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Kaewkungwal J, Roobsoong W, Lawpoolsri S, Nguitragool W, Thammapalo S, Prikchoo P, Khamsiriwatchara A, Pawarana R, Jarujareet P, Parker DM, Sripoorote P, Kengganpanich M, Ngamjarus C, Sattabongkot J, Cui L. Effectiveness, Safety, and Acceptability of Primaquine Mass Drug Administration in Low-Endemicity Areas in Southern Thailand: Proof-of-Concept Study. JMIR Public Health Surveill 2024; 10:e51993. [PMID: 38922648 DOI: 10.2196/51993] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2023] [Revised: 01/28/2024] [Accepted: 05/14/2024] [Indexed: 06/27/2024] Open
Abstract
BACKGROUND A challenge in achieving the malaria-elimination target in the Greater Mekong Subregion, including Thailand, is the predominance of Plasmodium vivax malaria, which has shown extreme resilience to control measures. OBJECTIVE This proof-of-concept study aimed to provide evidence for implementing primaquine mass drug administration (pMDA) as a strategy for P. vivax elimination in low-endemicity settings. METHODS The study employed a mixed-methods trial to thoroughly evaluate the effectiveness, safety, acceptability, and community engagement of pMDA. The quantitative part was designed as a 2-period cluster-crossover randomized controlled trial. The intervention was pMDA augmented to the national prevention and control standards with directly observed treatment (DOT) by village health volunteers. The qualitative part employed in-depth interviews and brainstorming discussions. The study involved 7 clusters in 2 districts of 2 southern provinces in Thailand with persistently low P. vivax transmission. In the quantitative part, 5 cross-sectional blood surveys were conducted in both the pMDA and control groups before and 3 months after pMDA. The effectiveness of pMDA was determined by comparing the proportions of P. vivax infections per 1000 population between the 2 groups, with a multilevel zero-inflated negative binomial model adjusted for cluster and time as covariates and the interaction. The safety data comprised adverse events after drug administration. Thematic content analysis was used to assess the acceptability and engagement of stakeholders. RESULTS In the pre-pMDA period, the proportions of P. vivax infections in the pMDA (n=1536) and control (n=1577) groups were 13.0 (95% CI 8.2-20.4) and 12.0 (95% CI 7.5-19.1), respectively. At month 3 post-pMDA, these proportions in the pMDA (n=1430) and control (n=1420) groups were 8.4 (95% CI 4.6-15.1) and 5.6 (95% CI 2.6-11.5), respectively. No statistically significant differences were found between the groups. The number of malaria cases reduced in all clusters in both groups, and thus, the impact of pMDA was inconclusive. There were no major safety concerns. Acceptance among the study participants and public health care providers at local and national levels was high, and they believed that pMDA had boosted awareness in the community. CONCLUSIONS pMDA was associated with high adherence, safety, and tolerability, but it may not significantly impact P. vivax transmission. As this was a proof-of-concept study, we decided not to scale up the intervention with larger clusters and samples. An alternative approach involving a targeted primaquine treatment strategy with primaquine and DOT is currently being implemented. We experienced success regarding effective health care workforces at point-of-care centers, effective collaborations in the community, and commitment from authorities at local and national levels. Our efforts boosted the acceptability of the malaria-elimination initiative. Community engagement is recommended to achieve elimination targets. TRIAL REGISTRATION Thai Clinical Trials Registry TCTR20190806004; https://www.thaiclinicaltrials.org/show/TCTR20190806004.
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Affiliation(s)
| | - Wanlapa Roobsoong
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | | | - Wang Nguitragool
- Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | | | | | - Amnat Khamsiriwatchara
- Center of Excellence for Biomedical and Public Health Informatics (BIOPHICS), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Rungrawee Pawarana
- Center of Excellence for Biomedical and Public Health Informatics (BIOPHICS), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Pawinee Jarujareet
- Center of Excellence for Biomedical and Public Health Informatics (BIOPHICS), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Daniel M Parker
- Department of Population Health and Disease Prevention, University of California, Irvine, Irvine, CA, United States
- Department of Epidemiology and Biostatistics, University of California, Irvine, Irvine, CA, United States
| | - Piyarat Sripoorote
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Mondha Kengganpanich
- Department of Health Education and Behavioral Sciences, Faculty of Public Health, Mahidol University, Bangkok, Thailand
| | - Chetta Ngamjarus
- Department of Epidemiology and Biostatistics, Faculty of Public Health, Khon Kaen University, Khon Kaen, Thailand
| | - Jetsumon Sattabongkot
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Liwang Cui
- Division of Infectious Diseases and Internal Medicine, Department of Internal Medicine, University of South Florida, Tampa, FL, United States
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Vanachayangkul P, Kodchakorn C, Ta-Aksorn W, Im-Erbsin R, Tungtaeng A, Tipthara P, Tarning J, Lugo-Roman LA, Wojnarski M, Vesely BA, Kobylinski KC. Safety, pharmacokinetics, and potential neurological interactions of ivermectin, tafenoquine, and chloroquine in Rhesus macaques. Antimicrob Agents Chemother 2024:e0018124. [PMID: 38742896 DOI: 10.1128/aac.00181-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Accepted: 04/19/2024] [Indexed: 05/16/2024] Open
Abstract
Ivermectin (IVM) could be used for malaria control as treated individuals are lethal to blood-feeding Anopheles, resulting in reduced transmission. Tafenoquine (TQ) is used to clear the liver reservoir of Plasmodium vivax and as a prophylactic treatment in high-risk populations. It has been suggested to use ivermectin and tafenoquine in combination, but the safety of these drugs in combination has not been evaluated. Early derivatives of 8-aminoquinolones (8-AQ) were neurotoxic, and ivermectin is an inhibitor of the P-glycoprotein (P-gp) blood brain barrier (BBB) transporter. Thus, there is concern that co-administration of these drugs could be neurotoxic. This study aimed to evaluate the safety and pharmacokinetic interaction of tafenoquine, ivermectin, and chloroquine (CQ) in Rhesus macaques. No clinical, biochemistry, or hematological outcomes of concern were observed. The Cambridge Neuropsychological Test Automated Battery (CANTAB) was employed to assess potential neurological deficits following drug administration. Some impairment was observed with tafenoquine alone and in the same monkeys with subsequent co-administrations. Co-administration of chloroquine and tafenoquine resulted in increased plasma exposure to tafenoquine. Urine concentrations of the 5,6 orthoquinone TQ metabolite were increased with co-administration of tafenoquine and ivermectin. There was an increase in ivermectin plasma exposure when co-administered with chloroquine. No interaction of tafenoquine on ivermectin was observed in vitro. Chloroquine and trace levels of ivermectin, but not tafenoquine, were observed in the cerebrospinal fluid. The 3''-O-demethyl ivermectin metabolite was observed in macaque plasma but not in urine or cerebrospinal fluid. Overall, the combination of ivermectin, tafenoquine, and chloroquine did not have clinical, neurological, or pharmacological interactions of concern in macaques; therefore, this combination could be considered for evaluation in human trials.
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Affiliation(s)
- Pattaraporn Vanachayangkul
- Department of Bacterial and Parasitic Diseases, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Chanikarn Kodchakorn
- Department of Bacterial and Parasitic Diseases, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Winita Ta-Aksorn
- Department of Bacterial and Parasitic Diseases, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Rawiwan Im-Erbsin
- Department of Veterinary Medicine, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Anchalee Tungtaeng
- Department of Veterinary Medicine, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Phornpimon Tipthara
- Mahidol Oxford Tropical Medicine Research Unit, Mahidol University, Bangkok, Thailand
| | - Joel Tarning
- Mahidol Oxford Tropical Medicine Research Unit, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, United Kingdom
| | - Luis A Lugo-Roman
- Department of Veterinary Medicine, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Mariusz Wojnarski
- Department of Bacterial and Parasitic Diseases, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Brian A Vesely
- Department of Bacterial and Parasitic Diseases, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Kevin C Kobylinski
- Mahidol Oxford Tropical Medicine Research Unit, Mahidol University, Bangkok, Thailand
- Department of Entomology, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
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El Moustapha I, Ouldabdallahi Moukah M, Ould Ahmedou Salem MS, Brahim K, Briolant S, Basco L, Ould Mohamed Salem Boukhary A. Malaria prevalence in Mauritania: a systematic review and meta-analysis. Malar J 2023; 22:146. [PMID: 37131226 PMCID: PMC10152621 DOI: 10.1186/s12936-023-04569-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Accepted: 04/20/2023] [Indexed: 05/04/2023] Open
Abstract
BACKGROUND Understanding malaria epidemiology is a critical step toward efficient malaria control and elimination. The objective of this meta-analysis was to derive robust estimates of malaria prevalence and Plasmodium species from studies conducted in Mauritania and published since 2000. METHODS The present review followed the PRISMA guidelines. Searches were conducted in various electronic databases such as PubMed, Web of Science, and Scopus. To obtain pooled prevalence of malaria, meta-analysis was performed using the DerSimonian-Laird random-effects model. Methodological quality of eligible prevalence studies was assessed using Joanna Briggs Institute tool. Inconsistency and heterogeneity between studies were quantified by the I2 index and Cochran's Q test. Publication bias was assessed with funnel plots and Egger's regression tests. RESULTS A total of 16 studies with a good individual methodological quality were included and analysed in this study. The overall random effects pooled prevalence of malaria infection (symptomatic and asymptomatic) across all included studies was 14.9% (95% confidence interval [95% CI]: 6.64, 25.80, I2 = 99.8%, P < 0.0001) by microscopy, 25.6% (95% CI: 8.74, 47.62, I2 = 99.6%, P < 0.0001) by PCR and 24.3% (95% CI: 12.05 to 39.14, I2 = 99.7%, P < 0.0001) by rapid diagnostic test. Using microscopy, the prevalence of asymptomatic malaria was 1.0% (95% CI: 0.00, 3.48) against 21.46% (95% CI: 11.03, 34.21) in symptomatic malaria. The overall prevalence of Plasmodium falciparum and Plasmodium vivax was 51.14% and 37.55%, respectively. Subgroup analysis showed significant variation (P = 0.039) in the prevalence of malaria between asymptomatic and symptomatic cases. CONCLUSION Plasmodium falciparum and P. vivax are widespread in Mauritania. Results of this meta-analysis implies that distinct intervention measures including accurate parasite-based diagnosis and appropriate treatment of confirmed malaria cases are critical for a successful malaria control and elimination programme in Mauritania.
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Affiliation(s)
- Inejih El Moustapha
- Université de Nouakchott, UR-GEMI, nouveau campus universitaire, BP 5026, Nouakchott, Mauritania
| | | | | | - Khyarhoum Brahim
- Université de Nouakchott, UR-GEMI, nouveau campus universitaire, BP 5026, Nouakchott, Mauritania
| | - Sébastien Briolant
- Aix Marseille Université, IRD, AP-HM, SSA, VITROME, Marseille, France
- IHU-Méditerranée Infection, Marseille, France
- Unité de Parasitologie Entomologie, Département de Microbiologie et Maladies Infectieuses, Institut de Recherche Biomédicale des Armées (IRBA), Marseille, France
| | - Leonardo Basco
- IHU-Méditerranée Infection, Marseille, France
- Unité de Parasitologie Entomologie, Département de Microbiologie et Maladies Infectieuses, Institut de Recherche Biomédicale des Armées (IRBA), Marseille, France
| | - Ali Ould Mohamed Salem Boukhary
- Université de Nouakchott, UR-GEMI, nouveau campus universitaire, BP 5026, Nouakchott, Mauritania.
- Aix Marseille Université, IRD, AP-HM, SSA, VITROME, Marseille, France.
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Hypnozoite dynamics for Plasmodium vivax malaria: the epidemiological effects of radical cure. J Theor Biol 2022; 537:111014. [PMID: 35016895 DOI: 10.1016/j.jtbi.2022.111014] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2021] [Revised: 11/30/2021] [Accepted: 01/03/2022] [Indexed: 01/27/2023]
Abstract
Malaria is a mosquito-borne disease with a devastating global impact. Plasmodium vivax is a major cause of human malaria beyond sub-Saharan Africa. Relapsing infections, driven by a reservoir of liver-stage parasites known as hypnozoites, present unique challenges for the control of P. vivax malaria. Following indeterminate dormancy periods, hypnozoites may activate to trigger relapses. Clearance of the hypnozoite reservoir through drug treatment (radical cure) has been proposed as a potential tool for the elimination of P. vivax malaria. Here, we introduce a stochastic, within-host model to jointly characterise hypnozoite and infection dynamics for an individual in a general transmission setting, allowing for radical cure. We begin by extending an existing activation-clearance model for a single hypnozoite, adapted to both short- and long-latency strains, to include drug treatment. We then embed this activation-clearance model in an epidemiological framework accounting for repeated mosquito inoculation and the administration of radical cure. By constructing an open network of infinite server queues, we derive analytic expressions for several quantities of epidemiological significance, including the size of the hypnozoite reservoir; the relapse rate; the relative contribution of relapses to the infection burden; the distribution of multiple infections; the cumulative number of recurrences over time, and the time to first recurrence following drug treatment. We derive from first principles the functional dependence between within-host and transmission parameters and patterns of blood- and liver-stage infection, whilst allowing for treatment under a mass drug administration regime. To yield population-level insights, our analytic within-host distributions can be embedded in multiscale models. Our work thus contributes to the epidemiological understanding of the effects of radical cure on P. vivax malaria.
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Abstract
BACKGROUND Studies evaluating mass drug administration (MDA) in malarious areas have shown reductions in malaria immediately following the intervention. However, these effects vary by endemicity and are not sustained. Since the 2013 version of this Cochrane Review on this topic, additional studies have been published. OBJECTIVES Primary objectives To assess the sustained effect of MDA with antimalarial drugs on: - the reduction in malaria transmission in moderate- to high-transmission settings; - the interruption of transmission in very low- to low-transmission settings. Secondary objective To summarize the risk of drug-associated adverse effects following MDA. SEARCH METHODS We searched several trial registries, citation databases, conference proceedings, and reference lists for relevant articles up to 11 February 2021. We also communicated with researchers to identify additional published and unpublished studies. SELECTION CRITERIA Randomized controlled trials (RCTs) and non-randomized studies comparing MDA to no MDA with balanced co-interventions across study arms and at least two geographically distinct sites per study arm. DATA COLLECTION AND ANALYSIS Two review authors independently assessed trials for eligibility and extracted data. We calculated relative risk (RR) and rate ratios with corresponding 95% confidence intervals (CIs) to compare prevalence and incidence, respectively, in MDA compared to no-MDA groups. We stratified analyses by malaria transmission and by malaria species. For cluster-randomized controlled trials (cRCTs), we adjusted standard errors using the intracluster correlation coefficient. We assessed the certainty of the evidence using the GRADE approach. For non-randomized controlled before-and-after (CBA) studies, we summarized the data using difference-in-differences (DiD) analyses. MAIN RESULTS Thirteen studies met our criteria for inclusion. Ten were cRCTs and three were CBAs. Cluster-randomized controlled trials Moderate- to high-endemicity areas (prevalence ≥ 10%) We included data from two studies conducted in The Gambia and Zambia. At one to three months after MDA, the Plasmodium falciparum (hereafter, P falciparum) parasitaemia prevalence estimates may be higher compared to control but the CIs included no effect (RR 1.76, 95% CI 0.58 to 5.36; Zambia study; low-certainty evidence); parasitaemia incidence was probably lower (RR 0.61, 95% CI 0.40 to 0.92; The Gambia study; moderate-certainty evidence); and confirmed malaria illness incidence may be substantially lower, but the CIs included no effect (rate ratio 0.41, 95% CI 0.04 to 4.42; Zambia study; low-certainty evidence). At four to six months after MDA, MDA showed little or no effect on P falciparum parasitaemia prevalence (RR 1.18, 95% CI 0.89 to 1.56; The Gambia study; moderate-certainty evidence) and, no persisting effect was demonstrated with parasitaemia incidence (rate ratio 0.91, 95% CI 0.55 to 1.50; The Gambia study). Very low- to low-endemicity areas (prevalence < 10%) Seven studies from Cambodia, Laos, Myanmar (two studies), Vietnam, Zambia, and Zanzibar evaluated the effects of multiple rounds of MDA on P falciparum. Immediately following MDA (less than one month after MDA), parasitaemia prevalence was reduced (RR 0.12, 95% CI 0.03 to 0.52; one study; low-certainty evidence). At one to three months after MDA, there was a reduction in both parasitaemia incidence (rate ratio 0.37, 95% CI 0.21 to 0.55; 1 study; moderate-certainty evidence) and prevalence (RR 0.25, 95% CI 0.15 to 0.41; 7 studies; low-certainty evidence). For confirmed malaria incidence, absolute rates were low, and it is uncertain whether MDA had an effect on this outcome (rate ratio 0.58, 95% CI 0.12 to 2.73; 2 studies; very low-certainty evidence). For P falciparum prevalence, the relative differences declined over time, from RR 0.63 (95% CI 0.36 to 1.12; 4 studies) at four to six months after MDA, to RR 0.86 (95% CI 0.55 to 1.36; 5 studies) at 7 to 12 months after MDA. Longer-term prevalence estimates showed overall low absolute risks, and relative effect estimates of the effect of MDA on prevalence varied from RR 0.82 (95% CI 0.20 to 3.34) at 13 to 18 months after MDA, to RR 1.25 (95% CI 0.25 to 6.31) at 31 to 36 months after MDA in one study. Five studies from Cambodia, Laos, Myanmar (2 studies), and Vietnam evaluated the effect of MDA on Plasmodium vivax (hereafter, P vivax). One month following MDA, P vivax prevalence was lower (RR 0.18, 95% CI 0.08 to 0.40; 1 study; low-certainty evidence). At one to three months after MDA, there was a reduction in P vivax prevalence (RR 0.15, 95% CI 0.10 to 0.24; 5 studies; low-certainty evidence). The immediate reduction on P vivax prevalence was not sustained over time, from RR 0.78 (95% CI 0.63 to 0.95; 4 studies) at four to six months after MDA, to RR 1.12 (95% CI 0.94 to 1.32; 5 studies) at 7 to 12 months after MDA. One of the studies in Myanmar provided estimates of longer-term effects, where overall absolute risks were low, ranging from RR 0.81 (95% CI 0.44 to 1.48) at 13 to 18 months after MDA, to RR 1.20 (95% CI 0.44 to 3.29) at 31 to 36 months after MDA. Non-randomized studies Three CBA studies were conducted in moderate- to high-transmission areas in Burkina Faso, Kenya, and Nigeria. There was a reduction in P falciparum parasitaemia prevalence in MDA groups compared to control groups during MDA (DiD range: -15.8 to -61.4 percentage points), but the effect varied at one to three months after MDA (DiD range: 14.9 to -41.1 percentage points). AUTHORS' CONCLUSIONS: In moderate- to high-transmission settings, no studies reported important effects on P falciparum parasitaemia prevalence within six months after MDA. In very low- to low-transmission settings, parasitaemia prevalence and incidence were reduced initially for up to three months for both P falciparum and P vivax; longer-term data did not demonstrate an effect after four months, but absolute risks in both intervention and control groups were low. No studies provided evidence of interruption of malaria transmission.
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Affiliation(s)
- Monica P Shah
- Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Jimee Hwang
- U.S. President's Malaria Initiative, Malaria Branch, Centers for Disease Control and Prevention, Atlanta, GA, USA
- Global Health Group, University of California San Francisco, San Francisco, USA
| | - Leslie Choi
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Kim A Lindblade
- Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - S Patrick Kachur
- Department of Population and Family Health, Columbia University Medical Center, New York, NY, USA
| | - Meghna Desai
- 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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Forgách L, Hegedűs N, Horváth I, Kiss B, Kovács N, Varga Z, Jakab G, Kovács T, Padmanabhan P, Szigeti K, Máthé D. Fluorescent, Prussian Blue-Based Biocompatible Nanoparticle System for Multimodal Imaging Contrast. NANOMATERIALS 2020; 10:nano10091732. [PMID: 32878344 PMCID: PMC7557721 DOI: 10.3390/nano10091732] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 08/21/2020] [Accepted: 08/27/2020] [Indexed: 02/06/2023]
Abstract
(1) Background. The main goal of this work was to develop a fluorescent dye-labelling technique for our previously described nanosized platform, citrate-coated Prussian blue (PB) nanoparticles (PBNPs). In addition, characteristics and stability of the PB nanoparticles labelled with fluorescent dyes were determined. (2) Methods. We adsorbed the fluorescent dyes Eosin Y and Rhodamine B and methylene blue (MB) to PB-nanoparticle systems. The physicochemical properties of these fluorescent dye-labeled PBNPs (iron(II);iron(III);octadecacyanide) were determined using atomic force microscopy, dynamic light scattering, zeta potential measurements, scanning- and transmission electron microscopy, X-ray diffraction, and Fourier-transformation infrared spectroscopy. A methylene-blue (MB) labelled, polyethylene-glycol stabilized PBNP platform was selected for further assessment of in vivo distribution and fluorescent imaging after intravenous administration in mice. (3) Results. The MB-labelled particles emitted a strong fluorescent signal at 662 nm. We found that the fluorescent light emission and steric stabilization made this PBNP-MB particle platform applicable for in vivo optical imaging. (4) Conclusion. We successfully produced a fluorescent and stable, Prussian blue-based nanosystem. The particles can be used as a platform for imaging contrast enhancement. In vivo stability and biodistribution studies revealed new aspects of the use of PBNPs.
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Affiliation(s)
- László Forgách
- Department of Biophysics and Radiation Biology, Semmelweis University, 1085 Budapest, Hungary; (N.H.); (I.H.); (B.K.); (N.K.); (Z.V.)
- Correspondence: (L.F.); (K.S.); (D.M.); Tel.: +36-1-459-1500 (ext. 60164) (L.F.); +36-1-459-1500 (ext. 60210) (D.M.)
| | - Nikolett Hegedűs
- Department of Biophysics and Radiation Biology, Semmelweis University, 1085 Budapest, Hungary; (N.H.); (I.H.); (B.K.); (N.K.); (Z.V.)
| | - Ildikó Horváth
- Department of Biophysics and Radiation Biology, Semmelweis University, 1085 Budapest, Hungary; (N.H.); (I.H.); (B.K.); (N.K.); (Z.V.)
| | - Bálint Kiss
- Department of Biophysics and Radiation Biology, Semmelweis University, 1085 Budapest, Hungary; (N.H.); (I.H.); (B.K.); (N.K.); (Z.V.)
| | - Noémi Kovács
- Department of Biophysics and Radiation Biology, Semmelweis University, 1085 Budapest, Hungary; (N.H.); (I.H.); (B.K.); (N.K.); (Z.V.)
| | - Zoltán Varga
- Department of Biophysics and Radiation Biology, Semmelweis University, 1085 Budapest, Hungary; (N.H.); (I.H.); (B.K.); (N.K.); (Z.V.)
- Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences, 1117 Budapest, Hungary
| | - Géza Jakab
- Department of Pharmaceutics, Semmelweis University, 1085 Budapest, Hungary;
| | - Tibor Kovács
- Institute of Radiochemistry and Radioecology, University of Pannonia, 8200 Veszprém, Hungary;
| | - Parasuraman Padmanabhan
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore 636921, Singapore;
| | - Krisztián Szigeti
- Department of Biophysics and Radiation Biology, Semmelweis University, 1085 Budapest, Hungary; (N.H.); (I.H.); (B.K.); (N.K.); (Z.V.)
- Correspondence: (L.F.); (K.S.); (D.M.); Tel.: +36-1-459-1500 (ext. 60164) (L.F.); +36-1-459-1500 (ext. 60210) (D.M.)
| | - Domokos Máthé
- Department of Biophysics and Radiation Biology, Semmelweis University, 1085 Budapest, Hungary; (N.H.); (I.H.); (B.K.); (N.K.); (Z.V.)
- In Vivo Imaging Advanced Core Facility, Hungarian Centre of Excellence for Molecular Medicine, 6723 Szeged, Hungary
- CROmed Translational Research Centers, 1047 Budapest, Hungary
- Correspondence: (L.F.); (K.S.); (D.M.); Tel.: +36-1-459-1500 (ext. 60164) (L.F.); +36-1-459-1500 (ext. 60210) (D.M.)
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Kaehler N, Adhikari B, Cheah PY, von Seidlein L, Day NPJ, Paris DH, Tanner M, Pell C. Prospects and strategies for malaria elimination in the Greater Mekong Sub-region: a qualitative study. Malar J 2019; 18:203. [PMID: 31221145 PMCID: PMC6585139 DOI: 10.1186/s12936-019-2835-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2019] [Accepted: 06/09/2019] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND As malaria elimination becomes a goal in malaria-endemic nations, questions of feasibility become critical. This article explores the potential challenges associated with this goal and future strategies for malaria elimination in the Greater Mekong Sub-region. METHODS Thirty-two semi-structured interviews were conducted with policy makers (n = 17) and principal investigators (n = 15) selected based on their involvement in malaria prevention, control and elimination in the GMS. Interviews were audio-recorded and transcribed for qualitative content (thematic) analysis using QSR NVivo. RESULTS All respondents described current malaria control and elimination strategies, such as case detection and management, prevention and strengthening of surveillance systems as critical and of equal priority. Aware of the emergence of multi-drug resistance in the GMS, researchers and policy makers outlined the need for additional elimination tools. As opposed to a centralized strategy, more targeted and tailored approaches to elimination were recommended. These included targeting endemic areas, consideration for local epidemiology and malaria species, and strengthening the peripheral health system. A decline in malaria transmission could lead to complacency amongst funders and policy makers resulting in a reduction or discontinuation of support for malaria elimination. Strong commitment of policymakers combined with strict monitoring and supervision by funders were considered pivotal to successful elimination programmes. CONCLUSION Against a backdrop of increasing anti-malarial resistance and decreasing choices of anti-malarial regimens, policy makers and researchers stressed the urgency of finding new malaria elimination strategies. There was consensus that multi-pronged strategies and approaches are needed, that no single potential tool/strategy can be appropriate to all settings. Hence there is a need to customize malaria control and elimination strategies based on the better surveillance data.
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Affiliation(s)
- Nils Kaehler
- Swiss Tropical and Public Health Institute, Basel, Switzerland.
- University of Basel, 4051, Basel, Switzerland.
- Mahidol Oxford Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.
| | - Bipin Adhikari
- Mahidol Oxford Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, OX3 7FZ, UK
| | - Phaik Yeong Cheah
- Mahidol Oxford Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, OX3 7FZ, UK
- The Ethox Centre, Nuffield Department of Population Health, University of Oxford, Old Road Campus, Oxford, OX3 7LF, UK
| | - Lorenz von Seidlein
- Mahidol Oxford Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, OX3 7FZ, UK
| | - Nicholas P J Day
- Mahidol Oxford Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, OX3 7FZ, UK
| | - Daniel H Paris
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, 4051, Basel, Switzerland
| | - Marcel Tanner
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, 4051, Basel, Switzerland
| | - Christopher Pell
- Amsterdam Institute for Global Health and Development (AIGHD), Amsterdam, The Netherlands
- Centre for Social Science and Global Health, University of Amsterdam, Amsterdam, The Netherlands
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8
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Haiyambo DH, Uusiku P, Mumbengegwi D, Pernica JM, Bock R, Malleret B, Rénia L, Greco B, Quaye IK. Molecular detection of P. vivax and P. ovale foci of infection in asymptomatic and symptomatic children in Northern Namibia. PLoS Negl Trop Dis 2019; 13:e0007290. [PMID: 31042707 PMCID: PMC6513099 DOI: 10.1371/journal.pntd.0007290] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2018] [Revised: 05/13/2019] [Accepted: 03/11/2019] [Indexed: 11/19/2022] Open
Abstract
Background Knowledge of the foci of Plasmodium species infections is critical for a country with an elimination agenda. Namibia is targeting malaria elimination by 2020. To support decision making regarding targeted intervention, we examined for the first time, the foci of Plasmodium species infections and regional prevalence in northern Namibia, using nested and quantitative polymerase chain reaction (PCR) methods. Methods We used cross-sectional multi-staged sampling to select 952 children below 9 years old from schools and clinics in seven districts in northern Namibia, to assess the presence of Plasmodium species. Results The median participant age was 6 years (25–75%ile 4–8 y). Participants had a median hemoglobin of 12.0 g/dL (25–75%ile 11.1–12.7 g/dL), although 21% of the cohort was anemic, with anemia being severer in the younger population (p<0.002). Most of children with Plasmodium infection were asymptomatic (63.4%), presenting a challenge for elimination. The respective parasite prevalence for Plasmodium falciparum (Pf), Plasmodium vivax (Pv) and Plasmodium ovale curtisi (Po) were (4.41%, 0.84% and 0.31%); with Kavango East and West (10.4%, 6.19%) and Ohangwena (4.5%) having the most prevalence. Pv was localized in Ohangwena, Omusati and Oshana, while Po was found in Kavango. All children with Pv/Pf coinfections in Ohangwena, had previously visited Angola, affirming that perennial migrations are risks for importation of Plasmodium species. The mean hemoglobin was lower in those with Plasmodium infection compared to those without (0.96 g/dL less, 95%CI 0.40–1.52 g/dL less, p = 0.0009) indicating that quasi-endemicity exists in the low transmission setting. Conclusions We conclude that Pv and Po species are present in northern Namibia. Additionally, the higher number of asymptomatic infections present challenges to the efforts at elimination for the country. Careful planning, coordination with neighboring Angola and execution of targeted active intervention, will be required for a successful elimination agenda. Namibia is a member of the SADC elimination 8 (E8) group with a target to eliminate malaria by 2020. This target stems from years of aggressive interventional strategies that has led to significant reductions in morbidity and mortality. The focus of this strategy is mainly on Plasmodium falciparum as the primary parasite species. Foci of transmission is found in the northern border with Angola and Zambia, which also carries the highest population density. Recently as part of the elimination efforts to predict areas likely to have rebound epidemics, three regions Ohangwena, Kavango and Zambezi were identified. In order to affirm these findings and decision-making process for intervention, we assessed the parasite prevalence in 7 northern regional sites for four Plasmodium species. We identified Pv and Po curtisi parasites in Omusati, Ohangwena and Kavango, as well as a significant number of asymptomatic Pf and Pv infections, part of which may be due to importation from neighboring Angola. As Namibia is targeting elimination by 2020, careful thought and planning will be required to reach the goal.
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Affiliation(s)
- Daniel H. Haiyambo
- Department of Biochemistry and Microbiology, University of Namibia School of Medicine, Windhoek, Namibia
| | - Petrina Uusiku
- National Vector Borne Disease Control Program, Ministry of Health and Social Services, Windhoek, Namibia
| | - Davies Mumbengegwi
- Multidisciplinary Research Center, University of Namibia, Windhoek, Namibia
| | - Jeff M. Pernica
- Division of Infectious Disease, Department of Pediatrics, McMaster University, Hamilton, Ontario, Canada
| | - Ronnie Bock
- Department of Biology, University of Namibia, Windhoek, Namibia
| | - Benoit Malleret
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, National University Health System, Singapore
- Singapore Immunology Network (SIgN), Agency for Science, Technology and Research (A*STAR), Biopolis, Singapore
| | - Laurent Rénia
- Singapore Immunology Network (SIgN), Agency for Science, Technology and Research (A*STAR), Biopolis, Singapore
| | - Beatrice Greco
- Research and Development Access, Global Health Institute, Merck KGaA, Darmstadt, Germany
| | - Isaac K. Quaye
- Department of Biochemistry and Microbiology, University of Namibia School of Medicine, Windhoek, Namibia
- * E-mail: ,
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9
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Pacheco MA, Schneider KA, Céspedes N, Herrera S, Arévalo-Herrera M, Escalante AA. Limited differentiation among Plasmodium vivax populations from the northwest and to the south Pacific Coast of Colombia: A malaria corridor? PLoS Negl Trop Dis 2019; 13:e0007310. [PMID: 30921317 PMCID: PMC6456216 DOI: 10.1371/journal.pntd.0007310] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Revised: 04/09/2019] [Accepted: 03/16/2019] [Indexed: 01/06/2023] Open
Abstract
Background Malaria remains endemic in several countries of South America with low to moderate transmission intensity. Regional human migration through underserved endemic areas may be responsible for significant parasite dispersion making the disease resilient to interventions. Thus, the genetic characterization of malarial parasites is an important tool to assess how endemic areas may connect via the movement of infected individuals. Here, four sites in geographically separated areas reporting 80% of the malaria morbidity in Colombia were studied. The sites are located on an imaginary transect line of 1,500 km from the northwest to the south Pacific Coast of Colombia with a minimal distance of 500 km between populations that display noticeable ethnic, economic, epidemiological, and ecological differences. Methodology/Principal findings A total of 624 Plasmodium vivax samples from the four populations were genotyped by using eight microsatellite loci. Although a strong geographic structure was expected between these populations, only moderate evidence of genetic differentiation was observed using a suite of population genetic analyses. High genetic diversity, shared alleles, and low linkage disequilibrium were also found in these P. vivax populations providing no evidence for a bottleneck or clonal expansions as expected from recent reductions in the transmission that could have been the result of scaling up interventions or environmental changes. These patterns are consistent with a disease that is not only endemic in each site but also imply that there is gene flow among these populations across 1,500 km. Conclusion /Significance The observed patterns in P. vivax are consistent with a “corridor” where connected endemic areas can sustain a high level of genetic diversity locally and can restore parasite-subdivided populations via migration of infected individuals even after local interventions achieved a substantial reduction of clinical cases. The consequences of these findings in terms of control and elimination are discussed. The regional movements of infected individuals that connect suitable transmission areas make malaria resilient to control efforts. Those movements are expected to leave genetic signatures in the parasite populations that can be detected using analytical tools. In this study, the genetic makeups of Plasmodium vivax populations were characterized to assess whether the most endemic areas in Colombia were connected. Samples were collected from passive surveillance studies in four locations across an imaginary transect line of 1,500 km from the northwest to the south Pacific Coast of Colombia (South America). Considering the distance, and contrary to expectations, we found weak levels of genetic differentiation between these parasite populations with no evidence indicating that their genetic diversity has been eroded as expected whenever the prevalence of the disease is successfully reduced, e.g., through control programs or environmental changes. Although the sampling lacks the geographic and temporal detail to describe how the dispersion of parasite lineages occurred, the observed patterns are consistent with a series of infected populations that are connected in space by human movements allowing the parasite to diffuse across this 1,500 km transect. This malaria corridor needs to be characterized to achieve elimination.
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Affiliation(s)
- M. Andreína Pacheco
- Department of Biology/Institute for Genomics and Evolutionary Medicine (iGEM), Temple University, Philadelphia, Pennsylvania, United States of America
| | | | - Nora Céspedes
- Caucaseco Scientific Research Center and Malaria Vaccine and Drug Development Center, Cali, Colombia
| | - Sócrates Herrera
- Caucaseco Scientific Research Center and Malaria Vaccine and Drug Development Center, Cali, Colombia
| | - Myriam Arévalo-Herrera
- Caucaseco Scientific Research Center and Malaria Vaccine and Drug Development Center, Cali, Colombia
- Faculty of Health, Universidad del Valle, Cali, Colombia
| | - Ananias A. Escalante
- Department of Biology/Institute for Genomics and Evolutionary Medicine (iGEM), Temple University, Philadelphia, Pennsylvania, United States of America
- * E-mail:
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10
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Kobylinski KC, Escobedo-Vargas KS, López-Sifuentes VM, Durand S, Smith ES, Baldeviano GC, Gerbasi RV, Ballard SB, Stoops CA, Vásquez GM. Ivermectin susceptibility, sporontocidal effect, and inhibition of time to re-feed in the Amazonian malaria vector Anopheles darlingi. Malar J 2017; 16:474. [PMID: 29162101 PMCID: PMC5696779 DOI: 10.1186/s12936-017-2125-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Accepted: 11/16/2017] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Outdoor malaria transmission hinders malaria elimination efforts in the Amazon region and novel vector control tools are needed. Ivermectin mass drug administration (MDA) to humans kills wild Anopheles, targets outdoor-feeding vectors, and can suppress malaria parasite transmission. Laboratory investigations were performed to determine ivermectin susceptibility, sporontocidal effect and inhibition of time to re-feed for the primary Amazonian malaria vector, Anopheles darlingi. METHODS To assess ivermectin susceptibility, various concentrations of ivermectin were mixed in human blood and fed to An. darlingi. Mosquito survival was monitored daily for 7 days and a non-linear mixed effects model with Probit analysis was used to calculate lethal concentrations of ivermectin that killed 50% (LC50), 25% (LC25) and 5% (LC5) of mosquitoes. To examine ivermectin sporonticidal effect, Plasmodium vivax blood samples were collected from malaria patients and offered to mosquitoes without or with ivermectin at the LC50, LC25 or LC5. To assess ivermectin inhibition of mosquito time to re-feed, concentrations of ivermectin predicted to occur after a single oral dose of 200 μg/kg ivermectin were fed to An. darlingi. Every day for 12 days thereafter, individual mosquitoes were given the opportunity to re-feed on a volunteer. Any mosquitoes that re-blood fed or died were removed from the study. RESULTS Ivermectin significantly reduced An. darlingi survivorship: 7-day-LC50 = 43.2 ng/ml [37.5, 48.6], -LC25 = 27.8 ng/ml [20.4, 32.9] and -LC5 = 14.8 ng/ml [7.9, 20.2]. Ivermectin compound was sporontocidal to P. vivax in An. darlingi at the LC50 and LC25 concentrations reducing prevalence by 22.6 and 17.1%, respectively, but not at the LC5. Oocyst intensity was not altered at any concentration. Ivermectin significantly delayed time to re-feed at the 4-h (48.7 ng/ml) and 12-h (26.9 ng/ml) concentrations but not 36-h (10.6 ng/ml) or 60-h (6.3 ng/ml). CONCLUSIONS Ivermectin is lethal to An. darlingi, modestly inhibits sporogony of P. vivax, and delays time to re-feed at concentrations found in humans up to 12 h post drug ingestion. The LC50 value suggests that a higher than standard dose (400-μg/kg) is necessary to target An. darlingi. These results suggest that ivermectin MDA has potential in the Amazon region to aid malaria elimination efforts.
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Affiliation(s)
- Kevin C Kobylinski
- Department of Entomology, Armed Forces Research Institute of Medical Sciences, 315/6 Rajvithi Road, Bangkok, 10400, Thailand. .,Entomology Branch, Walter Reed Army Institute of Research, 503 Robert Grant Ave, Silver Spring, MD, 20910, USA.
| | - Karín S Escobedo-Vargas
- Department of Entomology, U.S. Naval Medical Research Unit No. 6, Av. Venezuela block 36 s/n, Callao 2, Peru
| | - Victor M López-Sifuentes
- Department of Entomology, U.S. Naval Medical Research Unit No. 6, Av. Venezuela block 36 s/n, Callao 2, Peru
| | - Salomón Durand
- Department of Parasitology, U.S. Naval Medical Research Unit No. 6, Av. Venezuela block 36 s/n, Callao 2, Peru
| | - Edward S Smith
- Department of Parasitology, U.S. Naval Medical Research Unit No. 6, Av. Venezuela block 36 s/n, Callao 2, Peru
| | - G Christian Baldeviano
- Department of Parasitology, U.S. Naval Medical Research Unit No. 6, Av. Venezuela block 36 s/n, Callao 2, Peru
| | - Robert V Gerbasi
- Infectious Diseases Directorate, Naval Medical Research Center, Silver Spring, MD, 20910, USA
| | - Sara-Blythe Ballard
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe St., Rm. W5515, Baltimore, MD, 21205, USA
| | - Craig A Stoops
- Department of Entomology, U.S. Naval Medical Research Unit No. 6, Av. Venezuela block 36 s/n, Callao 2, Peru
| | - Gissella M Vásquez
- Department of Entomology, U.S. Naval Medical Research Unit No. 6, Av. Venezuela block 36 s/n, Callao 2, Peru
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11
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Yalew WG, Pal S, Bansil P, Dabbs R, Tetteh K, Guinovart C, Kalnoky M, Serda BA, Tesfay BH, Beyene BB, Seneviratne C, Littrell M, Yokobe L, Noland GS, Domingo GJ, Getachew A, Drakeley C, Steketee RW. Current and cumulative malaria infections in a setting embarking on elimination: Amhara, Ethiopia. Malar J 2017; 16:242. [PMID: 28595603 PMCID: PMC5465535 DOI: 10.1186/s12936-017-1884-y] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Accepted: 05/30/2017] [Indexed: 11/17/2022] Open
Abstract
Background Since 2005, Ethiopia has aggressively scaled up malaria prevention and case management. As a result, the number of malaria cases and deaths has significantly declined. In order to track progress towards the elimination of malaria in Amhara Region, coverage of malaria control tools and current malaria transmission need to be documented. Methods A cross-sectional household survey oversampling children under 5 years of age was conducted during the dry season in 2013. A bivalent rapid diagnostic test (RDT) detecting both Plasmodium falciparum and Plasmodium vivax and serology assays using merozoite antigens from both these species were used to assess the prevalence of malaria infections and exposure to malaria parasites in 16 woredas (districts) in Amhara Region. Results 7878 participants were included, with a mean age of 16.8 years (range 0.5–102.8 years) and 42.0% being children under 5 years of age. The age-adjusted RDT-positivity for P. falciparum and P. vivax infection was 1.5 and 0.4%, respectively, of which 0.05% presented as co-infections. Overall age-adjusted seroprevalence was 30.0% for P. falciparum, 21.8% for P. vivax, and seroprevalence for any malaria species was 39.4%. The prevalence of RDT-positive infections varied by woreda, ranging from 0.0 to 8.3% and by altitude with rates of 3.2, 0.7, and 0.4% at under 2000, 2000–2500, and >2500 m, respectively. Serological analysis showed heterogeneity in transmission intensity by area and altitude and evidence for a change in the force of infection in the mid-2000s. Conclusions Current and historic malaria transmission across Amhara Region show substantial variation by age and altitude with some settings showing very low or near-zero transmission. Plasmodium vivax infections appear to be lower but relatively more stable across geography and altitude, while P. falciparum is the dominant infection in the higher transmission, low-altitude areas. Age-dependent seroprevalence analyses indicates a drop in transmission occurred in the mid-2000s, coinciding with malaria control scale-up efforts. As malaria parasitaemia rates get very low with elimination efforts, serological evaluation may help track progress to elimination. Electronic supplementary material The online version of this article (doi:10.1186/s12936-017-1884-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Woyneshet G Yalew
- Regional Health Research Laboratory Center, Amhara National Regional State Health Bureau, P.O. Box 495, Bahir Dar, Ethiopia
| | - Sampa Pal
- PATH, 2201 Westlake Avenue, Suite 200, Seattle, WA, 98121, USA
| | - Pooja Bansil
- PATH, 2201 Westlake Avenue, Suite 200, Seattle, WA, 98121, USA
| | - Rebecca Dabbs
- Faculty of Infectious and Tropical Diseases, London School of Tropical Medicine and Hygiene, Keppel Street, London, WCIE 7HT, UK
| | - Kevin Tetteh
- Faculty of Infectious and Tropical Diseases, London School of Tropical Medicine and Hygiene, Keppel Street, London, WCIE 7HT, UK
| | | | - Michael Kalnoky
- PATH, 2201 Westlake Avenue, Suite 200, Seattle, WA, 98121, USA
| | | | | | - Belay B Beyene
- Regional Health Research Laboratory Center, Amhara National Regional State Health Bureau, P.O. Box 495, Bahir Dar, Ethiopia
| | | | - Megan Littrell
- PATH, 2201 Westlake Avenue, Suite 200, Seattle, WA, 98121, USA
| | - Lindsay Yokobe
- PATH, 2201 Westlake Avenue, Suite 200, Seattle, WA, 98121, USA
| | | | | | - Asefaw Getachew
- PATH, 2201 Westlake Avenue, Suite 200, Seattle, WA, 98121, USA
| | - Chris Drakeley
- Faculty of Infectious and Tropical Diseases, London School of Tropical Medicine and Hygiene, Keppel Street, London, WCIE 7HT, UK
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12
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Early Immune Regulatory Changes in a Primary Controlled Human Plasmodium vivax Infection: CD1c + Myeloid Dendritic Cell Maturation Arrest, Induction of the Kynurenine Pathway, and Regulatory T Cell Activation. Infect Immun 2017; 85:IAI.00986-16. [PMID: 28320838 DOI: 10.1128/iai.00986-16] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Accepted: 03/15/2017] [Indexed: 01/03/2023] Open
Abstract
Plasmodium vivax malaria remains a major public health problem. The requirements for acquisition of protective immunity to the species are not clear. Dendritic cells (DC) are essential for immune cell priming but also perform immune regulatory functions, along with regulatory T cells (Treg). An important function of DC involves activation of the kynurenine pathway via indoleamine 2,3-dioxygenase (IDO). Using a controlled human experimental infection study with blood-stage P. vivax, we characterized plasmacytoid DC (pDC) and myeloid DC (mDC) subset maturation, CD4+ CD25+ CD127lo Treg activation, and IDO activity. Blood samples were collected from six healthy adults preinoculation, at peak parasitemia (day 14; ∼31,400 parasites/ml), and 24 and 48 h after antimalarial treatment. CD1c+ and CD141+ mDC and pDC numbers markedly declined at peak parasitemia, while CD16+ mDC numbers appeared less affected. HLA-DR expression was selectively reduced on CD1c+ mDC, increased on CD16+ mDC, and was unaltered on pDC. Plasma IFN-γ increased significantly and was correlated with an increased kynurenine/tryptophan (KT) ratio, a measure of IDO activity. At peak parasitemia, Treg presented an activated CD4+ CD25+ CD127lo CD45RA- phenotype and upregulated TNFR2 expression. In a mixed-effects model, the KT ratio was positively associated with an increase in activated Treg. Our data demonstrate that a primary P. vivax infection exerts immune modulatory effects by impairing HLA-DR expression on CD1c+ mDC while activating CD16+ mDC. Induction of the kynurenine pathway and increased Treg activation, together with skewed mDC maturation, suggest P. vivax promotes an immunosuppressive environment, likely impairing the development of a protective host immune response.
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13
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Fola AA, Harrison GLA, Hazairin MH, Barnadas C, Hetzel MW, Iga J, Siba PM, Mueller I, Barry AE. Higher Complexity of Infection and Genetic Diversity of Plasmodium vivax Than Plasmodium falciparum Across All Malaria Transmission Zones of Papua New Guinea. Am J Trop Med Hyg 2017; 96:630-641. [PMID: 28070005 DOI: 10.4269/ajtmh.16-0716] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Plasmodium falciparum and Plasmodium vivax have varying transmission dynamics that are informed by molecular epidemiology. This study aimed to determine the complexity of infection and genetic diversity of P. vivax and P. falciparum throughout Papua New Guinea (PNG) to evaluate transmission dynamics across the country. In 2008-2009, a nationwide malaria indicator survey collected 8,936 samples from all 16 endemic provinces of PNG. Of these, 892 positive P. vivax samples were genotyped at PvMS16 and PvmspF3, and 758 positive P. falciparum samples were genotyped at Pfmsp2. The data were analyzed for multiplicity of infection (MOI) and genetic diversity. Overall, P. vivax had higher polyclonality (71%) and mean MOI (2.32) than P. falciparum (20%, 1.39). These measures were significantly associated with prevalence for P. falciparum but not for P. vivax. The genetic diversity of P. vivax (PvMS16: expected heterozygosity = 0.95, 0.85-0.98; PvMsp1F3: 0.78, 0.66-0.89) was higher and less variable than that of P. falciparum (Pfmsp2: 0.89, 0.65-0.97). Significant associations of MOI with allelic richness (rho = 0.69, P = 0.009) and expected heterozygosity (rho = 0.87, P < 0.001) were observed for P. falciparum. Conversely, genetic diversity was not correlated with polyclonality nor mean MOI for P. vivax. The results demonstrate higher complexity of infection and genetic diversity of P. vivax across the country. Although P. falciparum shows a strong association of these parameters with prevalence, a lack of association was observed for P. vivax and is consistent with higher potential for outcrossing of this species.
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Affiliation(s)
- Abebe A Fola
- Department of Medical Biology, University of Melbourne, Parkville, Australia.,Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
| | - G L Abby Harrison
- Department of Medical Biology, University of Melbourne, Parkville, Australia.,Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
| | - Mita Hapsari Hazairin
- Department of Epidemiology and Preventative Medicine, Monash University, Clayton, Australia.,Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
| | - Céline Barnadas
- Statens Serum Institut, Copenhagen, Denmark.,European Public Health Microbiology (EUPHEM) Training Programme, European Centre for Disease Prevention and Control (ECDC), Stockholm, Sweden.,Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
| | - Manuel W Hetzel
- University of Basel, Basel, Switzerland.,Swiss Tropical and Public Health Institute, Basel, Switzerland
| | - Jonah Iga
- Papua New Guinea Institute of Medical Research, Goroka, Papua New Guinea
| | - Peter M Siba
- Papua New Guinea Institute of Medical Research, Goroka, Papua New Guinea
| | - Ivo Mueller
- Institut Pasteur, Paris, France.,Department of Medical Biology, University of Melbourne, Parkville, Australia.,Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
| | - Alyssa E Barry
- Department of Medical Biology, University of Melbourne, Parkville, Australia.,Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
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14
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Howes RE, Battle KE, Mendis KN, Smith DL, Cibulskis RE, Baird JK, Hay SI. Global Epidemiology of Plasmodium vivax. Am J Trop Med Hyg 2016; 95:15-34. [PMID: 27402513 PMCID: PMC5198891 DOI: 10.4269/ajtmh.16-0141] [Citation(s) in RCA: 253] [Impact Index Per Article: 31.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Accepted: 04/19/2016] [Indexed: 01/09/2023] Open
Abstract
Plasmodium vivax is the most widespread human malaria, putting 2.5 billion people at risk of infection. Its unique biological and epidemiological characteristics pose challenges to control strategies that have been principally targeted against Plasmodium falciparum Unlike P. falciparum, P. vivax infections have typically low blood-stage parasitemia with gametocytes emerging before illness manifests, and dormant liver stages causing relapses. These traits affect both its geographic distribution and transmission patterns. Asymptomatic infections, high-risk groups, and resulting case burdens are described in this review. Despite relatively low prevalence measurements and parasitemia levels, along with high proportions of asymptomatic cases, this parasite is not benign. Plasmodium vivax can be associated with severe and even fatal illness. Spreading resistance to chloroquine against the acute attack, and the operational inadequacy of primaquine against the multiple attacks of relapse, exacerbates the risk of poor outcomes among the tens of millions suffering from infection each year. Without strategies accounting for these P. vivax-specific characteristics, progress toward elimination of endemic malaria transmission will be substantially impeded.
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Affiliation(s)
- Rosalind E. Howes
- Spatial Ecology and Epidemiology Group, Department of Zoology, University of Oxford, Oxford, United Kingdom
- Center for Global Health and Diseases, Case Western Reserve University, Cleveland, Ohio
| | - Katherine E. Battle
- Spatial Ecology and Epidemiology Group, Department of Zoology, University of Oxford, Oxford, United Kingdom
| | - Kamini N. Mendis
- Global Malaria Program, World Health Organization, Geneva, Switzerland
| | - David L. Smith
- Fogarty International Center, National Institutes of Health, Bethesda, Maryland
- Sanaria Institute for Global Health and Tropical Medicine, Rockville, Maryland
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, Washington
| | | | - J. Kevin Baird
- Eijkman-Oxford Clinical Research Unit, Jakarta, Indonesia
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Simon I. Hay
- Fogarty International Center, National Institutes of Health, Bethesda, Maryland
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, Washington
- Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, United Kingdom
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15
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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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Siqueira AM, Mesones-Lapouble O, Marchesini P, Sampaio VDS, Brasil P, Tauil PL, Fontes CJ, Costa FTM, Daniel-Ribeiro CT, Lacerda MVG, Damasceno CP, Santelli ACS. Plasmodium vivax Landscape in Brazil: Scenario and Challenges. Am J Trop Med Hyg 2016; 95:87-96. [PMID: 27708190 PMCID: PMC5201227 DOI: 10.4269/ajtmh.16-0204] [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: 03/14/2016] [Accepted: 08/19/2016] [Indexed: 01/01/2023] Open
Abstract
Brazil is the largest country of Latin America, with a considerable portion of its territoritory within the malaria-endemic Amazon region in the North. Furthermore, a considerable portion of its territory is located within the Amazon region in the north. As a result, Brazil has reported half of the total malaria cases in the Americas in the last four decades. Recent progress in malaria control has been accompanied by an increasing proportion of Plasmodium vivax, underscoring a need for a better understanding of management and control of this species and associated challenges. Among these challenges, the contribution of vivax malaria relapses, earlier production of gametocytes (compared with Plasmodium falciparum), inexistent methods to diagnose hypnozoite carriers, and decreasing efficacy of available antimalarials need to be addressed. Innovative tools, strategies, and technologies are needed to achieve further progress toward sustainable malaria elimination. Further difficulties also arise from dealing with the inherent socioeconomic and environmental particularities of the Amazon region and its dynamic changes.
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Affiliation(s)
- Andre M Siqueira
- Programa de Pós-Graduação em Medicina Tropical, Universidade do Estado do Amazonas, Manaus, Brazil.,Instituto Nacional de Infectologia Evandro Chagas, Fundação Oswaldo Cruz (Fiocruz), Rio de Janeiro, Brazil
| | | | - Paola Marchesini
- Coordenação Geral do Programa Nacional de Controle da Malaria, Ministério da Saúde, Brasilia, Brazil
| | - Vanderson de Souza Sampaio
- Fundação de Vigilância em Saúde, Manaus, Brazil.,Programa de Pós-Graduação em Medicina Tropical, Universidade do Estado do Amazonas, Manaus, Brazil
| | - Patricia Brasil
- Instituto Nacional de Infectologia Evandro Chagas, Fundação Oswaldo Cruz (Fiocruz), Rio de Janeiro, Brazil
| | - Pedro L Tauil
- Núcleo de Medicina Tropical, Universidade de Brasília, Brasilia, Brazil
| | | | | | | | - Marcus V G Lacerda
- Instituto Leônidas e Maria Deane, Fundação Oswaldo Cruz (Fiocruz), Manaus, Brazil.,Fundação de Medicina Tropical Dr. Heitor Vieira Dourado, Manaus, Brazil.,Programa de Pós-Graduação em Medicina Tropical, Universidade do Estado do Amazonas, Manaus, Brazil
| | - Camila P Damasceno
- Coordenação Geral do Programa Nacional de Controle da Malaria, Ministério da Saúde, Brasilia, Brazil
| | - Ana Carolina S Santelli
- Coordenação Geral do Programa Nacional de Controle da Malaria, Ministério da Saúde, Brasilia, Brazil
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Sheikh IH, Kaushal DC, Chandra D, Kaushal NA. Immunogenicity of a plasmid DNA vaccine encoding 42kDa fragment of Plasmodium vivax merozoite surface protein-1. Acta Trop 2016; 162:66-74. [PMID: 27311385 DOI: 10.1016/j.actatropica.2016.06.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2016] [Revised: 06/07/2016] [Accepted: 06/10/2016] [Indexed: 11/17/2022]
Abstract
Plasmodium vivax is the second major human malaria parasite that inflicts debilitating morbidity and consequent economic impact in South-East Asian countries. The relapsing nature of P. vivax along with the emergence of drug-resistant P. vivax strains has emphasized the urgent need for a vaccine. However, the development of an effective vivax vaccine is seriously hampered due to the diversity and variation in parasite antigens and non-availability of suitable animal models. DNA based vaccines represent an alternative approach in inducing immunity to multiple targets from different stages of malaria parasite. DNA prime-boosting strategies induce both antibody mediated and cell-mediated immune responses that are the major mechanisms of protection against malaria parasites. We have earlier studied the immunogenicity and protective efficacy of the soluble and refolded forms of recombinant 42kDa fragment of Plasmodium vivax merozoite surface protein-1 (PvMSP-142) using P. cynomolgi rhesus monkey model. In the present study, we have constructed a recombinant DNA vaccine encoding 42kDa fragment of P. vivax MSP-1 and studied the immunogenicity of PvMSP-142 DNA vaccine construct in mice. The 42kDa gene fragment of PvMSP-1 was PCR amplified using gene specific primers and subcloned into pcDNA 3.1 (+) eukaryotic expression vector. In vitro expression of PvMSP-142 plasmid construct was checked by transfection in COS-1 cell line. Indirect immunofluorescence of transfected COS-1 cells probed with monoclonal antibodies against PvMSP-142 exhibited positive fluorescence. Immunization of BALB/c mice with PvMSP-142-pcDNA vaccine construct revealed the immunogenicity of recombinant vaccine plasmid that can be enhanced by prime boosting with recombinant protein corresponding to the DNA vaccine as evidenced by significant elevation of antibody and the cytokines responses.
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Affiliation(s)
- Inayat Hussain Sheikh
- Division of Parasitology, CSIR- Central Drug Research Institute, Lucknow 226031, India; Department of Biochemistry, Lucknow University, Lucknow, India.
| | - Deep C Kaushal
- Amity University Uttar Pradesh, Lucknow Campus, Lucknow 226028, India.
| | - Deepak Chandra
- Department of Biochemistry, Lucknow University, Lucknow, India.
| | - Nuzhat A Kaushal
- Division of Parasitology, CSIR- Central Drug Research Institute, Lucknow 226031, India.
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Venkatesh A, Patel SK, Ray S, Shastri J, Chatterjee G, Kochar SK, Patankar S, Srivastava S. Proteomics ofPlasmodium vivaxmalaria: new insights, progress and potential. Expert Rev Proteomics 2016; 13:771-82. [DOI: 10.1080/14789450.2016.1210515] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Sharma VP, Dev V, Phookan S. Neglected Plasmodium vivax malaria in northeastern States of India. Indian J Med Res 2016; 141:546-55. [PMID: 26139771 PMCID: PMC4510752 DOI: 10.4103/0971-5916.159511] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
BACKGROUND & OBJECTIVES The northeastern States of India are co-endemic for Plasmodium falciparum and P. vivax malaria. The transmission intensity is low-to-moderate resulting in intermediate to stable malaria. Malaria control prioritized P. falciparum being the predominant and life threatening infection (>70%). P. vivax malaria remained somewhat neglected. The present study provides a status report of P. vivax malaria in the northeastern States of India. METHODS Data on spatial distribution of P. vivax from seven northeastern States (Arunachal Pradesh, Assam, Manipur, Meghalaya, Mizoram, Nagaland and Tripura) were analysed retrospectively from 2008-2013. In addition, cross-sectional malarial surveys were conducted during 1991-2012 in malaria endemic pockets across the States of Assam, Meghalaya, Mizoram and Tripura to ascertain the prevalence of P. vivax in different age groups. RESULTS Vivax malaria was encountered in all northeastern States but there existed a clear division of two malaria ecotypes supporting ≤30 and >30 per cent of total malaria cases. High proportions of P. vivax cases (60-80%) were seen in Arunachal Pradesh and Nagaland in the north with alpine environment, 42-67 per cent in Manipur, whereas in Assam it varied from 23-31 per cent with subtropical and tropical climate. Meghalaya, Tripura and Mizoram had the lowest proportion of P. vivax cases. Malaria cases were recorded in all age groups but a higher proportion of P. vivax consistently occurred among <5 yr age group compared to P. falciparum (P<0.05). P. vivax cases were recorded throughout the year with peak coinciding with rainy season although transmission intensity and duration varied. INTERPRETATION & CONCLUSIONS In northeast India, P. vivax is a neglected infection. Estimating the relapsing pattern and transmission dynamics of P. vivax in various ecological settings is an important pre-requisite for planning malaria elimination in the northeastern States.
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Affiliation(s)
| | - Vas Dev
- National Institute of Malaria Research (Field Station) (ICMR), Guwahati, Assam, India
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Noulin F. Malaria modeling: In vitro stem cells vs in vivo models. World J Stem Cells 2016; 8:88-100. [PMID: 27022439 PMCID: PMC4807312 DOI: 10.4252/wjsc.v8.i3.88] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Revised: 12/07/2015] [Accepted: 01/29/2016] [Indexed: 02/06/2023] Open
Abstract
The recent development of stem cell research and the possibility of generating cells that can be stably and permanently modified in their genome open a broad horizon in the world of in vitro modeling. The malaria field is gaining new opportunities from this important breakthrough and novel tools were adapted and opened new frontiers for malaria research. In addition to the new in vitro systems, in recent years there were also significant advances in the development of new animal models that allows studying the entire cell cycle of human malaria. In this paper, we review the different protocols available to study human Plasmodium species either by using stem cell or alternative animal models.
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Challenges in Antimalarial Drug Treatment for Vivax Malaria Control. Trends Mol Med 2015; 21:776-788. [DOI: 10.1016/j.molmed.2015.10.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2015] [Revised: 10/19/2015] [Accepted: 10/20/2015] [Indexed: 01/01/2023]
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Prevention of Malaria Resurgence in Greece through the Association of Mass Drug Administration (MDA) to Immigrants from Malaria-Endemic Regions and Standard Control Measures. PLoS Negl Trop Dis 2015; 9:e0004215. [PMID: 26583650 PMCID: PMC4652894 DOI: 10.1371/journal.pntd.0004215] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Accepted: 10/14/2015] [Indexed: 01/27/2023] Open
Abstract
Greece was declared malaria-free in 1974 after a long antimalarial fight. In 2011–2012, an outbreak of P. vivax malaria was reported in Evrotas, an agricultural area in Southern Greece, where a large number of immigrants from endemic countries live and work. A total of 46 locally acquired and 38 imported malaria cases were detected. Despite a significant decrease of the number of malaria cases in 2012, a mass drug administration (MDA) program was considered as an additional measure to prevent reestablishment of the disease in the area. During 2013 and 2014, a combination of 3-day chloroquine and 14-day primaquine treatment was administered under direct observation to immigrants living in the epicenter of the 2011 outbreak in Evrotas. Adverse events were managed and recorded on a daily basis. The control measures implemented since 2011 continued during the period of 2013–2014 as a part of a national integrated malaria control program that included active case detection (ACD), vector control measures and community education. The MDA program was started prior to the transmission periods (from May to December). One thousand ninety four (1094) immigrants successfully completed the treatment, corresponding to 87.3% coverage of the target population. A total of 688 adverse events were recorded in 397 (36.2%, 95% C.I.: 33.4–39.1) persons, the vast majority minor, predominantly dizziness and headache for chloroquine (284 events) and abdominal pain (85 events) for primaquine. A single case of primaquine-induced hemolysis was recorded in a person whose initial G6PD test proved incorrect. No malaria cases were recorded in Evrotas, Laconia, in 2013 and 2014, though three locally acquired malaria cases were recorded in other regions of Greece in 2013. Preventive antimalarial MDA to a high-risk population in a low transmission setting appears to have synergized with the usual antimalarial activities to achieve malaria elimination. This study suggests that judicious use of MDA can be a useful addition to the antimalarial armamentarium in areas threatened with the reintroduction of the disease. Greece was declared malaria-free in the year 1974 after a long antimalarial fight. In 2011–2012, a number of malaria cases reported in Evrotas, Laconia, in Southern Greece, where a large number of immigrants from malaria-endemic countries live and work. A total of 84 malaria cases, both in immigrants (38 cases) and in Greeks (46 cases), were detected. A number of malaria control measures were deployed in the area since 2011. Despite a decrease of the number of malaria cases in 2012, elimination could not be achieved, and thus antimalarial MDA was considered as an additional measure to prevent the reestablishment of the disease. During 2013 and 2014, a combination of two drugs was administered under direct observation to all immigrants in the epicenter of the 2011 Evrotas outbreak. The antimalarial MDA program was started on July-August and was successfully completed by 1094 immigrants (87.3% coverage). No serious adverse events were recorded except one case of primaquine-induced hemolysis due to false G6PD test result. In 2013 and 2014, no malaria cases were recorded in Evrotas, Laconia. This study suggests that careful use of supervised antimalarial MDA is a useful addition to the antimalarial control measures in areas threatened with the reintroduction of the disease.
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Kobayashi T, Gamboa D, Ndiaye D, Cui L, Sutton PL, Vinetz JM. Malaria Diagnosis Across the International Centers of Excellence for Malaria Research: Platforms, Performance, and Standardization. Am J Trop Med Hyg 2015; 93:99-109. [PMID: 26259937 PMCID: PMC4574279 DOI: 10.4269/ajtmh.15-0004] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2015] [Accepted: 06/23/2015] [Indexed: 12/14/2022] Open
Abstract
Diagnosis is “the act of identifying a disease, illness, or problem by examining someone or something.” When an individual with acute fever presents for clinical attention, accurate diagnosis leading to specific, prompt treatment often saves lives. As applied to malaria, not only individual patient diagnosis is important but also assessing population-level malaria prevalence using appropriate diagnostic methods is essential for public health purposes. Similarly, identifying (diagnosing) fake antimalarial medications prevents the use of counterfeit drugs that can have disastrous effects. Therefore, accurate diagnosis in broad areas related to malaria is fundamental to improving health-care delivery, informing funding agencies of current malaria situations, and aiding in the prioritization of regional and national control efforts. The International Centers of Excellence for Malaria Research (ICEMR), supported by the U.S. National Institute of Allergy and Infectious Diseases, has collaborated on global efforts to improve malaria diagnostics by working to harmonize and systematize procedures across different regions where endemicity and financial resources vary. In this article, the different diagnostic methods used across each ICEMR are reviewed and challenges are discussed.
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Affiliation(s)
- Tamaki Kobayashi
- *Address correspondence to Tamaki Kobayashi, Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe Street, W4612, Baltimore, MD 21205, E-mail: or Joseph M. Vinetz, Division of Infectious Diseases, Department of Medicine, University of California San Diego School of Medicine, 9500 Gilman Drive, La Jolla, CA 92093-0760, E-mail:
| | | | | | | | | | - Joseph M. Vinetz
- *Address correspondence to Tamaki Kobayashi, Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe Street, W4612, Baltimore, MD 21205, E-mail: or Joseph M. Vinetz, Division of Infectious Diseases, Department of Medicine, University of California San Diego School of Medicine, 9500 Gilman Drive, La Jolla, CA 92093-0760, E-mail:
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Newby G, Hwang J, Koita K, Chen I, Greenwood B, von Seidlein L, Shanks GD, Slutsker L, Kachur SP, Wegbreit J, Ippolito MM, Poirot E, Gosling R. Review of mass drug administration for malaria and its operational challenges. Am J Trop Med Hyg 2015; 93:125-134. [PMID: 26013371 PMCID: PMC4497884 DOI: 10.4269/ajtmh.14-0254] [Citation(s) in RCA: 152] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Accepted: 02/23/2015] [Indexed: 11/11/2022] Open
Abstract
Mass drug administration (MDA) was a component of many malaria programs during the eradication era, but later was seldomly deployed due to concerns regarding efficacy and feasibility and fear of accelerating drug resistance. Recently, however, there has been renewed interest in the role of MDA as an elimination tool. Following a 2013 Cochrane Review that focused on the quantitative effects of malaria MDA, we have conducted a systematic, qualitative review of published, unpublished, and gray literature documenting past MDA experiences. We have also consulted with field experts, using their historical experience to provide an informed, contextual perspective on the role of MDA in malaria elimination. Substantial knowledge gaps remain and more research is necessary, particularly on optimal target population size, methods to improve coverage, and primaquine safety. Despite these gaps, MDA has been used successfully to control and eliminate Plasmodium falciparum and P. vivax malaria in the past, and should be considered as part of a comprehensive malaria elimination strategy in specific settings.
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Affiliation(s)
| | - Jimee Hwang
- *Address correspondence to Jimee Hwang, The Malaria Elimination Initiative, Global Health Group, University of California, 550 16th Street, 3rd Floor, San Francisco, CA 94158. E-mail:
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High Rates of Asymptomatic, Sub-microscopic Plasmodium vivax Infection and Disappearing Plasmodium falciparum Malaria in an Area of Low Transmission in Solomon Islands. PLoS Negl Trop Dis 2015; 9:e0003758. [PMID: 25996619 PMCID: PMC4440702 DOI: 10.1371/journal.pntd.0003758] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Accepted: 04/13/2015] [Indexed: 12/26/2022] Open
Abstract
Introduction Solomon Islands is intensifying national efforts to achieve malaria elimination. A long history of indoor spraying with residual insecticides, combined recently with distribution of long lasting insecticidal nets and artemether-lumefantrine therapy, has been implemented in Solomon Islands. The impact of these interventions on local endemicity of Plasmodium spp. is unknown. Methods In 2012, a cross-sectional survey of 3501 residents of all ages was conducted in Ngella, Central Islands Province, Solomon Islands. Prevalence of Plasmodium falciparum, P. vivax, P. ovale and P. malariae was assessed by quantitative PCR (qPCR) and light microscopy (LM). Presence of gametocytes was determined by reverse transcription quantitative PCR (RT-qPCR). Results By qPCR, 468 Plasmodium spp. infections were detected (prevalence = 13.4%; 463 P. vivax, five mixed P. falciparum/P. vivax, no P. ovale or P. malariae) versus 130 by LM (prevalence = 3.7%; 126 P. vivax, three P. falciparum and one P. falciparum/P. vivax). The prevalence of P. vivax infection varied significantly among villages (range 3.0–38.5%, p<0.001) and across age groups (5.3–25.9%, p<0.001). Of 468 P. vivax infections, 72.9% were sub-microscopic, 84.5% afebrile and 60.0% were both sub-microscopic and afebrile. Local residency, low education level of the household head and living in a household with at least one other P. vivax infected individual increased the risk of P. vivax infection. Overall, 23.5% of P. vivax infections had concurrent gametocytaemia. Of all P. vivax positive samples, 29.2% were polyclonal by MS16 and msp1F3 genotyping. All five P. falciparum infections were detected in residents of the same village, carried the same msp2 allele and four were positive for P. falciparum gametocytes. Conclusion P. vivax infection remains endemic in Ngella, with the majority of cases afebrile and below the detection limit of LM. P. falciparum has nearly disappeared, but the risk of re-introductions and outbreaks due to travel to nearby islands with higher malaria endemicity remains. Solomon Islands, an island nation in the Southwest Pacific that has seen dramatic reductions in malaria transmission over the past 20 years, is aiming for malaria elimination. There is an increasing recognition that a substantial reservoir of asymptomatic and often sub-microscopic Plasmodium spp. infections exists even in low transmission settings. However, the potential role for these infections in sustaining transmission and the difference in response of the two most common malaria parasites, P. vivax and P. falciparum, to intensified control remains unclear. In May-June 2012, we therefore performed a cross-sectional survey of 3501 residents of all ages of Ngella, a low transmission area in Central Islands Province, to assess the prevalence of P. vivax and P. falciparum infection, determine the proportion of sub-microscopic and afebrile infections and evaluate whether gametocytaemic, and thus potentially infectious, individuals are present. Our survey showed a marked epidemiological contrast between P. vivax and P. falciparum. Although prevalence varied significantly among different regions of Ngella, P. vivax remains firmly endemic, with high rates of sub-microscopic, afebrile and genetically diverse infections. The presence of gametocytes among both sub-microscopic and microscopy positive, asymptomatic infections indicates that these infections contribute significantly to sustaining P. vivax transmission. P. falciparum, on the other hand, appears to be more amenable to control interventions. Only five P. falciparum infected individuals were detected, and all were residents of the same village. These infections carried the same msp2 clone. This difference highlights the larger challenge of eliminating P. vivax compared to P. falciparum in areas where they are co-endemic. In particular, the challenge posed by the presence of a large reservoir of silent P. vivax infections will need to be addressed if control of this parasite is to be accelerated and elimination achieved.
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Joshi VM, Devarajan PV. Receptor-mediated hepatocyte-targeted delivery of primaquine phosphate nanocarboplex using a carbohydrate ligand. Drug Deliv Transl Res 2015; 4:353-64. [PMID: 25787067 DOI: 10.1007/s13346-014-0200-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Primaquine phosphate is a drug of choice for the treatment of malarial relapse. However, poor drug concentration in the hepatocytes and dose-related toxicity pose severe limitations. We report a nanocarboplex of primaquine phosphate by a simple in situ process using dextran sulphate as a carbohydrate polymer and pullulan as an asialoglycoprotein receptor ligand. Our aim was to preferentially enhance accumulation of the nanocarboplex in the hepatocytes. The in situ pullulan-anchored primaquine nanocarboplex was prepared by simple addition of a solution of dextran sulphate and pullulan with stabilizer to a measured quantity of primaquine phosphate in a vial, followed by shaking to obtain the primaquine phosphate nanocarboplex ready for injection. The nanocarboplex was characterized and evaluated in vivo for pharmacokinetics and biodistribution in the rat model. Specific uptake by hepatocytes in the liver was also quantified. Increase in t ½ with significant uptake in the RES organ was observed. More importantly, anchoring pullulan favored high liver uptake and preferential accumulation in the hepatocytes with a hepatocytes/nonparenchymal cells ratio of 75:25. The in situ primaquine phosphate nanocarboplex anchored with pullulan provides both a significant technological advantage and the desired targeting to the hepatocytes.
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Affiliation(s)
- Vishvesh M Joshi
- Department of Pharmaceutical Sciences and Technology, Institute of Chemical Technology, N. P. Marg, Matunga (E), Mumbai, 400019, India
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Plasmodium vivax populations are more genetically diverse and less structured than sympatric Plasmodium falciparum populations. PLoS Negl Trop Dis 2015; 9:e0003634. [PMID: 25874894 PMCID: PMC4398418 DOI: 10.1371/journal.pntd.0003634] [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: 11/18/2014] [Accepted: 02/20/2015] [Indexed: 11/20/2022] Open
Abstract
Introduction The human malaria parasite, Plasmodium vivax, is proving more difficult to control and eliminate than Plasmodium falciparum in areas of co-transmission. Comparisons of the genetic structure of sympatric parasite populations may provide insight into the mechanisms underlying the resilience of P. vivax and can help guide malaria control programs. Methodology/Principle findings P. vivax isolates representing the parasite populations of four areas on the north coast of Papua New Guinea (PNG) were genotyped using microsatellite markers and compared with previously published microsatellite data from sympatric P. falciparum isolates. The genetic diversity of P. vivax (He = 0.83–0.85) was higher than that of P. falciparum (He = 0.64–0.77) in all four populations. Moderate levels of genetic differentiation were found between P. falciparum populations, even over relatively short distances (less than 50 km), with 21–28% private alleles and clear geospatial genetic clustering. Conversely, very low population differentiation was found between P. vivax catchments, with less than 5% private alleles and no genetic clustering observed. In addition, the effective population size of P. vivax (30353; 13043–69142) was larger than that of P. falciparum (18871; 8109–42986). Conclusions/Significance Despite comparably high prevalence, P. vivax had higher diversity and a panmictic population structure compared to sympatric P. falciparum populations, which were fragmented into subpopulations. The results suggest that in comparison to P. falciparum, P. vivax has had a long-term large effective population size, consistent with more intense and stable transmission, and limited impact of past control and elimination efforts. This underlines suggestions that more intensive and sustained interventions will be needed to control and eventually eliminate P. vivax. This research clearly demonstrates how population genetic analyses can reveal deeper insight into transmission patterns than traditional surveillance methods. The neglected human malaria parasite Plasmodium vivax is responsible for a large proportion of the global malaria burden. Efforts to control malaria have revealed that P. vivax is more resilient than the other major human malaria parasite, Plasmodium falciparum. This study utilised population genetics to compare patterns of P. vivax and P. falciparum transmission in Papua New Guinea, a region where infection rates of the two species are similar. The results demonstrated that P. vivax populations are more genetically diverse than those of P. falciparum suggestive of a parasite population that is more resilient to environmental challenges, undergoing higher levels of interbreeding locally and between distant parasite populations. Unique characteristics of P. vivax such as relapse, which allows different strains from past infections to produce subsequent infections, may provide more opportunities for the exchange and dissemination of genetic material. The contrasting patterns observed for the two species may be the result of a differential impact of past elimination attempts and indicate that more rigorous interventions will be needed in efforts to control and eventually eliminate P. vivax.
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Epidemiology of disappearing Plasmodium vivax malaria: a case study in rural Amazonia. PLoS Negl Trop Dis 2014; 8:e3109. [PMID: 25166263 PMCID: PMC4148206 DOI: 10.1371/journal.pntd.0003109] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Accepted: 07/11/2014] [Indexed: 11/19/2022] Open
Abstract
Background New frontier settlements across the Amazon Basin pose a major challenge for malaria elimination in Brazil. Here we describe the epidemiology of malaria during the early phases of occupation of farming settlements in Remansinho area, Brazilian Amazonia. We examine the relative contribution of low-density and asymptomatic parasitemias to the overall Plasmodium vivax burden over a period of declining transmission and discuss potential hurdles for malaria elimination in Remansinho and similar settings. Methods Eight community-wide cross-sectional surveys, involving 584 subjects, were carried out in Remansinho over 3 years and complemented by active and passive surveillance of febrile illnesses between the surveys. We used quantitative PCR to detect low-density asexual parasitemias and gametocytemias missed by conventional microscopy. Mixed-effects multiple logistic regression models were used to characterize independent risk factors for P. vivax infection and disease. Principal Findings/Conclusions P. vivax prevalence decreased from 23.8% (March–April 2010) to 3.0% (April–May 2013), with no P. falciparum infections diagnosed after March–April 2011. Although migrants from malaria-free areas were at increased risk of malaria, their odds of having P. vivax infection and disease decreased by 2–3% with each year of residence in Amazonia. Several findings indicate that low-density and asymptomatic P. vivax parasitemias may complicate residual malaria elimination in Remansinho: (a) the proportion of subpatent infections (i.e. missed by microscopy) increased from 43.8% to 73.1% as P. vivax transmission declined; (b) most (56.6%) P. vivax infections were asymptomatic and 32.8% of them were both subpatent and asymptomatic; (c) asymptomatic parasite carriers accounted for 54.4% of the total P. vivax biomass in the host population; (d) over 90% subpatent and asymptomatic P. vivax had PCR-detectable gametocytemias; and (e) few (17.0%) asymptomatic and subpatent P. vivax infections that were left untreated progressed to clinical disease over 6 weeks of follow-up and became detectable by routine malaria surveillance. Despite decades of control efforts, malaria remains a major public health concern in Brazil. A large proportion of the 243,000 cases diagnosed per year originate from areas of recent colonization in the densely forested Amazon Basin. This population-based longitudinal study addresses the epidemiology of malaria during the early stages of colonization of frontier settlements in Remansinho area, rural Amazonia. We documented a major decline in the prevalence of P. vivax infection, from 23.8% to 3.0%, between March–April 2010 and April–May 2013. Up to 73.1% of the P. vivax infections were missed by microscopy as malaria transmission declined and most (56.6%) of these infections caused no clinical signs or symptoms. Few (17.0%) asymptomatic P. vivax infections that were left untreated eventually progressed to clinical disease, becoming detectable by routine malaria surveillance, over 6 weeks of follow-up. Moreover, nearly all P. vivax infections that were undetected by microscopy had gametocytes, the parasite's blood stages responsible for malaria transmission to mosquito vectors, detected by molecular methods. These findings indicate that apparently healthy carriers of low-density parasitemias, who are often missed by conventional microscopy, contribute significantly to ongoing P. vivax transmission and may further complicate residual malaria elimination in Remansinho and similar endemic settings.
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Shanks GD. Standby therapy to prevent Plasmodium falciparum infections? J Travel Med 2014; 21:70-1. [PMID: 24251587 DOI: 10.1111/jtm.12079] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Revised: 08/15/2013] [Accepted: 08/16/2013] [Indexed: 11/27/2022]
Affiliation(s)
- G Dennis Shanks
- Australian Army Malaria Institute, Enoggera, Australia; Centre for Military and Veterans' Health, School of Population Health, University of Queensland, Brisbane, Australia; Queensland Institute of Medical Research, Brisbane, Australia
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Valizadeh V, Zakeri S, Mehrizi AA, Djadid ND. Population genetics and natural selection in the gene encoding the Duffy binding protein II in Iranian Plasmodium vivax wild isolates. INFECTION GENETICS AND EVOLUTION 2013; 21:424-35. [PMID: 24384095 DOI: 10.1016/j.meegid.2013.12.012] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Revised: 12/20/2013] [Accepted: 12/21/2013] [Indexed: 10/25/2022]
Abstract
Region II of Duffy binding protein (PvDBP-II) is one of the most promising blood-stage vaccine candidate antigens against Plasmodium vivax and having knowledge of the nature and genetic polymorphism of PvDBP-II among global P. vivax isolates is important for developing a DBP-based vaccine. By using PCR and sequencing, the present molecular population genetic approach was carried out to investigate sequence diversity and natural selection of dbp-II gene in 63 P. vivax isolates collected from unstable and low transmission malaria-endemic areas of Iran during 2008-2012. Also, phylogenetic analysis, the diversifying natural selection, and recombination across the pvdbp-II gene, including regions containing B-cell epitopes were analyzed using the DnaSP and MEGA4 programs. Twenty two single nucleotide polymorphisms (SNPs, including 20 non-synonymous and 2 synonymous) were identified in PvDBP-II, resulting in 16 different PvDBP-II haplotypes among the Iranian P. vivax isolates. High binding inhibitory B-cell epitope (H3) overlapping with intrinsically unstructured/disordered region (aa: 384-392) appeared to be highly polymorphic (D384G/E385K/ K386N/Q/R390H), and positive selective pressure acted on this region. Most of the polymorphic amino acids, which are located on the surface of the protein, are under selective pressure that implies increased recombination events and exposure to the human immune system. In summary, PvDBP-II gene displays genetic polymorphism among Iranian P. vivax isolates and it is under selective pressure. Mutations, recombination, and positive selection seem to play a role in the resulting genetic diversity, and phylogenetic analysis of DNA sequences demonstrates that Iranian isolates represent a sample of the global population. These results are useful for understanding the nature of the P. vivax population in Iran and also for development of PvDBP-II-based malaria vaccine.
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Affiliation(s)
- Vahideh Valizadeh
- Malaria and Vector Research Group (MVRG), Biotechnology Research Center (BRC), Pasteur Institute of Iran, Pasteur Avenue, P.O. Box 1316943551, Tehran, Iran
| | - Sedigheh Zakeri
- Malaria and Vector Research Group (MVRG), Biotechnology Research Center (BRC), Pasteur Institute of Iran, Pasteur Avenue, P.O. Box 1316943551, Tehran, Iran.
| | - Akram Abouie Mehrizi
- Malaria and Vector Research Group (MVRG), Biotechnology Research Center (BRC), Pasteur Institute of Iran, Pasteur Avenue, P.O. Box 1316943551, Tehran, Iran
| | - Navid Dinparast Djadid
- Malaria and Vector Research Group (MVRG), Biotechnology Research Center (BRC), Pasteur Institute of Iran, Pasteur Avenue, P.O. Box 1316943551, Tehran, Iran
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Abstract
BACKGROUND Mass drug administration (MDA), defined as the empiric administration of a therapeutic antimalarial regimen to an entire population at the same time, has been a historic component of many malaria control and elimination programmes, but is not currently recommended. With renewed interest in MDA and its role in malaria elimination, this review aims to summarize the findings from existing research studies and program experiences of MDA strategies for reducing malaria burden and transmission. OBJECTIVES To assess the impact of antimalarial MDA on population asexual parasitaemia prevalence, parasitaemia incidence, gametocytaemia prevalence, anaemia prevalence, mortality and MDA-associated adverse events. SEARCH METHODS We searched the Cochrane Infectious Disease Group Specialized Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE+, EMBASE, to February 2013. We also searched CABS Abstracts, LILACS, reference lists, and recent conference proceedings. SELECTION CRITERIA Cluster-randomized trials and non-randomized controlled studies comparing therapeutic MDA versus placebo or no MDA, and uncontrolled before-and-after studies comparing post-MDA to baseline data were selected. Studies administering intermittent preventive treatment (IPT) to sub-populations (for example, pregnant women, children or infants) were excluded. DATA COLLECTION AND ANALYSIS Two authors independently reviewed studies for inclusion, extracted data and assessed risk of bias. Studies were stratified by study design and then subgrouped by endemicity, by co-administration of 8-aminoquinoline plus schizonticide drugs and by plasmodium species. The quality of evidence was assessed using the GRADE approach. MAIN RESULTS Two cluster-randomized trials, eight non-randomized controlled studies and 22 uncontrolled before-and-after studies are included in this review. Twenty-two studies (29 comparisons) compared MDA to placebo or no intervention of which two comparisons were conducted in areas of low endemicity (≤5%), 12 in areas of moderate endemicity (6-39%) and 15 in areas of high endemicity (≥ 40%). Ten studies evaluated MDA plus other vector control measures. The studies used a wide variety of MDA regimens incorporating different drugs, dosages, timings and numbers of MDA rounds. Many of the studies are now more than 30 years old. Areas of low endemicity (≤5%)Within the first month post-MDA, a single uncontrolled before-and-after study conducted in 1955 on a small Taiwanese island reported a much lower prevalence of parasitaemia following a single course of chloroquine compared to baseline (1 study, very low quality evidence). This lower parasite prevalence was still present after more than 12 months (one study, very low quality evidence). In addition, one cluster-randomized trial evaluating MDA in a low endemic setting reported zero episodes of parasitaemia at baseline, and throughout five months of follow-up in both the control and intervention arms (one study, very low quality evidence). Areas of moderate endemicity (6-39%)Within the first month post-MDA, the prevalence of parasitaemia was much lower in three non-randomized controlled studies from Kenya and India in the 1950s (RR 0.03, 95% CI 0.01 to 0.08, three studies, moderate quality evidence), and in three uncontrolled before-and-after studies conducted between 1954 and 1961 (RR 0.29, 95% CI 0.17 to 0.48, three studies,low quality evidence).The longest follow-up in these settings was four to six months. At this time point, the prevalence of parasitaemia remained substantially lower than controls in the two non-randomized controlled studies (RR 0.18, 95% CI 0.10 to 0.33, two studies, low quality evidence). In contrast, the two uncontrolled before-and-after studies found mixed results: one found no difference and one found a substantially higher prevalence compared to baseline (not pooled, two studies, very low quality evidence). Areas of high endemicity (≥40%)Within the first month post-MDA, the single cluster-randomized trial from the Gambia in 1999 found no significant difference in parasite prevalence (one study, low quality evidence). However, prevalence was much lower during the MDA programmes in three non-randomized controlled studies conducted in the 1960s and 1970s (RR 0.17, 95% CI 0.11 to 0.27, three studies, moderate quality evidence), and within one month of MDA in four uncontrolled before-and-after studies (RR 0.37, 95% CI 0.28 to 0.49, four studies,low quality evidence).Four trials reported changes in prevalence beyond three months. In the Gambia, the single cluster-randomized trial found no difference at five months (one trial, moderate quality evidence). The three uncontrolled before-and-after studies had mixed findings with large studies from Palestine and Cambodia showing sustained reductions at four months and 12 months, respectively, and a small study from Malaysia showing no difference after four to six months of follow-up (three studies,low quality evidence). 8-aminoquinolines We found no studies directly comparing MDA regimens that included 8-aminoquinolines with regimens that did not. In a crude subgroup analysis with a limited number of studies, we were unable to detect any evidence of additional benefit of primaquine in moderate- and high-transmission settings. Plasmodium species In studies that reported species-specific outcomes, the same interventions resulted in a larger impact on Plasmodium falciparum compared to P. vivax. AUTHORS' CONCLUSIONS MDA appears to reduce substantially the initial risk of malaria parasitaemia. However, few studies showed sustained impact beyond six months post-MDA, and those that did were conducted on small islands or in highland settings.To assess whether there is an impact of MDA on malaria transmission in the longer term requires more quasi experimental studies with the intention of elimination, especially in low- and moderate-transmission settings. These studies need to address any long-term outcomes, any potential barriers for community uptake, and contribution to the development of drug resistance.
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Affiliation(s)
- Eugenie Poirot
- Centers for Disease Control and PreventionMalaria Branch4770 Buford Highway, NEMailstop F‐22AtlantaGAUSA30341
- University of California San FranciscoGlobal Health GroupSan FranciscoUSA
| | - Jacek Skarbinski
- Centers for Disease Control and PreventionMalaria Branch4770 Buford Highway, NEMailstop F‐22AtlantaGAUSA30341
| | - David Sinclair
- Liverpool School of Tropical MedicineDepartment of Clinical SciencesPembroke PlaceLiverpoolUKL3 5QA
| | - S Patrick Kachur
- Centers for Disease Control and PreventionMalaria Branch4770 Buford Highway, NEMailstop F‐22AtlantaGAUSA30341
| | - Laurence Slutsker
- Centers for Disease Control and PreventionMalaria Branch4770 Buford Highway, NEMailstop F‐22AtlantaGAUSA30341
| | - Jimee Hwang
- Centers for Disease Control and PreventionMalaria Branch4770 Buford Highway, NEMailstop F‐22AtlantaGAUSA30341
- University of California San FranciscoGlobal Health GroupSan FranciscoUSA
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Hsiang MS, Hwang J, Tao AR, Liu Y, Bennett A, Shanks GD, Cao J, Kachur SP, Feachem RGA, Gosling RD, Gao Q. Mass drug administration for the control and elimination of Plasmodium vivax malaria: an ecological study from Jiangsu province, China. Malar J 2013; 12:383. [PMID: 24175930 PMCID: PMC3842644 DOI: 10.1186/1475-2875-12-383] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Accepted: 10/24/2013] [Indexed: 12/05/2022] Open
Abstract
Background Recent progress in malaria control has caused renewed interest in mass drug administration (MDA) as a potential elimination strategy but the evidence base is limited. China has extensive experience with MDA, but it is not well documented. Methods An ecological study was conducted to describe the use of MDA for the control and elimination of Plasmodium vivax in Jiangsu Province and explore the association between MDA and malaria incidence. Two periods were focused on: 1973 to 1983 when malaria burden was high and MDA administered to highly endemic counties province-wide, and 2000 to 2009, when malaria burden was low and a focal approach was used in two counties. All available data about the strategies implemented, MDA coverage, co-interventions, incidence, and adverse events were collected and described. Joinpoint analysis was used to describe trends in incidence and the relationship between MDA coverage and incidence was explored in negative binomial regression models. Results From 1973 to 1983, MDA with pyrimethamine and primaquine was used on a large scale, with up to 30 million people in target counties covered in a peak year (50% of the total population). Joinpoint analyses identified declines in annual incidence, -56.7% (95% CI -75.5 to -23.7%) from 1973–1976 and -12.4% (95% CI -24.7 to 2.0%) from 1976–1983. Population average negative binomial models identified a relationship between higher total population MDA coverage and lower monthly incidence from 1973–1976, IRR 0.98 (95% CI 0.97 to 1.00), while co-interventions, rainfall and GDP were not associated. From 2000–2009, incidence in two counties declined (annual change -43.7 to -14.0%) during a time when focal MDA using chloroquine and primaquine was targeted to villages and/or individuals residing near passively detected index cases (median 0.04% of total population). Although safety data were not collected systematically, there were rare reports of serious but non-fatal events. Conclusions In Jiangsu Province, China, large-scale MDA was implemented and associated with declines in high P. vivax malaria transmission; a more recent focal approach may have contributed to interruption of transmission. MDA should be considered a potential key strategy for malaria control and elimination.
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Affiliation(s)
- Michelle S Hsiang
- Global Health Group, University of California San Francisco (UCSF), San Francisco, USA.
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Development of a capillary electrophoresis-based heteroduplex tracking assay to measure in-host genetic diversity of initial and recurrent Plasmodium vivax infections in Cambodia. J Clin Microbiol 2013; 52:298-301. [PMID: 24131693 DOI: 10.1128/jcm.02274-13] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A heteroduplex tracking assay used to genotype Plasmodium vivax merozoite surface protein 1 was adapted to a capillary electrophoresis format, obviating the need for radiolabeled probes and allowing its use in settings where malaria is endemic. This new assay achieved good allelic discrimination and detected high multiplicities of infection in 63 P. vivax infections in Cambodia. More than half of the recurrent parasitemias sampled displayed identical or highly related genotypes compared to the initial genotype, suggesting that they represented relapses.
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Sturrock HJW, Hsiang MS, Cohen JM, Smith DL, Greenhouse B, Bousema T, Gosling RD. Targeting asymptomatic malaria infections: active surveillance in control and elimination. PLoS Med 2013; 10:e1001467. [PMID: 23853551 PMCID: PMC3708701 DOI: 10.1371/journal.pmed.1001467] [Citation(s) in RCA: 246] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Hugh Sturrock and colleagues discuss the role of active case detection in low malaria transmission settings. They argue that the evidence for its effectiveness is sparse and that targeted mass drug administration should be evaluated as an alternative or addition to active case detection. Please see later in the article for the Editors' Summary
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Affiliation(s)
- Hugh J W Sturrock
- Malaria Elimination Initiative, Global Health Group, University of California, San Francisco, USA.
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