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Touré M, Keita M, Kané F, Sanogo D, Kanté S, Konaté D, Diarra A, Sogoba N, Coulibaly MB, Traoré SF, Alifrangis M, Diakité M, Shaffer JG, Krogstad DJ, Doumbia S. Trends in malaria epidemiological factors following the implementation of current control strategies in Dangassa, Mali. Malar J 2022; 21:65. [PMID: 35197053 PMCID: PMC8867639 DOI: 10.1186/s12936-022-04058-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Accepted: 01/21/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Over the past decade, three strategies have reduced severe malaria cases and deaths in endemic regions of Africa, Asia and the Americas, specifically: (1) artemisinin-based combination therapy (ACT); (2) insecticide-treated bed nets (ITNs); and, (3) intermittent preventive treatment with sulfadoxine-pyrimethamine in pregnancy (IPTp). The rationale for this study was to examine communities in Dangassa, Mali where, in 2015, two additional control strategies were implemented: ITN universal coverage and seasonal malaria chemoprevention (SMC) among children under 5 years old. METHODS This was a prospective study based on a rolling longitudinal cohort of 1401 subjects participating in bi-annual smear surveys for the prevalence of asymptomatic Plasmodium falciparum infection and continuous surveillance for the incidence of human disease (uncomplicated malaria), performed in the years from 2012 to 2020. Entomological collections were performed to examine the intensity of transmission based on pyrethroid spray catches, human landing catches and enzyme-linked immunosorbent assay (ELISA) testing for circumsporozoite antigen. RESULTS A total of 1401 participants of all ages were enrolled in the study in 2012 after random sampling of households from the community census list. Prevalence of infection was extremely high in Dangassa, varying from 9.5 to 62.8% at the start of the rainy season and from 15.1 to 66.7% at the end of the rainy season. Likewise, the number of vectors per house, biting rates, sporozoites rates, and entomological inoculation rates (EIRs) were substantially greater in Dangassa. DISCUSSION The findings for this study are consistent with the progressive implementation of effective malaria control strategies in Dangassa. At baseline (2012-2014), prevalence of P. falciparum was above 60% followed by a significant year-to-year decease starting in 2015. Incidence of uncomplicated infection was greater among children < 5 years old, while asymptomatic infection was more frequent among the 5-14 years old. A significant decrease in EIR was also observed from 2015 to 2020. Likewise, vector density, sporozoite rates, and EIRs decreased substantially during the study period. CONCLUSION Efficient implementation of two main malaria prevention strategies in Dangassa substantially contribute to a reduction of both asymptomatic and symptomatic malaria from 2015 to 2020.
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Affiliation(s)
- Mahamoudou Touré
- West African International Center of Excellence for Malaria Research, Bamako, Mali. .,Faculté de Médecine et d'Odonto-Stomatologie (FMOS), Université des Sciences, des Techniques et des Technologies de Bamako, Bamako, Mali.
| | - Moussa Keita
- West African International Center of Excellence for Malaria Research, Bamako, Mali.,Faculté de Médecine et d'Odonto-Stomatologie (FMOS), Université des Sciences, des Techniques et des Technologies de Bamako, Bamako, Mali
| | - Fousseyni Kané
- West African International Center of Excellence for Malaria Research, Bamako, Mali.,Faculté de Médecine et d'Odonto-Stomatologie (FMOS), Université des Sciences, des Techniques et des Technologies de Bamako, Bamako, Mali
| | - Daouda Sanogo
- West African International Center of Excellence for Malaria Research, Bamako, Mali.,Faculté de Médecine et d'Odonto-Stomatologie (FMOS), Université des Sciences, des Techniques et des Technologies de Bamako, Bamako, Mali
| | - Salim Kanté
- West African International Center of Excellence for Malaria Research, Bamako, Mali.,Faculté de Médecine et d'Odonto-Stomatologie (FMOS), Université des Sciences, des Techniques et des Technologies de Bamako, Bamako, Mali
| | - Drissa Konaté
- West African International Center of Excellence for Malaria Research, Bamako, Mali.,Faculté de Médecine et d'Odonto-Stomatologie (FMOS), Université des Sciences, des Techniques et des Technologies de Bamako, Bamako, Mali
| | - Ayouba Diarra
- West African International Center of Excellence for Malaria Research, Bamako, Mali.,Faculté de Médecine et d'Odonto-Stomatologie (FMOS), Université des Sciences, des Techniques et des Technologies de Bamako, Bamako, Mali
| | - Nafomon Sogoba
- West African International Center of Excellence for Malaria Research, Bamako, Mali.,Faculté de Médecine et d'Odonto-Stomatologie (FMOS), Université des Sciences, des Techniques et des Technologies de Bamako, Bamako, Mali
| | - Mamadou B Coulibaly
- West African International Center of Excellence for Malaria Research, Bamako, Mali.,Faculté de Médecine et d'Odonto-Stomatologie (FMOS), Université des Sciences, des Techniques et des Technologies de Bamako, Bamako, Mali
| | - Sekou F Traoré
- West African International Center of Excellence for Malaria Research, Bamako, Mali.,Faculté de Pharmacie (FAPH), Université des Sciences, des Techniques et des Technologies de Bamako, Bamako, Mali
| | - Michael Alifrangis
- West African International Center of Excellence for Malaria Research, Bamako, Mali.,Department of Immunology and Microbiology, Centre for Medical Parasitology, University of Copenhagen, Copenhagen, Denmark.,Department of Infectious Diseases, Copenhagen University Hospital, Copenhagen, Denmark
| | - Mahamadou Diakité
- West African International Center of Excellence for Malaria Research, Bamako, Mali.,Faculté de Pharmacie (FAPH), Université des Sciences, des Techniques et des Technologies de Bamako, Bamako, Mali
| | - Jeffrey G Shaffer
- West African International Center of Excellence for Malaria Research, Bamako, Mali.,Departments of Tropical Medicine and Biostatistics, Tulane School of Public Health and Tropical Medicine, New Orleans, LA, USA
| | - Donald J Krogstad
- West African International Center of Excellence for Malaria Research, Bamako, Mali.,Departments of Tropical Medicine and Biostatistics, Tulane School of Public Health and Tropical Medicine, New Orleans, LA, USA
| | - Seydou Doumbia
- West African International Center of Excellence for Malaria Research, Bamako, Mali.,Faculté de Médecine et d'Odonto-Stomatologie (FMOS), Université des Sciences, des Techniques et des Technologies de Bamako, Bamako, Mali
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Diarra Y, Koné O, Sangaré L, Doumbia L, Haidara DBB, Diallo M, Maiga A, Sango HA, Sidibé H, Mihigo J, Nace D, Ljolje D, Talundzic E, Udhayakumar V, Eckert E, Woodfill CJ, Moriarty LF, Lim P, Krogstad DJ, Halsey ES, Lucchi NW, Koita OA. Therapeutic efficacy of artemether-lumefantrine and artesunate-amodiaquine for the treatment of uncomplicated Plasmodium falciparum malaria in Mali, 2015-2016. Malar J 2021; 20:235. [PMID: 34034754 PMCID: PMC8146210 DOI: 10.1186/s12936-021-03760-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Accepted: 05/11/2021] [Indexed: 12/02/2022] Open
Abstract
BACKGROUND The current first-line treatments for uncomplicated malaria recommended by the National Malaria Control Programme in Mali are artemether-lumefantrine (AL) and artesunate-amodiaquine (ASAQ). From 2015 to 2016, an in vivo study was carried out to assess the clinical and parasitological responses to AL and ASAQ in Sélingué, Mali. METHODS Children between 6 and 59 months of age with uncomplicated Plasmodium falciparum infection and 2000-200,000 asexual parasites/μL of blood were enrolled, randomly assigned to either AL or ASAQ, and followed up for 42 days. Uncorrected and PCR-corrected efficacy results at days 28 and 42. were calculated. Known markers of resistance in the Pfk13, Pfmdr1, and Pfcrt genes were assessed using Sanger sequencing. RESULTS A total of 449 patients were enrolled: 225 in the AL group and 224 in the ASAQ group. Uncorrected efficacy at day 28 was 83.4% (95% CI 78.5-88.4%) in the AL arm and 93.1% (95% CI 89.7-96.5%) in the ASAQ arm. The per protocol PCR-corrected efficacy at day 28 was 91.0% (86.0-95.9%) in the AL arm and 97.1% (93.6-100%) in the ASAQ arm. ASAQ was significantly (p < 0.05) better than AL for each of the aforementioned efficacy outcomes. No mutations associated with artemisinin resistance were identified in the Pfk13 gene. Overall, for Pfmdr1, the N86 allele and the NFD haplotype were the most common. The NFD haplotype was significantly more prevalent in the post-treatment than in the pre-treatment isolates in the AL arm (p < 0.01) but not in the ASAQ arm. For Pfcrt, the CVIET haplotype was the most common. CONCLUSIONS The findings indicate that both AL and ASAQ remain effective for the treatment of uncomplicated malaria in Sélingué, Mali.
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Affiliation(s)
- Youssouf Diarra
- University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Oumar Koné
- University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Lansana Sangaré
- University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Lassina Doumbia
- University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | | | - Mouctar Diallo
- University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Ababacar Maiga
- University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Hamadoun A Sango
- University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Halidou Sidibé
- National Malaria Control Programme, Ministry of Health and Public Hygiene, Bamako, Mali
| | - Jules Mihigo
- U.S. President's Malaria Initiative, USAID Office, Bamako, Mali
| | - Douglas Nace
- Malaria Branch, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Dragan Ljolje
- Malaria Branch, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Eldin Talundzic
- Malaria Branch, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | | | | | | | - Leah F Moriarty
- Malaria Branch, Centers for Disease Control and Prevention, Atlanta, GA, USA
- U.S. President's Malaria Initiative, Atlanta, GA, USA
| | - Pharath Lim
- Medical Care Development International, Silver Spring, MD, USA
| | - Donald J Krogstad
- Tulane School of Public Health and Tropical Medicine, New Orleans, LA, USA
| | - Eric S Halsey
- Malaria Branch, Centers for Disease Control and Prevention, Atlanta, GA, USA
- U.S. President's Malaria Initiative, Atlanta, GA, USA
| | - Naomi W Lucchi
- Malaria Branch, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Ousmane A Koita
- University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali.
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Keïta M, Doumbia S, Sissoko I, Touré M, Diawara SI, Konaté D, Sodio AB, Traoré SF, Diakité M, Doumbia SO, Sogoba N, Krogstad DJ, Shaffer JG, Coulibaly MB. Indoor and outdoor malaria transmission in two ecological settings in rural Mali: implications for vector control. Malar J 2021; 20:127. [PMID: 33663515 PMCID: PMC7931590 DOI: 10.1186/s12936-021-03650-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Accepted: 02/15/2021] [Indexed: 11/17/2022] Open
Abstract
Background Implementation and upscale of effective malaria vector control strategies necessitates understanding the multi-factorial aspects of transmission patterns. The primary aims of this study are to determine the vector composition, biting rates, trophic preference, and the overall importance of distinguishing outdoor versus indoor malaria transmission through a study at two communities in rural Mali. Methods Mosquito collection was carried out between July 2012 and June 2016 at two rural Mali communities (Dangassa and Koïla Bamanan) using pyrethrum spray-catch and human landing catch approaches at both indoor and outdoor locations. Species of Anopheles gambiae complex were identified by polymerase chain reaction (PCR). Enzyme-Linked -Immuno-Sorbent Assay (ELISA) were used to determine the origin of mosquito blood meals and presence of Plasmodium falciparum sporozoite infections. Results A total of 11,237 An. gambiae sensu lato (s.l.) were collected during the study period (5239 and 5998 from the Dangassa and Koïla Bamanan sites, respectively). Of the 679 identified by PCR in Dangassa, Anopheles coluzzii was the predominant species with 91.4% of the catch followed by An. gambiae (8.0%) and Anopheles arabiensis (0.6%). At the same time in Koïla Bamanan, of the 623 An. gambiae s.l., An. coluzzii accounted for 99% of the catch, An. arabiensis 0.8% and An. gambiae 0.2%. Human Blood Index (HBI) measures were significantly higher in Dangassa (79.4%; 95% Bayesian credible interval (BCI) [77.4, 81.4]) than in Koïla Bamanan (15.9%; 95% BCI [14.7, 17.1]). The human biting rates were higher during the second half of the night at both sites. In Dangassa, the sporozoite rate was comparable between outdoor and indoor mosquito collections. For outdoor collections, the sporozoite positive rate was 3.6% (95% BCI [2.1–4.3]) and indoor collections were 3.1% (95% BCI [2.4–5.0]). In Koïla Bamanan, the sporozoite rate was higher indoors at 4.3% (95% BCI [2.7–6.3]) compared with outdoors at 2.4% (95% BCI [1.1–4.2]). In Dangassa, corrected entomological inoculation rates (cEIRs) using HBI were 13.74 [95% BCI 9.21–19.14] infective bites/person/month (ib/p/m) at indoor, and 18.66 [95% BCI 12.55–25.81] ib/p/m at outdoor. For Koïla Bamanan, cEIRs were 1.57 [95% BCI 2.34–2.72] ib/p/m and 0.94 [95% BCI 0.43–1.64] ib/p/m for indoor and outdoor, respectively. EIRs were significantly higher at the Dangassa site than the Koïla Bamanan site. Conclusion The findings in this work may indicate the occurrence of active, outdoor residual malaria transmission is comparable to indoor transmission in some geographic settings. The high outdoor transmission patterns observed here highlight the need for additional strategies to combat outdoor malaria transmission to complement traditional indoor preventive approaches such as long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS) which typically focus on resting mosquitoes.
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Affiliation(s)
- Moussa Keïta
- West African International Center of Excellence for Malaria Research, Bamako, Mali. .,Malaria Research and Training Center, Bamako, Mali. .,Faculty of Medicine and Odonto Stomatology, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali. .,Faculty of Science and Techniques, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali.
| | - Sidy Doumbia
- West African International Center of Excellence for Malaria Research, Bamako, Mali.,Malaria Research and Training Center, Bamako, Mali
| | - Ibrahim Sissoko
- West African International Center of Excellence for Malaria Research, Bamako, Mali.,Malaria Research and Training Center, Bamako, Mali
| | - Mahamoudou Touré
- West African International Center of Excellence for Malaria Research, Bamako, Mali.,Malaria Research and Training Center, Bamako, Mali
| | - Sory Ibrahim Diawara
- West African International Center of Excellence for Malaria Research, Bamako, Mali.,Malaria Research and Training Center, Bamako, Mali
| | - Drissa Konaté
- West African International Center of Excellence for Malaria Research, Bamako, Mali.,Malaria Research and Training Center, Bamako, Mali
| | - Ambièlè Bernard Sodio
- Faculty of Science and Techniques, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Sekou F Traoré
- West African International Center of Excellence for Malaria Research, Bamako, Mali.,Malaria Research and Training Center, Bamako, Mali
| | - Mahamadou Diakité
- West African International Center of Excellence for Malaria Research, Bamako, Mali.,Malaria Research and Training Center, Bamako, Mali
| | - Seydou O Doumbia
- West African International Center of Excellence for Malaria Research, Bamako, Mali.,Malaria Research and Training Center, Bamako, Mali.,Faculty of Medicine and Odonto Stomatology, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Nafomon Sogoba
- West African International Center of Excellence for Malaria Research, Bamako, Mali.,Malaria Research and Training Center, Bamako, Mali.,Faculty of Medicine and Odonto Stomatology, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Donald J Krogstad
- School of Public Health and Tropical Medicine, Tulane University, 1440 Canal Street, New Orleans, LA, 70112, USA
| | - Jeffrey G Shaffer
- School of Public Health and Tropical Medicine, Tulane University, 1440 Canal Street, New Orleans, LA, 70112, USA
| | - Mamadou B Coulibaly
- West African International Center of Excellence for Malaria Research, Bamako, Mali.,Malaria Research and Training Center, Bamako, Mali
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Ateba FF, Febrero-Bande M, Sagara I, Sogoba N, Touré M, Sanogo D, Diarra A, Magdalene Ngitah A, Winch PJ, Shaffer JG, Krogstad DJ, Marker HC, Gaudart J, Doumbia S. Predicting Malaria Transmission Dynamics in Dangassa, Mali: A Novel Approach Using Functional Generalized Additive Models. Int J Environ Res Public Health 2020; 17:E6339. [PMID: 32878174 PMCID: PMC7504016 DOI: 10.3390/ijerph17176339] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/26/2020] [Revised: 08/19/2020] [Accepted: 08/26/2020] [Indexed: 01/22/2023]
Abstract
Mali aims to reach the pre-elimination stage of malaria by the next decade. This study used functional regression models to predict the incidence of malaria as a function of past meteorological patterns to better prevent and to act proactively against impending malaria outbreaks. All data were collected over a five-year period (2012-2017) from 1400 persons who sought treatment at Dangassa's community health center. Rainfall, temperature, humidity, and wind speed variables were collected. Functional Generalized Spectral Additive Model (FGSAM), Functional Generalized Linear Model (FGLM), and Functional Generalized Kernel Additive Model (FGKAM) were used to predict malaria incidence as a function of the pattern of meteorological indicators over a continuum of the 18 weeks preceding the week of interest. Their respective outcomes were compared in terms of predictive abilities. The results showed that (1) the highest malaria incidence rate occurred in the village 10 to 12 weeks after we observed a pattern of air humidity levels >65%, combined with two or more consecutive rain episodes and a mean wind speed <1.8 m/s; (2) among the three models, the FGLM obtained the best results in terms of prediction; and (3) FGSAM was shown to be a good compromise between FGLM and FGKAM in terms of flexibility and simplicity. The models showed that some meteorological conditions may provide a basis for detection of future outbreaks of malaria. The models developed in this paper are useful for implementing preventive strategies using past meteorological and past malaria incidence.
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Affiliation(s)
- François Freddy Ateba
- Malaria Research and Training Center, Faculty of Medicine, Pharmacy and Dentistry, University of Sciences, Techniques and Technologies of Bamako, Bamako BP 1805, Mali; (F.F.A.); (I.S.); (N.S.); (M.T.); (D.S.); (A.D.)
- Department of Mathematics, University of Quebec at Montreal (UQAM), Montréal, QC H2X 3Y7, Canada
- Faculty of Health Sciences, University of Buea, Buea BP 63, Cameroon;
| | - Manuel Febrero-Bande
- Department of Statistics, Mathematical Analysis and Optimization, University of Santiago de Compostela, Santiago de Compostela, 15782 Galicia, Spain;
| | - Issaka Sagara
- Malaria Research and Training Center, Faculty of Medicine, Pharmacy and Dentistry, University of Sciences, Techniques and Technologies of Bamako, Bamako BP 1805, Mali; (F.F.A.); (I.S.); (N.S.); (M.T.); (D.S.); (A.D.)
- Department of Public Health Education and Research, Faculty of Medicine and Odonto-Stomatology, University of Sciences, Techniques and Technologies of Bamako, Bamako 1805, Mali
| | - Nafomon Sogoba
- Malaria Research and Training Center, Faculty of Medicine, Pharmacy and Dentistry, University of Sciences, Techniques and Technologies of Bamako, Bamako BP 1805, Mali; (F.F.A.); (I.S.); (N.S.); (M.T.); (D.S.); (A.D.)
| | - Mahamoudou Touré
- Malaria Research and Training Center, Faculty of Medicine, Pharmacy and Dentistry, University of Sciences, Techniques and Technologies of Bamako, Bamako BP 1805, Mali; (F.F.A.); (I.S.); (N.S.); (M.T.); (D.S.); (A.D.)
| | - Daouda Sanogo
- Malaria Research and Training Center, Faculty of Medicine, Pharmacy and Dentistry, University of Sciences, Techniques and Technologies of Bamako, Bamako BP 1805, Mali; (F.F.A.); (I.S.); (N.S.); (M.T.); (D.S.); (A.D.)
| | - Ayouba Diarra
- Malaria Research and Training Center, Faculty of Medicine, Pharmacy and Dentistry, University of Sciences, Techniques and Technologies of Bamako, Bamako BP 1805, Mali; (F.F.A.); (I.S.); (N.S.); (M.T.); (D.S.); (A.D.)
| | | | - Peter J. Winch
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA; (P.J.W.); (H.C.M.)
| | - Jeffrey G. Shaffer
- Department of Global Biostatistics and Data Science, School of Public Health and Tropical Medicine, Tulane University, 1440 Canal Street New Orleans, New Orleans, Louisiana, LA 70112, USA; (J.G.S.); (D.J.K.)
| | - Donald J. Krogstad
- Department of Global Biostatistics and Data Science, School of Public Health and Tropical Medicine, Tulane University, 1440 Canal Street New Orleans, New Orleans, Louisiana, LA 70112, USA; (J.G.S.); (D.J.K.)
| | - Hannah C. Marker
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA; (P.J.W.); (H.C.M.)
| | - Jean Gaudart
- Aix Marseille University, APHM, INSERM, IRD, SESSTIM, Hop Timone, BioSTIC, Biostatistics & ICT, 13005 Marseille, France;
| | - Seydou Doumbia
- Malaria Research and Training Center, Faculty of Medicine, Pharmacy and Dentistry, University of Sciences, Techniques and Technologies of Bamako, Bamako BP 1805, Mali; (F.F.A.); (I.S.); (N.S.); (M.T.); (D.S.); (A.D.)
- Department of Public Health Education and Research, Faculty of Medicine and Odonto-Stomatology, University of Sciences, Techniques and Technologies of Bamako, Bamako 1805, Mali
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5
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Thompson TA, Touré MB, Sanogo D, Shaffer JG, Doumbia SO, Krogstad DJ. Template copy number and the sensitivity of quantitative PCR for Plasmodium falciparum in asymptomatic individuals. Malar J 2020; 19:295. [PMID: 32811534 PMCID: PMC7436962 DOI: 10.1186/s12936-020-03365-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Accepted: 08/10/2020] [Indexed: 01/15/2023] Open
Abstract
BACKGROUND The identification of asymptomatic individuals with Plasmodium falciparum infection is difficult because they do not seek medical treatment and often have too few asexual parasites detectable using microscopy or rapid diagnostic tests (≤ 200 parasites per μl). Quantitative PCR (qPCR) may provide greater sensitivity and permits estimation of the initial template DNA concentration. This study examined the hypothesis that qPCR assays using templates with higher copy numbers may be more sensitive for P. falciparum than assays based on templates with lower copy numbers. METHODS To test this hypothesis, ten qPCR assays for DNA sequences with template copy numbers from 1 to 160 were compared using parasite DNA standards (n = 2) and smear-positive filter paper blots from asymptomatic smear-positive subjects (n = 96). RESULTS Based on the testing of P. falciparum parasite DNA standards and filter paper blots, cycle threshold values decreased as the concentrations of template DNA and template copy numbers increased (p < 0.001). Likewise, the analytical and clinical sensitivities of qPCR assays for P. falciparum DNA (based on DNA standards and filter paper blots, respectively) increased with template copy number. Despite the gains in clinical sensitivity from increased template copy numbers, qPCR assays failed to detect more than half of the filter paper blots with low parasite densities (≤ 200 asexual parasites per μl). CONCLUSIONS These results confirm the hypothesis that the sensitivity of qPCR for P. falciparum in the blood of individuals with asymptomatic infection increases with template copy number. However, because even the most sensitive qPCR assays (with template copy numbers from 32 to 160) detected fewer than 50% of infections with ≤ 200 asexual parasites per μl, the sensitivity of qPCR must be increased further to identify all smear-positive, asymptomatic individuals in order to interrupt transmission.
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Affiliation(s)
- Trevor A Thompson
- West African International Center of Excellence for Malaria Research, Bamako, Mali.
- Tulane School of Public Health and Tropical Medicine, 1430 Tulane Avenue, #8317, J.B. Johnston Building, Room 510, New Orleans, LA, 70112-2699, USA.
| | - Mahamoudou B Touré
- West African International Center of Excellence for Malaria Research, Bamako, Mali
- University of the Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Daouda Sanogo
- West African International Center of Excellence for Malaria Research, Bamako, Mali
- University of the Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Jeffrey G Shaffer
- West African International Center of Excellence for Malaria Research, Bamako, Mali.
- Tulane School of Public Health and Tropical Medicine, 1430 Tulane Avenue, #8317, J.B. Johnston Building, Room 510, New Orleans, LA, 70112-2699, USA.
| | - Seydou O Doumbia
- West African International Center of Excellence for Malaria Research, Bamako, Mali
- University of the Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Donald J Krogstad
- West African International Center of Excellence for Malaria Research, Bamako, Mali.
- Tulane School of Public Health and Tropical Medicine, 1430 Tulane Avenue, #8317, J.B. Johnston Building, Room 510, New Orleans, LA, 70112-2699, USA.
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6
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Shaffer JG, Mather FJ, Wele M, Li J, Tangara CO, Kassogue Y, Srivastav SK, Thiero O, Diakite M, Sangare M, Dabitao D, Toure M, Djimde AA, Traore S, Diakite B, Coulibaly MB, Liu Y, Lacey M, Lefante JJ, Koita O, Schieffelin JS, Krogstad DJ, Doumbia SO. Expanding Research Capacity in Sub-Saharan Africa Through Informatics, Bioinformatics, and Data Science Training Programs in Mali. Front Genet 2019; 10:331. [PMID: 31031807 PMCID: PMC6473184 DOI: 10.3389/fgene.2019.00331] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Accepted: 03/28/2019] [Indexed: 12/04/2022] Open
Abstract
Bioinformatics and data science research have boundless potential across Africa due to its high levels of genetic diversity and disproportionate burden of infectious diseases, including malaria, tuberculosis, HIV and AIDS, Ebola virus disease, and Lassa fever. This work lays out an incremental approach for reaching underserved countries in bioinformatics and data science research through a progression of capacity building, training, and research efforts. Two global health informatics training programs sponsored by the Fogarty International Center (FIC) were carried out at the University of Sciences, Techniques and Technologies of Bamako, Mali (USTTB) between 1999 and 2011. Together with capacity building efforts through the West Africa International Centers of Excellence in Malaria Research (ICEMR), this progress laid the groundwork for a bioinformatics and data science training program launched at USTTB as part of the Human Heredity and Health in Africa (H3Africa) initiative. Prior to the global health informatics training, its trainees published first or second authorship and third or higher authorship manuscripts at rates of 0.40 and 0.10 per year, respectively. Following the training, these rates increased to 0.70 and 1.23 per year, respectively, which was a statistically significant increase (p < 0.001). The bioinformatics and data science training program at USTTB commenced in 2017 focusing on student, faculty, and curriculum tiers of enhancement. The program's sustainable measures included institutional support for core elements, university tuition and fees, resource sharing and coordination with local research projects and companion training programs, increased student and faculty publication rates, and increased research proposal submissions. Challenges reliance of high-speed bandwidth availability on short-term funding, lack of a discounted software portal for basic software applications, protracted application processes for United States visas, lack of industry job positions, and low publication rates in the areas of bioinformatics and data science. Long-term, incremental processes are necessary for engaging historically underserved countries in bioinformatics and data science research. The multi-tiered enhancement approach laid out here provides a platform for generating bioinformatics and data science technicians, teachers, researchers, and program managers. Increased literature on bioinformatics and data science training approaches and progress is needed to provide a framework for establishing benchmarks on the topics.
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Affiliation(s)
- Jeffrey G. Shaffer
- Department of Global Biostatistics and Data Science, Tulane University School of Public Health and Tropical Medicine, New Orleans, LA, United States
| | - Frances J. Mather
- Department of Global Biostatistics and Data Science, Tulane University School of Public Health and Tropical Medicine, New Orleans, LA, United States
| | - Mamadou Wele
- Faculty of Medicine and Odontostomatology, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Jian Li
- Department of Global Biostatistics and Data Science, Tulane University School of Public Health and Tropical Medicine, New Orleans, LA, United States
| | - Cheick Oumar Tangara
- Faculty of Medicine and Odontostomatology, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Yaya Kassogue
- Faculty of Medicine and Odontostomatology, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Sudesh K. Srivastav
- Department of Global Biostatistics and Data Science, Tulane University School of Public Health and Tropical Medicine, New Orleans, LA, United States
| | - Oumar Thiero
- Faculty of Medicine and Odontostomatology, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Mahamadou Diakite
- Faculty of Medicine and Odontostomatology, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Modibo Sangare
- Faculty of Medicine and Odontostomatology, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Djeneba Dabitao
- Faculty of Medicine and Odontostomatology, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Mahamoudou Toure
- Faculty of Medicine and Odontostomatology, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Abdoulaye A. Djimde
- Faculty of Medicine and Odontostomatology, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Sekou Traore
- Faculty of Medicine and Odontostomatology, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Brehima Diakite
- Faculty of Medicine and Odontostomatology, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Mamadou B. Coulibaly
- Faculty of Medicine and Odontostomatology, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Yaozhong Liu
- Department of Global Biostatistics and Data Science, Tulane University School of Public Health and Tropical Medicine, New Orleans, LA, United States
| | - Michelle Lacey
- Department of Mathematics, Tulane University, New Orleans, LA, United States
| | - John J. Lefante
- Department of Global Biostatistics and Data Science, Tulane University School of Public Health and Tropical Medicine, New Orleans, LA, United States
| | - Ousmane Koita
- Faculty of Medicine and Odontostomatology, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - John S. Schieffelin
- Sections of Pediatric & Adult Infectious Diseases, School of Medicine, Tulane University, New Orleans, LA, United States
| | - Donald J. Krogstad
- Department of Global Biostatistics and Data Science, Tulane University School of Public Health and Tropical Medicine, New Orleans, LA, United States
| | - Seydou O. Doumbia
- Faculty of Medicine and Odontostomatology, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
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Koita OA, Krogstad DJ. Converting a Liability to an Asset: Using the Clearance of a Malaria Parasite Protein From the Blood of Infected Subjects to Predict the Outcome of Treatment. J Infect Dis 2019; 217:683-684. [PMID: 29220495 DOI: 10.1093/infdis/jix623] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Accepted: 11/19/2017] [Indexed: 11/13/2022] Open
Affiliation(s)
- Ousmane A Koita
- Faculties of Science and Medicine, University of the Sciences, Techniques and Technologies of Bamako, Mali.,Department of Tropical Medicine, Tulane University Health Sciences Center, New Orleans, Louisiana.,Department of Medicine, Tulane University Health Sciences Center, New Orleans, Louisiana
| | - Donald J Krogstad
- Faculties of Science and Medicine, University of the Sciences, Techniques and Technologies of Bamako, Mali.,Department of Tropical Medicine, Tulane University Health Sciences Center, New Orleans, Louisiana.,Department of Medicine, Tulane University Health Sciences Center, New Orleans, Louisiana
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Shaffer JG, Doumbia SO, Ndiaye D, Diarra A, Gomis JF, Nwakanma D, Abubakar I, Ahmad A, Affara M, Lukowski M, Valim C, Welty JC, Mather FJ, Keating J, Krogstad DJ. Development of a data collection and management system in West Africa: challenges and sustainability. Infect Dis Poverty 2018; 7:125. [PMID: 30541626 PMCID: PMC6292095 DOI: 10.1186/s40249-018-0494-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Accepted: 10/17/2018] [Indexed: 12/03/2022] Open
Abstract
BACKGROUND Developing and sustaining a data collection and management system (DCMS) is difficult in malaria-endemic countries because of limitations in internet bandwidth, computer resources and numbers of trained personnel. The premise of this paper is that development of a DCMS in West Africa was a critically important outcome of the West African International Centers of Excellence for Malaria Research. The purposes of this paper are to make that information available to other investigators and to encourage the linkage of DCMSs to international research and Ministry of Health data systems and repositories. METHODS We designed and implemented a DCMS to link study sites in Mali, Senegal and The Gambia. This system was based on case report forms for epidemiologic, entomologic, clinical and laboratory aspects of plasmodial infection and malarial disease for a longitudinal cohort study and included on-site training for Principal Investigators and Data Managers. Based on this experience, we propose guidelines for the design and sustainability of DCMSs in environments with limited resources and personnel. RESULTS From 2012 to 2017, we performed biannual thick smear surveys for plasmodial infection, mosquito collections for anopheline biting rates and sporozoite rates and year-round passive case detection for malarial disease in four longitudinal cohorts with 7708 individuals and 918 households in Senegal, The Gambia and Mali. Major challenges included the development of uniform definitions and reporting, assessment of data entry error rates, unstable and limited internet access and software and technology maintenance. Strengths included entomologic collections linked to longitudinal cohort studies, on-site data centres and a cloud-based data repository. CONCLUSIONS At a time when research on diseases of poverty in low and middle-income countries is a global priority, the resources available to ensure accurate data collection and the electronic availability of those data remain severely limited. Based on our experience, we suggest the development of a regional DCMS. This approach is more economical than separate data centres and has the potential to improve data quality by encouraging shared case definitions, data validation strategies and analytic approaches including the molecular analysis of treatment successes and failures.
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Affiliation(s)
- Jeffrey G. Shaffer
- Departments of Biostatistics (1440 Canal St., Suite 1610) and Tropical Medicine, (#8317 1430 Tulane Avenue, J.B. Johnston Building, Room 510), New Orleans, LA 70112-2699 USA
| | - Seydou O. Doumbia
- University of the Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | | | - Ayouba Diarra
- University of the Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | | | | | | | | | - Muna Affara
- Medical Research Council Unit, Fajara, The Gambia
| | | | - Clarissa Valim
- Harvard T.H. Chan School of Public Health, Boston, MA USA
| | - James C. Welty
- Departments of Biostatistics (1440 Canal St., Suite 1610) and Tropical Medicine, (#8317 1430 Tulane Avenue, J.B. Johnston Building, Room 510), New Orleans, LA 70112-2699 USA
| | - Frances J. Mather
- Departments of Biostatistics (1440 Canal St., Suite 1610) and Tropical Medicine, (#8317 1430 Tulane Avenue, J.B. Johnston Building, Room 510), New Orleans, LA 70112-2699 USA
| | - Joseph Keating
- Departments of Biostatistics (1440 Canal St., Suite 1610) and Tropical Medicine, (#8317 1430 Tulane Avenue, J.B. Johnston Building, Room 510), New Orleans, LA 70112-2699 USA
| | - Donald J. Krogstad
- Departments of Biostatistics (1440 Canal St., Suite 1610) and Tropical Medicine, (#8317 1430 Tulane Avenue, J.B. Johnston Building, Room 510), New Orleans, LA 70112-2699 USA
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9
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Koita OA, Sangaré L, Miller HD, Sissako A, Coulibaly M, Thompson TA, Fongoro S, Diarra Y, Ba M, Maiga A, Diallo B, Mushatt DM, Mather FJ, Shaffer JG, Anwar AH, Krogstad DJ. AQ-13, an investigational antimalarial, versus artemether plus lumefantrine for the treatment of uncomplicated Plasmodium falciparum malaria: a randomised, phase 2, non-inferiority clinical trial. Lancet Infect Dis 2017; 17:1266-1275. [PMID: 28916443 PMCID: PMC5700806 DOI: 10.1016/s1473-3099(17)30365-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Revised: 05/16/2017] [Accepted: 06/08/2017] [Indexed: 12/02/2022]
Abstract
BACKGROUND Chloroquine was used for malaria treatment until resistant Plasmodium falciparum was identified. Because 4-aminoquinolines with modified side chains, such as AQ-13, are active against resistant parasites, we compared AQ-13 against artemether plus lumefantrine for treatment of uncomplicated P falciparum malaria. METHODS We did a randomised, non-inferiority trial. We screened men (≥18 years) with uncomplicated malaria in Missira (northeast Mali) and Bamako (capital of Mali) for eligibility (≥2000 asexual P falciparum parasites per μL of blood). Eligible participants were randomly assigned to either the artemether plus lumefantrine group or AQ-13 group by permuting blocks of four with a random number generator. Physicians and others caring for the participants were masked, except for participants who received treatment and the research pharmacist who implemented the randomisation and provided treatment. Participants received either 80 mg of oral artemether and 480 mg of oral lumefantrine twice daily for 3 days or 638·50 mg of AQ-13 base (two oral capsules) on days 1 and 2, and 319·25 mg base (one oral capsule) on day 3. Participants were monitored for parasite clearance (50 μL blood samples twice daily at 12 h intervals until two consecutive negative samples were obtained) and interviewed for adverse events (once every day) as inpatients during week 1. During the 5-week outpatient follow-up, participants were examined for adverse events and recurrent infection twice per week. All participants were included in the intention-to-treat analysis and per-protocol analysis, except for those who dropped out in the per-protocol analysis. The composite primary outcome was clearance of asexual parasites and fever by day 7, and absence of recrudescent infection by parasites with the same molecular markers from days 8 to 42 (defined as cure). Non-inferiority was considered established if the proportion of patients who were cured was higher for artemether plus lumefantrine than for AQ-13 and the upper limit of the 95% CI was less than the non-inferiority margin of 15%. This trial is registered at ClinicalTrials.gov, number NCT01614964. FINDINGS Between Aug 6 and Nov 18, 2013, and between Sept 18 and Nov 20, 2015, 66 Malian men with uncomplicated malaria were enrolled. 33 participants were randomly assigned to each group. There were no serious adverse events (grade 2-4) and asexual parasites were cleared by day 7 in both groups. 453 less-severe adverse events (≤grade 1) were reported: 214 in the combination group and 239 in the AQ-13 group. Two participants withdrew from the AQ-13 group after parasite clearance and three were lost to follow-up. In the artemether plus lumefantrine group, two participants had late treatment failures (same markers as original isolates). On the basis of the per-protocol analysis, the AQ-13 and artemether plus lumefantrine groups had similar proportions cured (28 [100%] of 28 vs 31 [93·9%] of 33; p=0·50) and AQ-13 was not inferior to artemether plus lumefantrine (difference -6·1%, 95% CI -14·7 to 2·4). Proportions cured were also similar between the groups in the intention-to-treat analysis (28 of 33, 84·8% for AQ-13 vs 31 of 33, 93·9% for artemether and lumefantrine; p=0·43) but the upper bound of the 95% CI exceeded the 15% non-inferiority margin (difference 9·1%, 95% CI -5·6 to 23·8). INTERPRETATION The per-protocol analysis suggested non-inferiority of AQ-13 to artemether plus lumefantrine. By contrast, the intention-to-treat analysis, which included two participants who withdrew and three who were lost to follow-up from the AQ-13 group, did not meet the criterion for non-inferiority of AQ-13, although there were no AQ-13 treatment failures. Studies with more participants (and non-immune participants) are needed to decide whether widespread use of modified 4-aminoquinolones should be recommended. FUNDING US Food and Drug Administration Orphan Product Development, National Institutes of Health, US Centers for Disease Control and Prevention, Burroughs-Wellcome Fund, US State Department, and WHO.
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Affiliation(s)
- Ousmane A Koita
- University of the Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Lansana Sangaré
- University of the Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Haiyan D Miller
- Department of Tropical Medicine and the Center for Infectious Diseases, Tulane University Health Sciences Center, New Orleans, LA, USA
| | - Aliou Sissako
- University of the Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Moctar Coulibaly
- University of the Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Trevor A Thompson
- Department of Tropical Medicine and the Center for Infectious Diseases, Tulane University Health Sciences Center, New Orleans, LA, USA
| | - Saharé Fongoro
- University of the Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Youssouf Diarra
- University of the Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Mamadou Ba
- University of the Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Ababacar Maiga
- University of the Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Boubakar Diallo
- University of the Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - David M Mushatt
- Department of Medicine, Tulane University Health Sciences Center, New Orleans, LA, USA
| | - Frances J Mather
- Department of Global Biostatistics and Data Science, Tulane University Health Sciences Center, New Orleans, LA, USA
| | - Jeffrey G Shaffer
- Department of Global Biostatistics and Data Science, Tulane University Health Sciences Center, New Orleans, LA, USA
| | - Asif H Anwar
- Department of Medicine, Tulane University Health Sciences Center, New Orleans, LA, USA
| | - Donald J Krogstad
- Department of Medicine, Tulane University Health Sciences Center, New Orleans, LA, USA; Department of Tropical Medicine and the Center for Infectious Diseases, Tulane University Health Sciences Center, New Orleans, LA, USA.
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Mbaye A, Gaye A, Dieye B, Ndiaye YD, Bei AK, Affara M, Deme AB, Yade MS, Diongue K, Ndiaye IM, Ndiaye T, Sy M, Sy N, Koita O, Krogstad DJ, Volkman S, Nwakanma D, Ndiaye D. Ex vivo susceptibility and genotyping of Plasmodium falciparum isolates from Pikine, Senegal. Malar J 2017; 16:250. [PMID: 28615016 PMCID: PMC5471902 DOI: 10.1186/s12936-017-1897-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Accepted: 06/06/2017] [Indexed: 01/21/2023] Open
Abstract
Background The monitoring of Plasmodium falciparum sensitivity to anti-malarial drugs is a necessity for effective case management of malaria. This species is characterized by a strong resistance to anti-malarial drugs. In Senegal, the first cases of chloroquine resistance were reported in the Dakar region in 1988 with nearly 7% population prevalence, reaching 47% by 1990. It is in this context that sulfadoxine–pyrimethamine temporarily replaced chloroquine as first line treatment in 2003, pending the introduction of artemisinin-based combination therapy in 2006. The purpose of this study is to assess the ex vivo sensitivity to different anti-malarial drugs of the P. falciparum population from Pikine. Methods Fifty-four samples were collected from patients with non-complicated malaria and aged between 2 and 20 years in the Deggo health centre in Pikine in 2014. An assay in which parasites are stained with 4′, 6-di-amidino-2-phenylindole (DAPI), was used to study the ex vivo sensitivity of isolates to chloroquine, amodiaquine, piperaquine, pyrimethamine, and dihydroartemisinin. High resolution melting was used for genotyping of pfdhps, pfdhfr, pfmdr1, and pfcrt genes. Results The mean IC50s of chloroquine, amodiaquine, piperaquine, dihydroartemisinin, and pyrimethamine were, respectively, 39.44, 54.02, 15.28, 2.23, and 64.70 nM. Resistance mutations in pfdhfr gene, in codon 437 of pfdhps gene, and an absence of mutation at position 540 of pfdhps were observed. Mutations in codons K76T of pfcrt and N86Y of pfmdr1 were observed at 51 and 11% population prevalence, respectively. A relationship was found between the K76T and N86Y mutations and ex vivo resistance to chloroquine. Conclusion An increase in sensitivity of isolates to chloroquine was observed. A high sensitivity to dihydroartemisinin was observed; whereas, a decrease in sensitivity to pyrimethamine was observed in the parasite population from Pikine.
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Affiliation(s)
- Aminata Mbaye
- Laboratory of Parasitology/Mycology HALD, Cheikh Anta Diop University of Dakar, PO Box 5005, Dakar, Senegal.
| | - Amy Gaye
- Laboratory of Parasitology/Mycology HALD, Cheikh Anta Diop University of Dakar, PO Box 5005, Dakar, Senegal
| | - Baba Dieye
- Laboratory of Parasitology/Mycology HALD, Cheikh Anta Diop University of Dakar, PO Box 5005, Dakar, Senegal
| | - Yaye D Ndiaye
- Laboratory of Parasitology/Mycology HALD, Cheikh Anta Diop University of Dakar, PO Box 5005, Dakar, Senegal
| | - Amy K Bei
- Laboratory of Parasitology/Mycology HALD, Cheikh Anta Diop University of Dakar, PO Box 5005, Dakar, Senegal.,Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, MA, USA
| | - Muna Affara
- Medical Research Council Unit, The Gambia, Fajara, Gambia
| | - Awa B Deme
- Laboratory of Parasitology/Mycology HALD, Cheikh Anta Diop University of Dakar, PO Box 5005, Dakar, Senegal
| | - Mamadou S Yade
- Laboratory of Parasitology/Mycology HALD, Cheikh Anta Diop University of Dakar, PO Box 5005, Dakar, Senegal
| | - Khadim Diongue
- Laboratory of Parasitology/Mycology HALD, Cheikh Anta Diop University of Dakar, PO Box 5005, Dakar, Senegal
| | - Ibrahima M Ndiaye
- Laboratory of Parasitology/Mycology HALD, Cheikh Anta Diop University of Dakar, PO Box 5005, Dakar, Senegal
| | - Tolla Ndiaye
- Laboratory of Parasitology/Mycology HALD, Cheikh Anta Diop University of Dakar, PO Box 5005, Dakar, Senegal
| | - Mouhamed Sy
- Laboratory of Parasitology/Mycology HALD, Cheikh Anta Diop University of Dakar, PO Box 5005, Dakar, Senegal
| | - Ngayo Sy
- Laboratory of Parasitology/Mycology HALD, Cheikh Anta Diop University of Dakar, PO Box 5005, Dakar, Senegal
| | | | | | - Sarah Volkman
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, MA, USA
| | - Davis Nwakanma
- Medical Research Council Unit, The Gambia, Fajara, Gambia
| | - Daouda Ndiaye
- Laboratory of Parasitology/Mycology HALD, Cheikh Anta Diop University of Dakar, PO Box 5005, Dakar, Senegal.,Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, MA, USA
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11
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Kozycki CT, Umulisa N, Rulisa S, Mwikarago EI, Musabyimana JP, Habimana JP, Karema C, Krogstad DJ. False-negative malaria rapid diagnostic tests in Rwanda: impact of Plasmodium falciparum isolates lacking hrp2 and declining malaria transmission. Malar J 2017; 16:123. [PMID: 28320390 PMCID: PMC5359811 DOI: 10.1186/s12936-017-1768-1] [Citation(s) in RCA: 83] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Accepted: 03/08/2017] [Indexed: 11/10/2022] Open
Abstract
Background Rapid diagnostic tests (RDTs) for histidine rich protein 2 (HRP2) are often used to determine whether persons with fever should be treated with anti-malarials. However, Plasmodium falciparum parasites with a deletion of the hrp2 gene yield false-negative RDTs and there are concerns the sensitivity of HRP2-based RDTs may fall when the intensity of transmission decreases. Methods This observational study enrolled 9226 patients at three health centres in Rwanda from April 2014 to April 2015. It then compared the sensitivity of RDTs based on HRP2 and the Plasmodium lactate dehydrogenase (pLDH) to microscopy (thick smears) for the diagnosis of malaria. PCR was used to determine whether deletions of the histidine-rich central repeat region of the hrp2 gene (exon 2) were associated with false-negative HRP2-based RDTs. Results In comparison to microscopy, the sensitivity and specificity of HRP2- and pLDH-based RDTs were 89.5 and 86.2% and 80.2 and 94.3%, respectively. When the results for both RDTs were combined, sensitivity rose to 91.8% and specificity was 85.7%. Additionally, when smear positivity fell from 46 to 3%, the sensitivity of the HRP2-based RDT fell from 88 to 67%. Of 370 samples with false-negative HRP2 RDT results for which PCR was performed, 140 (38%) were identified as P. falciparum by PCR. Of the isolates identified as P. falciparum by PCR, 32 (23%) were negative for the hrp2 gene based on PCR. Of the 32 P. falciparum isolates negative for hrp2 by PCR, 17 (53%) were positive based on the pLDH RDT. Conclusion This prospective study of RDT performance coincided with a decline in the intensity of malaria transmission in Kibirizi (fall in slide positivity from 46 to 3%). This decline was associated with a decrease in HRP2 RDT sensitivity (from 88 to 67%). While P. falciparum isolates without the hrp2 gene were an important cause of false-negative HRP2-based RDTs, most were identified by the pLDH-based RDT. Although WHO does not recommend the use of combined HRP2/pLDH testing in sub-Saharan Africa, these results suggest that combination HRP2/pLDH-based RDTs could reduce the impact of false-negative HRP2-based RDTs for detection of symptomatic P. falciparum malaria. Electronic supplementary material The online version of this article (doi:10.1186/s12936-017-1768-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | - Noella Umulisa
- Malaria and Other Parasitic Diseases Division, Rwanda Biomedical Centre, Ministry of Health, Kigali, Rwanda.,Maternal and Child Survival Programme, Jhpiego, Kigali, Rwanda
| | - Stephen Rulisa
- School of Medicine and Pharmacy, University of Rwanda, Kigali, Rwanda
| | - Emil I Mwikarago
- National Reference Laboratory, Rwanda Biomedical Centre, Ministry of Health, Kigali, Rwanda
| | | | - Jean Pierre Habimana
- Malaria and Other Parasitic Diseases Division, Rwanda Biomedical Centre, Ministry of Health, Kigali, Rwanda
| | - Corine Karema
- Malaria and Other Parasitic Diseases Division, Rwanda Biomedical Centre, Ministry of Health, Kigali, Rwanda.,Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland.,Quality and Equity Healthcare, Kigali, Rwanda
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12
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Ramanathan-Girish S, Catz P, Creek MR, Wu B, Thomas D, Krogstad DJ, De D, Mirsalis JC, Green CE. Pharmacokinetics of the Antimalarial Drug, AQ-13, in Rats and Cynomolgus Macaques. Int J Toxicol 2016; 23:179-89. [PMID: 15204721 DOI: 10.1080/10915810490471352] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The purpose of this study was to evaluate the bioavailability and pharmacokinetics of a new antimalarial drug, AQ-13, a structural analog of chloroquine (CQ) that is active against CQ-resistant Plasmodium species, in rats and cynomolgus macaques. Sprague-Dawley rats ( n = 4 /sex) were administered a single dose of AQ-13 intravenously (i.v.) (10 mg/kg) or orally (20 or 102 mg/kg). Blood and plasma samples were collected at several timepoints. AQ-13 achieved Cmax after oral administration at approximately 3 to 4 h and could be detected in blood for 2 to 5 days after oral administration. The ratio of area under the curve (AUC) values at the high and low dose for AQ-13 deviated from an expected ratio of 5.0, indicating nonlinear kinetics. A metabolite peak was noted in the chromatograms that was identified as monodesethyl AQ-13. Oral bioavailability of AQ-13 was good, approximately 70%. The pharmacokinetics of AQ-13 was also determined in cynomolgus macaques after single (i.v., 10 mg/kg; oral, 20 or 100 mg/kg) and multiple doses (oral loading dose of 50, 100, or 200 mg/kg on first day followed by oral maintenance dose of 25, 50, or 100 mg/kg, respectively, for 6 days). The AUC and Cmax values following single oral dose administration were not dose proportional; the Cmax value for AQ-13 was 15-fold higher following an oral dose of 100 mg/kg compared to 20 mg/kg. MonodesethylAQ-13 was a significant metabolite formed by cynomolgus macaques and the corresponding Cmax values for this metabolite increased only 3.8-fold over the dose range, suggesting that the formation of monodesethyl AQ-13 is saturable in this species. The bioavailability of AQ-13 in cynomolgus macaques following oral administration was 23.8% for the 20-mg/kg group and 47.6% for the 100-mg/kg group. Following repeat dose administration, high concentrations of monodesethyl AQ-13 were observed in the blood by day 4, exceeding the AQ-13 blood concentrations through day 22. Saturation of metabolic pathways and reduced metabolite elimination after higher doses are suggested to play a key role in AQ-13 pharmacokinetics in macaques. In summary, the pharmacokinetic profile and metabolism ofAQ-13 are very similar to that reported in the literature for chloroquine, suggesting that this new agent is a promising candidate for further development for the treatment of chloroquine-resistant malaria.
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13
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Mbaye A, Dieye B, Ndiaye YD, Bei AK, Muna A, Deme AB, Yade MS, Diongue K, Gaye A, Ndiaye IM, Ndiaye T, Sy M, Diallo MA, Badiane AS, Ndiaye M, Seck MC, Sy N, Koita O, Krogstad DJ, Nwakanma D, Ndiaye D. Selection of N86F184D1246 haplotype of Pfmrd1 gene by artemether-lumefantrine drug pressure on Plasmodium falciparum populations in Senegal. Malar J 2016; 15:433. [PMID: 27562216 PMCID: PMC5000460 DOI: 10.1186/s12936-016-1490-4] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Accepted: 08/16/2016] [Indexed: 01/06/2023] Open
Abstract
Background The use of artemisinin as a monotherapy resulted in the emergence of artemisinin resistance in 2005 in Southeast Asia. Monitoring of artemisinin combination therapy (ACT) is critical in order to detect and prevent the spread of resistance in endemic areas. Ex vivo studies and genotyping of molecular markers of resistance can be used as part of this routine monitoring strategy. One gene that has been associated in some ACT partner drug resistance is the Plasmodium falciparum multidrug resistance protein 1 (pfmdr1) gene. The purpose of this study was to assess the drug susceptibility of P. falciparum populations from Thiès, Senegal by ex vivo assay and typing molecular markers of resistance to drug components of ACT currently used for treatment. Methods The ex vivo susceptibility of 170 P. falciparum isolates to chloroquine, amodiaquine, lumefantrine, artesunate, and artemether was determined using the DAPI ex vivo assay. The high resolution melting technique was used to genotype the pfmdr1 gene at codons 86, 184 and 1246. Results A significant decrease in IC50 values was observed between 2012 and 2013: from 13.84 to 6.484 for amodiaquine, 173.4 to 113.2 for lumefantrine, and 39.72 to 18.29 for chloroquine, respectively. Increase of the wild haplotype NYD and the decrease of the mutant haplotype NFD (79 and 62.26 %) was also observed. A correlation was observed between the wild type allele Y184 in pfmdr1 and higher IC50 for all drugs, except amodiaquine. Conclusion This study has shown an increase in sensitivity over the span of two transmission seasons, marked by an increase in the WT alleles at pfmdr1. Continuous the monitoring of the ACT used for treatment of uncomplicated malaria will be helpful.
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Affiliation(s)
- Aminata Mbaye
- Laboratory of Parasitology/Mycology HALD, Cheikh Anta Diop University of Dakar, PO Box 5005, Dakar, Senegal.
| | - Baba Dieye
- Laboratory of Parasitology/Mycology HALD, Cheikh Anta Diop University of Dakar, PO Box 5005, Dakar, Senegal
| | - Yaye D Ndiaye
- Laboratory of Parasitology/Mycology HALD, Cheikh Anta Diop University of Dakar, PO Box 5005, Dakar, Senegal
| | - Amy K Bei
- Laboratory of Parasitology/Mycology HALD, Cheikh Anta Diop University of Dakar, PO Box 5005, Dakar, Senegal.,Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, MA, USA
| | | | - Awa B Deme
- Laboratory of Parasitology/Mycology HALD, Cheikh Anta Diop University of Dakar, PO Box 5005, Dakar, Senegal
| | - Mamadou S Yade
- Laboratory of Parasitology/Mycology HALD, Cheikh Anta Diop University of Dakar, PO Box 5005, Dakar, Senegal
| | - Khadim Diongue
- Laboratory of Parasitology/Mycology HALD, Cheikh Anta Diop University of Dakar, PO Box 5005, Dakar, Senegal
| | - Amy Gaye
- Laboratory of Parasitology/Mycology HALD, Cheikh Anta Diop University of Dakar, PO Box 5005, Dakar, Senegal
| | - Ibrahima M Ndiaye
- Laboratory of Parasitology/Mycology HALD, Cheikh Anta Diop University of Dakar, PO Box 5005, Dakar, Senegal
| | - Tolla Ndiaye
- Laboratory of Parasitology/Mycology HALD, Cheikh Anta Diop University of Dakar, PO Box 5005, Dakar, Senegal
| | - Mouhamad Sy
- Laboratory of Parasitology/Mycology HALD, Cheikh Anta Diop University of Dakar, PO Box 5005, Dakar, Senegal
| | - Mamadou A Diallo
- Laboratory of Parasitology/Mycology HALD, Cheikh Anta Diop University of Dakar, PO Box 5005, Dakar, Senegal
| | - Aida S Badiane
- Laboratory of Parasitology/Mycology HALD, Cheikh Anta Diop University of Dakar, PO Box 5005, Dakar, Senegal
| | - Mouhamadou Ndiaye
- Laboratory of Parasitology/Mycology HALD, Cheikh Anta Diop University of Dakar, PO Box 5005, Dakar, Senegal
| | - Mame C Seck
- Laboratory of Parasitology/Mycology HALD, Cheikh Anta Diop University of Dakar, PO Box 5005, Dakar, Senegal
| | - Ngayo Sy
- Laboratory of Parasitology/Mycology HALD, Cheikh Anta Diop University of Dakar, PO Box 5005, Dakar, Senegal
| | | | | | | | - Daouda Ndiaye
- Laboratory of Parasitology/Mycology HALD, Cheikh Anta Diop University of Dakar, PO Box 5005, Dakar, Senegal.,Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, MA, USA
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14
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Dieye B, Affara M, Sangare L, Joof F, Ndiaye YD, Gomis JF, Ndiaye M, Mbaye A, Diakite M, Sy N, Mbengue B, Deme AB, Daniels R, Ahouidi AD, Dieye T, Abdullahi A, Doumbia S, Ndiaye JL, Diarra A, Ismaela A, Coulibaly M, Welty C, Ngwa AA, Shaffer J, D'Alessandro U, Volkman SK, Wirth DF, Krogstad DJ, Koita O, Nwakanma D, Ndiaye D. West Africa International Centers of Excellence for Malaria Research: Drug Resistance Patterns to Artemether-Lumefantrine in Senegal, Mali, and The Gambia. Am J Trop Med Hyg 2016; 95:1054-1060. [PMID: 27549635 DOI: 10.4269/ajtmh.16-0053] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Accepted: 06/29/2016] [Indexed: 01/09/2023] Open
Abstract
In 2006, artemether-lumefantrine (AL) became the first-line treatment of uncomplicated malaria in Senegal, Mali, and the Gambia. To monitor its efficacy, between August 2011 and November 2014, children with uncomplicated Plasmodium falciparum malaria were treated with AL and followed up for 42 days. A total of 463 subjects were enrolled in three sites (246 in Senegal, 97 in Mali, and 120 in Gambia). No early treatment failure was observed and malaria infection cleared in all patients by day 3. Polymerase chain reaction (PCR)-adjusted adequate clinical and parasitological response (ACPR) was 100% in Mali, and the Gambia, and 98.8% in Senegal. However, without PCR adjustment, ACPR was 89.4% overall; 91.5% in Mali, 98.8% in Senegal, and 64.3% in the Gambia (the lower value in the Gambia attributed to poor compliance of the full antimalarial course). However, pfmdr1 mutations were prevalent in Senegal and a decrease in parasite sensitivity to artesunate and lumefantrine (as measured by ex vivo drug assay) was observed at all sites. Recrudescent parasites did not show Kelch 13 (K13) mutations and AL remains highly efficacious in these west African sites.
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Affiliation(s)
- Baba Dieye
- Cheikh Anta Diop University, Dakar, Senegal
| | | | | | | | | | | | | | | | | | - Ngayo Sy
- Cheikh Anta Diop University, Dakar, Senegal
| | | | - Awa B Deme
- Cheikh Anta Diop University, Dakar, Senegal
| | - Rachel Daniels
- Harvard T.H. Chan School of Public Health, Boston, Massachusetts
| | | | | | | | | | | | | | | | | | | | | | | | - Umberto D'Alessandro
- Medical Research Council, The Gambia.,London School of Hygiene and Tropical Medicine, London, United Kingdom.,Institute of Tropical Medicine, Antwerp, Belgium
| | - Sarah K Volkman
- Harvard T.H. Chan School of Public Health, Boston, Massachusetts.,The Broad Institute of MIT and Harvard, Cambridge, Massachusetts.,Simmons College School of Nursing and Health Sciences, Boston, Massachusetts
| | - Dyann F Wirth
- Harvard T.H. Chan School of Public Health, Boston, Massachusetts.,The Broad Institute of MIT and Harvard, Cambridge, Massachusetts
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15
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Koita OA, Murphy RL, Fongoro S, Diallo B, Doumbia SO, Traoré M, Krogstad DJ. Clinical Research and the Training of Host Country Investigators: Essential Health Priorities for Disease-Endemic Regions. Am J Trop Med Hyg 2015; 94:253-257. [PMID: 26598570 PMCID: PMC4751934 DOI: 10.4269/ajtmh.15-0366] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2015] [Accepted: 09/25/2015] [Indexed: 11/23/2022] Open
Abstract
The health-care needs and resources of disease-endemic regions such as west Africa have been a major focus during the recent Ebola outbreak. On the basis of that experience, we call attention to two priorities that have unfortunately been ignored thus far: 1) the development of clinical research facilities and 2) the training of host country investigators to ensure that the facilities and expertise necessary to evaluate candidate interventions are available on-site in endemic regions when and where they are needed. In their absence, as illustrated by the recent uncertainty about the use of antivirals and other interventions for Ebola virus disease, the only treatment available may be supportive care, case fatality rates may be unacceptably high and there may be long delays between the time potential interventions become available and it becomes clear whether those interventions are safe or effective. On the basis of our experience in Mali, we urge that the development of clinical research facilities and the training of host country investigators be prioritized in disease-endemic regions such as west Africa.
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Affiliation(s)
- Ousmane A. Koita
- *Address correspondence to Ousmane A. Koita, Faculty of Medicine, University of the Sciences, Techniques and Technologies, BP 1805, Point G, Bamako, Mali. E-mail:
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16
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Krogstad DJ, Koita OA, Diallo M, Gerone JL, Poudiougou B, Diakité M, Touré YT. Molecular incidence and clearance of Plasmodium falciparum infection. Malar J 2015; 14:415. [PMID: 26492968 PMCID: PMC4618950 DOI: 10.1186/s12936-015-0941-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2015] [Accepted: 10/11/2015] [Indexed: 11/14/2022] Open
Abstract
Background Although the epidemiology of malaria has been based primarily on microscopy and rapid diagnostic tests, molecular methods are necessary to understand the complexity of natural infection in regions where transmission is intense and simultaneous infection with multiple parasite genotypes is common such as sub-Saharan Africa. Methods To compare microscopic and molecular estimates of the incidence and clearance of Plasmodium falciparum infection, we followed 80 children monthly for 1 year in the village of Bancoumana in Mali. Results and discussion Similar seasonal patterns were observed with both methods (rainy season peak, dry season nadir), although molecular methods detected more infections than microscopy (571 vs 331 in 906 specimens), more new infections (311 vs 104 during 829 person-months) and spontaneous clearance events (317 vs 116) and found higher incidence (0.38 vs 0.13 new genotypes/person/month, p < 0.001) and spontaneous clearance rates (0.38 vs 0.14 genotypes cleared/person/month, p < 0.001). These differences were greatest for persistently-infected subjects in whom neither new infections nor the clearance of old infections could be detected by microscopy (0.71 new infections and 0.73 cleared infections per month using molecular methods vs 0.000 by microscopy, p < 0.001). Conclusions Molecular methods provide information about genetic diversity, the intensity of transmission and spontaneous clearance in the absence of drug treatment that cannot be obtained by microscopy. They will be necessary to evaluate the efficacy of vaccines, drugs and other control strategies for diseases such as malaria in which simultaneous infection with more than one organism (genotype) is common.
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Affiliation(s)
- Donald J Krogstad
- Center for Infectious Diseases, Tulane University School of Public Health and Tropical Medicine, #8317, J. Bennett Johnston Building, Room 510, 1324 Tulane Avenue, New Orleans, LA, 70112, USA. .,Department of Tropical Medicine, Tulane University School of Public Health and Tropical Medicine, New Orleans, LA, USA. .,Faculty of Medicine, Pharmacy and Odontostomatology, Mali-Tulane Tropical Medicine Research Center, University of Bamako, Bamako, Mali.
| | - Ousmane A Koita
- Center for Infectious Diseases, Tulane University School of Public Health and Tropical Medicine, #8317, J. Bennett Johnston Building, Room 510, 1324 Tulane Avenue, New Orleans, LA, 70112, USA. .,Faculty of Medicine, Pharmacy and Odontostomatology, Mali-Tulane Tropical Medicine Research Center, University of Bamako, Bamako, Mali.
| | - Mouctar Diallo
- Faculty of Medicine, Pharmacy and Odontostomatology, Mali-Tulane Tropical Medicine Research Center, University of Bamako, Bamako, Mali.
| | - John L Gerone
- Department of Epidemiology, Tulane University School of Public Health and Tropical Medicine, New Orleans, LA, USA.
| | - Belco Poudiougou
- Faculty of Medicine, Pharmacy and Odontostomatology, Mali-Tulane Tropical Medicine Research Center, University of Bamako, Bamako, Mali.
| | - Mahamadou Diakité
- Faculty of Medicine, Pharmacy and Odontostomatology, Mali-Tulane Tropical Medicine Research Center, University of Bamako, Bamako, Mali.
| | - Yéya T Touré
- Faculty of Medicine, Pharmacy and Odontostomatology, Mali-Tulane Tropical Medicine Research Center, University of Bamako, Bamako, Mali.
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17
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Wilson ML, Krogstad DJ, Arinaitwe E, Arevalo-Herrera M, Chery L, Ferreira MU, Ndiaye D, Mathanga DP, Eapen A. Urban Malaria: Understanding its Epidemiology, Ecology, and Transmission Across Seven Diverse ICEMR Network Sites. Am J Trop Med Hyg 2015; 93:110-123. [PMID: 26259941 PMCID: PMC4574269 DOI: 10.4269/ajtmh.14-0834] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2014] [Accepted: 06/19/2015] [Indexed: 11/30/2022] Open
Abstract
A major public health question is whether urbanization will transform malaria from a rural to an urban disease. However, differences about definitions of urban settings, urban malaria, and whether malaria control should differ between rural and urban areas complicate both the analysis of available data and the development of intervention strategies. This report examines the approach of the International Centers of Excellence for Malaria Research (ICEMR) to urban malaria in Brazil, Colombia, India (Chennai and Goa), Malawi, Senegal, and Uganda. Its major theme is the need to determine whether cases diagnosed in urban areas were imported from surrounding rural areas or resulted from transmission within the urban area. If infections are being acquired within urban areas, malaria control measures must be targeted within those urban areas to be effective. Conversely, if malaria cases are being imported from rural areas, control measures must be directed at vectors, breeding sites, and infected humans in those rural areas. Similar interventions must be directed differently if infections were acquired within urban areas. The hypothesis underlying the ICEMR approach to urban malaria is that optimal control of urban malaria depends on accurate epidemiologic and entomologic information about transmission.
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Affiliation(s)
- Mark L. Wilson
- Department of Epidemiology, School of Public Health, University of Michigan, Ann Arbor, Michigan; Department of Tropical Medicine, Tulane University School of Public Health and Tropical Medicine, New Orleans, Louisiana; Infectious Diseases Research Collaboration, Mulago Hospital Campus, Kampala, Uganda; Caucaseo Research Center/School of Health, Universidad del Valle, Cali, Colombia; Department of Chemistry, University of Washington, Seattle, Washington; Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil; University Cheikh Anta Diop, Dakar, Senegal; College of Medicine, University of Malawi, Blantyre, Malawi; National Institute of Malaria Research (Indian Council of Medical Research), National Institute of Epidemiology Campus, Tamil Nadu, India
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18
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Escalante AA, Ferreira MU, Vinetz JM, Volkman SK, Cui L, Gamboa D, Krogstad DJ, Barry AE, Carlton JM, van Eijk AM, Pradhan K, Mueller I, Greenhouse B, Andreina Pacheco M, Vallejo AF, Herrera S, Felger I. Malaria Molecular Epidemiology: Lessons from the International Centers of Excellence for Malaria Research Network. Am J Trop Med Hyg 2015; 93:79-86. [PMID: 26259945 PMCID: PMC4574277 DOI: 10.4269/ajtmh.15-0005] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2015] [Accepted: 05/15/2015] [Indexed: 01/31/2023] Open
Abstract
Molecular epidemiology leverages genetic information to study the risk factors that affect the frequency and distribution of malaria cases. This article describes molecular epidemiologic investigations currently being carried out by the International Centers of Excellence for Malaria Research (ICEMR) network in a variety of malaria-endemic settings. First, we discuss various novel approaches to understand malaria incidence and gametocytemia, focusing on Plasmodium falciparum and Plasmodium vivax. Second, we describe and compare different parasite genotyping methods commonly used in malaria epidemiology and population genetics. Finally, we discuss potential applications of molecular epidemiological tools and methods toward malaria control and elimination efforts.
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Affiliation(s)
- Ananias A. Escalante
- *Address correspondence to Ananias A. Escalante, Institute for Genomics and Evolutionary Medicine, Temple University, SERC Building, 1925 N. 12th Street Philadelphia, PA 19122-1801, E-mail: or Marcelo U. Ferreira, Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, Avenida Professor Lineu Prestes, 1374 - Edifício Biomédicas II, São Paulo, Brazil CEP CEP 05508-900, E-mail: or Ingrid Felger, Swiss Tropical and Public Health Institute, 4002 Basel, Switzerland, E-mail:
| | - Marcelo U. Ferreira
- *Address correspondence to Ananias A. Escalante, Institute for Genomics and Evolutionary Medicine, Temple University, SERC Building, 1925 N. 12th Street Philadelphia, PA 19122-1801, E-mail: or Marcelo U. Ferreira, Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, Avenida Professor Lineu Prestes, 1374 - Edifício Biomédicas II, São Paulo, Brazil CEP CEP 05508-900, E-mail: or Ingrid Felger, Swiss Tropical and Public Health Institute, 4002 Basel, Switzerland, E-mail:
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Ingrid Felger
- *Address correspondence to Ananias A. Escalante, Institute for Genomics and Evolutionary Medicine, Temple University, SERC Building, 1925 N. 12th Street Philadelphia, PA 19122-1801, E-mail: or Marcelo U. Ferreira, Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, Avenida Professor Lineu Prestes, 1374 - Edifício Biomédicas II, São Paulo, Brazil CEP CEP 05508-900, E-mail: or Ingrid Felger, Swiss Tropical and Public Health Institute, 4002 Basel, Switzerland, E-mail:
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19
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Moss WJ, Dorsey G, Mueller I, Laufer MK, Krogstad DJ, Vinetz JM, Guzman M, Rosas-Aguirre AM, Herrera S, Arevalo-Herrera M, Chery L, Kumar A, Mohapatra PK, Ramanathapuram L, Srivastava HC, Cui L, Zhou G, Parker DM, Nankabirwa J, Kazura JW. Malaria Epidemiology and Control Within the International Centers of Excellence for Malaria Research. Am J Trop Med Hyg 2015; 93:5-15. [PMID: 26259946 PMCID: PMC4574274 DOI: 10.4269/ajtmh.15-0006] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2015] [Accepted: 05/29/2015] [Indexed: 11/22/2022] Open
Abstract
Understanding the epidemiological features and metrics of malaria in endemic populations is a key component to monitoring and quantifying the impact of current and past control efforts to inform future ones. The International Centers of Excellence for Malaria Research (ICEMR) has the opportunity to evaluate the impact of malaria control interventions across endemic regions that differ in the dominant Plasmodium species, mosquito vector species, resistance to antimalarial drugs and human genetic variants thought to confer protection from infection and clinical manifestations of plasmodia infection. ICEMR programs are conducting field studies at multiple sites with the aim of generating standardized surveillance data to improve the understanding of malaria transmission and to monitor and evaluate the impact of interventions to inform malaria control and elimination programs. In addition, these epidemiological studies provide a vast source of biological samples linked to clinical and environmental “meta-data” to support translational studies of interactions between the parasite, human host, and mosquito vector. Importantly, epidemiological studies at the ICEMR field sites are integrated with entomological studies, including the measurement of the entomological inoculation rate, human biting index, and insecticide resistance, as well as studies of parasite genetic diversity and antimalarial drug resistance.
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Affiliation(s)
- William J. Moss
- *Address correspondence to William J. Moss, Department of Epidemiology, Bloomberg School of Public Health, Johns Hopkins University, 615 North Wolfe Street, Baltimore, MD 21205. E-mail:
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20
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Billo MA, Diakité M, Dolo A, Diallo M, Poudiougou B, Diawara SI, Johnson ES, Rice JC, Krogstad DJ, Doumbo OK. Inter-observer agreement according to malaria parasite density. Malar J 2013; 12:335. [PMID: 24053719 PMCID: PMC3849530 DOI: 10.1186/1475-2875-12-335] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Accepted: 09/15/2013] [Indexed: 11/21/2022] Open
Abstract
Background Recent developments in diagnostic techniques for malaria, particularly DNA probes and sero-immunology, have raised questions as to how these techniques might be used to facilitate malaria diagnosis at the most peripheral levels of the primary health care system. At present, malaria diagnosis is based on the standard microscopic examination of blood films in most field epidemiologic studies and is likely to remain so in the immediate future in Africa. The objective of this study was to assess inter-observer agreement for the examination of Giemsa-stained slides for Plasmodium falciparum parasites. Methods Children aged 0 to 10 years were enrolled yearly in Bancoumana village (West Africa), mainly during the transmission season (June to October). The blood smears obtained from the persistently negative children in June 1996, August 1996, October 1996 and March 1997 were systematically re-examined. A stratified random sample (10%) proportional to the following parasite density classes 1–100, 101–5000, and 5001 and over was taken from the slides collected. The kappa statistics and the intra-class correlation were used as measures of agreement the first and the second slide examinations. Results The weighted kappa statistic, widely used as a chance-corrected measure for nominal agreement, showed excellent inter-observer agreement (κw=0.7926; 95% CI [0.7588, 0.8263]; p=0.01). The intra-class correlation co-efficient had the same value of 0.7926 confirming the appropriateness of the weighted kappa statistic. Inter-observer agreement for slides read as negative by one observer, or as containing more than 100 parasites per μl, was excellent: 97% (493/506) and 92% (145/158), respectively. In contrast, the inter-observer agreement for slides read by one observer as containing 1–100 parasites/μl was poor, 36% (96/268). Conclusions In field conditions in Mali, there was a high reproducibility for slides reported as negative or as having more than 100 parasites per μl. However, smears with readings of 1–100 parasites per μl were less reproducible and should be re-examined carefully.
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21
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Billo MA, Johnson ES, Doumbia SO, Poudiougou B, Sagara I, Diawara SI, Diakité M, Diallo M, Doumbo OK, Tounkara A, Rice J, James MA, Krogstad DJ. Sickle cell trait protects against Plasmodium falciparum infection. Am J Epidemiol 2012; 176 Suppl 7:S175-85. [PMID: 23035141 DOI: 10.1093/aje/kws323] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Although sickle cell trait protects against severe disease due to Plasmodium falciparum, it has not been clear whether sickle trait also protects against asymptomatic infection (parasitemia). To address this question, the authors identified 171 persistently smear-negative children and 450 asymptomatic persistently smear-positive children in Bancoumana, Mali (June 1996 to June 1998). They then followed both groups for 2 years using a cohort-based strategy. Among the 171 children with persistently negative smears, the median time for conversion to smear-positive was longer for children with sickle trait than for children without (274 vs. 108 days, P < 0.001; Cox hazard ratio = 0.56, 95% confidence interval: 0.33, 0.96; P = 0.036). Similar differences were found in the median times to reinfection after spontaneous clearance without treatment (365 days vs. 184 days; P = 0.01). Alternatively, among the 450 asymptomatic children with persistently positive smears, the median time for conversion to smear-negative (spontaneous clearance) was shorter for children with sickle trait than for children without (190 vs. 365 days; P = 0.02). These protective effects of sickle trait against asymptomatic P. falciparum infection under conditions of natural transmission were demonstrable using a cohort-based approach but not when the same data were examined using a cross-sectional approach.
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Affiliation(s)
- Mounkaila A Billo
- Mali-Tulane Tropical Medicine Research Center, Malaria Research and Training Center, Bamako, Mali.
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Koita OA, Doumbo OK, Ouattara A, Tall LK, Konaré A, Diakité M, Diallo M, Sagara I, Masinde GL, Doumbo SN, Dolo A, Tounkara A, Traoré I, Krogstad DJ. False-negative rapid diagnostic tests for malaria and deletion of the histidine-rich repeat region of the hrp2 gene. Am J Trop Med Hyg 2012; 86:194-8. [PMID: 22302847 DOI: 10.4269/ajtmh.2012.10-0665] [Citation(s) in RCA: 198] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
We identified 480 persons with positive thick smears for asexual Plasmodium falciparum parasites, of whom 454 had positive rapid diagnostic tests (RDTs) for the histidine-rich protein 2 (HRP2) product of the hrp2 gene and 26 had negative tests. Polymerase chain reaction (PCR) amplification for the histidine-rich repeat region of that gene was negative in one-half (10/22) of false-negative specimens available, consistent with spontaneous deletion. False-negative RDTs were found only in persons with asymptomatic infections, and multiplicities of infection (MOIs) were lower in persons with false-negative RDTs (both P < 0.001). These results show that parasites that fail to produce HRP2 can cause patent bloodstream infections and false-negative RDT results. The importance of these observations is likely to increase as malaria control improves, because lower MOIs are associated with false-negative RDTs and false-negative RDTs are more frequent in persons with asymptomatic infections. These findings suggest that the use of HRP2-based RDTs should be reconsidered.
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Affiliation(s)
- Ousmane A Koita
- Mali-Tulane Tropical Medicine Research Center, Faculty of Medicine, Pharmacy, and Dentistry, University of Bamako, Bamako, Mali.
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Ceesay SJ, Bojang KA, Nwakanma D, Conway DJ, Koita OA, Doumbia SO, Ndiaye D, Coulibaly TF, Diakité M, Traoré SF, Coulibaly M, Ndiaye JL, Sarr O, Gaye O, Konaté L, Sy N, Faye B, Faye O, Sogoba N, Jawara M, Dao A, Poudiougou B, Diawara S, Okebe J, Sangaré L, Abubakar I, Sissako A, Diarra A, Kéita M, Kandeh B, Long CA, Fairhurst RM, Duraisingh M, Perry R, Muskavitch MA, Valim C, Volkman SK, Wirth DF, Krogstad DJ. Sahel, savana, riverine and urban malaria in West Africa: Similar control policies with different outcomes. Acta Trop 2012; 121:166-74. [PMID: 22119584 DOI: 10.1016/j.actatropica.2011.11.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2011] [Revised: 11/09/2011] [Accepted: 11/09/2011] [Indexed: 11/26/2022]
Abstract
The study sites for the West African ICEMR are in three countries (The Gambia, Senegal, Mali) and are located within 750 km of each other. In addition, the National Malaria Control Programmes of these countries have virtually identical policies: (1) Artemisinin Combination Therapies (ACTs) for the treatment of symptomatic Plasmodium falciparum infection, (2) Long-Lasting Insecticide-treated bed Nets (LLINs) to reduce the Entomololgic Inoculation Rate (EIR), and (3) sulfadoxine-pyrimethamine for the Intermittent Preventive Treatment of malaria during pregnancy (IPTp). However, the prevalence of P. falciparum malaria and the status of malaria control vary markedly across the four sites with differences in the duration of the transmission season (from 4-5 to 10-11 months), the intensity of transmission (with EIRs from unmeasurably low to 4-5 per person per month), multiplicity of infection (from a mean of 1.0 to means of 2-5) and the status of malaria control (from areas which have virtually no control to areas that are at the threshold of malaria elimination). The most important priority is the need to obtain comparable data on the population-based prevalence, incidence and transmission of malaria before new candidate interventions or combinations of interventions are introduced for malaria control.
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Doumbia SO, Ndiaye D, Koita OA, Diakité M, Nwakanma D, Coulibaly M, Traoré SF, Keating J, Milner DA, Ndiaye JL, Sene PD, Ahouidi A, Dieye TN, Gaye O, Okebe J, Ceesay SJ, Ngwa A, Oriero EC, Konaté L, Sy N, Jawara M, Faye O, Kéita M, Cissé M, Sogoba N, Poudiougou B, Diawara S, Sangaré L, Coulibaly T, Seck I, Abubakar I, Gomis J, Mather FJ, Sissako A, Diarra A, Kandeh B, Whalen C, Moyer B, Nnedu O, Thiero O, Bei AK, Daniels R, Miura K, Long CA, Fairhurst RM, Duraisingh M, Muskavitch MA, D’Alessandro U, Conway DJ, Volkman SK, Valim C, Wirth DF, Krogstad DJ. Improving malaria control in West Africa: interruption of transmission as a paradigm shift. Acta Trop 2012; 121:175-83. [PMID: 22142790 DOI: 10.1016/j.actatropica.2011.11.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2011] [Revised: 11/10/2011] [Accepted: 11/20/2011] [Indexed: 11/27/2022]
Abstract
With the paradigm shift from the reduction of morbidity and mortality to the interruption of transmission, the focus of malaria control broadens from symptomatic infections in children ≤5 years of age to include asymptomatic infections in older children and adults. In addition, as control efforts intensify and the number of interventions increases, there will be decreases in prevalence, incidence and transmission with additional decreases in morbidity and mortality. Expected secondary consequences of these changes include upward shifts in the peak ages for infection (parasitemia) and disease, increases in the ages for acquisition of antiparasite humoral and cellular immune responses and increases in false-negative blood smears and rapid diagnostic tests. Strategies to monitor these changes must include: (1) studies of the entire population (that are not restricted to children ≤5 or ≤10 years of age), (2) study sites in both cities and rural areas (because of increasing urbanization across sub-Saharan Africa) and (3) innovative strategies for surveillance as the prevalence of infection decreases and the frequency of false-negative smears and rapid diagnostic tests increases.
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Koita OA, Krogstad DJ. Biotechnology and medicinal plants, which approach for developing country? J Biotechnol 2010. [DOI: 10.1016/j.jbiotec.2010.08.245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Krogstad DJ, Diop S, Diallo A, Mzayek F, Keating J, Koita OA, Touré YT. Informed consent in international research: the rationale for different approaches. Am J Trop Med Hyg 2010; 83:743-7. [PMID: 20889858 DOI: 10.4269/ajtmh.2010.10-0014] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
In developed countries, informed consent is based on the autonomy of the individual, a written description of the studies proposed, and previous experience of the participant with Western medicine. Consent is documented by the signature of the participant and supervised by institutional review boards (IRBs), which have conflicts of interest because they are also responsible for limiting institutional liability. In developing countries, the initial decision-making for informed consent is typically vested in the community rather than the individual, and illiteracy is common-limiting the value of written documents and signatures. The challenges in developing countries are exacerbated by the fact that persons at greatest risk of disease are often illiterate, have limited experience with Western medicine, and have limited understanding of the scientific rationale for the studies proposed. Given these differences, it is unrealistic to expect that consent strategies used in developed countries would be effective in such diverse settings.
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Affiliation(s)
- Donald J Krogstad
- Department of Tropical Medicine, Tulane University Health Sciences Center, New Orleans, Louisiana, USA.
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Janka JJ, Koita OA, Traoré B, Traoré JM, Mzayek F, Sachdev V, Wang X, Sanogo K, Sangaré L, Mendelsohn L, Masur H, Kato GJ, Gladwin MT, Krogstad DJ. Increased pulmonary pressures and myocardial wall stress in children with severe malaria. J Infect Dis 2010; 202:791-800. [PMID: 20662718 DOI: 10.1086/655225] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
BACKGROUND Chronic intravascular hemolysis leads to nitric oxide (NO) depletion and pulmonary hypertension in sickle cell disease. To test whether this pathophysiology occurs in malaria, we examined in Mali 53 children who were admitted to the hospital with severe malaria (excluding cerebral malaria) and 31 age-matched controls. METHODS Severity of hemolysis was assessed from plasma levels of free hemoglobin and arginase-1. NO metabolism was assessed by whole-blood nitrite levels and plasma NO consumption. Effects on the cardiovascular system and endothelial function were assessed by using echocardiography to measure peak tricuspid regurgitant jet velocity and by evaluating plasma levels of N-terminal prohormone brain natriuretic peptide (NT-proBNP) and soluble vascular cell adhesion molecule-1. RESULTS Children with severe malaria had higher plasma levels of hemoglobin and arginase-1, reduced whole-blood levels of nitrite, and increased NO consumption relative to controls. They also had increased pulmonary arterial pressures (P< .05) with elevated levels of NT-proBNP and soluble vascular cell adhesion molecule-1 (P< .001). CONCLUSION Children with severe malaria have increased pulmonary pressures and myocardial wall stress. These complications are consistent with NO depletion from intravascular hemolysis, and they indicate that the pathophysiologic cascade from intravascular hemolysis to NO depletion and its cardiopulmonary effects is activated in children with severe malaria.
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Affiliation(s)
- Jacqueline J Janka
- Clinical Center (Critical Care Medicine Department) and Pulmonary and Vascular Medicine and Translational Medicine Branches, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
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Koehler JW, Bolton M, Rollins A, Snook K, deHaro E, Henson E, Rogers L, Martin LN, Krogstad DJ, James MA, Rice J, Davison B, Veazey RS, Prabhu R, Amedee AM, Garry RF, Cogswell FB. Altered immune responses in rhesus macaques co-infected with SIV and Plasmodium cynomolgi: an animal model for coincident AIDS and relapsing malaria. PLoS One 2009; 4:e7139. [PMID: 19774084 PMCID: PMC2744481 DOI: 10.1371/journal.pone.0007139] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2009] [Accepted: 08/21/2009] [Indexed: 11/22/2022] Open
Abstract
Background Dual epidemics of the malaria parasite Plasmodium and HIV-1 in sub-Saharan Africa and Asia present a significant risk for co-infection in these overlapping endemic regions. Recent studies of HIV/Plasmodium falciparum co-infection have reported significant interactions of these pathogens, including more rapid CD4+ T cell loss, increased viral load, increased immunosuppression, and increased episodes of clinical malaria. Here, we describe a novel rhesus macaque model for co-infection that supports and expands upon findings in human co-infection studies and can be used to identify interactions between these two pathogens. Methodology/Principal Findings Five rhesus macaques were infected with P. cynomolgi and, following three parasite relapses, with SIV. Compared to macaques infected with SIV alone, co-infected animals had, as a group, decreased survival time and more rapid declines in markers for SIV progression, including peripheral CD4+ T cells and CD4+/CD8+ T cell ratios. The naïve CD4+ T cell pool of the co-infected animals was depleted more rapidly than animals infected with SIV alone. The co-infected animals also failed to generate proliferative responses to parasitemia by CD4+ and CD8+ T cells as well as B cells while also having a less robust anti-parasite and altered anti-SIV antibody response. Conclusions/Significance These data suggest that infection with both SIV and Plasmodium enhances SIV-induced disease progression and impairs the anti-Plasmodium immune response. These data support findings in HIV/Plasmodium co-infection studies. This animal model can be used to further define impacts of lentivirus and Plasmodium co-infection and guide public health and therapeutic interventions.
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Affiliation(s)
- Jeffrey W Koehler
- Department of Microbiology and Immunology, Tulane University School of Medicine, New Orleans, Louisiana, United States of America.
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Londono BL, Eisele TP, Keating J, Bennett A, Chattopadhyay C, Heyliger G, Mack B, Rawson I, Vely JF, Désinor O, Krogstad DJ. Chloroquine-resistant haplotype Plasmodium falciparum parasites, Haiti. Emerg Infect Dis 2009; 15:735-40. [PMID: 19402959 PMCID: PMC2686998 DOI: 10.3201/eid1505.081063] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Plasmodium falciparum parasites have been endemic to Haiti for >40 years without evidence of chloroquine (CQ) resistance. In 2006 and 2007, we obtained blood smears for rapid diagnostic tests (RDTs) and filter paper blots of blood from 821 persons by passive and active case detection. P. falciparum infections diagnosed for 79 persons by blood smear or RDT were confirmed by PCR for the small subunit rRNA gene of P. falciparum. Amplification of the P. falciparum CQ resistance transporter (pfcrt) gene yielded 10 samples with amplicons resistant to cleavage by ApoI. A total of 5 of 9 samples had threonine at position 76 of pfcrt, which is consistent with CQ resistance (haplotypes at positions 72-76 were CVIET [n = 4] and CVMNT [n = 1]); 4 had only the wild-type haplotype associated with CQ susceptibility (CVMNK). These results indicate that CQ-resistant haplotype P. falciparum malaria parasites are present in Haiti.
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Colborn JM, Koita OA, Krogstad DJ, Byrd BD. Estimation of Copy Number using SYBR Green: Confounding by AT-rich DNA and by Variation in Amplicon Length. Am J Trop Med Hyg 2008. [DOI: 10.4269/ajtmh.2008.79.887] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Colborn JM, Byrd BD, Koita OA, Krogstad DJ. Estimation of copy number using SYBR Green: confounding by AT-rich DNA and by variation in amplicon length. Am J Trop Med Hyg 2008; 79:887-892. [PMID: 19052298] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023] Open
Abstract
Although SYBR Green is used to estimate copy number, its fluorescence varies with amplicon length and adenine/thymine (AT) content. As a result, threshold cycle (Ct) values obtained using real-time polymerase chain reaction (PCR) are lower for longer amplicons (P<0.001) and amplicons with greater AT content (P<0.001). In contrast, neither amplicon length nor AT content affects the Ct with TaqMan probes or LUX-labeled primers. Because SYBR Green yields lower Cts with AT-rich templates and longer templates, it overestimates copy number for those templates. Therefore, sequence-specific methods such as TaqMan probes or LUX-labeled primers should be considered when using real-time PCR to estimate copy number if the amplicons generated are AT-rich or vary in length.
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Affiliation(s)
- James M Colborn
- Department of Tropical Medicine, and the Center for Infectious Diseases, Tulane University Health Sciences Center, New Orleans, Louisiana 70112, USA.
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Eisele TP, Keating J, Bennett A, Londono B, Johnson D, Lafontant C, Krogstad DJ. Prevalence of Plasmodium falciparum infection in rainy season, Artibonite Valley, Haiti, 2006. Emerg Infect Dis 2008; 13:1494-6. [PMID: 18257993 PMCID: PMC2851522 DOI: 10.3201/eid1310.070567] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
We conducted a population-based survey to estimate the prevalence of Plasmodium falciparum infection among persons older than 1 month in the Artibonite Valley of Haiti during the high malaria transmission season in 2006. Results from PCR for 714 persons showed a prevalence of 3.1% for P. falciparum infection.
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Affiliation(s)
- Thomas P Eisele
- Tulane University School of Public Health and Tropical Medicine, New Orleans, Louisiana 70112, USA.
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Parekh FK, Casapia WM, Krogstad DJ, Branch OH, Hernandez JN. Prevalence and Risk of Plasmodium falciparum and P. vivax Malaria among Pregnant Women Living in the Hypoendemic Communities of the Peruvian Amazon. Am J Trop Med Hyg 2007. [DOI: 10.4269/ajtmh.2007.77.451] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Parekh FK, Hernandez JN, Krogstad DJ, Casapia WM, Branch OH. Prevalence and risk of Plasmodium falciparum and P. vivax malaria among pregnant women living in the hypoendemic communities of the Peruvian Amazon. Am J Trop Med Hyg 2007; 77:451-7. [PMID: 17827359 PMCID: PMC3773697] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/17/2023] Open
Abstract
The Amazon region of Iquitos, Peru is hypoendemic for Plasmodium vivax and P. falciparum. There is limited information regarding the epidemiology of malaria during pregnancy in this region. Passive surveillance for clinical malaria among pregnant women was conducted in eight health posts in 2004 and 2005. Community-based active surveillance was conducted to determine the incidence of malarial infection among pregnant women in the community of Zungarococha in 2004 and 2005. Passive surveillance demonstrated that pregnant women had a prevalence of clinical malaria of 7.5% in 2004 and 6.6% in 2005 compared with 20.6% and 22.4% of the total population. Active surveillance showed that pregnant women were 2.3 (95% confidence interval = 1.32-3.95, P = 0.004) times more likely to have a P. falciparum infection compared with non-pregnant women. This study demonstrated that because of detection bias, passive surveillance underestimates the burden of malarial infection during pregnancy, and that subclinical malarial infections may occur frequently among pregnant women in this region. Furthermore, pregnant women in this low-transmission and P. vivax-dominant setting, experience an increased risk for P. falciparum infection, but not P. vivax infection.
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Affiliation(s)
| | | | | | | | - Oralee H. Branch
- Address correspondence to Oralee H. Branch, Division of Geographic Medicine, Department of Medicine, University of Alabama at Birmingham, 845 19th Street South, BBRB 554, Birmingham, AL 35294-2170.
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Mzayek F, Deng H, Mather FJ, Wasilevich EC, Liu H, Hadi CM, Chansolme DH, Murphy HA, Melek BH, Tenaglia AN, Mushatt DM, Dreisbach AW, Lertora JJL, Krogstad DJ. Randomized dose-ranging controlled trial of AQ-13, a candidate antimalarial, and chloroquine in healthy volunteers. PLoS Clin Trials 2007; 2:e6. [PMID: 17213921 PMCID: PMC1764434 DOI: 10.1371/journal.pctr.0020006] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/11/2006] [Accepted: 11/03/2006] [Indexed: 11/18/2022]
Abstract
Objectives: To determine: (1) the pharmacokinetics and safety of an investigational aminoquinoline active against multidrug–resistant malaria parasites (AQ-13), including its effects on the QT interval, and (2) whether it has pharmacokinetic and safety profiles similar to chloroquine (CQ) in humans. Design: Phase I double-blind, randomized controlled trials to compare AQ-13 and CQ in healthy volunteers. Randomizations were performed at each step after completion of the previous dose. Setting: Tulane–Louisiana State University–Charity Hospital General Clinical Research Center in New Orleans. Participants: 126 healthy adults 21–45 years of age. Interventions: 10, 100, 300, 600, and 1,500 mg oral doses of CQ base in comparison with equivalent doses of AQ-13. Outcome Measures: Clinical and laboratory adverse events (AEs), pharmacokinetic parameters, and QT prolongation. Results: No hematologic, hepatic, renal, or other organ toxicity was observed with AQ-13 or CQ at any dose tested. Headache, lightheadedness/dizziness, and gastrointestinal (GI) tract–related symptoms were the most common AEs. Although symptoms were more frequent with AQ-13, the numbers of volunteers who experienced symptoms with AQ-13 and CQ were similar (for AQ-13 and CQ, respectively: headache, 17/63 and 10/63, p = 0.2; lightheadedness/dizziness, 11/63 and 8/63, p = 0.6; GI symptoms, 14/63 and 13/63; p = 0.9). Both AQ-13 and CQ exhibited linear pharmacokinetics. However, AQ-13 was cleared more rapidly than CQ (respectively, median oral clearance 14.0–14.7 l/h versus 9.5–11.3 l/h; p ≤ 0.03). QTc prolongation was greater with CQ than AQ-13 (CQ: mean increase of 28 ms; 95% confidence interval [CI], 18 to 38 ms, versus AQ-13: mean increase of 10 ms; 95% CI, 2 to 17 ms; p = 0.01). There were no arrhythmias or other cardiac AEs with either AQ-13 or CQ. Conclusions: These studies revealed minimal differences in toxicity between AQ-13 and CQ, and similar linear pharmacokinetics. Background: Chloroquine (CQ) is a drug that has been widely used for over 40 years for the treatment and prevention of malaria. It is cheap, safe, and, except in areas where resistant malaria parasites exist, effective. However, the spread of resistant malaria parasites in most malarial regions of the world has meant that this drug, and many others, can no longer be relied upon to control disease. New drug candidates are therefore needed, and ideally should be cheap to produce as well as safe and effective. Some research groups are working on potential drug candidates from the aminoquinoline family of compounds, which includes chloroquine. One candidate, AQ-13 (aminoquinoline-13) has already been studied in animal and in vitro experiments, and seemed to be a good candidate for further testing in humans. Therefore, as the first stage in evaluating AQ-13 further, this group of researchers carried out a Phase I trial in healthy humans. The researchers specifically wanted to compare how often people given AQ-13, as compared to those given CQ, had side effects, and to find out how AQ-13 is handled in the body (i.e., how quickly the compound is taken into the bloodstream, gets broken down, and how it affects normal body functions). These sorts of studies do not tell researchers anything about the efficacy of the drug in treating malaria, but the results are absolutely essential before trials can be done that do test efficacy in people with malaria. 126 healthy volunteers were recruited into the study, and each received capsules containing a different dosage of either AQ-13 or CQ. Side effects data were collected for four weeks after the drugs were given. What this trial shows: The most common side effects experienced by volunteers in the trial were headache, light-headedness, dizziness, and gastrointestinal symptoms such as nausea, vomiting, and diarrhea. Overall, the frequencies of such events were roughly similar among people receiving AQ-13 and those receiving CQ, but due to the small numbers of participants in the trial, it is not possible to say whether any observed differences in frequency of side effects between the two groups are meaningful or not. The data collected in this trial also showed that both AQ-13 and CQ were absorbed into the bloodstream in a similar way, but AQ-13 was absorbed more slowly than CQ. On ECG testing, both compounds increased the QT interval (part of the heart's electrical cycle, and used as a measure of heart function), particularly at high dosage levels, and volunteers given CQ experienced a greater increase in QT interval than those receiving AQ-13. No volunteers experienced any symptoms related to heart function. The researchers concluded that on the basis of these data, AQ-13 could proceed to further trials to evaluate the drug's efficacy in treating clinical malaria. Strengths and limitations: The trial was appropriately designed as a randomized controlled Phase I study, allowing the researchers to assess safety and physiological outcomes after giving AQ-13 as compared to an existing and widely used drug, CQ. A key limitation inherent to such studies is the small number of participants studied. This means that the study cannot prove that AQ-13 is safe, or even as safe as CQ, but rather simply that the findings do not raise immediate safety concerns. Contribution to the evidence: Data from animal experiments suggest that AQ-13 could potentially be a safe and effective antimalarial compound. The results reported here provide crucial safety data from the first study known to this research group that evaluates the effects of AQ-13 in humans.
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Affiliation(s)
- Fawaz Mzayek
- Center for Infectious Diseases, Tulane University Health Sciences Center, New Orleans, Louisiana, United States of America
- Department of Epidemiology, Tulane University Health Sciences Center, New Orleans, Louisiana, United States of America
- Department of Tropical Medicine, Tulane University Health Sciences Center, New Orleans, Louisiana, United States of America
| | - Haiyan Deng
- Center for Infectious Diseases, Tulane University Health Sciences Center, New Orleans, Louisiana, United States of America
- Department of Tropical Medicine, Tulane University Health Sciences Center, New Orleans, Louisiana, United States of America
| | - Frances J Mather
- Department of Biostatistics, Tulane University Health Sciences Center, New Orleans, Louisiana, United States of America
| | - Elizabeth C Wasilevich
- Center for Infectious Diseases, Tulane University Health Sciences Center, New Orleans, Louisiana, United States of America
- Department of Epidemiology, Tulane University Health Sciences Center, New Orleans, Louisiana, United States of America
- Department of Tropical Medicine, Tulane University Health Sciences Center, New Orleans, Louisiana, United States of America
| | - Huayin Liu
- Center for Infectious Diseases, Tulane University Health Sciences Center, New Orleans, Louisiana, United States of America
- Department of Tropical Medicine, Tulane University Health Sciences Center, New Orleans, Louisiana, United States of America
| | - Christiane M Hadi
- Department of Medicine, Tulane University Health Sciences Center, New Orleans, Louisiana, United States of America
| | - David H Chansolme
- Department of Medicine, Tulane University Health Sciences Center, New Orleans, Louisiana, United States of America
| | - Holly A Murphy
- Center for Infectious Diseases, Tulane University Health Sciences Center, New Orleans, Louisiana, United States of America
- Department of Tropical Medicine, Tulane University Health Sciences Center, New Orleans, Louisiana, United States of America
- Department of Medicine, Tulane University Health Sciences Center, New Orleans, Louisiana, United States of America
| | - Bekir H Melek
- Department of Medicine, Tulane University Health Sciences Center, New Orleans, Louisiana, United States of America
| | - Alan N Tenaglia
- Department of Medicine, Tulane University Health Sciences Center, New Orleans, Louisiana, United States of America
| | - David M Mushatt
- Center for Infectious Diseases, Tulane University Health Sciences Center, New Orleans, Louisiana, United States of America
- Department of Tropical Medicine, Tulane University Health Sciences Center, New Orleans, Louisiana, United States of America
- Department of Medicine, Tulane University Health Sciences Center, New Orleans, Louisiana, United States of America
| | - Albert W Dreisbach
- Department of Medicine, Tulane University Health Sciences Center, New Orleans, Louisiana, United States of America
- Department of Pharmacology, Tulane University Health Sciences Center, New Orleans, Louisiana, United States of America
- Tulane–Louisiana State University–Charity Hospital General Clinical Research Center, New Orleans, Louisiana, United States of America
| | - Juan J. L Lertora
- Department of Medicine, Tulane University Health Sciences Center, New Orleans, Louisiana, United States of America
- Department of Pharmacology, Tulane University Health Sciences Center, New Orleans, Louisiana, United States of America
- Tulane–Louisiana State University–Charity Hospital General Clinical Research Center, New Orleans, Louisiana, United States of America
| | - Donald J Krogstad
- Center for Infectious Diseases, Tulane University Health Sciences Center, New Orleans, Louisiana, United States of America
- Department of Tropical Medicine, Tulane University Health Sciences Center, New Orleans, Louisiana, United States of America
- Department of Medicine, Tulane University Health Sciences Center, New Orleans, Louisiana, United States of America
- Tulane–Louisiana State University–Charity Hospital General Clinical Research Center, New Orleans, Louisiana, United States of America
- * To whom correspondence should be addressed. E-mail:
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Colborn JM, Koita OA, Cissé O, Bagayoko MW, Guthrie EJ, Krogstad DJ. Identifying and quantifying genotypes in polyclonal infections due to single species. Emerg Infect Dis 2006; 12:475-82. [PMID: 16704787 PMCID: PMC3291430 DOI: 10.3201/eid1203.05057] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The combination of real-time PCR and capillary electrophoresis permits the rapid identification and quantification of pathogen genotypes. Simultaneous infection with multiple pathogens of the same species occurs with HIV, hepatitis C, Epstein-Barr virus, dengue, tuberculosis, and malaria. However, available methods do not distinguish among or quantify pathogen genotypes in individual patients; they also cannot test for novel insertions and deletions in genetically modified organisms. The strategy reported here accomplishes these goals with real-time polymerase chain reaction (PCR) and capillary electrophoresis. Real-time PCR with allotype-specific primers defines the allotypes (strains) present and the intensity of infection (copy number). Capillary electrophoresis defines the number of genotypes within each allotype and the intensity of infection by genotype. This strategy can be used to study the epidemiology of emerging infectious diseases with simultaneous infection by multiple genotypes, as demonstrated here with malaria. It also permits testing for insertions or deletions in genetically modified organisms that may be used for bioterrorism.
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Affiliation(s)
- James M. Colborn
- Tulane University Health Sciences Center, New Orleans, Louisiana, USA
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38
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Davison BB, Kaack MB, Rogers LB, Rasmussen KK, Rasmussen TA, Henson EW, Henson MC, Parekh FK, Krogstad DJ. The role of soluble tumor necrosis factor receptor types I and II and tumor necrosis factor-alpha in malaria during pregnancy. J Infect Dis 2006; 194:123-32. [PMID: 16741891 DOI: 10.1086/504694] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2006] [Accepted: 02/17/2006] [Indexed: 11/03/2022] Open
Abstract
In a prospective study of rhesus monkeys inoculated with Plasmodium coatneyi or saline on an infection/gestational timeline, we determined the serum levels of tumor necrosis factor-alpha (TNF-alpha), soluble tumor necrosis factor receptor type I (sTNFR-I), and soluble tumor necrosis factor receptor type II (sTNFR-II) in peripheral blood throughout primigravid pregnancy, malaria infection, and a combination of the two. Our goal was to determine the association between levels of TNF-alpha and of its 2 soluble receptors and the course of pregnancy and/or malaria and infant outcome. We found that any detectable level of TNF-alpha was always associated with fetal death and that the sTNFRs may be important for fetal protection, possibly through neutralizing the toxic effects of TNF-alpha. Our findings also showed that increased levels of sTNFR-II were associated specifically with malaria and not with normal pregnancy or even pregnancy with low birth weight due to other causes. In contrast, increases in sTNFR-I levels during the later half of normal pregnancies indicate that sTNFR-I may be important in regulating TNF-alpha levels in preparation for normal labor and delivery.
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MESH Headings
- Animals
- Birth Weight
- Blood Cell Count
- Disease Models, Animal
- Female
- Fetal Death/parasitology
- Macaca mulatta
- Malaria/physiopathology
- Plasmodium/pathogenicity
- Pregnancy
- Pregnancy Complications, Parasitic/physiopathology
- Prospective Studies
- Receptors, Tumor Necrosis Factor, Type I/blood
- Receptors, Tumor Necrosis Factor, Type I/immunology
- Receptors, Tumor Necrosis Factor, Type II/blood
- Receptors, Tumor Necrosis Factor, Type II/immunology
- Time Factors
- Tumor Necrosis Factor-alpha/analysis
- Tumor Necrosis Factor-alpha/immunology
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Affiliation(s)
- Billie B Davison
- Division of Comparative Pathology, Tulane National Primate Research Center, Covington, Louisiana 70433, USA.
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39
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Deng H, Liu H, Krogstad FM, Krogstad DJ. Sensitive fluorescence HPLC assay for AQ-13, a candidate aminoquinoline antimalarial, that also detects chloroquine and N-dealkylated metabolites. J Chromatogr B Analyt Technol Biomed Life Sci 2006; 833:122-8. [PMID: 16520100 DOI: 10.1016/j.jchromb.2005.12.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2004] [Revised: 05/10/2005] [Accepted: 12/12/2005] [Indexed: 11/17/2022]
Abstract
A sensitive, specific and reproducible fluorescence high performance liquid chromatography (HPLC) assay has been developed for the separate or simultaneous measurement of AQ-13 (a candidate 4-aminoquinoline antimalarial), chloroquine (CQ), and their metabolites in whole blood. After liquid-solid extraction using commercially available extraction cartridges, these two aminoquinolines (AQs) and their metabolites were separated on C18 (Xterra RP18) columns using a mobile phase containing 60% borate buffer (20 mM, pH 9.0) and 40% acetonitrile with isocratic elution at a flow-rate of 1.0 ml/min. The assay uses a biologically inactive 8-chloro-4-aminoquinoline (AQ-18) as its internal standard (IS). There is a linear relationship between the concentrations of these AQs and the peak area ratio (ratio between the peak area of the AQ or metabolite and the peak area of the IS) on the chromatogram. Linear calibration curves with correlation coefficients > or = 0.997 (r2 > or = 0.995, p < 0.001) were obtained for AQ-13, CQ and their N-dealkylated metabolites. Reproducibility of the assay was excellent with coefficients of variation (CVs) < or = 3.8% for AQ-13 and its metabolites, and < or =2.5% for CQ and its metabolites. The sensitivity of the assay is 5 nM using 1.0 ml of blood and a 20 microl injection volume, and can be increased by using 5.0 ml of blood with an injection volume of 40 microl.
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Affiliation(s)
- Haiyan Deng
- Center for Infectious Diseases and the Department of Tropical Medicine and Medicine, Tulane university Health Center, New Orleans, LA 70112, USA
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40
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Lakshmanan V, Bray PG, Verdier-Pinard D, Johnson DJ, Horrocks P, Muhle RA, Alakpa GE, Hughes RH, Ward SA, Krogstad DJ, Sidhu ABS, Fidock DA. A critical role for PfCRT K76T in Plasmodium falciparum verapamil-reversible chloroquine resistance. EMBO J 2005; 24:2294-305. [PMID: 15944738 PMCID: PMC1173140 DOI: 10.1038/sj.emboj.7600681] [Citation(s) in RCA: 145] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2004] [Accepted: 04/26/2005] [Indexed: 02/08/2023] Open
Abstract
Chloroquine resistance (CQR) in Plasmodium falciparum is associated with mutations in the digestive vacuole transmembrane protein PfCRT. However, the contribution of individual pfcrt mutations has not been clarified and other genes have been postulated to play a substantial role. Using allelic exchange, we show that removal of the single PfCRT amino-acid change K76T from resistant strains leads to wild-type levels of CQ susceptibility, increased binding of CQ to its target ferriprotoporphyrin IX in the digestive vacuole and loss of verapamil reversibility of CQ and quinine resistance. Our data also indicate that PfCRT mutations preceding residue 76 modulate the degree of verapamil reversibility in CQ-resistant lines. The K76T mutation accounts for earlier observations that CQR can be overcome by subtly altering the CQ side-chain length. Together, these findings establish PfCRT K76T as a critical component of CQR and suggest that CQ access to ferriprotoporphyrin IX is determined by drug-protein interactions involving this mutant residue.
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Affiliation(s)
- Viswanathan Lakshmanan
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Patrick G Bray
- Molecular and Biochemical Parasitology Group, Liverpool School of Tropical Medicine, Liverpool, UK
- Molecular and Biochemical Parasitology Group, Liverpool School of Tropical Medicine, Liverpool L3 5QA, UK. Tel.: +44 151 705 3119; Fax: +44 151 708 9007; E-mail:
| | - Dominik Verdier-Pinard
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY, USA
| | - David J Johnson
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Paul Horrocks
- Weatherall Institute of Molecular Medicine, University of Oxford, UK
| | - Rebecca A Muhle
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY, USA
| | - George E Alakpa
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Ruth H Hughes
- Molecular and Biochemical Parasitology Group, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Steve A Ward
- Molecular and Biochemical Parasitology Group, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Donald J Krogstad
- Department of Tropical Medicine, Tulane School of Public Health, New Orleans, LA, USA
| | - Amar Bir Singh Sidhu
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY, USA
| | - David A Fidock
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY, USA
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Forchheimer 403, 1300 Morris Park Avenue, Bronx, NY 10461, USA. Tel.: +1 718 430 3759; Fax: +1 718 430 8711; E-mail:
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41
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Rogers LB, Kaack MB, Henson MC, Rasmussen T, Henson E, Veazey RS, Krogstad DJ, Davison BB. Hematologic and lymphocyte immunophenotypic reference values for normal rhesus monkey (Macaca mulatta) umbilical cord blood; gravidity may play a role in study design. J Med Primatol 2005; 34:147-53. [PMID: 15860123 DOI: 10.1111/j.1600-0684.2005.00104.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Hematology and flow cytometry reference values for rhesus umbilical cord blood (UCB) were established in 17 healthy infant rhesus monkeys delivered by elective cesarean section 10 days preterm. The infants were born to age matched, singly caged primigravid or secundigravid dams. The hematology and flow cytometry values were determined by automated cell counter and by FACS. No significant differences were observed with respect to infant gender. With respect to gravida, the primigravid infants had a significantly higher percentage (P= 0.05) of CD20(+) B lymphocytes in UCB. These results provide useful reference values for future studies of maternal - fetal disease transmission, vaccine and drug evaluation in non-human primate pregnancy, as well as fetal programming and immune modulation, gene therapy and the use of UCB as a source of stem cells for research and transplantation. Importantly, our results suggest that maternal gravidity may be an important variable to consider.
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Affiliation(s)
- Linda B Rogers
- Division of Comparative Pathology, Tulane National Primate Research Center, 18703 Three Rivers Road, Covington, LA 70433, USA.
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42
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Davison BB, Kaack MB, Rogers LB, Rasmussen KK, Rasmussen T, Henson EW, Montenegro S, Henson MC, Mzwaek F, Krogstad DJ. Alterations in the profile of blood cell types during malaria in previously unexposed primigravid monkeys. J Infect Dis 2005; 191:1940-52. [PMID: 15871129 DOI: 10.1086/430004] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2004] [Accepted: 01/04/2005] [Indexed: 11/03/2022] Open
Abstract
Malaria in nonimmune, primigravid women threatens both mother and fetus. We used the Plasmodium coatneyi/rhesus monkey model to examine factors associated with this. Clinical and immunologic responses during the blood stage of chronic malaria (4 months) were evaluated in 8 malaria-naive primigravid (PMI) and 8 age-matched nulligravid (NMI) infected monkeys, compared with those in 8 primigravid, noninfected control monkeys. Although parasitemia levels were similar, recrudescence was more frequent and prolonged, and anemia was more severe in PMI than in NMI monkeys. During infection, CD2+, CD4+, and CD8+ lymphocyte levels were higher in NMI than in PMI monkeys. Monocyte and neutrophil levels were lower in PMI than in NMI monkeys. During chronic, untreated malaria, NMI monkeys had a B lymphocyte count 23 times greater than that of PMI monkeys. Pregnancy-induced immunomodulation, defined as a lack of appropriate cellular responses to malaria, was indiscernible until the immune system was challenged by a pathogen.
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Affiliation(s)
- Billie B Davison
- Division of Comparative Pathology, Tulane National Primate Research Center, Covington, Louisiana 70433, USA.
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43
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Ylostalo J, Randall AC, Myers TA, Metzger M, Krogstad DJ, Cogswell FB. Transcriptome profiles of host gene expression in a monkey model of human malaria. J Infect Dis 2004; 191:400-9. [PMID: 15633100 DOI: 10.1086/426868] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2004] [Accepted: 08/09/2004] [Indexed: 11/03/2022] Open
Abstract
We used human microarrays to examine gene expression in a rhesus monkey model of human Plasmodium vivax malaria (P. cynomolgi in Macaca mulatta). Whole-blood cells were collected for extraction of RNA before infection, during both the initial liver phase of infection and bloodstream infection, and during the course of 2 bloodstream relapses. Clustering analysis showed that similarities in gene expression were greater at similar stages of the protocol for the 2 different monkeys than for the same monkey at different stages of the protocol. Interestingly, a large number of genes involved in RNA processing showed distinct down-regulation during the initial liver phase of infection. When only up-regulated genes were examined, there was evidence of an increasing number of "defense response" genes as the infection evolved but not of "cytoskeleton" genes (P</=.001). These results demonstrate the value of microarrays for studying the response of the primate transcriptome to malaria infection; they suggest that the host response is modulated by groups of genes.
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Affiliation(s)
- Joni Ylostalo
- Center for Gene Therapy, Tulane University Health Sciences Center, New Orleans, Louisiana, USA
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44
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Mayence A, Vanden Eynde JJ, Krogstad FM, Krogstad DJ, Cushion MT, Huang TL. Parallel Solution-Phase Synthesis of Conformationally Restricted Congeners of Pentamidine and Evaluation of Their Antiplasmodial Activities. J Med Chem 2004; 47:2700-5. [PMID: 15115412 DOI: 10.1021/jm030545e] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Conformationally restricted bisbenzamidines and related congeners have been synthesized and evaluated for activity against two Plasmodium falciparum strains. The most active compounds, bisbenzamidines linked by a 1,4-piperazinediyl core, had IC(50) values between 3 and 18 nM against both chloroquine-susceptible and -resistant parasites and IC(50) values for cytotoxicity greater than 5 microM, using the A549 human lung epithelial cell line. DNA binding affinity, as estimated by DeltaT(m), did not correlate with either antiparasite effects or cytotoxicity. Each of the active bisbenzamidines interfered with the formation of hemozoin in cell-free systems.
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Affiliation(s)
- Annie Mayence
- College of Pharmacy, Division of Basic Pharmaceutical Sciences, Xavier University of Louisiana, 1 Drexel Drive, New Orleans, Louisiana 70125, USA
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45
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Riccio ES, Lee PS, Winegar RA, Krogstad DJ, De D, Mirsalis JC. Genetic toxicology testing of the antimalarial drugs chloroquine and a new analog, AQ-13. Environ Mol Mutagen 2001; 38:69-79. [PMID: 11473390 DOI: 10.1002/em.1052] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
AQ-13 ([N1-(7-chloro-quinolin-4yl)-3-(N3,N3-diethylamino)propylamine] dihydrochloride trihydrate) is an aminoquinoline antimalarial drug that is effective against chloroquine-resistant strains of Plasmodium falciparum. It is structurally similar to the widely used chloroquine diphosphate (CQ). We evaluated these drugs in the three assays currently recommended by the International Conference on Harmonization (ICH): bacterial mutagenesis in Salmonella typhimurium and Escherichia coli, mammalian cell mutagenesis in L5178Y mouse lymphoma cells, and micronucleus induction in rat bone marrow. A small but statistically significant increase in revertant colonies was produced by CQ with Salmonella tester strain TA98 without metabolic activation (MA) and by AQ-13 with strain TA1537 both with and without MA. In L5178Y cells, testing of CQ and AQ-13 up to cytotoxic concentrations with and without MA produced no increase in mutant colonies and no increase in the numbers of small colonies. Slight decreases in the ratio of polychromatic erythrocytes (PCE) to red blood cells (RBC) were observed in male and female rats treated with CQ and in females only treated with AQ-13; however, none of these changes was statistically significant. No increases in the frequency of micronucleated PCE were observed at any dose level of CQ or AQ-13. Although both CQ and AQ-13 showed weak bacterial mutagenicity, this mutagenic effect was not confirmed in either the mouse lymphoma mutagenesis assay or the micronucleus assay. These results indicate that CQ and AQ-13 should pose minimal risk of genotoxic damage in human populations being administered these drugs.
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Affiliation(s)
- E S Riccio
- Biopharmaceutical Development Division, SRI International, Menlo Park, California, USA
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46
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Davison BB, Cogswell FB, Baskin GB, Falkenstein KP, Henson EW, Krogstad DJ. Placental changes associated with fetal outcome in the Plasmodium coatneyi/rhesus monkey model of malaria in pregnancy. Am J Trop Med Hyg 2000; 63:158-73. [PMID: 11388509 DOI: 10.4269/ajtmh.2000.63.158] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Term placentas collected surgically from seven Plasmodium coatneyi-infected rhesus monkeys, one abortion, and five controls were evaluated histopathologically. The placentas from Plasmodium-infected dams had more significant pathologic changes than those from controls for six parameters (P < 0.05) and higher numbers of activated (LN5 + Zymed) macrophages in the intervillous space (IVS) (P = 0.0173). Total parasite load (TPL) was defined as the sum of all weekly peripheral infected red blood cell counts for each trimester and for the entire pregnancy. High first trimester PLs were more likely to result in fetal demise (P = 0.0476) or increased placental damage in surviving infants. As trimester 2-3 TPL increased, so did the number of activated macrophages (P < 0.05) and the total malaria pigment scores (P < 0.05). Low birth weight (LBW) and intrauterine growth retardation (IUGR) were associated with high pigment scores and high numbers of activated macrophages in the IVS. High placental damage scores were not associated with IUGR, LBW, or early infant mortality.
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Affiliation(s)
- B B Davison
- Department of Pathology, Tulane Regional Primate Research Center, Covington, Louisiana 70433, USA
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47
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Abstract
Bis[1,2-bis(diphenylphosphino)ethane]palladium(0) [Pd(DIPHOS)2] catalyzes cross-coupling reactions of free or polymer-bound aryl halides with organoboron compounds to produce biaryls in overall yields of 60-96%.
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Affiliation(s)
- D De
- Department of Tropical Medicine, Tulane University, New Orleans, Louisiana 70112, USA
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48
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Abstract
Aminoquinolines (AQs) with diaminoalkane side chains (-HNRNEt2) shorter or longer than the isopentyl side chain [-HNCHMe(CH2)3NEt2] of chloroquine are active against both chloroquine-susceptible and -resistant Plasmodium falciparum. (De, D.; et al. Am. J. Trop. Med. Hyg. 1996, 55, 579-583). In the studies reported here, we examined structure-activity relationships (SARs) among AQs with different N, N-diethyldiaminoalkane side chains and different substituents at the 7-position occupied by Cl in chloroquine. 7-Iodo- and 7-bromo-AQs with diaminoalkane side chains [-HN(CH2)2NEt2, -HN(CH2)3NEt2, or -HNCHMeCH2NEt2] were as active as the corresponding 7-chloro-AQs against both chloroquine-susceptible and -resistant P. falciparum (IC50s of 3-12 nM). In contrast, with one exception, 7-fluoro-AQs and 7-trifluoromethyl-AQs were less active against chloroquine-susceptible P. falciparum (IC50s of 15-50 nM) and substantially less active against chloroquine-resistant P. falciparum (IC50s of 18-500 nM). Furthermore, most 7-OMe-AQs were inactive against both chloroquine-susceptible (IC50s of 17-150 nM) and -resistant P. falciparum (IC50s of 90-3000 nM).
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Affiliation(s)
- D De
- Department of Tropical Medicine and the Center for Infectious Diseases, Tulane School of Public Health and Tropical Medicine, Tulane University, New Orleans, Louisiana 70112, USA
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49
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Masinde GL, Krogstad DJ, Gordon DM, Duffy PE. Immunization with SPf66 and subsequent infection with homologous and heterologous Plasmodium falciparum parasites. Am J Trop Med Hyg 1998; 59:600-5. [PMID: 9790438 DOI: 10.4269/ajtmh.1998.59.600] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
In an area of intense transmission, a malaria vaccine could reduce infection due to the parasite types represented in the vaccine, but have no detectable effect on the overall frequency of infection if it did not protect against infection with heterologous parasites. These studies were performed to determine whether immunization with SPf66 decreased infection with homologous parasites containing the 11 amino acid peptide from merozoite surface protein-1 (MSP-1) in SPf66, or increased infection due to heterologous parasites containing heterologous (alternative) MSP-1 sequences. Based on this 11 amino acid peptide (YSLFQKEKMVL), three forward primers (S,Q,V) were designed to amplify the MSP-1 sequence present in SPf66, and 3 additional forward primers (G,H,I) to amplify the alternative MSP-1 sequence (YGLFHKEKMIL). This strategy was validated by polymerase chain reaction (PCR) amplification and dideoxy sequencing with 14 cloned laboratory isolates, which demonstrated that each primer amplified one MSP-1 sequence or the other, but not both. The technique was then used to examine filter paper blots from an SPf66 vaccine study of 69 subjects in Saradidi, Kenya. In that study, the prevalence of infection with YSLFQKEKMVL or YGLFHKEKMIL type parasites was unaffected by immunization with SPf66 (based on PCR amplification with the S, Q, V, G, H and I primers, respectively). These results suggest that immunization with SPf66 does not produce a selective effect in vivo. They demonstrate a molecular method to test for selection in vivo as an indirect measure of vaccine efficacy.
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Affiliation(s)
- G L Masinde
- Kenya Medical Research Institute (KEMRI), Nairobi
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50
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Davison BB, Cogswell FB, Baskin GB, Falkenstein KP, Henson EW, Tarantal AF, Krogstad DJ. Plasmodium coatneyi in the rhesus monkey (Macaca mulatta) as a model of malaria in pregnancy. Am J Trop Med Hyg 1998; 59:189-201. [PMID: 9715932 DOI: 10.4269/ajtmh.1998.59.189] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Pregnant women with Plasmodium falciparum infection are at increased risk for complications such as anemia and cerebral malaria. In addition, the infants of these women suffer intrauterine growth retardation (IUGR), low birth weight (LBW), congenital infection, and high infant mortality. Although much has been learned from studies of malaria during human pregnancy, progress has been limited by the lack of a suitable animal model. Nonhuman primates are of particular interest because, other than the armadillo, they are the only animals with a discoidal, villous, hemochorial placenta like that of humans. We have established a model of malaria during human pregnancy by inoculating pregnant rhesus monkeys (Macaca mulatta) with Plasmodium coatneyi (a sequestering parasite) during the first trimester. In our initial experiment, four monkeys were inoculated with a fresh inoculum containing 10(8) viable parasites from an infected donor monkey. All four monkeys became parasitemic seven days postinoculation (PI) and three monkeys aborted 7-10 days PI coincident with high peak parasitemias (41,088-374,325 parasites/mm3). Although abortion is one of the outcomes observed in Plasmodium-infected women, the intent of this study was to examine the effects of Plasmodium infection throughout gestation. Since the rapid onset of high parasitemia may have been responsible for the abortions, a decision was made to reduce the size of the effective inoculum. Six additional pregnant monkeys were inoculated with a frozen isolate taken from the same donor containing 10(6) parasites. These six animals became parasitemic by 14 days PI and, along with monkey E412, carried their infants to term. These seven infants weighed significantly less at term than the infants of uninfected mothers (P = 0.0355). Symmetrical IUGR was detected by ultrasound in one fetus with an LBW of 334 g. Another LBW infant (300 g) had asymmetrical growth retardation, which has been associated with uteroplacental insufficiency and was consistent with the lower placental weights found in infected dams compared with controls (P = 0.0455). The infant with symmetric IUGR died at five days of age, while the other is alive but congenitally infected. The IUGR, LBW, congenital infection, postnatal infant mortality, and early abortions observed in these animals suggest that P. coatneyi in pregnant rhesus monkeys is a valid model of malaria in human pregnancy. This model should provide the opportunity to study questions about malaria in pregnancy that have been difficult to study in humans.
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Affiliation(s)
- B B Davison
- Department of Pathology, Tulane Regional Primate Research Center, and Tulane School of Public Health and Tropical Medicine, Tulane University Medical Center, New Orleans, Louisiana 70433, USA
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