ACC, G. Teles CB, Medeiros JF, Pereira DB, Vinetz JM, Gazzinelli RT, Araújo MS. Transmission-blocking activity of antimalarials for Plasmodium vivax malaria in Anopheles darlingi. PLoS Negl Trop Dis 2023; 17:e0011425. [PMID: 37327209 PMCID: PMC10310017 DOI: 10.1371/journal.pntd.0011425] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Revised: 06/29/2023] [Accepted: 05/30/2023] [Indexed: 06/18/2023] Open
Abstract
Malaria is caused by parasite of the genus Plasmodium and is still one of the most important infectious diseases in the world. Several biological characteristics of Plasmodium vivax contribute to the resilience of this species, including early gametocyte production, both of which lead to efficient malaria transmission to mosquitoes. This study evaluated the impact of currently used drugs on the transmission of P. vivax. Participants received one of the following treatments for malaria: i) chloroquine [10 mg/kg on day 1 and 7.5 mg/kg on day 2 and 3] co-administered with Primaquine [0.5 mg/kg/day for 7 days]; ii) Chloroquine [10 mg/kg on day 1 and 7.5 mg/kg on day 2 and 3] co-administered with one-dose of Tafenoquine [300 mg on day 1]; and iii) Artesunate and Mefloquine [100 mg and 200 mg on day 1, 2 and 3] co-administered with Primaquine [0.5 mg/kg/day for 14 days]. Patient blood was collected before treatment and 4 h, 24 h, 48 h and 72 h after treatment. The blood was used to perform a direct membrane feeding assay (DMFA) using Anopheles darlingi mosquitoes. The results showed 100% inhibition of the mosquito infection after 4 h using ASMQ+PQ, after 24 h for the combination of CQ+PQ and 48 h using CQ+TQ. The density of gametocytes declined over time in all treatment groups, although the decline was more rapid in the ASMQ+PQ group. In conclusion, it was possible to demonstrate the transmission-blocking efficacy of the malaria vivax treatment and that ASMQ+PQ acts faster than the two other treatments.
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Affiliation(s)
- Alice O. Andrade
- Plataforma de Produção e Infecção de Vetores da Malária (PIVEM), Laboratório de Entomologia, Fiocruz Rondônia, Porto Velho, Rondônia, Brazil
| | - Najara A. C. Santos
- Plataforma de Produção e Infecção de Vetores da Malária (PIVEM), Laboratório de Entomologia, Fiocruz Rondônia, Porto Velho, Rondônia, Brazil
- Programa de Pós-Graduação em Biologia Experimental, Fundação Universidade Federal de Rondônia, FIOCRUZ Rondônia, Porto Velho, Rondônia, Brazil
| | - Alessandra S. Bastos
- Plataforma de Produção e Infecção de Vetores da Malária (PIVEM), Laboratório de Entomologia, Fiocruz Rondônia, Porto Velho, Rondônia, Brazil
| | - José D. C. Pontual
- Plataforma de Produção e Infecção de Vetores da Malária (PIVEM), Laboratório de Entomologia, Fiocruz Rondônia, Porto Velho, Rondônia, Brazil
| | - Jéssica E. Araújo
- Plataforma de Produção e Infecção de Vetores da Malária (PIVEM), Laboratório de Entomologia, Fiocruz Rondônia, Porto Velho, Rondônia, Brazil
- Programa de Pós-Graduação em Biologia Experimental, Fundação Universidade Federal de Rondônia, FIOCRUZ Rondônia, Porto Velho, Rondônia, Brazil
| | - Alexia M. V. Silva
- Ambulatório de Malária, Centro de Pesquisa em Medicina Tropical, Porto Velho, Rondônia, Brazil
| | - Leandro N. Martinez
- Programa de Pós-Graduação em Biologia Experimental, Fundação Universidade Federal de Rondônia, FIOCRUZ Rondônia, Porto Velho, Rondônia, Brazil
- Plataforma de Bioensaios de Malária e Leishmaniose da Fiocruz (PBML), Fiocruz Rondônia, Porto Velho, Rondônia, Brazil
| | - Alzemar A. Lima
- Ambulatório de Malária, Centro de Pesquisa em Medicina Tropical, Porto Velho, Rondônia, Brazil
| | | | - Carolina B. G. Teles
- Programa de Pós-Graduação em Biologia Experimental, Fundação Universidade Federal de Rondônia, FIOCRUZ Rondônia, Porto Velho, Rondônia, Brazil
- Plataforma de Bioensaios de Malária e Leishmaniose da Fiocruz (PBML), Fiocruz Rondônia, Porto Velho, Rondônia, Brazil
| | - Jansen F. Medeiros
- Plataforma de Produção e Infecção de Vetores da Malária (PIVEM), Laboratório de Entomologia, Fiocruz Rondônia, Porto Velho, Rondônia, Brazil
- Programa de Pós-Graduação em Biologia Experimental, Fundação Universidade Federal de Rondônia, FIOCRUZ Rondônia, Porto Velho, Rondônia, Brazil
| | - Dhelio B. Pereira
- Ambulatório de Malária, Centro de Pesquisa em Medicina Tropical, Porto Velho, Rondônia, Brazil
| | - Joseph M. Vinetz
- Section of Infectious Diseases, Department of Internal Medicine, Yale School of Medicine, New Haven, Connecticut, United States of America
| | - Ricardo T. Gazzinelli
- Laboratório de Imunopatologia, Instituto René Rachou, Fundação Oswaldo Cruz, Belo Horizonte, Minas Gerais, Brazil
- Department of Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Maisa S. Araújo
- Plataforma de Produção e Infecção de Vetores da Malária (PIVEM), Laboratório de Entomologia, Fiocruz Rondônia, Porto Velho, Rondônia, Brazil
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2
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Alemayehu A. Biology and epidemiology of Plasmodium falciparum and Plasmodium vivax gametocyte carriage: Implication for malaria control and elimination. Parasite Epidemiol Control 2023; 21:e00295. [PMID: 36950502 PMCID: PMC10025134 DOI: 10.1016/j.parepi.2023.e00295] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 01/01/2023] [Accepted: 02/27/2023] [Indexed: 03/09/2023] Open
Abstract
Malaria is among the leading public health problems worldwide. Female anopheles mosquito orchestrates the transmission of malaria by taking gametocytes and introducing sporozoite while taking blood meals. Interrupting transmission is the major strategy for malaria elimination. The gametocyte stage is essential for the onward transmission of malaria. Thus, understanding its basic biology and epidemiology is key to malaria control and elimination. Therefore, the current review focuses on revealing the biology, prevalence, and determinants of gametocyte carriage as well as its implication on mitigation of malaria. It also illustrates the role of asymptomatic and sub-microscopic Plasmodium infections and G-6-PD deficiency in gametocyte carriage and hence malaria transmission. Gametocytogenesis is initiated at committed merozoites and gives rise to the development of gametocytes. The trigger for gametocytogenesis depends on the host, parasite, and intervention factors. Gametocytes pass through five developmental stages identifiable by molecular markers. A considerable number of malaria patients carry gametocytes at a sub-microscopic level, thereby serving as a potential infectious reservoir of transmission. Factors involving the human host, Plasmodium parasite, and intervention parameters play a critical role in gametocyte biology and prevalence. The contribution of asymptomatic and sub-microscopic infections to malaria transmission is unknown. The clear impact of G-6-PD deficiency on malaria control and elimination remains unclear. Lack of clarity on such issues might impede the success of interventions. Basic science and epidemiological studies should continue to overcome the challenges and cope with the ever-evolving parasite and guide interventions.
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Affiliation(s)
- Aklilu Alemayehu
- School of Medical Laboratory Sciences, Institute of Health, Jimma University, Jimma, Ethiopia
- Department of Medical Laboratory Sciences, College of Medicine and Health Sciences, Arba Minch University, Arba Minch, Ethiopia
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3
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Bahk YY, Cho SH, Kim KN, Shin EH, Jeon BH, Kim JH, Park S, Kwon J, Kan H, Kim M, Kim TS. An Epidemiological Analysis of 28 Vivax Malaria Cases in Gimpo-si, Korea, 2020. THE KOREAN JOURNAL OF PARASITOLOGY 2021; 59:507-512. [PMID: 34724771 PMCID: PMC8561053 DOI: 10.3347/kjp.2021.59.5.507] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Accepted: 10/06/2021] [Indexed: 11/23/2022]
Abstract
Since 1993, vivax malaria has been recognized as a public health burden in Korea. Despite of pan-governmental malaria-control efforts and the dramatic reduction in the burden of this disease over the last 10 years, vivax malaria has not been well controlled and has remained continuously endemic. We focused interviewed and examined the charts of 28 confirmed vivax malaria patients given malarial therapy for whom daily records were kept from Gimpo-si, Gyeonggi-do of Korea. Various epidemiological characteristics of vivax malaria, including the incubation period, medication used, and recurrence, and an evaluation of the parasitic characteristics from the focused interviews of patients from this region are described here. Most of the participants indicated the 3 most common symptoms of malaria (headache, chills and fever). Of the 28 cases, 2 experienced a second attack and there were 17 and 11 cases with short- and long-term incubation periods, respectively, yielding a short-term to long-term ratio of 1.5. Based on the parasitemia stages, most of the participants were tested at 5 to 7 days (11 cases) and 7 to 15 days (11 cases) after initial wave of asexual parasites. In conclusion, public health authorities should consider developing management measures to decrease the time lag for diagnosis and drafting unified and robust guidelines for drug use for malaria and drawing up unified and robust guidelines on the use of medication for malaria. It also suggests that routine monitoring, surveillance, and precise medical surveys in high-risk vivax malaria endemic areas are pivotal to controlling this persistent public disease and finally eliminating it from Korea.
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Affiliation(s)
- Young Yil Bahk
- Department of Biotechnology, College of Biomedical and Health Science, Konkuk University, Chungju 27478, Korea
| | | | - Kyoung-Nam Kim
- Department of Preventive Medicine, Ajou University School of Medicine, Suwon 16499, Korea
| | - Eun-Hee Shin
- Department of Parasitology and Tropical Medicine, Seoul National University School of Medicine, Seoul 03080, Korea.,Seoul National University Bundang Hospital, Seongnam 13620, Korea
| | - Byoung-Hak Jeon
- Department of Municipal Hospital Policy & Management, Seoul Health Foundation, Seoul 04512, Korea
| | | | - Sookkyung Park
- Bureau of Infectious Disease Policy, Korea Disease Control and Prevention Agency, Osong 28159, Korea
| | - Jeongran Kwon
- Bureau of Infectious Disease Policy, Korea Disease Control and Prevention Agency, Osong 28159, Korea
| | - Hyesu Kan
- Bureau of Infectious Disease Policy, Korea Disease Control and Prevention Agency, Osong 28159, Korea
| | - Miyoung Kim
- Bureau of Infectious Disease Policy, Korea Disease Control and Prevention Agency, Osong 28159, Korea
| | - Tong-Soo Kim
- Department of Tropical Medicine & Global Resource Bank of Parasitic Protozoa Pathogens, Inha University School of Medicine, Incheon 22212, Korea.,Convergence Research Center for Insect Vectors, Incheon National University, Incheon 22012, Korea
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Salazar Alvarez LC, Vera Lizcano O, da Silva Barros DKA, Baia-da-Silva DC, Monteiro WM, Pimenta PFP, de Lacerda MVG, Costa FTM, Lopes SCP. Plasmodium vivax Gametocytes Adherence to Bone Marrow Endothelial Cells. Front Cell Infect Microbiol 2021; 11:614985. [PMID: 34249772 PMCID: PMC8265044 DOI: 10.3389/fcimb.2021.614985] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Accepted: 04/12/2021] [Indexed: 11/13/2022] Open
Abstract
In a Plasmodium vivax infection, it was shown a proportionally increased on gametocyte distribution within the bone marrow aspirant, suggesting a role of this organ as a reservoir for this parasite stage. Here, we evaluated the ex vivo cytoadhesive capacity of P. vivax gametocytes to bone marrow endothelial cells (HBMEC) and investigated the involvement of some receptors in the cytoadhesion process by using transfected CHO cells (CHO-ICAM1, CHO-CD36 and CHO-VCAM), wild type (CHO-K1) or deficient in heparan and chondroitin sulfate (CHO-745). Ex-vivo cytoadhesion assays were performed using a total of 44 P. vivax isolates enriched in gametocyte stages by Percoll gradient in the different cell lines. The majority of isolates (88.9%) were able to adhere to HBMEC monolayer. ICAM1 seemed to be the sole receptor significantly involved. CD-36 was the receptor with higher adhesion rate, despite no significance was noticed when compared to CHO-745. We demonstrated that gametocyte P. vivax adheres ex vivo to bone marrow endothelial cells. Moreover, P. vivax gametocytes display the ability to adhere to all CHO cells investigated, especially to CHO-ICAM1. These findings bring insights to the comprehension of the role of the bone marrow as a P. vivax reservoir and the potential impact on parasite transmission to the vector.
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Affiliation(s)
- Luis Carlos Salazar Alvarez
- Fundação de Medicina Tropical Dr. Heitor Vieira Dourado (FMT-HVD), Manaus, Brazil.,Programa de Pós-Graduação em Medicina Tropical, Universidade do Estado do Amazonas, Manaus, Brazil.,Laboratório de Doenças Tropicais Prof. Dr. Luiz Jacintho da Silva, Departamento de Genética, Evolução, Microbiologia e Imunologia, Universidade de Campinas - UNICAMP, Campinas, Brazil
| | - Omaira Vera Lizcano
- Fundação de Medicina Tropical Dr. Heitor Vieira Dourado (FMT-HVD), Manaus, Brazil.,Laboratório de Doenças Tropicais Prof. Dr. Luiz Jacintho da Silva, Departamento de Genética, Evolução, Microbiologia e Imunologia, Universidade de Campinas - UNICAMP, Campinas, Brazil.,Grupo de Investigación QUIBIO, Facultad de Ciencias Básicas, Universidad Santiago de Cali, Cali, Colombia
| | - Dayanne Kamylla Alves da Silva Barros
- Fundação de Medicina Tropical Dr. Heitor Vieira Dourado (FMT-HVD), Manaus, Brazil.,Instituto Leonidas & Maria Deane - ILMD/Fiocruz Amazônia, Manaus, Brazil
| | | | - Wuelton Marcelo Monteiro
- Fundação de Medicina Tropical Dr. Heitor Vieira Dourado (FMT-HVD), Manaus, Brazil.,Programa de Pós-Graduação em Medicina Tropical, Universidade do Estado do Amazonas, Manaus, Brazil
| | - Paulo Filemon Paolluci Pimenta
- Fundação de Medicina Tropical Dr. Heitor Vieira Dourado (FMT-HVD), Manaus, Brazil.,Instituto René Rachou - IRR/Fiocruz Minas, Belo Horizonte, Brazil
| | - Marcus Vinicius Guimarães de Lacerda
- Fundação de Medicina Tropical Dr. Heitor Vieira Dourado (FMT-HVD), Manaus, Brazil.,Instituto Leonidas & Maria Deane - ILMD/Fiocruz Amazônia, Manaus, Brazil
| | - Fabio Trindade Maranhão Costa
- Laboratório de Doenças Tropicais Prof. Dr. Luiz Jacintho da Silva, Departamento de Genética, Evolução, Microbiologia e Imunologia, Universidade de Campinas - UNICAMP, Campinas, Brazil
| | - Stefanie Costa Pinto Lopes
- Fundação de Medicina Tropical Dr. Heitor Vieira Dourado (FMT-HVD), Manaus, Brazil.,Instituto Leonidas & Maria Deane - ILMD/Fiocruz Amazônia, Manaus, Brazil
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5
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Pasini EM, Kocken CHM. Parasite-Host Interaction and Pathophysiology Studies of the Human Relapsing Malarias Plasmodium vivax and Plasmodium ovale Infections in Non-Human Primates. Front Cell Infect Microbiol 2021; 10:614122. [PMID: 33680982 PMCID: PMC7925837 DOI: 10.3389/fcimb.2020.614122] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Accepted: 12/24/2020] [Indexed: 12/26/2022] Open
Abstract
Malaria remains a serious health concern across the globe. Historically neglected, non-Falciparum human malarias were put back on the agenda by a paradigm shift in the fight against malaria from malaria control to malaria eradication. Here, we review the modeling of the relapsing parasites Plasmodium vivax (P. vivax) and Plasmodium ovale (P. ovale) in non-human primates with a specific focus on the contribution of these models to our current understanding of the factors that govern parasite-host interactions in P. vivax and P. ovale parasite biology and pathophysiology.
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Affiliation(s)
- Erica M Pasini
- Department of Parasitology, Biomedical Primate Research Center, Rijswijk, Netherlands
| | - Clemens H M Kocken
- Department of Parasitology, Biomedical Primate Research Center, Rijswijk, Netherlands
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6
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Sato S. Plasmodium-a brief introduction to the parasites causing human malaria and their basic biology. J Physiol Anthropol 2021; 40:1. [PMID: 33413683 PMCID: PMC7792015 DOI: 10.1186/s40101-020-00251-9] [Citation(s) in RCA: 110] [Impact Index Per Article: 36.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 12/21/2020] [Indexed: 02/07/2023] Open
Abstract
Malaria is one of the most devastating infectious diseases of humans. It is problematic clinically and economically as it prevails in poorer countries and regions, strongly hindering socioeconomic development. The causative agents of malaria are unicellular protozoan parasites belonging to the genus Plasmodium. These parasites infect not only humans but also other vertebrates, from reptiles and birds to mammals. To date, over 200 species of Plasmodium have been formally described, and each species infects a certain range of hosts. Plasmodium species that naturally infect humans and cause malaria in large areas of the world are limited to five-P. falciparum, P. vivax, P. malariae, P. ovale and P. knowlesi. The first four are specific for humans, while P. knowlesi is naturally maintained in macaque monkeys and causes zoonotic malaria widely in South East Asia. Transmission of Plasmodium species between vertebrate hosts depends on an insect vector, which is usually the mosquito. The vector is not just a carrier but the definitive host, where sexual reproduction of Plasmodium species occurs, and the parasite's development in the insect is essential for transmission to the next vertebrate host. The range of insect species that can support the critical development of Plasmodium depends on the individual parasite species, but all five Plasmodium species causing malaria in humans are transmitted exclusively by anopheline mosquitoes. Plasmodium species have remarkable genetic flexibility which lets them adapt to alterations in the environment, giving them the potential to quickly develop resistance to therapeutics such as antimalarials and to change host specificity. In this article, selected topics involving the Plasmodium species that cause malaria in humans are reviewed.
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Affiliation(s)
- Shigeharu Sato
- Borneo Medical and Health Research Centre, Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, Jalan UMS, 88400 Kota Kinabalu, Sabah, Malaysia.
- Department of Pathobiology and Medical Diagnostics, Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, Jalan UMS, 88400, Kota Kinabalu, Sabah, Malaysia.
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7
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Plasmodium falciparum sexual differentiation in malaria patients is associated with host factors and GDV1-dependent genes. Nat Commun 2019; 10:2140. [PMID: 31086187 PMCID: PMC6514009 DOI: 10.1038/s41467-019-10172-6] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Accepted: 04/12/2019] [Indexed: 01/06/2023] Open
Abstract
Plasmodium sexual differentiation is required for malaria transmission, yet much remains unknown about its regulation. Here, we quantify early gametocyte-committed ring (gc-ring) stage, P. falciparum parasites in 260 uncomplicated malaria patient blood samples 10 days before maturation to transmissible stage V gametocytes using a gametocyte conversion assay (GCA). Seventy six percent of the samples have gc-rings, but the ratio of gametocyte to asexual-committed rings (GCR) varies widely (0–78%). GCR correlates positively with parasitemia and is negatively influenced by fever, not hematocrit, age or leukocyte counts. Higher expression levels of GDV1-dependent genes, ap2-g, msrp1 and gexp5, as well as a gdv1 allele encoding H217 are associated with high GCR, while high plasma lysophosphatidylcholine levels are associated with low GCR in the second study year. The results provide a view of sexual differentiation in the field and suggest key regulatory roles for clinical factors and gdv1 in gametocytogenesis in vivo. Here, the authors quantify early gametocyte-committed ring (gc-ring) stage Plasmodium falciparum parasites in 260 malaria patients 10 days before maturation to transmissible stage V gametocytes, and show that the ratio of circulating gc-rings is positively correlated with parasitemia and negatively correlated with body temperature.
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Yap XZ, Lundie RJ, Beeson JG, O'Keeffe M. Dendritic Cell Responses and Function in Malaria. Front Immunol 2019; 10:357. [PMID: 30886619 PMCID: PMC6409297 DOI: 10.3389/fimmu.2019.00357] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 02/12/2019] [Indexed: 12/24/2022] Open
Abstract
Malaria remains a serious threat to global health. Sustained malaria control and, eventually, eradication will only be achieved with a broadly effective malaria vaccine. Yet a fundamental lack of knowledge about how antimalarial immunity is acquired has hindered vaccine development efforts to date. Understanding how malaria-causing parasites modulate the host immune system, specifically dendritic cells (DCs), key initiators of adaptive and vaccine antigen-based immune responses, is vital for effective vaccine design. This review comprehensively summarizes how exposure to Plasmodium spp. impacts human DC function in vivo and in vitro. We have highlighted the heterogeneity of the data observed in these studies, compared and critiqued the models used to generate our current understanding of DC function in malaria, and examined the mechanisms by which Plasmodium spp. mediate these effects. This review highlights potential research directions which could lead to improved efficacy of existing vaccines, and outlines novel targets for next-generation vaccine strategies to target malaria.
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Affiliation(s)
- Xi Zen Yap
- Burnet Institute, Melbourne, VIC, Australia.,Department of Medicine, Dentistry, and Health Sciences, The University of Melbourne, Parkville, VIC, Australia
| | - Rachel J Lundie
- Burnet Institute, Melbourne, VIC, Australia.,Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - James G Beeson
- Burnet Institute, Melbourne, VIC, Australia.,Department of Medicine, Dentistry, and Health Sciences, The University of Melbourne, Parkville, VIC, Australia.,Department of Microbiology and Central Clinical School, Monash University, Clayton, VIC, Australia
| | - Meredith O'Keeffe
- Burnet Institute, Melbourne, VIC, Australia.,Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
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Rodrigues-da-Silva RN, Correa-Moreira D, Soares IF, de-Luca PM, Totino PRR, Morgado FN, Oliveira Henriques MDGD, Peixoto Candea AL, Singh B, Galinski MR, Moreno A, Oliveira-Ferreira J, Lima-Junior JDC. Immunogenicity of synthetic peptide constructs based on PvMSP9 E795-A808, a linear B-cell epitope of the P. vivax Merozoite Surface Protein-9. Vaccine 2018; 37:306-313. [PMID: 30509693 DOI: 10.1016/j.vaccine.2018.10.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Revised: 09/26/2018] [Accepted: 10/04/2018] [Indexed: 11/17/2022]
Abstract
Plasmodium vivax Merozoite Surface Protein-9 (PvMSP-9) is a malaria vaccine candidate naturally immunogenic in humans and able to induce high antibody titers in animals when delivered as a recombinant protein. Recently, we identified the sequence EAAPENAEPVHENA (PvMSP9E795-A808) as the main linear B-cell epitope in naturally exposed individuals. However, the potential of PvMSP9E795-A808 as an immunogen in experimental animal models remained unexplored. Here we assess the immunogenicity of PvMSP9E795-A808 using synthetic peptides. The peptides tested in BALB/c mice include two repeats of the sequence EAAPENAEPVHENA tested alone (peptide RII), or linked to an autologous (PvMSP9 peptide pL; pLRII) or heterologous (p2 tetanus toxin universal T cell epitope; TTRII) T cell epitope. Immune responses were evaluated by ELISA, FLUOROSPOT, and indirect immunofluorescence. We show that all of the peptide constructs tested were immunogenic eliciting specific IgG antibodies at different levels, with a prevalence of IgG1 and IgG2. Animals immunized with synthetic peptides containing T cell epitopes (pLRII or TTRII) had more efficient antibody responses that resulted in higher antibody titers able to recognize the native protein by immunofluorescence. Relevantly, the frequency of IFN-γ secreting SFC elicited by immunization with TTRII synthetic peptide was comparable to that reported to the PvMSP9-Nt recombinant protein. Taken together, our study indicates that PvMSP9E795-A808 is highly immunogenic in mice and further studies to evaluate its value as promising vaccine target are warranted. Moreover, our study supports the critical role of CD4 T cell epitopes to enhance humoral responses induced by subunit based vaccines.
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Affiliation(s)
| | - Daniely Correa-Moreira
- Laboratory of Taxonomy, Biochemistry and Fungi Bioprospecting, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil
| | - Isabela Ferreira Soares
- Laboratory of Immunoparasitology, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, (FIOCRUZ), Rio de Janeiro, RJ, Brazil
| | - Paula Melo de-Luca
- Laboratory of Immunoparasitology, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, (FIOCRUZ), Rio de Janeiro, RJ, Brazil
| | - Paulo Renato Rivas Totino
- Laboratory of Malaria Research, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil
| | - Fernanda Nazaré Morgado
- Laboratory of Leishmaniasis Research, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil
| | | | | | - Balwan Singh
- Emory Vaccine Center, Yerkes National Primate Research Center, Emory University, Atlanta, GA, USA
| | - Mary R Galinski
- Emory Vaccine Center, Yerkes National Primate Research Center, Emory University, Atlanta, GA, USA; Division of Infectious Diseases, Emory Vaccine Center, Yerkes National Primate Research Center, Emory University School of Medicine, Emory University, Atlanta, GA, USA
| | - Alberto Moreno
- Emory Vaccine Center, Yerkes National Primate Research Center, Emory University, Atlanta, GA, USA; Division of Infectious Diseases, Emory Vaccine Center, Yerkes National Primate Research Center, Emory University School of Medicine, Emory University, Atlanta, GA, USA
| | - Joseli Oliveira-Ferreira
- Laboratory of Immunoparasitology, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, (FIOCRUZ), Rio de Janeiro, RJ, Brazil
| | - Josué da Costa Lima-Junior
- Laboratory of Immunoparasitology, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, (FIOCRUZ), Rio de Janeiro, RJ, Brazil.
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10
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Febrile Temperature Elevates the Expression of Phosphatidylserine on Plasmodium falciparum (FCR3CSA) Infected Red Blood Cell Surface Leading to Increased Cytoadhesion. Sci Rep 2018; 8:15022. [PMID: 30302009 PMCID: PMC6177484 DOI: 10.1038/s41598-018-33358-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Accepted: 09/26/2018] [Indexed: 11/17/2022] Open
Abstract
During the asexual intra-erythrocytic cycle, Plasmodium (P.) falciparum exports parasitic proteins to the surface of infected red blood cells (iRBCs) facilitating its cytoadhesion to various endothelial host receptors. This adhesive behavior is a critical contributor towards disease manifestation. However, little is known about the influence of recurring elevated temperature – a common symptom of the malaria infection – on the adhesive properties of iRBCs to endothelial receptors. To address this, we performed dual-micropipette step-pressure technique between P. falciparum (strain FCR3CSA) iRBCs and Chinese Hamster Ovary cells expressing Chondroitin sulfate A (CHO-CSA) after transient iRBCs incubation at febrile temperatures which revealed increase in adhesion parameters. Furthermore, flow cytometry analysis revealed an increase in phosphatidylserine (PS) expression on the iRBC surface following exposure to febrile temperature. The adhesion between iRBCs and CHO-CSA cells was remarkably reduced in presence of soluble Annexin V, indicating the mediation of PS on the adhesion events. Our results suggest that elevated PS recruitment on iRBC under thermally stressed conditions contributes to the increased adhesive behavior of iRBCs CSA-binding phenotype to CHO-CSA.
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Roth A, Maher SP, Conway AJ, Ubalee R, Chaumeau V, Andolina C, Kaba SA, Vantaux A, Bakowski MA, Thomson-Luque R, Adapa SR, Singh N, Barnes SJ, Cooper CA, Rouillier M, McNamara CW, Mikolajczak SA, Sather N, Witkowski B, Campo B, Kappe SHI, Lanar DE, Nosten F, Davidson S, Jiang RHY, Kyle DE, Adams JH. A comprehensive model for assessment of liver stage therapies targeting Plasmodium vivax and Plasmodium falciparum. Nat Commun 2018; 9:1837. [PMID: 29743474 PMCID: PMC5943321 DOI: 10.1038/s41467-018-04221-9] [Citation(s) in RCA: 101] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Accepted: 04/10/2018] [Indexed: 12/26/2022] Open
Abstract
Malaria liver stages represent an ideal therapeutic target with a bottleneck in parasite load and reduced clinical symptoms; however, current in vitro pre-erythrocytic (PE) models for Plasmodium vivax and P. falciparum lack the efficiency necessary for rapid identification and effective evaluation of new vaccines and drugs, especially targeting late liver-stage development and hypnozoites. Herein we report the development of a 384-well plate culture system using commercially available materials, including cryopreserved primary human hepatocytes. Hepatocyte physiology is maintained for at least 30 days and supports development of P. vivax hypnozoites and complete maturation of P. vivax and P. falciparum schizonts. Our multimodal analysis in antimalarial therapeutic research identifies important PE inhibition mechanisms: immune antibodies against sporozoite surface proteins functionally inhibit liver stage development and ion homeostasis is essential for schizont and hypnozoite viability. This model can be implemented in laboratories in disease-endemic areas to accelerate vaccine and drug discovery research.
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Affiliation(s)
- Alison Roth
- Department of Global Health, College of Public Health, Center for Global Health and Infectious Diseases Research, University of South Florida, 3720 Spectrum Blvd 404, Tampa, FL, 33612, USA
| | - Steven P Maher
- Department of Global Health, College of Public Health, Center for Global Health and Infectious Diseases Research, University of South Florida, 3720 Spectrum Blvd 404, Tampa, FL, 33612, USA
- Center for Tropical and Emerging Global Diseases, University of Georgia, 500 DW Brooks Dr. Suite 370, Athens, GA, 30602, USA
| | - Amy J Conway
- Department of Global Health, College of Public Health, Center for Global Health and Infectious Diseases Research, University of South Florida, 3720 Spectrum Blvd 404, Tampa, FL, 33612, USA
| | - Ratawan Ubalee
- Department of Entomology, Armed Forces Research Institute of Medical Sciences (AFRIMS), 315/6 Rajvithi Rd, Bangkok, 10400, Thailand
| | - Victor Chaumeau
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
- Shoklo Malaria Research Unit, Mahidol Oxford Research Unit, Faculty of Tropical Medicine, Mahidol University, 68/30 Bantung Rd, Mae Sot, Tak, 63110, Thailand
| | - Chiara Andolina
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
- Shoklo Malaria Research Unit, Mahidol Oxford Research Unit, Faculty of Tropical Medicine, Mahidol University, 68/30 Bantung Rd, Mae Sot, Tak, 63110, Thailand
| | - Stephen A Kaba
- Malaria Vaccine Branch, Walter Reed Army Institute of Research, 503 Robert Grant Ave, Silver Spring, MD, 20910, USA
| | - Amélie Vantaux
- Malaria Molecular Epidemiology Unit, Institut Pasteur du Cambodge, 5 Boulevard Monivong-PO Box 983, Phnom Penh, 12 201, Cambodia
| | - Malina A Bakowski
- California Institute for Biomedical Research (Calibr), 11119N. Torrey Pines Rd, Suite 100, La Jolla, CA, 92037, USA
| | - Richard Thomson-Luque
- Department of Global Health, College of Public Health, Center for Global Health and Infectious Diseases Research, University of South Florida, 3720 Spectrum Blvd 404, Tampa, FL, 33612, USA
| | - Swamy Rakesh Adapa
- Department of Global Health, College of Public Health, Center for Global Health and Infectious Diseases Research, University of South Florida, 3720 Spectrum Blvd 404, Tampa, FL, 33612, USA
| | - Naresh Singh
- Department of Global Health, College of Public Health, Center for Global Health and Infectious Diseases Research, University of South Florida, 3720 Spectrum Blvd 404, Tampa, FL, 33612, USA
| | - Samantha J Barnes
- Department of Global Health, College of Public Health, Center for Global Health and Infectious Diseases Research, University of South Florida, 3720 Spectrum Blvd 404, Tampa, FL, 33612, USA
| | - Caitlin A Cooper
- Center for Tropical and Emerging Global Diseases, University of Georgia, 500 DW Brooks Dr. Suite 370, Athens, GA, 30602, USA
| | - Mélanie Rouillier
- Medicines for Malaria Venture, Pré-Bois Rd 20, Meyrin, 1215, Switzerland
| | - Case W McNamara
- California Institute for Biomedical Research (Calibr), 11119N. Torrey Pines Rd, Suite 100, La Jolla, CA, 92037, USA
| | - Sebastian A Mikolajczak
- Center for Infectious Disease Research, 307 Westlake Ave N Suite 500, Seattle, WA, 98109, USA
| | - Noah Sather
- Center for Infectious Disease Research, 307 Westlake Ave N Suite 500, Seattle, WA, 98109, USA
| | - Benoît Witkowski
- California Institute for Biomedical Research (Calibr), 11119N. Torrey Pines Rd, Suite 100, La Jolla, CA, 92037, USA
| | - Brice Campo
- Medicines for Malaria Venture, Pré-Bois Rd 20, Meyrin, 1215, Switzerland
| | - Stefan H I Kappe
- Center for Infectious Disease Research, 307 Westlake Ave N Suite 500, Seattle, WA, 98109, USA
| | - David E Lanar
- Malaria Vaccine Branch, Walter Reed Army Institute of Research, 503 Robert Grant Ave, Silver Spring, MD, 20910, USA
| | - François Nosten
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
- Shoklo Malaria Research Unit, Mahidol Oxford Research Unit, Faculty of Tropical Medicine, Mahidol University, 68/30 Bantung Rd, Mae Sot, Tak, 63110, Thailand
| | - Silas Davidson
- Department of Entomology, Armed Forces Research Institute of Medical Sciences (AFRIMS), 315/6 Rajvithi Rd, Bangkok, 10400, Thailand
| | - Rays H Y Jiang
- Department of Global Health, College of Public Health, Center for Global Health and Infectious Diseases Research, University of South Florida, 3720 Spectrum Blvd 404, Tampa, FL, 33612, USA
| | - Dennis E Kyle
- Department of Global Health, College of Public Health, Center for Global Health and Infectious Diseases Research, University of South Florida, 3720 Spectrum Blvd 404, Tampa, FL, 33612, USA
- Center for Tropical and Emerging Global Diseases, University of Georgia, 500 DW Brooks Dr. Suite 370, Athens, GA, 30602, USA
| | - John H Adams
- Department of Global Health, College of Public Health, Center for Global Health and Infectious Diseases Research, University of South Florida, 3720 Spectrum Blvd 404, Tampa, FL, 33612, USA.
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Pizzitutti F, Pan W, Feingold B, Zaitchik B, Álvarez CA, Mena CF. Out of the net: An agent-based model to study human movements influence on local-scale malaria transmission. PLoS One 2018; 13:e0193493. [PMID: 29509795 PMCID: PMC5839546 DOI: 10.1371/journal.pone.0193493] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Accepted: 02/12/2018] [Indexed: 01/08/2023] Open
Abstract
Though malaria control initiatives have markedly reduced malaria prevalence in recent decades, global eradication is far from actuality. Recent studies show that environmental and social heterogeneities in low-transmission settings have an increased weight in shaping malaria micro-epidemiology. New integrated and more localized control strategies should be developed and tested. Here we present a set of agent-based models designed to study the influence of local scale human movements on local scale malaria transmission in a typical Amazon environment, where malaria is transmission is low and strongly connected with seasonal riverine flooding. The agent-based simulations show that the overall malaria incidence is essentially not influenced by local scale human movements. In contrast, the locations of malaria high risk spatial hotspots heavily depend on human movements because simulated malaria hotspots are mainly centered on farms, were laborers work during the day. The agent-based models are then used to test the effectiveness of two different malaria control strategies both designed to reduce local scale malaria incidence by targeting hotspots. The first control scenario consists in treat against mosquito bites people that, during the simulation, enter at least once inside hotspots revealed considering the actual sites where human individuals were infected. The second scenario involves the treatment of people entering in hotspots calculated assuming that the infection sites of every infected individual is located in the household where the individual lives. Simulations show that both considered scenarios perform better in controlling malaria than a randomized treatment, although targeting household hotspots shows slightly better performance.
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Affiliation(s)
- Francesco Pizzitutti
- Universidad San Francisco de Quito, Instituto de Geografía, Quito, Ecuador
- Duke University, Duke global Health Institute, Durham, NC, United States of America
| | - William Pan
- Duke University, Duke global Health Institute, Durham, NC, United States of America
| | - Beth Feingold
- SUNY-Albany, School of Public Health, Rensselaer, Albany, NY, United States of America
| | - Ben Zaitchik
- Johns Hopkins University, Morton K. Blaustein Department of Earth & Planetary Sciences, Baltimore, MD, United States of America
| | | | - Carlos F. Mena
- Universidad San Francisco de Quito, Instituto de Geografía, Quito, Ecuador
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Kim HS, Kang G, Lee S, Yoon CG, Kim M. Cost-Benefit Analysis of Malaria Chemoprophylaxis and Early Diagnosis for Korean Soldiers in Malaria Risk Regions. J Korean Med Sci 2018; 33:e59. [PMID: 29495139 PMCID: PMC5832939 DOI: 10.3346/jkms.2018.33.e59] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2017] [Accepted: 12/07/2017] [Indexed: 11/20/2022] Open
Abstract
BACKGROUND Chemoprophylaxis has been used to prevent malaria among soldiers and secondary transmission, as it effectively facilitates a decline in disease occurrence and secondary prevention. However, poor compliance and decreased risk of exposure to malaria necessitate that control strategies be reestablished. METHODS To predict the incidence of malaria according to a control strategy, we proposed a mathematical model for its transmission using epidemiological data from 2010 to 2012. The benefit component included in the analyses was the averted cost with each control strategy, and the cost components were the cost of implementing chemoprophylaxis and early diagnosis. RESULTS The chemoprophylaxis regimen with hydroxychloroquine sulfate and primaquine was Intervention 1, the regimen with primaquine only was Intervention 2, and diagnosis with a rapid diagnostic test (RDT) kit within 5 days of fever was Intervention 3. The simulation indicated that the combined control program with chemoprophylaxis and early diagnosis would be the most effective strategy, whereas sole early diagnosis would be the least effective strategy. However, the cost-benefit ratio of chemoprophylaxis was less than Intervention 1, irrespective of the varying range of chemoprophylaxis compliance, and that of early diagnosis was more than Intervention 1, regardless of the varying early diagnosis rate and demand for the RDT kit. Although chemoprophylaxis would be more effective at reducing the incidence of malaria than early diagnosis, it is less economical due to the higher cost. CONCLUSION Our results support the introduction of early diagnosis with a RDT kit to control malaria in the Republic of Korea Army.
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Affiliation(s)
- Hee Sung Kim
- Department of Internal Medicine, Cheongju Medical Center, Cheongju, Korea
- Department of Health Informatics and Management, College of Medicine, Chungbuk National University, Cheongju, Korea
| | - Gilwon Kang
- Department of Internal Medicine, Cheongju Medical Center, Cheongju, Korea
- Department of Health Informatics and Management, College of Medicine, Chungbuk National University, Cheongju, Korea.
| | - Sunmi Lee
- Department of Applied Mathematics, Kyung Hee University, Yongin, Korea
| | | | - Minyoung Kim
- Armed Forces Gangneung Hospital, Gangneung, Korea
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Mechanisms of Plasmodium-Enhanced Attraction of Mosquito Vectors. Trends Parasitol 2017; 33:961-973. [DOI: 10.1016/j.pt.2017.08.010] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2017] [Revised: 06/14/2017] [Accepted: 08/21/2017] [Indexed: 12/14/2022]
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15
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Effects of liver-stage clearance by Primaquine on gametocyte carriage of Plasmodium vivax and P. falciparum. PLoS Negl Trop Dis 2017; 11:e0005753. [PMID: 28732068 PMCID: PMC5540608 DOI: 10.1371/journal.pntd.0005753] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Revised: 08/02/2017] [Accepted: 06/27/2017] [Indexed: 01/08/2023] Open
Abstract
Background Primaquine (PQ) is the only currently licensed antimalarial that prevents Plasmodium vivax (Pv) relapses. It also clears mature P. falciparum (Pf) gametocytes, thereby reducing post-treatment transmission. Randomized PQ treatment in a treatment-to-reinfection cohort in Papua New Guinean children permitted the study of Pv and Pf gametocyte carriage after radical cure and to investigate the contribution of Pv relapses. Methods Children received radical cure with Chloroquine, Artemether-Lumefantrine plus either PQ or placebo. Blood samples were subsequently collected in 2-to 4-weekly intervals over 8 months. Gametocytes were detected by quantitative reverse transcription-PCR targeting pvs25 and pfs25. Results PQ treatment reduced the incidence of Pv gametocytes by 73%, which was comparable to the effect of PQ on incidence of blood-stage infections. 92% of Pv and 79% of Pf gametocyte-positive infections were asymptomatic. Pv and to a lesser extent Pf gametocyte positivity and density were associated with high blood-stage parasite densities. Multivariate analysis revealed that the odds of gametocytes were significantly reduced in mixed-species infections compared to single-species infections for both species (ORPv = 0.39 [95% CI 0.25–0.62], ORPf = 0.33 [95% CI 0.18–0.60], p<0.001). No difference between the PQ and placebo treatment arms was observed in density of Pv gametocytes or in the proportion of Pv infections that carried gametocytes. First infections after blood-stage and placebo treatment, likely caused by a relapsing hypnozoite, were equally likely to carry gametocytes than first infections after PQ treatment, likely caused by an infective mosquito bite. Conclusion Pv relapses and new infections are associated with similar levels of gametocytaemia. Relapses thus contribute considerably to the Pv reservoir highlighting the importance of effective anti-hypnozoite treatment for efficient control of Pv. Trial registration ClinicalTrials.gov NCT02143934 Plasmodium vivax (Pv) mainly affects Asia, Central and South America as well as Ethiopia. In Papua New Guinea (PNG) Pv prevalence is among the highest worldwide. The biggest challenge for the control of Pv infections is the formation of dormant liver stages, which have the ability to relapse and cause disease even after successful clearance of asexual stages in the blood circulation. Primaquine is the only licensed drug that is able to prevent Pv relapses. A randomized treatment-to-reinfection cohort in Papua New Guinean children permitted permitted the study of Pv and P. falciparum gametocyte carriage after radical cure with Primaquine and to investigate the contribution of Pv relapses to transmission. We found that most gametocyte carriers in this study were detected in asymptomatic infections and that relapses and new infections are associated with similar Pv gametocyte production. These are strong arguments emphasizing the importance of sensitive detection and early treatment of asymptomatic and submicroscopic Plasmodium spp. infections and of anti-hypnozoite treatment for an effective control of Pv.
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Balabaskaran Nina P, Mohanty AK, Ballav S, Vernekar S, Bhinge S, D'souza M, Walke J, Manoharan SK, Mascarenhas A, Gomes E, Chery L, Valecha N, Kumar A, Rathod PK. Dynamics of Plasmodium vivax sporogony in wild Anopheles stephensi in a malaria-endemic region of Western India. Malar J 2017; 16:284. [PMID: 28693607 PMCID: PMC5504555 DOI: 10.1186/s12936-017-1931-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Accepted: 07/04/2017] [Indexed: 11/16/2022] Open
Abstract
Background In global efforts to track mosquito infectivity and parasite elimination, controlled mosquito-feeding experiments can help in understanding the dynamics of parasite development in vectors. Anopheles stephensi is often accepted as the major urban malaria vector that transmits Plasmodium in Goa and elsewhere in South Asia. However, much needs to be learned about the interactions of Plasmodium vivax with An. stephensi. As a component of the US NIH International Center of Excellence for Malaria Research (ICEMR) for Malaria Evolution in South Asia (MESA), a series of membrane-feeding experiments with wild An. stephensi and P. vivax were carried out to better understand this vector-parasite interaction. Methods Wild An. stephensi larvae and pupae were collected from curing water in construction sites in the city of Ponda, Goa, India. The larvae and pupae were reared at the MESA ICEMR insectary within the National Institute of Malaria Research (NIMR) field unit in Goa until they emerged into adult mosquitoes. Blood for membrane-feeding experiments was obtained from malaria patients at the local Goa Medical College and Hospital who volunteered for the study. Parasites were counted by Miller reticule technique and correlation between gametocytaemia/parasitaemia and successful mosquito infection was studied. Results A weak but significant correlation was found between patient blood gametocytaemia/parasitaemia and mosquito oocyst load. No correlation was observed between gametocytaemia/parasitaemia and oocyst infection rates, and between gametocyte sex ratio and oocyst load. When it came to development of the parasite in the mosquito, a strong positive correlation was observed between oocyst midgut levels and sporozoite infection rates, and between oocyst levels and salivary gland sporozoite loads. Kinetic studies showed that sporozoites appeared in the salivary gland as early as day 7, post-infection. Conclusions This is the first study in India to carry out membrane-feeding experiments with wild An. stephensi and P. vivax. A wide range of mosquito infection loads and infection rates were observed, pointing to a strong interplay between parasite, vector and human factors. Most of the present observations are in agreement with feeding experiments conducted with P. vivax elsewhere in the world. Electronic supplementary material The online version of this article (doi:10.1186/s12936-017-1931-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | - Ajeet Kumar Mohanty
- National Institute of Malaria Research, Field Unit, Campal, Goa, 403001, India
| | - Shuvankar Ballav
- National Institute of Malaria Research, Field Unit, Campal, Goa, 403001, India
| | - Smita Vernekar
- National Institute of Malaria Research, Field Unit, Campal, Goa, 403001, India
| | - Sushma Bhinge
- National Institute of Malaria Research, Field Unit, Campal, Goa, 403001, India
| | - Maria D'souza
- National Institute of Malaria Research, Field Unit, Campal, Goa, 403001, India
| | - Jayashree Walke
- Departments of Chemistry and of Global Health, University of Washington, Seattle, WA, 98195, USA.,Goa Medical College and Hospital, Bambolim, Goa, 403202, India
| | - Suresh Kumar Manoharan
- Departments of Chemistry and of Global Health, University of Washington, Seattle, WA, 98195, USA.,Goa Medical College and Hospital, Bambolim, Goa, 403202, India
| | - Anjali Mascarenhas
- Departments of Chemistry and of Global Health, University of Washington, Seattle, WA, 98195, USA.,Goa Medical College and Hospital, Bambolim, Goa, 403202, India
| | - Edwin Gomes
- Goa Medical College and Hospital, Bambolim, Goa, 403202, India
| | - Laura Chery
- Departments of Chemistry and of Global Health, University of Washington, Seattle, WA, 98195, USA
| | - Neena Valecha
- National Institute of Malaria Research (ICMR), Sector 8, Dwarka, New Delhi, 110077, India
| | - Ashwani Kumar
- National Institute of Malaria Research, Field Unit, Campal, Goa, 403001, India
| | - Pradipsinh K Rathod
- Departments of Chemistry and of Global Health, University of Washington, Seattle, WA, 98195, USA.
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Natural immune response to Plasmodium vivax alpha-helical coiled coil protein motifs and its association with the risk of P. vivax malaria. PLoS One 2017. [PMID: 28651021 PMCID: PMC5484505 DOI: 10.1371/journal.pone.0179863] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Protein α-helical coiled coil structures are known to induce antibodies able to block critical functions in different pathogens. In a previous study, a total of 50 proteins of Plasmodium vivax erythrocytic asexual stages containing α-helical coiled coil structural motifs were identified in silico, and the corresponding peptides were chemically synthesized. A total of 43 peptides were recognized by naturally acquired antibodies in plasma samples from both Papua New Guinea (PNG) and Colombian adult donors. In this study, the association between IgG antibodies to these peptides and clinical immunity was further explored by measuring total IgG antibody levels to 24 peptides in baseline samples from a longitudinal study of children aged 1–3 years (n = 164) followed for 16 months. Samples were reactive to all peptides tested. Eight peptides were recognized by >50% of individuals, whereas only one peptide had < 20% reactivity. Children infected at baseline were seropositive to 23/24 peptides. No significant association was observed between antibody titers and age or molecular force of infection, suggesting that antibody levels had already reached an equilibrium. There was a strong association between antibody levels to all peptides and protection against P. vivax clinical episodes during the 16 months follow-up. These results suggest that the selected coiled coil antigens might be good markers of both exposure and acquired immunity to P. vivax malaria, and further preclinical investigation should be performed to determine their potential as P. vivax vaccine antigens.
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Defining the next generation of Plasmodium vivax diagnostic tests for control and elimination: Target product profiles. PLoS Negl Trop Dis 2017; 11:e0005516. [PMID: 28369085 PMCID: PMC5391123 DOI: 10.1371/journal.pntd.0005516] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Revised: 04/13/2017] [Accepted: 03/21/2017] [Indexed: 12/28/2022] Open
Abstract
The global prevalence of malaria has decreased over the past fifteen years, but similar gains have not been realized against Plasmodium vivax because this species is less responsive to conventional malaria control interventions aimed principally at P. falciparum. Approximately half of all malaria cases outside of Africa are caused by P. vivax. This species places dormant forms in human liver that cause repeated clinical attacks without involving another mosquito bite. The diagnosis of acute patent P. vivax malaria relies primarily on light microscopy. Specific rapid diagnostic tests exist but typically perform relatively poorly compared to those for P. falciparum. Better diagnostic tests are needed for P. vivax. To guide their development, FIND, in collaboration with P. vivax experts, identified the specific diagnostic needs associated with this species and defined a series of three distinct target product profiles, each aimed at a particular diagnostic application: (i) point-of-care of acutely ill patients for clinical care purposes; (ii) point-of-care asymptomatic and otherwise sub-patent residents for public health purposes, e.g., mass screen and treat campaigns; and (iii) ultra-sensitive not point-of-care diagnosis for epidemiological research/surveillance purposes. This report presents and discusses the rationale for these P. vivax-specific diagnostic target product profiles. These contribute to the rational development of fit-for-purpose diagnostic tests suitable for the clinical management, control and elimination of P. vivax malaria. Plasmodium vivax is the second most prevalent Plasmodium species amongst the five that can infect humans and cause malaria. The control and elimination of P. vivax is complicated by its specific biology, such as hard-to-detect low densities of blood-circulating parasites in infected individuals, the existence of persistent liver forms causing relapse, or the early appearance of sexual stages of the parasite during the course of an infection, which facilitates its transmission. These difficulties are reinforced by the fact that most antimalarial tools have been developed primarily for P. falciparum, the most prevalent malaria species, and are not always as effective for P. vivax. Current tools for the diagnosis of P. vivax are of limited effectiveness. Rapid diagnostic tests exist but show, in average, lower performance than similar test for P. falciparum. P. vivax diagnosis often relies on light microscopy which is challenging to maintain at a high quality and not sensitive enough to detect a large fraction of all infections. Recognizing that better diagnostic tools for P. vivax are needed, we report in this study the development of new target product profiles to define the specific characteristics of such tests. The establishment of these consensus-based documents is an important first step to guide research and development efforts toward better diagnostic solutions for P. vivax malaria and to accelerate the elimination of this species alongside P. falciparum.
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Tadesse FG, van den Hoogen L, Lanke K, Schildkraut J, Tetteh K, Aseffa A, Mamo H, Sauerwein R, Felger I, Drakeley C, Gadissa E, Bousema T. The shape of the iceberg: quantification of submicroscopic Plasmodium falciparum and Plasmodium vivax parasitaemia and gametocytaemia in five low endemic settings in Ethiopia. Malar J 2017; 16:99. [PMID: 28253867 PMCID: PMC5335517 DOI: 10.1186/s12936-017-1749-4] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Accepted: 02/24/2017] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND The widespread presence of low-density asymptomatic infections with concurrent gametocytes may be a stumbling block for malaria elimination. This study investigated the asymptomatic reservoir of Plasmodium falciparum and Plasmodium vivax infections in schoolchildren from five settings in northwest Ethiopia. METHODS Two cross-sectional surveys were conducted in June and November 2015, enrolling 551 students from five schools and 294 students from three schools, respectively. Finger prick whole blood and plasma samples were collected. The prevalence and density of P. falciparum and P. vivax parasitaemia and gametocytaemia were determined by 18S rRNA quantitative PCR (qPCR) and pfs25 and pvs25 reverse transcriptase qPCR. Antibodies against blood stage antigens apical membrane antigen-1 (AMA-1) and merozoite surface protein-1 (MSP-119) were measured for both species. RESULTS Whilst only 6 infections were detected by microscopy in 881 slides (0.7%), 107 of 845 blood samples (12.7%) were parasite positive by (DNA-based) qPCR. qPCR parasite prevalence between sites and surveys ranged from 3.8 to 19.0% for P. falciparum and 0.0 to 9.0% for P. vivax. The median density of P. falciparum infections (n = 85) was 24.4 parasites/µL (IQR 18.0-34.0) and the median density of P. vivax infections (n = 28) was 16.4 parasites/µL (IQR 8.8-55.1). Gametocyte densities by (mRNA-based) qRT-PCR were strongly associated with total parasite densities for both P. falciparum (correlation coefficient = 0.83, p = 0.010) and P. vivax (correlation coefficient = 0.58, p = 0.010). Antibody titers against P. falciparum AMA-1 and MSP-119 were higher in individuals who were P. falciparum parasite positive in both surveys (p < 0.001 for both comparisons). DISCUSSION This study adds to the available evidence on the wide-scale presence of submicroscopic parasitaemia by quantifying submicroscopic parasite densities and concurrent gametocyte densities. There was considerable heterogeneity in the occurrence of P. falciparum and P. vivax infections and serological markers of parasite exposure between the examined low endemic settings in Ethiopia.
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Affiliation(s)
- Fitsum G Tadesse
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands.,Medical Biotechnology Unit, Institute of Biotechnology, Addis Ababa University, Addis Ababa, Ethiopia.,Armauer Hansen Research Institute (AHRI), Addis Ababa, Ethiopia
| | - Lotus van den Hoogen
- Department of Immunology and Infection, London School of Hygiene & Tropical Medicine, London, UK
| | - Kjerstin Lanke
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Jodie Schildkraut
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Kevin Tetteh
- Department of Immunology and Infection, London School of Hygiene & Tropical Medicine, London, UK
| | - Abraham Aseffa
- Armauer Hansen Research Institute (AHRI), Addis Ababa, Ethiopia
| | - Hassen Mamo
- Department of Microbial, Cellular and Molecular Biology, College of Natural Sciences, Addis Ababa University, Addis Ababa, Ethiopia
| | - Robert Sauerwein
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Ingrid Felger
- Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Chris Drakeley
- Department of Immunology and Infection, London School of Hygiene & Tropical Medicine, London, UK
| | | | - Teun Bousema
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands. .,Department of Immunology and Infection, London School of Hygiene & Tropical Medicine, London, UK.
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20
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Abstract
Understanding transmission biology at an individual level is a key component of intervention strategies that target the spread of malaria parasites from human to mosquito. Gametocytes are specialized sexual stages of the malaria parasite life cycle developed during evolution to achieve crucial steps in transmission. As sexual differentiation and transmission are tightly linked, a deeper understanding of molecular and cellular events defining this relationship is essential to combat malaria. Recent advances in the field are gradually revealing mechanisms underlying sexual commitment, gametocyte sequestration, and dynamics of transmissible stages; however, key questions on fundamental gametocyte biology still remain. Moreover, species-specific variation between Plasmodium falciparum and Plasmodium vivax transmission dynamics pose another significant challenge for worldwide malaria elimination efforts. Here, we review the biology of transmission stages, highlighting numerous factors influencing development and dynamics of gametocytes within the host and determinants of human infectiousness.
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Affiliation(s)
- Elamaran Meibalan
- Harvard T.H. Chan School of Public Health, Department of Immunology and Infectious Diseases, Boston, Massachusetts 02115
| | - Matthias Marti
- Harvard T.H. Chan School of Public Health, Department of Immunology and Infectious Diseases, Boston, Massachusetts 02115
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21
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Olliaro PL, Barnwell JW, Barry A, Mendis K, Mueller I, Reeder JC, Shanks GD, Snounou G, Wongsrichanalai C. Implications of Plasmodium vivax Biology for Control, Elimination, and Research. Am J Trop Med Hyg 2016; 95:4-14. [PMID: 27799636 PMCID: PMC5201222 DOI: 10.4269/ajtmh.16-0160] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2016] [Accepted: 09/29/2016] [Indexed: 12/03/2022] Open
Abstract
This paper summarizes our current understanding of the biology of Plasmodium vivax, how it differs from Plasmodium falciparum, and how these differences explain the need for P. vivax-tailored interventions. The article further pinpoints knowledge gaps where investments in research are needed to help identify and develop such specific interventions. The principal obstacles to reduce and eventually eliminate P. vivax reside in 1) its higher vectorial capacity compared with P. falciparum due to its ability to develop at lower temperature and over a shorter sporogonic cycle in the vector, allowing transmission in temperate zones and making it less sensitive to vector control measures that are otherwise effective on P. falciparum; 2) the presence of dormant liver forms (hypnozoites), sustaining multiple relapsing episodes from a single infectious bite that cannot be diagnosed and are not susceptible to any available antimalarial except primaquine, with routine deployment restricted by toxicity; 3) low parasite densities, which are difficult to detect with current diagnostics leading to missed diagnoses and delayed treatments (and protracted transmission), coupled with 4) transmission stages (gametocytes) occurring early in acute infections, before infection is diagnosed.
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Affiliation(s)
- Piero L Olliaro
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom.,UNICEF/UNDP/World Bank/WHO Special Programme on Research and Training in Tropical Diseases (TDR), World Health Organization, Geneva, Switzerland
| | - John W Barnwell
- Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Alyssa Barry
- Department of Medical Biology, University of Melbourne, Melbourne, Australia.,Division of Population Health and Immunity, Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
| | | | - Ivo Mueller
- Institute of Global Health (ISGLOBAL), Barcelona, Spain.,Division of Population Health and Immunity, Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
| | - John C Reeder
- UNICEF/UNDP/World Bank/WHO Special Programme on Research and Training in Tropical Diseases (TDR), World Health Organization, Geneva, Switzerland
| | - G Dennis Shanks
- School of Population Health, University of Queensland, Brisbane, Australia
| | - Georges Snounou
- Centre d'Immunologie et de Maladies Infectieuses (CIMI)-Paris, Institut National de la Santé et de la Recherche Médicale (INSERM) U1135-Centre National de la Recherche Scientifique (CNRS) ERL 8255, Paris, France.,Sorbonne Universités, UPMC Univ Paris 06, UPMC UMRS CR7, Paris, France
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22
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Zhou Z, Mitchell RM, Kariuki S, Odero C, Otieno P, Otieno K, Onyona P, Were V, Wiegand RE, Gimnig JE, Walker ED, Desai M, Shi YP. Assessment of submicroscopic infections and gametocyte carriage of Plasmodium falciparum during peak malaria transmission season in a community-based cross-sectional survey in western Kenya, 2012. Malar J 2016; 15:421. [PMID: 27543112 PMCID: PMC4992329 DOI: 10.1186/s12936-016-1482-4] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Accepted: 08/10/2016] [Indexed: 11/10/2022] Open
Abstract
Background Although malaria control intervention has greatly decreased malaria morbidity and mortality in many African countries, further decline in parasite prevalence has stagnated in western Kenya. In order to assess if malaria transmission reservoir is associated with this stagnation, submicroscopic infection and gametocyte carriage was estimated. Risk factors and associations between malaria control interventions and gametocyte carriage were further investigated in this study. Methods A total of 996 dried blood spot samples were used from two strata, all smear-positives (516 samples) and randomly selected smear-negatives (480 samples), from a community cross-sectional survey conducted at peak transmission season in 2012 in Siaya County, western Kenya. Plasmodium falciparum parasite presence and density were determined by stained blood smear and by 18S mRNA transcripts using nucleic acid sequence-based amplification assay (NASBA), gametocyte presence and density were determined by blood smear and by Pfs25 mRNA-NASBA, and gametocyte diversity by Pfg377 mRNA RT-PCR and RT-qPCR. Results Of the randomly selected smear-negative samples, 69.6 % (334/480) were positive by 18S-NASBA while 18S-NASBA detected 99.6 % (514/516) smear positive samples. Overall, 80.2 % of the weighted population was parasite positive by 18S-NASBA vs 30.6 % by smear diagnosis and 44.0 % of the weighted population was gametocyte positive by Pfs25-NASBA vs 2.6 % by smear diagnosis. Children 5–15 years old were more likely to be parasitaemic and gametocytaemic by NASBA than individuals >15 years old or children <5 years old while gametocyte density decreased with age. Anaemia and self-reported fever within the past 24 h were associated with increased odds of gametocytaemia. Fever was also positively associated with parasite density, but not with gametocyte density. Anti-malarial use within the past 2 weeks decreased the odds of gametocytaemia, but not the odds of parasitaemia. In contrast, recent anti-malarial use was associated with lowered parasite density, but not the gametocyte density. Use of ITNs was associated with lower odds for parasitaemia in part of the study area with a longer history of ITN interventions. In the same part of study area, the odds of having multiple gametocyte alleles were also lower in individuals using ITNs than in those not using ITNs and parasite density was positively associated with gametocyte diversity. Conclusion A large proportion of submicroscopic parasites and gametocytes in western Kenya might contribute to the stagnation in malaria prevalence, suggesting that additional interventions targeting the infectious reservoir are needed. As school aged children and persons with anaemia and fever were major sources for gametocyte reservoir, these groups should be targeted for intervention and prevention to reduce malaria transmission. Anti-malarial use was associated with lower parasite density and odds of gametocytaemia, but not the gametocyte density, indicating a limitation of anti-malarial impact on the transmission reservoir. ITN use had a protective role against parasitaemia and gametocyte diversity in western Kenya. Electronic supplementary material The online version of this article (doi:10.1186/s12936-016-1482-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Zhiyong Zhou
- Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA.
| | - Rebecca M Mitchell
- Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Simon Kariuki
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Christopher Odero
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Peter Otieno
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Kephas Otieno
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Philip Onyona
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Vincent Were
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Ryan E Wiegand
- Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - John E Gimnig
- Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Edward D Walker
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, USA
| | - Meghna Desai
- Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Ya Ping Shi
- Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA.
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23
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Pizzitutti F, Pan W, Barbieri A, Miranda JJ, Feingold B, Guedes GR, Alarcon-Valenzuela J, Mena CF. A validated agent-based model to study the spatial and temporal heterogeneities of malaria incidence in the rainforest environment. Malar J 2015; 14:514. [PMID: 26696294 PMCID: PMC4688926 DOI: 10.1186/s12936-015-1030-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2015] [Accepted: 12/02/2015] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND The Amazon environment has been exposed in the last decades to radical changes that have been accompanied by a remarkable rise of both Plasmodium falciparum and Plasmodium vivax malaria. The malaria transmission process is highly influenced by factors such as spatial and temporal heterogeneities of the environment and individual-based characteristics of mosquitoes and humans populations. All these determinant factors can be simulated effectively trough agent-based models. METHODS This paper presents a validated agent-based model of local-scale malaria transmission. The model reproduces the environment of a typical riverine village in the northern Peruvian Amazon, where the malaria transmission is highly seasonal and apparently associated with flooding of large areas caused by the neighbouring river. Agents representing humans, mosquitoes and the two species of Plasmodium (P. falciparum and P. vivax) are simulated in a spatially explicit representation of the environment around the village. The model environment includes: climate, people houses positions and elevation. A representation of changes in the mosquito breeding areas extension caused by the river flooding is also included in the simulation environment. RESULTS A calibration process was carried out to reproduce the variations of the malaria monthly incidence over a period of 3 years. The calibrated model is also able to reproduce the spatial heterogeneities of local scale malaria transmission. A "what if" eradication strategy scenario is proposed: if the mosquito breeding sites are eliminated through mosquito larva habitat management in a buffer area extended at least 200 m around the village, the malaria transmission is eradicated from the village. CONCLUSIONS The use of agent-based models can reproduce effectively the spatiotemporal variations of the malaria transmission in a low endemicity environment dominated by river floodings like in the Amazon.
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Affiliation(s)
| | - William Pan
- Duke University, 310 Trent Drive, Room 227, Box 90519, Durham, NC, 27708, USA.
| | - Alisson Barbieri
- Instituto de Geociências-IGC Belo Horizonte, Universidade Federal de Minas Gerais, Belo Horozonte, Brazil.
| | - J Jaime Miranda
- Oswaldo Cruz Foundation (FIOCRUZ), Universidad Peruana Cayetano Heredia, Lima, Peru.
| | - Beth Feingold
- Department of Environmental Health Sciences, School of Public Health, University at Albany, State University of New York, 1 University Place GEC, 145 Rensselaer, New York, NY, 12144, USA.
| | - Gilvan R Guedes
- College of Economics Departamento de Demografia/FACE/UFMG, Office 3093, Av. Antônio Carlos, 6627-Pampulha, Belo Horizonte, Minas Gerais, 31270-901, Brazil.
| | | | - Carlos F Mena
- Universidad San Francisco de Quito, Diego de Robles, s/n, Cumbayá, Ecuador.
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24
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Thanh PV, Van Hong N, Van Van N, Van Malderen C, Obsomer V, Rosanas-Urgell A, Grietens KP, Xa NX, Bancone G, Chowwiwat N, Duong TT, D'Alessandro U, Speybroeck N, Erhart A. Epidemiology of forest malaria in Central Vietnam: the hidden parasite reservoir. Malar J 2015; 14:86. [PMID: 25880664 PMCID: PMC4342195 DOI: 10.1186/s12936-015-0601-y] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Accepted: 02/01/2015] [Indexed: 11/17/2022] Open
Abstract
Background After successfully reducing the malaria burden to pre-elimination levels over the past two decades, the national malaria programme in Vietnam has recently switched from control to elimination. However, in forested areas of Central Vietnam malaria elimination is likely to be jeopardized by the high occurrence of asymptomatic and submicroscopic infections as shown by previous reports. This paper presents the results of a malaria survey carried out in a remote forested area of Central Vietnam where we evaluated malaria prevalence and risk factors for infection. Methods After a full census (four study villages = 1,810 inhabitants), the study population was screened for malaria infections by standard microscopy and, if needed, treated according to national guidelines. An additional blood sample on filter paper was also taken in a random sample of the population for later polymerase chain reaction (PCR) and more accurate estimation of the actual burden of malaria infections. The risk factor analysis for malaria infections was done using survey multivariate logistic regression as well as the classification and regression tree method (CART). Results A total of 1,450 individuals were screened. Malaria prevalence by microscopy was 7.8% (ranging from 3.9 to 10.9% across villages) mostly Plasmodium falciparum (81.4%) or Plasmodium vivax (17.7%) mono-infections; a large majority (69.9%) was asymptomatic. By PCR, the prevalence was estimated at 22.6% (ranging from 16.4 to 42.5%) with a higher proportion of P. vivax mono-infections (43.2%). The proportion of sub-patent infections increased with increasing age and with decreasing prevalence across villages. The main risk factors were young age, village, house structure, and absence of bed net. Conclusion This study confirmed that in Central Vietnam a substantial part of the human malaria reservoir is hidden. Additional studies are urgently needed to assess the contribution of this hidden reservoir to the maintenance of malaria transmission. Such evidence will be crucial for guiding elimination strategies.
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Affiliation(s)
- Pham Vinh Thanh
- National Institute of Malariology, Parasitology and Entomology (NIMPE), Hanoi, Vietnam.
| | - Nguyen Van Hong
- National Institute of Malariology, Parasitology and Entomology (NIMPE), Hanoi, Vietnam.
| | - Nguyen Van Van
- Provincial Malaria Station, Tam Ky City, Quang Nam Province, Vietnam.
| | | | - Valérie Obsomer
- Université Ccatholique de Louvain (UCL), Louvain-la-Neuve, Belgium.
| | | | | | - Nguyen Xuan Xa
- National Institute of Malariology, Parasitology and Entomology (NIMPE), Hanoi, Vietnam.
| | - Germana Bancone
- Shoklo Malaria Research Unit, Mae Sot, Tak Province, Thailand.
| | | | - Tran Thanh Duong
- National Institute of Malariology, Parasitology and Entomology (NIMPE), Hanoi, Vietnam.
| | - Umberto D'Alessandro
- Institute of Tropical Medicine Prince Leopold (ITM), Antwerp, Belgium. .,Medical Research Council Unit (MRC Unit), Fajara, The Gambia.
| | | | - Annette Erhart
- Institute of Tropical Medicine Prince Leopold (ITM), Antwerp, Belgium.
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25
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Sortica VA, Cunha MG, Ohnishi MDO, Souza JM, Ribeiro-dos-Santos ÂKC, Santos SEB, Hutz MH. Role of IL6, IL12B and VDR gene polymorphisms in Plasmodium vivax malaria severity, parasitemia and gametocytemia levels in an Amazonian Brazilian population. Cytokine 2013; 65:42-7. [PMID: 24139871 DOI: 10.1016/j.cyto.2013.09.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Revised: 09/09/2013] [Accepted: 09/19/2013] [Indexed: 12/29/2022]
Abstract
OBJECTIVE To investigate the influence of IL6, IL12B and VDR single nucleotide polymorphisms (SNPs) in uncomplicated Plasmodium vivax infection symptoms intensity, parasitemia and gametocytemia levels in a Brazilian Amazonian population. METHODS A total of 167 malaria patients infected by P. vivax have parasitemia and gametocytemia levels estimated before treatment. Fourteen clinical symptoms were evaluated and included in a principal component analysis to derive a clinical symptom index. Patients were genotyped for IL6-174C>G, IL12B 735T>C, 458A>G, 159A>C, and VDR FokI, TaqI, BsmI SNPs by Taqman 5' nuclease assays. A General Linear Model analysis of covariance with age, gender, exposure period and infection history and genetic ancestry was performed to investigate the association of genotypes with parasitemia and gametocytemia levels and with a clinical symptom index. RESULTS Higher parasitemia levels were observed in IL6-174C carriers (p=0.02) whereas IL12B CGT haplotype carriers presented lower parasitemia levels (p=0.008). VDR TaqIC/BsmIA haplotype carriers showed higher gametocyte levels than non-carriers (p=0.013). Based on the clinical index values the IL6-174C>G polymorphism was associated with malaria severity. The IL6-174C carriers presented a more severe clinical index when compared to GG homozygotes (p=0.001). CONCLUSION The present study suggests that IL6, IL12 and VDR influence severity, parasitemia and gametocytemia clearance in P. vivax infections, and highlights their potential role in malaria immune response in an Amazonian population.
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Affiliation(s)
- Vinicius A Sortica
- Departamento de Genética, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
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26
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Abstract
Drugs that kill or inhibit the sexual stages of Plasmodium in order to prevent transmission are important components of malaria control programmes. Reducing gametocyte carriage is central to the control of Plasmodium falciparum transmission as infection can result in extended periods of gametocytaemia. Unfortunately the number of drugs with activity against gametocytes is limited. Primaquine is currently the only licensed drug with activity against the sexual stages of malaria parasites and its use is hampered by safety concerns. This shortcoming is likely the result of the technical challenges associated with gametocyte studies together with the focus of previous drug discovery campaigns on asexual parasite stages. However recent emphasis on malaria eradication has resulted in an upsurge of interest in identifying compounds with activity against gametocytes. This review examines the gametocytocidal properties of currently available drugs as well as those in the development pipeline and examines the prospects for discovery of new anti-gametocyte compounds.
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27
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Laurens MB, Billingsley P, Richman A, Eappen AG, Adams M, Li T, Chakravarty S, Gunasekera A, Jacob CG, Sim BKL, Edelman R, Plowe CV, Hoffman SL, Lyke KE. Successful human infection with P. falciparum using three aseptic Anopheles stephensi mosquitoes: a new model for controlled human malaria infection. PLoS One 2013; 8:e68969. [PMID: 23874828 PMCID: PMC3712927 DOI: 10.1371/journal.pone.0068969] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2012] [Accepted: 05/31/2013] [Indexed: 11/18/2022] Open
Abstract
UNLABELLED Controlled human malaria infection (CHMI) is a powerful method for assessing the efficacy of anti-malaria vaccines and drugs targeting pre-erythrocytic and erythrocytic stages of the parasite. CHMI has heretofore required the bites of 5 Plasmodium falciparum (Pf) sporozoite (SPZ)-infected mosquitoes to reliably induce Pf malaria. We reported that CHMI using the bites of 3 PfSPZ-infected mosquitoes reared aseptically in compliance with current good manufacturing practices (cGMP) was successful in 6 participants. Here, we report results from a subsequent CHMI study using 3 PfSPZ-infected mosquitoes reared aseptically to validate the initial clinical trial. We also compare results of safety, tolerability, and transmission dynamics in participants undergoing CHMI using 3 PfSPZ-infected mosquitoes reared aseptically to published studies of CHMI using 5 mosquitoes. Nineteen adults aged 18-40 years were bitten by 3 Anopheles stephensi mosquitoes infected with the chloroquine-sensitive NF54 strain of Pf. All 19 participants developed malaria (100%); 12 of 19 (63%) on Day 11. The mean pre-patent period was 258.3 hours (range 210.5-333.8). The geometric mean parasitemia at first diagnosis by microscopy was 9.5 parasites/µL (range 2-44). Quantitative polymerase chain reaction (qPCR) detected parasites an average of 79.8 hours (range 43.8-116.7) before microscopy. The mosquitoes had a geometric mean of 37,894 PfSPZ/mosquito (range 3,500-152,200). Exposure to the bites of 3 aseptically-raised, PfSPZ-infected mosquitoes is a safe, effective procedure for CHMI in malaria-naïve adults. The aseptic model should be considered as a new standard for CHMI trials in non-endemic areas. Microscopy is the gold standard used for the diagnosis of Pf malaria after CHMI, but qPCR identifies parasites earlier. If qPCR continues to be shown to be highly specific, and can be made to be practical, rapid, and standardized, it should be considered as an alternative for diagnosis. TRIAL REGISTRATION ClinicalTrials.gov NCT00744133 NCT00744133.
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Affiliation(s)
- Matthew B Laurens
- Howard Hughes Medical Institute/Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
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28
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McQueen PG, Williamson KC, McKenzie FE. Host immune constraints on malaria transmission: insights from population biology of within-host parasites. Malar J 2013; 12:206. [PMID: 23767770 PMCID: PMC3691866 DOI: 10.1186/1475-2875-12-206] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Accepted: 05/30/2013] [Indexed: 02/07/2023] Open
Abstract
Background Plasmodium infections trigger complex immune reactions from their hosts against several life stages of the parasite, including gametocytes. These immune responses are highly variable, depending on age, genetics, and exposure history of the host as well as species and strain of parasite. Although the effects of host antibodies that act against gamete stages in the mosquito (due to uptake in the blood meal) are well documented, the effects of host immunity upon within-host gametocytes are not as well understood. This report consists of a theoretical population biology-based analysis to determine constraints that host immunity impose upon gametocyte population growth. The details of the mathematical models used for the analysis were guided by published reports of clinical and animal studies, incorporated plausible modalities of immune reactions to parasites, and were tailored to the life cycl es of the two most widespread human malaria pathogens, Plasmodium falciparum and Plasmodium vivax. Results For the same ability to bind and clear a target, the model simulations suggest that an antibody attacking immature gametocytes would tend to lower the overall density of transmissible mature gametocytes more than an antibody attacking the mature forms directly. Transmission of P. falciparum would be especially vulnerable to complete blocking by antibodies to its immature forms since its gametocytes take much longer to reach maturity than those of P. vivax. On the other hand, antibodies attacking the mature gametocytes directly would reduce the time the mature forms can linger in the host. Simulation results also suggest that varying the standard deviation in the time necessary for individual asexual parasites to develop and produce schizonts can affect the efficiency of production of transmissible gametocytes. Conclusions If mature gametocyte density determines the probability of transmission, both Plasmodium species, but especially P. falciparum, could bolster this probability through evasion or suppression of host immune responses against the immature gametocytes. However, if the long term lingering of mature gametocytes at low density in the host is also important to ensure transmission, then evasion or suppression of antibodies against the mature stages would bolster probability of transmission as well.
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Affiliation(s)
- Philip G McQueen
- Mathematical and Statistical Computing Laboratory, Division of Computational Bioscience, Center for Information Technology, National Institutes of Health, Bethesda, Maryland, USA.
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29
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Johnston GL, Smith DL, Fidock DA. Malaria's missing number: calculating the human component of R0 by a within-host mechanistic model of Plasmodium falciparum infection and transmission. PLoS Comput Biol 2013; 9:e1003025. [PMID: 23637586 PMCID: PMC3630126 DOI: 10.1371/journal.pcbi.1003025] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2012] [Accepted: 02/25/2013] [Indexed: 11/18/2022] Open
Abstract
Human infection by malarial parasites of the genus Plasmodium begins with the bite of an infected Anopheles mosquito. Current estimates place malaria mortality at over 650,000 individuals each year, mostly in African children. Efforts to reduce disease burden can benefit from the development of mathematical models of disease transmission. To date, however, comprehensive modeling of the parameters defining human infectivity to mosquitoes has remained elusive. Here, we describe a mechanistic within-host model of Plasmodium falciparum infection in humans and pathogen transmission to the mosquito vector. Our model incorporates the entire parasite lifecycle, including the intra-erythrocytic asexual forms responsible for disease, the onset of symptoms, the development and maturation of intra-erythrocytic gametocytes that are transmissible to Anopheles mosquitoes, and human-to-mosquito infectivity. These model components were parameterized from malaria therapy data and other studies to simulate individual infections, and the ensemble of outputs was found to reproduce the full range of patient responses to infection. Using this model, we assessed human infectivity over the course of untreated infections and examined the effects in relation to transmission intensity, expressed by the basic reproduction number R0 (defined as the number of secondary cases produced by a single typical infection in a completely susceptible population). Our studies predict that net human-to-mosquito infectivity from a single non-immune individual is on average equal to 32 fully infectious days. This estimate of mean infectivity is equivalent to calculating the human component of malarial R0. We also predict that mean daily infectivity exceeds five percent for approximately 138 days. The mechanistic framework described herein, made available as stand-alone software, will enable investigators to conduct detailed studies into theories of malaria control, including the effects of drug treatment and drug resistance on transmission. We report a new mathematical model of the progression, within a human host, of a malaria infection caused by the parasite Plasmodium falciparum. This model incorporates probability distributions for the key parameters of infection and transmission so that model outputs match the entire range of observed responses in patients, without the requirement for fitting individual data. Further, we simulate the daily densities of both the disease-causing and transmissible forms of the parasite within an individual, as well as the onset of fever and the probability of parasite transmission to mosquitoes. This model allows us to reproduce aspects of infection that are critical for malaria control modeling. As a first application, we calculate the net infectiousness of humans to mosquitoes and predict that net human infectivity from a single infection is on average equal to approximately 32 fully infectious days. This value has been used to help map the worldwide intensity of malaria transmission. We also predict that mean daily infectivity is greater than five percent for approximately 138 days. Our modeling framework, available as downloadable software, will allow researchers to probe the effects of treatment and drug resistance on malaria transmission in unprecedented detail, helping to improve malaria control efforts.
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Affiliation(s)
- Geoffrey L. Johnston
- Department of Microbiology and Immunology, Columbia University College of Physicians and Surgeons, New York, New York, United States of America
- School of International and Public Affairs, Columbia University, New York, New York, United States of America
- Bloomberg School of Public Health, John Hopkins University, Baltimore, Maryland, United States of America
| | - David L. Smith
- Bloomberg School of Public Health, John Hopkins University, Baltimore, Maryland, United States of America
- * E-mail: (DLS); (DAF)
| | - David A. Fidock
- Department of Microbiology and Immunology, Columbia University College of Physicians and Surgeons, New York, New York, United States of America
- Division of Infectious Diseases, Department of Medicine, Columbia University College of Physicians and Surgeons, New York, New York, United States of America
- * E-mail: (DLS); (DAF)
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Snounou G, Pérignon JL. Malariotherapy--insanity at the service of malariology. ADVANCES IN PARASITOLOGY 2013; 81:223-55. [PMID: 23384625 DOI: 10.1016/b978-0-12-407826-0.00006-0] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
From the early 1920s until the advent of penicillin in the mid 1940s, a clinical course of malaria was the only effective treatment of general paresis, a common manifestation of tertiary syphilis that was nearly always fatal. For a number of reasons, Plasmodium vivax became the parasite species most often employed for what became known as malariotherapy. This provided an opportunity, probably unique in the annals of medicine, to observe and investigate the biology, immunology and clinical evolution of a dangerous human pathogen in its natural host. There is little doubt that the lessons learned from these studies influenced the malaria research and control agendas. It is equally true that over the last 40 years, the insights afforded by malariotherapy have remained largely undisturbed on the dusty shelves of institutional libraries. In this chapter, we broadly review the published data derived from malariotherapy, and discuss its relevance to current challenges of P. vivax epidemiology, immunology and pathology.
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Schneider KA, Escalante AA. Fitness components and natural selection: why are there different patterns on the emergence of drug resistance in Plasmodium falciparum and Plasmodium vivax? Malar J 2013; 12:15. [PMID: 23305428 PMCID: PMC3571882 DOI: 10.1186/1475-2875-12-15] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2012] [Accepted: 01/04/2013] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Considering the distinct biological characteristics of Plasmodium species is crucial for control and elimination efforts, in particular when facing the spread of drug resistance. Whereas the evolutionary fitness of all malarial species could be approximated by the probability of being taken by a mosquito and then infecting a new host, the actual steps in the malaria life cycle leading to a successful transmission event show differences among Plasmodium species. These "steps" are called fitness components. Differences in terms of fitness components may affect how selection imposed by interventions, e.g. drug treatments, differentially acts on each Plasmodium species. Thus, a successful malaria control or elimination programme should understand how differences in fitness components among different malaria species could affect adaptive evolution (e.g. the emergence of drug resistance). In this investigation, the interactions between some fitness components and natural selection are explored. METHODS A population-genetic model is formulated that qualitatively explains how different fitness components (in particular gametocytogenesis and longevity of gametocytes) affect selection acting on merozoites during the erythrocytic cycle. By comparing Plasmodium falciparum and Plasmodium vivax, the interplay of parasitaemia and gametocytaemia dynamics in determining fitness is modelled under circumstances that allow contrasting solely the differences between these two parasites in terms of their fitness components. RESULTS By simulating fitness components, it is shown that selection acting on merozoites (e.g., on drug resistant mutations or malaria antigens) is more efficient in P. falciparum than in P. vivax. These results could explain, at least in part, why resistance against drugs, such as chloroquine (CQ) is highly prevalent in P. falciparum worldwide, while CQ is still a successful treatment for P. vivax despite its massive use. Furthermore, these analyses are used to explore the importance of understanding the dynamic of gametocytaemia to ascertain the spreading of drug resistance. CONCLUSIONS The strength of natural selection on mutations that express their advantage at the merozoite stage is different in P. vivax and P. falciparum. Species-specific differences in gametocytogenesis and longevity of gametocytes need to be accounted for when designing effective malaria control and elimination programmes. There is a need for reliable data on gametocytogenesis from field studies.
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Affiliation(s)
- Kristan A Schneider
- Department of MNI, University of Applied Sciences Mittweida, Mittweida, Germany.
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Eksi S, Morahan BJ, Haile Y, Furuya T, Jiang H, Ali O, Xu H, Kiattibutr K, Suri A, Czesny B, Adeyemo A, Myers TG, Sattabongkot J, Su XZ, Williamson KC. Plasmodium falciparum gametocyte development 1 (Pfgdv1) and gametocytogenesis early gene identification and commitment to sexual development. PLoS Pathog 2012; 8:e1002964. [PMID: 23093935 PMCID: PMC3475683 DOI: 10.1371/journal.ppat.1002964] [Citation(s) in RCA: 103] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2012] [Accepted: 08/27/2012] [Indexed: 12/13/2022] Open
Abstract
Malaria transmission requires the production of male and female gametocytes in the human host followed by fertilization and sporogonic development in the mosquito midgut. Although essential for the spread of malaria through the population, little is known about the initiation of gametocytogenesis in vitro or in vivo. Using a gametocyte-defective parasite line and genetic complementation, we show that Plasmodium falciparumgametocyte development 1 gene (Pfgdv1), encoding a peri-nuclear protein, is critical for early sexual differentiation. Transcriptional analysis of Pfgdv1 negative and positive parasite lines identified a set of gametocytogenesis early genes (Pfge) that were significantly down-regulated (>10 fold) in the absence of Pfgdv1 and expression was restored after Pfgdv1 complementation. Progressive accumulation of Pfge transcripts during successive rounds of asexual replication in synchronized cultures suggests that gametocytes are induced continuously during asexual growth. Comparison of Pfge gene transcriptional profiles in patient samples divided the genes into two groups differing in their expression in mature circulating gametocytes and providing candidates to evaluate gametocyte induction and maturation separately in vivo. The expression profile of one of the early gametocyte specific genes, Pfge1, correlated significantly with asexual parasitemia, which is consistent with the ongoing induction of gametocytogenesis during asexual growth observed in vitro and reinforces the need for sustained transmission-blocking strategies to eliminate malaria. As malaria control efforts move toward eradication it becomes increasingly important to develop interventions that block transmission. Consequently, advances are needed in our understanding of the production of gametocytes, which are required to transmit the disease. This report provides a first view of the initial stages of gametocytogenesis in vitro and in vivo and demonstrates that during each asexual replication cycle a subpopulation of parasites convert to gametocyte development providing a long transmission window. We also identify a gene that is critical for gametocyte production, P. falciparumgametocyte development 1 (Pfgdv1) and a set of genes specifically expressed during early gametocytogenesis in P. falciparum (Pfge genes). The expression profile and peri-nuclear location of Pfgdv1 in a subpopulation of schizonts is consistent with a role in an early step in gametocytogenesis. The RNA levels of Pfgdv1 and the Pfge genes accumulated gradually over several asexual cycles in vitro suggesting ongoing gametocyte formation during asexual growth. The further evaluation of these genes in a cohort of malaria infected patients indicated they are good candidates for markers to distinguish ring stage parasites committed to gametocyte production from circulating mature gametocytes, allowing direct analysis of the initiation of sexual differentiation in vivo.
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Affiliation(s)
- Saliha Eksi
- Department of Biology, Loyola University Chicago, Chicago, Illinois, United States of America
| | - Belinda J. Morahan
- Department of Biology, Loyola University Chicago, Chicago, Illinois, United States of America
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Yoseph Haile
- Department of Biology, Loyola University Chicago, Chicago, Illinois, United States of America
| | - Tetsuya Furuya
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Hongying Jiang
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Omar Ali
- Department of Biology, Loyola University Chicago, Chicago, Illinois, United States of America
| | - Huichun Xu
- Center for Research on Genomics and Global Health, Inherited Disease Research Branch, National Human Genomics Research Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Kirakorn Kiattibutr
- Department of Entomology, U.S. Army Medical Component, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Amreena Suri
- Department of Biology, Loyola University Chicago, Chicago, Illinois, United States of America
| | - Beata Czesny
- Department of Biology, Loyola University Chicago, Chicago, Illinois, United States of America
| | - Adebowale Adeyemo
- Center for Research on Genomics and Global Health, Inherited Disease Research Branch, National Human Genomics Research Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Timothy G. Myers
- Genomic Technologies Section, Research Technologies Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Jetsumon Sattabongkot
- Department of Entomology, U.S. Army Medical Component, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Xin-zhuan Su
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Kim C. Williamson
- Department of Biology, Loyola University Chicago, Chicago, Illinois, United States of America
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail:
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Nóbrega de Sousa T, Carvalho LH, Alves de Brito CF. Worldwide genetic variability of the Duffy binding protein: insights into Plasmodium vivax vaccine development. PLoS One 2011; 6:e22944. [PMID: 21829672 PMCID: PMC3149059 DOI: 10.1371/journal.pone.0022944] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2011] [Accepted: 07/08/2011] [Indexed: 11/19/2022] Open
Abstract
The dependence of Plasmodium vivax on invasion mediated by Duffy binding protein (DBP) makes this protein a prime candidate for development of a vaccine. However, the development of a DBP-based vaccine might be hampered by the high variability of the protein ligand (DBPII), known to bias the immune response toward a specific DBP variant. Here, the hypothesis being investigated is that the analysis of the worldwide DBPII sequences will allow us to determine the minimum number of haplotypes (MNH) to be included in a DBP-based vaccine of broad coverage. For that, all DBPII sequences available were compiled and MNH was based on the most frequent nonsynonymous single nucleotide polymorphisms, the majority mapped on B and T cell epitopes. A preliminary analysis of DBPII genetic diversity from eight malaria-endemic countries estimated that a number between two to six DBP haplotypes (17 in total) would target at least 50% of parasite population circulating in each endemic region. Aiming to avoid region-specific haplotypes, we next analyzed the MNH that broadly cover worldwide parasite population. The results demonstrated that seven haplotypes would be required to cover around 60% of DBPII sequences available. Trying to validate these selected haplotypes per country, we found that five out of the eight countries will be covered by the MNH (67% of parasite populations, range 48–84%). In addition, to identify related subgroups of DBPII sequences we used a Bayesian clustering algorithm. The algorithm grouped all DBPII sequences in six populations that were independent of geographic origin, with ancestral populations present in different proportions in each country. In conclusion, in this first attempt to undertake a global analysis about DBPII variability, the results suggest that the development of DBP-based vaccine should consider multi-haplotype strategies; otherwise a putative P. vivax vaccine may not target some parasite populations.
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Affiliation(s)
- Taís Nóbrega de Sousa
- Laboratory of Malaria, Centro de Pesquisa Rene Rachou/Fiocruz, Belo Horizonte, Brazil
| | - Luzia Helena Carvalho
- Laboratory of Malaria, Centro de Pesquisa Rene Rachou/Fiocruz, Belo Horizonte, Brazil
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Oakley MS, Gerald N, McCutchan TF, Aravind L, Kumar S. Clinical and molecular aspects of malaria fever. Trends Parasitol 2011; 27:442-9. [PMID: 21795115 DOI: 10.1016/j.pt.2011.06.004] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2011] [Revised: 06/14/2011] [Accepted: 06/17/2011] [Indexed: 10/17/2022]
Abstract
Although clinically benign, malaria fever is thought to have significant relevance in terms of parasite growth and survival and its virulence which in turn may alter the clinical course of illness. In this article, the historical literature is reviewed, providing some evolutionary perspective on the genesis and biological relevance of malaria fever, and the available molecular data on the febrile-temperature-inducible parasite factors that may contribute towards the regulation of parasite density and alteration of virulence in the host is also discussed. The potential molecular mechanisms that could be responsible for the induction and regulation of cyclical malaria fevers caused by different species of Plasmodium are also discussed.
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Affiliation(s)
- Miranda S Oakley
- Division of Bacterial, Parasitic, and Allergenic Products, Center for Biologics Evaluation and Research, Food and Drug Administration, Rockville, MD, USA
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Bousema T, Drakeley C. Epidemiology and infectivity of Plasmodium falciparum and Plasmodium vivax gametocytes in relation to malaria control and elimination. Clin Microbiol Rev 2011; 24:377-410. [PMID: 21482730 PMCID: PMC3122489 DOI: 10.1128/cmr.00051-10] [Citation(s) in RCA: 508] [Impact Index Per Article: 39.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Malaria remains a major cause of morbidity and mortality in the tropics, with Plasmodium falciparum responsible for the majority of the disease burden and P. vivax being the geographically most widely distributed cause of malaria. Gametocytes are the sexual-stage parasites that infect Anopheles mosquitoes and mediate the onward transmission of the disease. Gametocytes are poorly studied despite this crucial role, but with a recent resurgence of interest in malaria elimination, the study of gametocytes is in vogue. This review highlights the current state of knowledge with regard to the development and longevity of P. falciparum and P. vivax gametocytes in the human host and the factors influencing their distribution within endemic populations. The evidence for immune responses, antimalarial drugs, and drug resistance influencing infectiousness to mosquitoes is reviewed. We discuss how the application of molecular techniques has led to the identification of submicroscopic gametocyte carriage and to a reassessment of the human infectious reservoir. These components are drawn together to show how control measures that aim to reduce malaria transmission, such as mass drug administration and a transmission-blocking vaccine, might better be deployed.
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Affiliation(s)
- Teun Bousema
- Department of Immunology & Infection, London School of Hygiene and Tropical Medicine, London W1CE 7HT, United Kingdom
| | - Chris Drakeley
- Department of Immunology & Infection, London School of Hygiene and Tropical Medicine, London W1CE 7HT, United Kingdom
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36
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In vivo and in vitro gametocyte production of Plasmodium falciparum isolates from Northern Thailand. Int J Parasitol 2011; 41:317-23. [DOI: 10.1016/j.ijpara.2010.10.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2010] [Revised: 10/08/2010] [Accepted: 10/13/2010] [Indexed: 11/24/2022]
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Huh AJ, Kwak YG, Kim ES, Lee KS, Yeom JS, Cho YK, Kim CS, Park JW. Parasitemia characteristics of Plasmodium vivax malaria patients in the Republic of Korea. J Korean Med Sci 2011; 26:42-6. [PMID: 21218028 PMCID: PMC3012848 DOI: 10.3346/jkms.2011.26.1.42] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2010] [Accepted: 10/18/2010] [Indexed: 11/20/2022] Open
Abstract
Parasitemia characteristics of Plasmodium vivax malaria in temperate regions may differ from those in tropical zones. However, most parasitological and clinical features of P. vivax malaria have been investigated in the latter. In this study, we investigated 383 malaria patients to clarify the parasitemia characteristics of a P. vivax strain in the Republic of Korea (ROK). The mean parasitemia (8,396/µL) was less than half of tropical P. vivax malaria, and multiple invasions of erythrocytes were not rare (53.5% of the patients, 2.4% of the total investigated RBCs), but less than the observations in tropical zones. The intervals between the first symptom onset and diagnosis were significantly longer in gametocyte (+) patients than in gametocyte (-) patients. Only half of the total patients had both genders of gametocytes (191 of 353), and the male gametocyte density (169/µL) was lower than that of P. vivax strains of a previous study. Multiple invasions of erythrocytes and gametocytemia were coincident factors of the degree of anemia in P. vivax malaria. The present findings demonstrate the P. vivax strain in ROK reveals relatively low parasitemia and low male to female gametocyte ratio. The low ratio may be related with low transmission efficacy.
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Affiliation(s)
- Ae-Jung Huh
- Department of Internal Medicine, National Health Insurance Corporation Ilsan Hospital, Goyang, Korea
| | - Yee Gyung Kwak
- Department of Internal Medicine, Inje University College of Medicine, Goyang, Korea
| | - Eu Suk Kim
- Department of Internal Medicine, Dongguk University College of Medicine, Goyang, Korea
| | - Kkot Sil Lee
- Department of Internal Medicine, Kwandong University College of Medicine, Goyang, Korea
| | - Joon-Sup Yeom
- Department of Internal Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Yong-Kyun Cho
- Department of Internal Medicine, Graduate School of Medicine, Gachon University of Medicine and Science, Incheon, Korea
| | - Chang-Seok Kim
- Department of Microbiology, Graduate School of Medicine, Gachon University of Medicine and Science, Incheon, Korea
| | - Jae-Won Park
- Department of Microbiology, Graduate School of Medicine, Gachon University of Medicine and Science, Incheon, Korea
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McQueen PG. Population dynamics of a pathogen: the conundrum of vivax malaria. Biophys Rev 2010; 2:111-120. [PMID: 20730124 PMCID: PMC2920408 DOI: 10.1007/s12551-010-0034-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2010] [Accepted: 06/25/2010] [Indexed: 11/27/2022] Open
Abstract
Building a mathematical model of population dynamics of pathogens within their host involves considerations of factors similar to those in ecology, as pathogens can prey on cells in the host. But within the multicellular host, attacked cell types are integrated with other cellular systems, which in turn intervene in the infection. For example, immune responses attempt to sense and then eliminate or contain pathogens, and homeostatic mechanisms try to compensate for cell loss. This review focuses on modeling applied to malarias, diseases caused by single-cell eukaryote parasites that infect red blood cells, with special concern given to vivax malaria, a disease often thought to be benign (if sometimes incapacitating) because the parasite only attacks a small proportion of red blood cells, the very youngest ones. However, I will use mathematical modeling to argue that depletion of this pool of red blood cells can be disastrous to the host if growth of the parasite is not vigorously check by host immune responses. Also, modeling can elucidate aspects of new field observations that indicate that vivax malaria is more dangerous than previously thought.
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Affiliation(s)
- Philip G. McQueen
- Mathematical and Statistical Computing Laboratory, Division of Computational Bioscience, Center for Information Technology, National Institutes of Health, 12 South Drive, Bethesda, MD 20892-5620 USA
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Key gaps in the knowledge of Plasmodium vivax, a neglected human malaria parasite. THE LANCET. INFECTIOUS DISEASES 2009; 9:555-66. [PMID: 19695492 DOI: 10.1016/s1473-3099(09)70177-x] [Citation(s) in RCA: 472] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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40
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Abstract
The gravity of the threat posed by vivax malaria to public health has been poorly appreciated. The widely held misperception of Plasmodium vivax as being relatively infrequent, benign, and easily treated explains its nearly complete neglect across the range of biological and clinical research. Recent evidence suggests a far higher and more-severe disease burden imposed by increasingly drug-resistant parasites. The two frontline therapies against vivax malaria, chloroquine and primaquine, may be failing. Despite 60 years of nearly continuous use of these drugs, their respective mechanisms of activity, resistance, and toxicity remain unknown. Although standardized means of assessing therapeutic efficacy against blood and liver stages have not been developed, this review examines the provisional in vivo, ex vivo, and animal model systems for doing so. The rationale, design, and interpretation of clinical trials of therapies for vivax malaria are discussed in the context of the nuance and ambiguity imposed by the hypnozoite. Fielding new drug therapies against real-world vivax malaria may require a reworking of the strategic framework of drug development, namely, the conception, testing, and evaluation of sets of drugs designed for the cure of both blood and liver asexual stages as well as the sexual blood stages within a single therapeutic regimen.
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Affiliation(s)
- J Kevin Baird
- Eijkman-Oxford Clinical Research Unit, Jalan Diponegoro No. 69, Jakarta 10430, Indonesia.
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Sutherland CJ. Surface antigens of Plasmodium falciparum gametocytes--a new class of transmission-blocking vaccine targets? Mol Biochem Parasitol 2009; 166:93-8. [PMID: 19450726 DOI: 10.1016/j.molbiopara.2009.03.007] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2008] [Revised: 03/07/2009] [Accepted: 03/10/2009] [Indexed: 10/21/2022]
Abstract
The re-establishment of elimination and eradication on the malaria control agenda has led to calls for renewed effort in the development of parasite transmission-blocking interventions. Vaccines are ideally suited to this task, but progress towards an anti-gamete transmission-blocking vaccine, designed to act on parasites in blood-fed mosquitoes, has been slow. Recent work has confirmed that the surface of the gametocyte-infected erythrocyte presents antigens to the host immune system, and elicits specific humoral immune responses to these antigens, termed gametocyte surface antigens (GSAs). Likely candidate molecules, including antigens encoded by sub-telomeric multi-gene families, are discussed, and a hypothetical group of parasite molecules involved in spatial and temporal signal transduction in the human host is proposed, the tropins and circadins. The next steps for development of anti-gametocyte transmission-blocking vaccines for P. falciparum and the other human malaria species are considered.
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Affiliation(s)
- Colin J Sutherland
- HPA Malaria Reference Laboratory, Department of Infectious & Tropical Diseases, London School of Hygiene & Tropical Medicine, Keppel Street, London WC1E 7HT, United Kingdom.
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Abstract
Effective anti-malarial drug treatment reduces malaria transmission. This alone can reduce the incidence and prevalence of malaria, although the effects are greater in areas of low transmission where a greater proportion of the infectious reservoir is symptomatic and receives anti-malarial treatment. Effective treatment has greater effects on the transmission of falciparum malaria, where gametocytogenesis is delayed, compared with the other human malarias in which peak gametocytaemia and transmissibility coincides with peak asexual parasite densities. Mature Plasmodium falciparum gametocytes are more drug resistant and affected only by artemisinins and 8-aminoquinolines. The key operational question now is whether primaquine should be added to artemisinin combination treatments for the treatment of falciparum malaria to reduce further the transmissibility of the treated infection. Radical treatment with primaquine plays a key role in the eradication of vivax and ovale malaria. More evidence is needed on the safety of primaquine when administered without screening for G6PD deficiency to inform individual and mass treatment approaches in the context of malaria elimination programmes.
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Affiliation(s)
- Nicholas J White
- Mahidol - Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.
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Kooij TW, Matuschewski K. Triggers and tricks of Plasmodium sexual development. Curr Opin Microbiol 2007; 10:547-53. [PMID: 18006365 DOI: 10.1016/j.mib.2007.09.015] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2007] [Revised: 09/27/2007] [Accepted: 09/28/2007] [Indexed: 11/27/2022]
Abstract
Irrespective of the tremendous suffering caused by malaria, a Plasmodium infection by pathogenic blood stages is only transient and an obligate step toward the Anopheles vector where sexual reproduction and genetic recombination of the unicellular parasite takes place. Recent expression profiling studies identified the molecular make-up of female and male gametocytes. Differential promoters and translational repression through mRNA binding by a female-specific helicase help to fine-tune the expression of these sexual stage-specific genes. However, we are only just beginning to discover the triggers that initiate gametocytogenesis and the developmental programs that drive sexual development.
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Affiliation(s)
- Taco Wa Kooij
- Department of Parasitology, Heidelberg University School of Medicine, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany.
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