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Pacheco MA, Schneider KA, Cheng Q, Munde EO, Ndege C, Onyango C, Raballah E, Anyona SB, Ouma C, Perkins DJ, Escalante AA. Changes in the frequencies of Plasmodium falciparum dhps and dhfr drug-resistant mutations in children from Western Kenya from 2005 to 2018: the rise of Pfdhps S436H. Malar J 2020; 19:378. [PMID: 33092587 PMCID: PMC7583259 DOI: 10.1186/s12936-020-03454-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Accepted: 10/18/2020] [Indexed: 01/29/2023] Open
Abstract
BACKGROUND Sulfadoxine-pyrimethamine (SP) is the only anti-malarial drug formulation approved for intermittent preventive treatment in pregnancy (IPTp). However, mutations in the Plasmodium falciparum dhfr (Pfdhfr) and dhps (Pfdhps) genes confer resistance to pyrimethamine and sulfadoxine, respectively. Here, the frequencies of SP resistance-associated mutations from 2005 to 2018 were compared in samples from Kenyan children with malaria residing in a holoendemic transmission region. METHODS Partial sequences of the Pfdhfr and Pfdhps genes were amplified and sequenced from samples collected in 2005 (n = 81), 2010 (n = 95), 2017 (n = 43), and 2018 (n = 55). The frequency of known mutations conferring resistance to pyrimethamine and sulfadoxine were estimated and compared. Since artemisinin-based combination therapy (ACT) is the current first-line treatment for malaria, the presence of mutations in the propeller domain of P. falciparum kelch13 gene (Pfk13) linked to ACT-delayed parasite clearance was studied in the 2017/18 samples. RESULTS Among other changes, the point mutation of Pfdhps S436H increased in frequency from undetectable in 2005 to 28% in 2017/18. Triple Pfdhfr mutant allele (CIRNI) increased in frequency from 84% in 2005 to 95% in 2017/18, while the frequency of Pfdhfr double mutant alleles declined (allele CICNI from 29% in 2005 to 6% in 2017/18, and CNRNI from 9% in 2005 to undetectable in 2010 and 2017/18). Thus, a multilocus Pfdhfr/Pfdhps genotype with six mutations (HGEAA/CIRNI), including Pfdhps S436H, increased in frequency from 2010 to 2017/18. Although none of the mutations associated with ACT-delayed parasite clearance was observed, the Pfk13 mutation A578S, the most widespread Pfk13 SNP found in Africa, was detected in low frequency (2.04%). CONCLUSIONS There were changes in SP resistance mutant allele frequencies, including an increase in the Pfdhps S436H. Although these patterns seem consistent with directional selection due to drug pressure, there is a lack of information to determine the actual cause of such changes. These results suggest incorporating molecular surveillance of Pfdhfr/Pfdhps mutations in the context of SP efficacy studies for intermittent preventive treatment in pregnancy (IPTp).
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Affiliation(s)
- M Andreína Pacheco
- Biology Department/Institute of Genomics and Evolutionary Medicine (iGEM), Temple University, Philadelphia, PA, USA
| | - Kristan A Schneider
- Department of Applied Computer and Biosciences, University of Applied Sciences Mittweida, Technikumplatz, Mittweida, Germany
| | - Qiuying Cheng
- Center for Global Health, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
| | - Elly O Munde
- University of New Mexico-Kenya Global Health Programs, Kisumu, Siaya, Kenya
- Department of Clinical Medicine, School of Health Sciences, Kirinyaga University, Kerugoya, Kenya
| | - Caroline Ndege
- University of New Mexico-Kenya Global Health Programs, Kisumu, Siaya, Kenya
- Department of Biomedical Sciences and Technology, Maseno University, Maseno, Kenya
| | - Clinton Onyango
- University of New Mexico-Kenya Global Health Programs, Kisumu, Siaya, Kenya
- Department of Biomedical Sciences and Technology, Maseno University, Maseno, Kenya
| | - Evans Raballah
- University of New Mexico-Kenya Global Health Programs, Kisumu, Siaya, Kenya
- Department of Medical Laboratory Sciences, School of Public Health, Biomedical Sciences and Technology, Masinde Muliro University of Science and Technology, Kakamega, Kenya
| | - Samuel B Anyona
- University of New Mexico-Kenya Global Health Programs, Kisumu, Siaya, Kenya
- Department of Medical Biochemistry, School of Medicine, Maseno University, Maseno, Kenya
| | - Collins Ouma
- University of New Mexico-Kenya Global Health Programs, Kisumu, Siaya, Kenya
- Department of Biomedical Sciences and Technology, Maseno University, Maseno, Kenya
| | - Douglas J Perkins
- Center for Global Health, University of New Mexico Health Sciences Center, Albuquerque, NM, USA.
- University of New Mexico-Kenya Global Health Programs, Kisumu, Siaya, Kenya.
| | - Ananias A Escalante
- Biology Department/Institute of Genomics and Evolutionary Medicine (iGEM), Temple University, Philadelphia, PA, USA.
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Sottas O, Guidi M, Thieffry B, Schneider M, Décosterd L, Mueller I, Genton B, Csajka C, Senn N. Adherence to intermittent preventive treatment for malaria in Papua New Guinean infants: A pharmacological study alongside the randomized controlled trial. PLoS One 2019; 14:e0210789. [PMID: 30726224 PMCID: PMC6364960 DOI: 10.1371/journal.pone.0210789] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Accepted: 12/28/2018] [Indexed: 11/18/2022] Open
Abstract
Background The intermittent preventive treatment in infants (IPTi) trial that took place in Papua New Guinea showed an overall reduction of 29% of the risk of malaria when delivering single-dose sulfadoxine-pyrimethamine (SP) associated to 3 days of amodiaquine (AQ) every three months to children during the first year of life. The aim of the present study was to assess if the last two doses of AQ were truly administered as prescribed by the parents at home based on drug level measurement and PK modelling, which is a good proxy of medication adherence. It provides also important information to discuss the efficacy of the intervention and on feasibility of self-administered preventive malaria treatment. Methods and findings During the three-arm randomized double-blinded IPTi trial, each child was prescribed one dose of SP (day 0) and 3 doses of either AQ or artesunate (AS) at day 0, 1 & 2 adjusted to weight or placebo. Treatments were given at 3, 6, 9 and 12 months of age. The first day of treatment was delivered by nursing staff (initiation under directly observed treatment (DOT)) and the two last doses of AQ or AS by parents at home without supervision. For this cross-sectional study, 206 consecutive children already involved in the IPTi trial were enrolled over a 2-month period. At the time of the survey, allocation of the children to one of the three arms was not known. Blood samples for drug level measurement were collected from finger pricks one day after the planned last third dose intake. Only children allocated to the SP-AQ arm were included in the present analysis. Indeed, the half-life of AS is too short to assess if drugs were given on not. Because of the short half-life of AQ, desethyl-AQ (metabolite of AQ (DAQ)) measurements were used to investigate AQ medication adherence. Two PK (PK) models from previously published studies in paediatric populations were applied to the dataset using non-linear mixed effect modelling (NONMEM) to estimate the number of doses really given by the parents. The study nurse reported the administration time for the first AQ dose while it was estimated by the parents for the remaining two doses. Out of 206 children, 64 were in the SP-AQ arm. The adjusted dosing history for each individual was identified as the one with the lowest difference between observed and individual predicted concentrations estimated by the two PK models for all the possible adherence schemes. The median (range) blood concentration AQ in AQ arm was 9.3 ng/mL (0–1427.8 ng/mL), (Quartiles 1–3: 2.4 ng/mL -22.2 ng/mL). The median (range) for DAQ was 162.0 ng/mL (0–712 ng/mL), (Quartiles 1–3: 80.4 ng/mL-267.7 ng/mL). Under the assumption of full adherence for all participants, a marked underprediction of concentrations was observed using both PK models. Our results suggest that only 39–50% of children received the three scheduled doses of AQ as prescribed, 33–37% two doses and 17–24% received only the first dose administered by the study nurse. Both models were highly congruent to classify adherence patterns. Conclusions Considering the IPTi intervention, our results seem to indicate that medication adherence is low in the ideal trial research setting and is likely to be even lower if given in day-to-day practice, questioning the real impact that this intervention might have. More generally, the estimation of the number of doses truly administered, a proxy measure of adherence and an assessment of the feasibility of the mode of administration, should be more thoroughly studied when discussing the efficacy of the interventions in trials investigating self-administered malaria preventive treatments.
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Affiliation(s)
- Oriane Sottas
- Department of Ambulatory Care and Community Medicine, Lausanne, Switzerland
| | - Monia Guidi
- Service of Clinical Pharmacology, Lausanne University Hospital, Lausanne, Switzerland
- Clinical Pharmacy Sciences, School of Pharmaceutical Sciences, University of Geneva, University of Lausanne, Geneva, Switzerland
| | - Benjamin Thieffry
- Service of Clinical Pharmacology, Lausanne University Hospital, Lausanne, Switzerland
| | - Marie Schneider
- Department of Ambulatory Care and Community Medicine, Lausanne, Switzerland
- Clinical Pharmacy Sciences, School of Pharmaceutical Sciences, University of Geneva, University of Lausanne, Geneva, Switzerland
| | - Laurent Décosterd
- Service of Clinical Pharmacology, Lausanne University Hospital, Lausanne, Switzerland
| | - Ivo Mueller
- Walter and Eliza Hall Institute, Melbourne, Australia
- Papua New Guinea Institute of medical research (PNG IMR), Madang, Papua New Guinea
| | - Blaise Genton
- Department of Ambulatory Care and Community Medicine, Lausanne, Switzerland
- Swiss Tropical and Public Health Institute, Basel, Switzerland
| | - Chantal Csajka
- Service of Clinical Pharmacology, Lausanne University Hospital, Lausanne, Switzerland
- Clinical Pharmacy Sciences, School of Pharmaceutical Sciences, University of Geneva, University of Lausanne, Geneva, Switzerland
| | - Nicolas Senn
- Department of Ambulatory Care and Community Medicine, Lausanne, Switzerland
- Papua New Guinea Institute of medical research (PNG IMR), Madang, Papua New Guinea
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- * E-mail:
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Gosling RD, Cairns ME, Chico RM, Chandramohan D. Intermittent preventive treatment against malaria: an update. Expert Rev Anti Infect Ther 2014; 8:589-606. [DOI: 10.1586/eri.10.36] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Cunnington AJ, Riley EM. Suppression of vaccine responses by malaria: insignificant or overlooked? Expert Rev Vaccines 2014; 9:409-29. [DOI: 10.1586/erv.10.16] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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Bardají A, Bassat Q, Alonso PL, Menéndez C. Intermittent preventive treatment of malaria in pregnant women and infants: making best use of the available evidence. Expert Opin Pharmacother 2012; 13:1719-36. [PMID: 22775553 DOI: 10.1517/14656566.2012.703651] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION Malaria continues to represent a huge global health burden on the most vulnerable populations. The Intermittent Preventive Treatment (IPT) strategy has been shown to be an efficacious intervention in preventing most of the deleterious effects of malaria in pregnant women and infants. Yet, the effectiveness of the IPT strategy may be impaired by the increasing resistance to sulfadoxine-pyrimethamine (SP), and the scarcity of alternative antimalarial drugs. AREAS COVERED This review examines all the available information on IPT, in an aim to provide the scientific community with a framework to understand the benefits and limitations of this malaria control strategy. It includes the understanding of the historical background of the IPT strategy, the drug's mechanisms of actions, updated information on current available evidence, the implications of drug resistance and choice of alternative drugs, and a comprehensive discussion on the perspectives of IPT for malaria control in pregnant women and infants. EXPERT OPINION IPT in pregnancy and infants is a cost-effective strategy that can contribute significantly to the control of malaria in endemic areas. Monitoring its effectiveness will allow tracking of progress, evaluation of the adequacy of currently used drugs and will highlight the eventual need for new therapies or alternative interventions.
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Affiliation(s)
- Azucena Bardají
- University of Barcelona, Hospital Clínic, Barcelona Centre for International Health Research, Roselló, 132, 08036, Barcelona, Spain.
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Gutman J, Kachur SP, Slutsker L, Nzila A, Mutabingwa T. Combination of probenecid-sulphadoxine-pyrimethamine for intermittent preventive treatment in pregnancy. Malar J 2012; 11:39. [PMID: 22321288 PMCID: PMC3295670 DOI: 10.1186/1475-2875-11-39] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2011] [Accepted: 02/09/2012] [Indexed: 01/01/2023] Open
Abstract
The antifolate sulphadoxine-pyrimethamine (SP) has been used in the intermittent prevention of malaria in pregnancy (IPTp). SP is an ideal choice for IPTp, however, as resistance of Plasmodium falciparum to SP increases, data are accumulating that SP may no longer provide benefit in areas of high-level resistance. Probenecid was initially used as an adjunctive therapy to increase the blood concentration of penicillin; it has since been used to augment concentrations of other drugs, including antifolates. The addition of probenecid has been shown to increase the treatment efficacy of SP against malaria, suggesting that the combination of probenecid plus SP may prolong the useful lifespan of SP as an effective agent for IPTp. Here, the literature on the pharmacokinetics, adverse reactions, interactions and available data on the use of these drugs in pregnancy is reviewed, and the possible utility of an SP-probenecid combination is discussed. This article concludes by calling for further research into this potentially useful combination.
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Affiliation(s)
- Julie Gutman
- Division of Parasitic Diseases & Malaria, Malaria Branch, 1600 Clifton Rd. NE, Mailstop A06, Atlanta, GA 30329, USA
| | - S Patrick Kachur
- Division of Parasitic Diseases & Malaria, Malaria Branch, 1600 Clifton Rd. NE, Mailstop A06, Atlanta, GA 30329, USA
| | - Laurence Slutsker
- Center for Global Health, Centers for Disease Control and Prevention, 1600 Clifton Rd. NE, Mailstop D-69, Atlanta, GA 30329-4018, USA
| | - Alexis Nzila
- Department of Chemistry, King Fahd University of Petroleum and Minerals, PO Box 468, Dhahran, 31261, Saudi Arabia
| | - Theonest Mutabingwa
- Department of Community Medicine, Hubert Kairuki Memorial University, Dar-es-Salaam, Tanzania
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Faye SL. Responsabiliser les relais communautaires pour le traitement préventif intermittent saisonnier du paludisme (TPI) au Sénégal : enjeux, modalités, défis. ACTA ACUST UNITED AC 2012. [DOI: 10.3917/autr.060.0129] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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Willey BA, Armstrong Schellenberg JRM, Maokola W, Shirima K, Chemba M, Mshinda H, Alonso P, Tanner M, Schellenberg D. Evaluating the effectiveness of IPTi on malaria using routine health information from sentinel health centres in southern Tanzania. Malar J 2011; 10:41. [PMID: 21320346 PMCID: PMC3055223 DOI: 10.1186/1475-2875-10-41] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2010] [Accepted: 02/14/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Intermittent preventive treatment of malaria in infants (IPTi) consists of the administration of a treatment dose of sulphadoxine-pyrimethamine (SP) at the time of routine vaccinations. The use of routine Health Management and Information Services (HMIS) data to investigate the effect of IPTi on malaria, anaemia, and all-cause attendance in children aged 2-11 months presenting to 11 health centres in southern Tanzania is described. METHODS Clinical diagnosis of malaria was confirmed with a positive blood slide reading from a quality assurance laboratory. Anaemia was defined using two thresholds (mild [Hb<11 g/dL], severe [Hb<8 g/dL]). Incidence rates between IPTi and non-implementing health centres were calculated using Poisson regression, and all statistical testing was based on the t test due to the clustered nature of the data. RESULTS Seventy two per cent of infants presenting in intervention areas received at least one dose of IPTi--22% received all three. During March 2006-April 2007, the incidence of all cause attendance was two attendances per person, per year (pppy), including 0.2 episodes pppy of malaria, 0.7 episodes of mild and 0.13 episodes of severe anaemia. Point estimates for the effect of IPTi on malaria varied between 18% and 52%, depending on the scope of the analysis, although adjustment for clustering rendered these not statistically significant. CONCLUSIONS The point estimate of the effect of IPTi on malaria is consistent with that from a large pooled analysis of randomized control trials. As such, it is plausible that the difference seen in health centre data is due to IPTi, even thought the effect did not reach statistical significance. Findings draw attention to the challenges of robust inference of effects of interventions based on routine health centre data. Analysis of routine health information can reassure that interventions are being made available and having desired effects, but unanticipated effects should trigger data collection from representative samples of the target population.
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Affiliation(s)
- Barbara A Willey
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
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Boulanger D, Sarr JB, Fillol F, Sokhna C, Cisse B, Schacht AM, Trape JF, Riveau G, Simondon F, Greenwood B, Remoué F. Immunological consequences of intermittent preventive treatment against malaria in Senegalese preschool children. Malar J 2010; 9:363. [PMID: 21167018 PMCID: PMC3012051 DOI: 10.1186/1475-2875-9-363] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2010] [Accepted: 12/17/2010] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Intermittent preventive treatment in children (IPTc) is a promising strategy to control malaria morbidity. A significant concern is whether IPTc increases children's susceptibility to subsequent malaria infection by altering their anti-Plasmodium acquired immunity. METHODS To investigate this concern, IgG antibody (Ab) responses to Plasmodium falciparum schizont extract were measured in Senegalese children (6 months-5 years old) who had received three rounds of IPTc with artesunate + sulphadoxine-pyrimethamine (or placebo) at monthly intervals eight months earlier. Potential confounding factors, such as asexual malaria parasitaemia and nutritional status were also evaluated. RESULTS Firstly, a bivariate analysis showed that children who had received IPTc had lower anti-Plasmodium IgG Ab levels than the non-treated controls. When epidemiological parameters were incorporated into a multivariate regression, gender, nutritional status and haemoglobin concentration did not have any significant influence. In contrast, parasitaemia, past malaria morbidity and increasing age were strongly associated with a higher specific IgG response. CONCLUSIONS The intensity of the contacts with P. falciparum seems to represent the main factor influencing anti-schizont IgG responses. Previous IPTc does not seem to interfere with this parasite-dependent acquired humoral response eight months after the last drug administration.
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Affiliation(s)
- Denis Boulanger
- Unité Mixte de Recherche 145, Institut de Recherche pour le Développement and Université Montpellier 1, 911 avenue Agropolis, BP64501, 34394 Montpellier, France.
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Spalding MD, Eyase FL, Akala HM, Bedno SA, Prigge ST, Coldren RL, Moss WJ, Waters NC. Increased prevalence of the pfdhfr/phdhps quintuple mutant and rapid emergence of pfdhps resistance mutations at codons 581 and 613 in Kisumu, Kenya. Malar J 2010; 9:338. [PMID: 21106088 PMCID: PMC3001743 DOI: 10.1186/1475-2875-9-338] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2010] [Accepted: 11/24/2010] [Indexed: 12/01/2022] Open
Abstract
Background Anti-malarial drug resistance in Kenya prompted two drug policy changes within a decade: sulphadoxine-pyrimethamine (SP) replaced chloroquine (CQ) as the first-line anti-malarial in 1998 and artemether-lumefantrine (AL) replaced SP in 2004. Two cross-sectional studies were conducted to monitor changes in the prevalence of molecular markers of drug resistance over the period in which SP was used as the first-line anti-malarial. The baseline study was carried out from 1999-2000, shortly after implementation of SP, and the follow-up study occurred from 2003-2005, during the transition to AL. Materials and methods Blood was collected from malaria smear-positive, symptomatic patients presenting to outpatient centers in Kisumu, Kenya, during the baseline and follow-up studies. Isolates were genotyped at codons associated with SP and CQ resistance. In vitro IC50 values for antifolates and quinolones were determined for isolates from the follow-up study. Results The prevalence of isolates containing the pfdhfr N51I/C59R/S108N/pfdhps A437G/K540E quintuple mutant associated with SP-resistance rose from 21% in the baseline study to 53% in the follow-up study (p < 0.001). Isolates containing the pfdhfr I164L mutation were absent from both studies. The pfdhps mutations A581G and A613S/T were absent from the baseline study but were present in 85% and 61%, respectively, of isolates from the follow-up study. At follow-up, parasites with mutations at five pfdhps codons, 436, 437, 540, 581, and 613, accounted for 39% of isolates. The CQ resistance-associated mutations pfcrt K76T and pfmdr1 N86Y rose from 82% to 97% (p = 0.001) and 44% to 76% (p < 0.001), respectively, from baseline to follow-up. Conclusions During the period in which SP was the first-line anti-malarial in Kenya, highly SP-resistant parasites emerged, including isolates harboring pfdhps mutations not previously observed there. SP continues to be widely used in Kenya; however, given the highly resistant genotypes observed in this study, its use as a first-line anti-malarial should be discouraged, particularly for populations without acquired immunity to malaria. The increase in the pfcrt K76T prevalence, despite efforts to reduce CQ use, suggests that either these efforts are not adequate to alleviate CQ pressure in Kisumu, or that drug pressure is derived from another source, such as the second-line anti-malarial amodiaquine.
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Affiliation(s)
- Maroya D Spalding
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
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A natural immunization process prevents malaria. Trends Parasitol 2010; 26:219-21. [PMID: 20189878 DOI: 10.1016/j.pt.2010.02.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2009] [Revised: 01/14/2010] [Accepted: 02/03/2010] [Indexed: 10/19/2022]
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Mosha JF, Conteh L, Tediosi F, Gesase S, Bruce J, Chandramohan D, Gosling R. Cost implications of improving malaria diagnosis: findings from north-eastern Tanzania. PLoS One 2010; 5:e8707. [PMID: 20090933 PMCID: PMC2806838 DOI: 10.1371/journal.pone.0008707] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2009] [Accepted: 12/03/2009] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Over diagnosis of malaria contributes to improper treatment, wastage of drugs and resistance to the few available drugs. This paper attempts to estimate the rates of over diagnosis of malaria among children attending dispensaries in rural Tanzania and examines the potential cost implications of improving the quality of diagnosis. METHODOLOGY/PRINCIPAL FINDINGS The magnitude of over diagnosis of malaria was estimated by comparing the proportion of outpatient attendees of all ages clinically diagnosed as malaria to the proportion of attendees having a positive malaria rapid diagnostic test over a two month period. Pattern of causes of illness observed in a <2 year old cohort of children over one year was compared to the pattern of causes of illness in <5 year old children recorded in the routine health care system during the same period. Drug and diagnostic costs were modelled using local and international prices. Over diagnosis of malaria by the routine outpatient care system compared to RDT confirmed cases of malaria was highest among <5 year old children in the low transmission site (RR 17.9, 95% CI 5.8-55.3) followed by the >or=5 year age group in the lower transmission site (RR 14.0 95%CI 8.2-24.2). In the low transmission site the proportion of morbidity attributable to malaria was substantially lower in <2 year old cohort compared to children seen at routine care system. (0.08% vs 28.2%; p<0.001). A higher proportion of children were diagnosed with ARI in the <2 year old cohort compared to children seen at the routine care system ( 42% vs 26%; p<0.001). Using a RDT reduced overall drug and diagnostic costs by 10% in the high transmission site and by 15% in the low transmission site compared to total diagnostic and drug costs of treatment based on clinical judgment in routine health care system. IMPLICATIONS The introduction of RDTs is likely to lead to financial savings. However, improving diagnosis to one disease may lead to over diagnosis of another illness. Quality improvement is complex but introducing RDTs for the diagnosis of malaria is a good start.
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Affiliation(s)
| | - Lesong Conteh
- London School of Hygiene and Tropical Medicine, London, United Kingdom
- Swiss Tropical Institute, Basel, Switzerland
| | - Fabrizio Tediosi
- Swiss Tropical Institute, Basel, Switzerland
- Università Bocconi, Milan, Italy
| | - Samwel Gesase
- National Institute for Medical Research, Tanga, Tanzania
| | - Jane Bruce
- London School of Hygiene and Tropical Medicine, London, United Kingdom
| | | | - Roly Gosling
- London School of Hygiene and Tropical Medicine, London, United Kingdom
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