scholarly journals Antibodies to a Single, Conserved Epitope in Anopheles APN1 Inhibit Universal Transmission of Plasmodium falciparum and Plasmodium vivax Malaria

2013 ◽  
Vol 82 (2) ◽  
pp. 818-829 ◽  
Author(s):  
Jennifer S. Armistead ◽  
Isabelle Morlais ◽  
Derrick K. Mathias ◽  
Juliette G. Jardim ◽  
Jaimy Joy ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Plasmodium Vivax ◽  
Content Type ◽  
Block Transmission ◽  
Antibody Recognition ◽  
Protective Epitope ◽  
Product Profile ◽  
Plasmodium Vivax Malaria ◽  
Transmission Blocking Vaccines ◽  
Conserved Epitope

ABSTRACTMalaria transmission-blocking vaccines (TBVs) represent a promising approach for the elimination and eradication of this disease. AnAPN1 is a lead TBV candidate that targets a surface antigen on the midgut of the obligate vector of thePlasmodiumparasite, theAnophelesmosquito. In this study, we demonstrated that antibodies targeting AnAPN1 block transmission ofPlasmodium falciparumandPlasmodium vivaxacross distantly related anopheline species in countries to which malaria is endemic. Using a biochemical and immunological approach, we determined that the mechanism of action for this phenomenon stems from antibody recognition of a single protective epitope on AnAPN1, which we found to be immunogenic in murine and nonhuman primate models and highly conserved among anophelines. These data indicate that AnAPN1 meets the established target product profile for TBVs and suggest a potential key role for an AnAPN1-based panmalaria TBV in the effort to eradicate malaria.

scholarly journals Chloroquine Remains Effective for Treating Plasmodium vivax Malaria in Pursat Province, Western Cambodia

2014 ◽  
Vol 58 (10) ◽  
pp. 6270-6272 ◽  
Author(s):  
Chanaki Amaratunga ◽  
Sokunthea Sreng ◽  
Sivanna Mao ◽  
Gregory S. Tullo ◽  
Jennifer M. Anderson ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Plasmodium Vivax ◽  
Vivax Malaria ◽  
Combination Therapies ◽  
Content Type ◽  
Plasmodium Vivax Malaria

ABSTRACTChloroquine (CQ) is used to treatPlasmodium vivaxmalaria in areas where CQ resistance has not been reported. The use of artemisinin (ART)-based combination therapies (ACTs) to treat CQ-sensitiveP. vivaxinfections is effective and convenient but may promote the emergence and worsening of ART resistance in sympatricPlasmodium falciparumpopulations. Here, we show that CQ effectively treatsP. vivaxmalaria in Pursat Province, western Cambodia, where ART-resistantP. falciparumis highly prevalent and spreading. (This study has been registered at ClinicalTrials.gov under registration no. NCT00663546.)

scholarly journals Reduced Polymorphism in the Kelch Propeller Domain in Plasmodium vivax Isolates from Cambodia

2014 ◽  
Vol 59 (1) ◽  
pp. 730-733 ◽  
Author(s):  
Jean Popovici ◽  
Sokheng Kao ◽  
Leanghor Eal ◽  
Sophalai Bin ◽  
Saorin Kim ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Plasmodium Vivax ◽  
Preliminary Data ◽  
Mutant Allele ◽  
Chloroquine Resistance ◽  
Wild Type ◽  
Nonsynonymous Mutation ◽  
Content Type

ABSTRACTPolymorphism in the ortholog gene of thePlasmodium falciparumK13 gene was investigated inPlasmodium vivaxisolates collected in Cambodia. All of them were Sal-1 wild-type alleles except two (2/284, 0.7%), andP. vivaxK12 polymorphism was reduced compared to that of theP. falciparumK13 gene. Both mutant allele isolates had the same nonsynonymous mutation at codon 552 (V552I) and were from Ratanak Kiri province. These preliminary data should encourage additional studies for associating artemisinin or chloroquine resistance and K12 polymorphism.

scholarly journals Pharmacokinetics of Amodiaquine and Desethylamodiaquine in Pregnant and Postpartum Women with Plasmodium vivax Malaria

2011 ◽  
Vol 55 (9) ◽  
pp. 4338-4342 ◽  
Author(s):  
Marcus J. Rijken ◽  
Rose McGready ◽  
Vincent Jullien ◽  
Joel Tarning ◽  
Niklas Lindegardh ◽  
...  
Keyword(s):  
Plasmodium Vivax ◽  
Dosing Regimen ◽  
Noncompartmental Analysis ◽  
Time Data ◽  
Content Type ◽  
Concentration Time ◽  
Chromatography Tandem Mass Spectrometry ◽  
Pharmacokinetic Properties ◽  
Plasmodium Vivax Malaria ◽  
Liquid Chromatography Tandem Mass

ABSTRACTIn order to study the pharmacokinetic properties of amodiaquine and desethylamodiaquine during pregnancy, 24 pregnant women in the second and third trimesters of pregnancy and withPlasmodium vivaxmalaria were treated with amodiaquine (10 mg/kg of body weight/day) for 3 days. The same women were studied again at 3 months postpartum. Plasma was analyzed for amodiaquine and desethylamodiaquine by use of a liquid chromatography-tandem mass spectrometry method. Individual concentration-time data were evaluated using noncompartmental analysis. There were no clinically relevant differences in the pharmacokinetics of amodiaquine and desethylamodiaquine between pregnant (n= 24) and postpartum (n= 18) women. The results suggest that the current amodiaquine dosing regimen is adequate for the treatment ofP. vivaxinfections during pregnancy.

scholarly journals Prospective Study of Plasmodium vivax Malaria Recurrence after Radical Treatment with a Chloroquine-Primaquine Standard Regimen in Turbo, Colombia

2016 ◽  
Vol 60 (8) ◽  
pp. 4610-4619 ◽  
Author(s):  
Lina Zuluaga-Idárraga ◽  
Silvia Blair ◽  
Sheila Akinyi Okoth ◽  
Venkatachalam Udhayakumar ◽  
Paula L. Marcet ◽  
...  
Keyword(s):  
Plasmodium Vivax ◽  
Standard Regimen ◽  
High Genetic Diversity ◽  
Content Type ◽  
Longitudinal Observational Study ◽  
High Incidence ◽  
Plasmodium Vivax Malaria ◽  
Previous Infection ◽  
First Recurrence ◽  
Infection Episode

ABSTRACTPlasmodium vivaxrecurrences help maintain malaria transmission. They are caused by recrudescence, reinfection, or relapse, which are not easily differentiated. A longitudinal observational study took place in Turbo municipality, Colombia. Participants with uncomplicatedP. vivaxinfection received supervised treatment concomitantly with 25 mg/kg chloroquine and 0.25 mg/kg/day primaquine for 14 days. Incidence of recurrence was assessed over 180 days. Samples were genotyped, and origins of recurrences were established. A total of 134 participants were enrolled between February 2012 and July 2013, and 87 were followed for 180 days, during which 29 recurrences were detected. The cumulative incidence of first recurrence was 24.1% (21/87) (95% confidence interval [CI], 14.6 to 33.7%), and 86% (18/21) of these events occurred between days 51 and 110. High genetic diversity ofP. vivaxstrains was found, and 12.5% (16/128) of the infections were polyclonal. Among detected recurrences, 93.1% (27/29) of strains were genotyped as genetically identical to the strain from the previous infection episode, and 65.5% (19/29) of infections were classified as relapses. Our results indicate that there is a high incidence ofP. vivaxmalaria recurrence after treatment in Turbo municipality, Colombia, and that a large majority of these episodes are likely relapses from the previous infection. We attribute this to the primaquine regimen currently used in Colombia, which may be insufficient to eliminate hypnozoites.

scholarly journals Amplification ofpfmdr1,pfcrt,pvmdr1, and K13 Propeller Polymorphisms Associated with Plasmodium falciparum and Plasmodium vivax Isolates from the China-Myanmar Border

2015 ◽  
Vol 59 (5) ◽  
pp. 2554-2559 ◽  
Author(s):  
Jun Feng ◽  
Daili Zhou ◽  
Yingxue Lin ◽  
Huihui Xiao ◽  
He Yan ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Plasmodium Vivax ◽  
Vivax Malaria ◽  
Yunnan Province ◽  
Point Mutations ◽  
Border Region ◽  
Molecular Surveillance ◽  
Content Type ◽  
Antimalarial Resistance ◽  
Local Transmission

ABSTRACTMalaria in the China-Myanmar border region is still severe; local transmission of both falciparum and vivax malaria persists, and there is a risk of geographically expanding antimalarial resistance. In this research, thepfmdr1,pfcrt,pvmdr1, and K13-propeller genotypes were determined in 26Plasmodium falciparumand 64Plasmodium vivaxisolates from Yingjiang county of Yunnan province. Thepfmdr1(11.5%),pfcrt(34.6%), andpvmdr1(3.1%) mutations were prevalent at the China-Myanmar border. The indigenous samples exhibited prevalences of 14.3%, 28.6%, and 14.3% forpfmdr1N86Y,pfcrtK76T, andpfcrtM74I, respectively, whereas the samples from Myanmar showed prevalences of 10.5%, 21.1%, and 5.3%, respectively. The most prevalent genotypes ofpfmdr1andpfcrtwere Y86Y184and M74N75T76, respectively. Nopvmdr1mutation occurred in the indigenous samples but was observed in two cases coming from Myanmar. In addition, we are the first to report on 10 patients (38.5%) with five different K13 point mutations. The F446I allele is predominant (19.2%), and its prevalence was 28.6% in the indigenous samples of Yingjiang county and 15.8% in samples from Myanmar. The present data might be helpful for enrichment of the molecular surveillance of antimalarial resistance and useful for developing and updating guidance for the use of antimalarials in this region.

scholarly journals Population Pharmacokinetic and Pharmacodynamic Modeling of Amodiaquine and Desethylamodiaquine in Women with Plasmodium vivax Malaria during and after Pregnancy

2012 ◽  
Vol 56 (11) ◽  
pp. 5764-5773 ◽  
Author(s):  
Joel Tarning ◽  
Palang Chotsiri ◽  
Vincent Jullien ◽  
Marcus J. Rijken ◽  
Martin Bergstrand ◽  
...  
Keyword(s):  
Pregnant Women ◽  
Plasmodium Vivax ◽  
Plasma Concentrations ◽  
Inhibitory Effect ◽  
Biologically Active ◽  
Pharmacodynamic Modeling ◽  
Population Pharmacokinetic ◽  
Content Type ◽  
Plasmodium Vivax Malaria

ABSTRACTAmodiaquine is effective for the treatment ofPlasmodium vivaxmalaria, but there is little information on the pharmacokinetic and pharmacodynamic properties of amodiaquine in pregnant women with malaria. This study evaluated the population pharmacokinetic and pharmacodynamic properties of amodiaquine and its biologically active metabolite, desethylamodiaquine, in pregnant women withP. vivaxinfection and again after delivery. Twenty-seven pregnant women infected withP. vivaxmalaria on the Thai-Myanmar border were treated with amodiaquine monotherapy (10 mg/kg/day) once daily for 3 days. Nineteen women, with and withoutP. vivaxinfections, returned to receive the same amodiaquine dose postpartum. Nonlinear mixed-effects modeling was used to evaluate the population pharmacokinetic and pharmacodynamic properties of amodiaquine and desethylamodiaquine. Amodiaquine plasma concentrations were described accurately by lagged first-order absorption with a two-compartment disposition model followed by a three-compartment disposition of desethylamodiaquine under the assumption of completein vivoconversion. Body weight was implemented as an allometric function on all clearance and volume parameters. Amodiaquine clearance decreased linearly with age, and absorption lag time was reduced in pregnant patients. Recurrent malaria infections in pregnant women were modeled with a time-to-event model consisting of a constant-hazard function with an inhibitory effect of desethylamodiaquine. Amodiaquine treatment reduced the risk of recurrent infections from 22.2% to 7.4% at day 35. In conclusion, pregnancy did not have a clinically relevant impact on the pharmacokinetic properties of amodiaquine or desethylamodiaquine. No dose adjustments are required in pregnancy.

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