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Frempong NA, Ahiabor C, Anyan WK, Mama A, Kusi KA, Ofori MF, Adu B, Debrah AY, Anang AK, Ndam NT, Courtin D. Malaria, Urogenital Schistosomiasis, and Anaemia in Pregnant Ghanaian Women. J Parasitol Res 2023; 2023:7500676. [PMID: 37808169 PMCID: PMC10558271 DOI: 10.1155/2023/7500676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 09/03/2023] [Accepted: 09/08/2023] [Indexed: 10/10/2023] Open
Abstract
Background Anaemia is common in sub-Saharan Africa, and parasitic infections could worsen its burden during pregnancy. Moreover, women become susceptible to malaria during pregnancy. We investigated Plasmodium falciparum (P. falciparum) and Schistosoma haematobium (S. haematobium) infections and determined their association with anaemia during pregnancy. Methods A cross-sectional study involving 707 pregnant women attending antenatal care visits (ANC) and 446 at delivery was conducted in Battor and Adidome hospitals. Pregnant women were screened by microscopy and qPCR for P. falciparum and S. haematobium infections. Haemoglobin (Hb) levels were determined, and most participants received intermittent preventive treatment during pregnancy (IPTp) during ANC till delivery. Regression analyses were performed for associations between parasite infection and anaemia. Results P. falciparum microscopy prevalence at ANC and delivery was 8% and 2%, respectively, and by PCR 24% at ANC and 12% at delivery. Anaemia prevalence at ANC was 52% and 49% at delivery. There was an increased risk of anaemia with P. falciparum infection (aOR = 1.92; p = 0.04). IPTp (p = 0.003) and age (p = 0.004) were associated with increased Hb levels at delivery. S. haematobium prevalence by microscopy was 4% at ANC and 2% at delivery. No significant correlation between S. haematobium and Hb levels was observed (coef. = -0.62 g/dl; p = 0.07). Conclusion High anaemia prevalence was observed during pregnancy, and P. falciparum infection was associated with anaemia at ANC. Low S. haematobium prevalence could be attributed to previous praziquantel treatment during mass drug administration. Routine diagnosis and treatment of S. haematobium infections in endemic areas could be initiated to reduce schistosomiasis during pregnancy.
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Affiliation(s)
- Naa Adjeley Frempong
- Clinical Microbiology Department, Kwame Nkrumah University of Science and Technology, Ghana
- Parasitology Department, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Charity Ahiabor
- Science Laboratory Technology, Accra Technical University, Ghana
| | - William K. Anyan
- Parasitology Department, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Atikatou Mama
- Inserm U 1016, Institut Cochin, Université de Paris, 75014, France
| | - Kwadwo Asamoah Kusi
- Immunology Department, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Michael F. Ofori
- Immunology Department, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Bright Adu
- Immunology Department, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Alex Yaw Debrah
- Faculty of Health Sciences, Kwame Nkrumah University of Science and Technology, Ghana
| | - Abraham K. Anang
- Institute of Environment and Sanitation Studies(IESS), University of Ghana, Legon, Ghana
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Eboumbou Moukoko CE, Kojom Foko LP, Ayina A, Tornyigah B, Epote AR, Penda IC, Epee Eboumbou P, Ebong SB, Texier G, Nsango SE, Ayong L, Tuikue Ndam N, Same Ekobo A. Effectiveness of Intermittent Preventive Treatment with Sulfadoxine-Pyrimethamine in Pregnancy: Low Coverage and High Prevalence of Plasmodium falciparum dhfr-dhps Quintuple Mutants as Major Challenges in Douala, an Urban Setting in Cameroon. Pathogens 2023; 12:844. [PMID: 37375534 DOI: 10.3390/pathogens12060844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 06/02/2023] [Accepted: 06/17/2023] [Indexed: 06/29/2023] Open
Abstract
Intermittent preventive treatment in pregnancy with sulfadoxine and pyrimethamine (IPTp-SP) is a key component in the malaria control strategy implemented in Africa. The aim of this study was to determine IPTp-SP adherence and coverage, and the impact on maternal infection and birth outcomes in the context of widespread SP resistance in the city of Douala, Cameroon. Clinical and demographic information were documented among 888 pregnant women attending 3 health facilities, from the antenatal care visit to delivery. Positive samples were genotyped for P. falciparum gene (dhfr, dhps, and k13) mutations. The overall IPTp-SP coverage (≥three doses) was 17.5%, and 5.1% received no dose. P. falciparum prevalence was 16%, with a predominance of submicroscopic infections (89.3%). Malaria infection was significantly associated with locality and history of malaria, and it was reduced among women using indoor residual spraying. Optimal doses of IPTp-SP were significantly associated with reduced infection among newborns and women (secundiparous and multiparous), but there was no impact of IPTp-SP on the newborn bodyweight. Pfdhfr-Pfdhps quintuple mutants were over-represented (IRNI-FGKAA, IRNI-AGKAA), and sextuple mutants (IRNI-AGKAS, IRNI-FGEAA, IRNI-AGKGS) were also reported. The Pfk13 gene mutations associated with artemisinin resistance were not detected. This study highlights the role of ANC in achieving optimal SP coverage in pregnant women, the mitigated impact of IPTp-SP on malaria outcomes, and the high prevalence of multiple SP-resistant P. falciparum parasites in the city of Douala that could compromise the efficacy of IPTp-SP.
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Affiliation(s)
- Carole Else Eboumbou Moukoko
- Malaria Research Unit, Centre Pasteur Cameroon, Yaoundé P.O. Box 1274, Cameroon
- Department of Biological Sciences, Faculty of Medicine and Pharmaceutical Sciences, The University of Douala, Douala P.O. Box 24157, Cameroon
- Laboratory of Parasitology, Mycology and Virology, Postgraduate Training Unit for Health Sciences, Postgraduate School for Pure and Applied Sciences, The University of Douala, Douala P.O. Box 24157, Cameroon
| | | | - Angèle Ayina
- Malaria Research Unit, Centre Pasteur Cameroon, Yaoundé P.O. Box 1274, Cameroon
- Pharmaceutical Sciences Department, Faculty of Medicine and Pharmaceutical Sciences, The University of Douala, Douala P.O. Box 24157, Cameroon
| | - Bernard Tornyigah
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Accra P.O. Box 1181, Ghana
- UMR 261 MERIT, Institut de Recherche pour le Développement (IRD), Université de Paris, 75006 Paris, France
| | - Annie Rachel Epote
- Haematology Laboratory, Centre Pasteur Cameroon, Yaoundé P.O. Box 1274, Cameroon
| | - Ida Calixte Penda
- Clinical Sciences Department, Faculty of Medicine and Pharmaceutical Sciences, The University of Douala, Douala P.O. Box 24157, Cameroon
| | - Patricia Epee Eboumbou
- Clinical Sciences Department, Faculty of Medicine and Pharmaceutical Sciences, The University of Douala, Douala P.O. Box 24157, Cameroon
- Pediatric Wards, Bonassama Hospital, Douala P.O. Box 9023, Cameroon
| | - Serge Bruno Ebong
- Animal Organisms Biology and Physiology Department, Faculty of Sciences, The University of Douala, Douala P.O. Box 24157, Cameroon
| | - Gaetan Texier
- UMR 257-Vecteurs, Infections Tropicales et Méditerranéennes-VITROME-IRD/SSA/AP-HM, Aix-Marseille University, 13005 Marseille, France
| | - Sandrine Eveline Nsango
- Malaria Research Unit, Centre Pasteur Cameroon, Yaoundé P.O. Box 1274, Cameroon
- Department of Biological Sciences, Faculty of Medicine and Pharmaceutical Sciences, The University of Douala, Douala P.O. Box 24157, Cameroon
| | - Lawrence Ayong
- Malaria Research Unit, Centre Pasteur Cameroon, Yaoundé P.O. Box 1274, Cameroon
| | - Nicaise Tuikue Ndam
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Accra P.O. Box 1181, Ghana
- UMR 261 MERIT, Institut de Recherche pour le Développement (IRD), Université de Paris, 75006 Paris, France
| | - Albert Same Ekobo
- Department of Biological Sciences, Faculty of Medicine and Pharmaceutical Sciences, The University of Douala, Douala P.O. Box 24157, Cameroon
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Vanhuysse S, Diédhiou SM, Grippa T, Georganos S, Konaté L, Niang EHA, Wolff E. Fine-scale mapping of urban malaria exposure under data scarcity: an approach centred on vector ecology. Malar J 2023; 22:113. [PMID: 37009873 PMCID: PMC10069057 DOI: 10.1186/s12936-023-04527-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Accepted: 03/08/2023] [Indexed: 04/04/2023] Open
Abstract
BACKGROUND Although malaria transmission has experienced an overall decline in sub-Saharan Africa, urban malaria is now considered an emerging health issue due to rapid and uncontrolled urbanization and the adaptation of vectors to urban environments. Fine-scale hazard and exposure maps are required to support evidence-based policies and targeted interventions, but data-driven predictive spatial modelling is hindered by gaps in epidemiological and entomological data. A knowledge-based geospatial framework is proposed for mapping the heterogeneity of urban malaria hazard and exposure under data scarcity. It builds on proven geospatial methods, implements open-source algorithms, and relies heavily on vector ecology knowledge and the involvement of local experts. METHODS A workflow for producing fine-scale maps was systematized, and most processing steps were automated. The method was evaluated through its application to the metropolitan area of Dakar, Senegal, where urban transmission has long been confirmed. Urban malaria exposure was defined as the contact risk between adult Anopheles vectors (the hazard) and urban population and accounted for socioeconomic vulnerability by including the dimension of urban deprivation that is reflected in the morphology of the built-up fabric. Larval habitat suitability was mapped through a deductive geospatial approach involving the participation of experts with a strong background in vector ecology and validated with existing geolocated entomological data. Adult vector habitat suitability was derived through a similar process, based on dispersal from suitable breeding site locations. The resulting hazard map was combined with a population density map to generate a gridded urban malaria exposure map at a spatial resolution of 100 m. RESULTS The identification of key criteria influencing vector habitat suitability, their translation into geospatial layers, and the assessment of their relative importance are major outcomes of the study that can serve as a basis for replication in other sub-Saharan African cities. Quantitative validation of the larval habitat suitability map demonstrates the reliable performance of the deductive approach, and the added value of including local vector ecology experts in the process. The patterns displayed in the hazard and exposure maps reflect the high degree of heterogeneity that exists throughout the city of Dakar and its suburbs, due not only to the influence of environmental factors, but also to urban deprivation. CONCLUSIONS This study is an effort to bring geospatial research output closer to effective support tools for local stakeholders and decision makers. Its major contributions are the identification of a broad set of criteria related to vector ecology and the systematization of the workflow for producing fine-scale maps. In a context of epidemiological and entomological data scarcity, vector ecology knowledge is key for mapping urban malaria exposure. An application of the framework to Dakar showed its potential in this regard. Fine-grained heterogeneity was revealed by the output maps, and besides the influence of environmental factors, the strong links between urban malaria and deprivation were also highlighted.
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Affiliation(s)
- Sabine Vanhuysse
- Department of Geosciences, Environment and Society, Université Libre de Bruxelles (ULB), 1050, Brussels, Belgium.
| | - Seynabou Mocote Diédhiou
- Laboratoire d'Ecologie Vectorielle et Parasitaire, Université Cheikh-Anta-Diop de Dakar, Dakar, Sénégal
| | - Taïs Grippa
- Department of Geosciences, Environment and Society, Université Libre de Bruxelles (ULB), 1050, Brussels, Belgium
| | - Stefanos Georganos
- Geomatics, Department of Environmental and Life Sciences, Faculty of Health, Science and Technology, Karlstad University, Karlstad, Sweden
| | - Lassana Konaté
- Laboratoire d'Ecologie Vectorielle et Parasitaire, Université Cheikh-Anta-Diop de Dakar, Dakar, Sénégal
| | - El Hadji Amadou Niang
- Laboratoire d'Ecologie Vectorielle et Parasitaire, Université Cheikh-Anta-Diop de Dakar, Dakar, Sénégal
| | - Eléonore Wolff
- Department of Geosciences, Environment and Society, Université Libre de Bruxelles (ULB), 1050, Brussels, Belgium
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Akindeh NM, Ngum LN, Niba PTN, Ali IM, Ayem OLO, Chedjou JPK, Fomboh CT, Ekollo AHM, Mbu’u CM, Mbacham WF. Assessing Asymptomatic Malaria Carriage of Plasmodium falciparum and Non- falciparum Species in Children Resident in Nkolbisson, Yaoundé, Cameroon. Children (Basel) 2021; 8:children8110960. [PMID: 34828673 PMCID: PMC8623063 DOI: 10.3390/children8110960] [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] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 10/16/2021] [Accepted: 10/21/2021] [Indexed: 11/16/2022]
Abstract
Malaria is still a threat to public health as it remains the first endemic disease in the world. It is a pervasive parasitic disease in tropical and subtropical regions where asymptomatic malaria infection among humans serves as a significant reservoir for transmission. A rapid and correct diagnosis is considered to be an important strategy in the control of the disease especially in children, who are the most vulnerable group. This study assessed the prevalence of asymptomatic malaria in children at the Nkolbisson health area in Yaoundé, Cameroon. A cross-sectional study design and a convenience sampling plan were used. A total of 127 participants were recruited after informed and signed consent from parents and/or guardians. Blood samples were collected by finger-pricking and venipuncture from children aged 6 months to 10 years and then screened for asymptomatic parasitemia by a rapid diagnostic test (RDT), light microscopy (LM) staining with Giemsa and 18S rRNA polymerase chain reaction (PCR) for speciation. The data were analyzed using SPSS version 20 software. The study identified 85 children who were positive from the PCR, 95 positive from the RDT and 71 from the LM, revealing a malaria prevalence of 66.9%, 74.8% and 55.9%, respectively. The prevalence was not observed to be dependent on the sex and age group of the participants. Plasmodium falciparum was the predominant species followed by Plasmodium malariae and then Plasmodium ovale. The RDT and LM had the same sensitivity (90.6%) with a slight difference in their specificity (RDT: 57.1%; LM: 54.8%). The RDT also demonstrated higher positive and negative predictive values compared with those of the LM.
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Affiliation(s)
- Nji Mbuh Akindeh
- Biotechnology Center, University of Yaoundé I, Messa, Yaoundé P.O. Box 3851, Cameroon; (L.N.N.); (P.T.N.N.); (I.M.A.); (O.L.O.A.); (J.P.K.C.); (C.T.F.); (A.H.M.E.); (C.M.M.)
- Department of Biochemistry, Faculty of Science, University of Yaoundé I, Messa, Yaoundé P.O. Box 3851, Cameroon
- Correspondence: (N.M.A.); (W.F.M.); Tel.: +237-675354405 (N.M.A.); +237-677579180 (W.F.M.)
| | - Lesley Ngum Ngum
- Biotechnology Center, University of Yaoundé I, Messa, Yaoundé P.O. Box 3851, Cameroon; (L.N.N.); (P.T.N.N.); (I.M.A.); (O.L.O.A.); (J.P.K.C.); (C.T.F.); (A.H.M.E.); (C.M.M.)
- Department of Biochemistry, Faculty of Medicine and Biomedical Science, University of Yaoundé I, Messa, Yaoundé P.O. Box 3851, Cameroon
- Institute of Medicine and Medicinal Plants Studies, Dschang 00237, Cameroon
| | - Peter Thelma Ngwa Niba
- Biotechnology Center, University of Yaoundé I, Messa, Yaoundé P.O. Box 3851, Cameroon; (L.N.N.); (P.T.N.N.); (I.M.A.); (O.L.O.A.); (J.P.K.C.); (C.T.F.); (A.H.M.E.); (C.M.M.)
- Department of Biochemistry, Faculty of Science, University of Yaoundé I, Messa, Yaoundé P.O. Box 3851, Cameroon
| | - Innocent Mbulli Ali
- Biotechnology Center, University of Yaoundé I, Messa, Yaoundé P.O. Box 3851, Cameroon; (L.N.N.); (P.T.N.N.); (I.M.A.); (O.L.O.A.); (J.P.K.C.); (C.T.F.); (A.H.M.E.); (C.M.M.)
- Department of Biochemistry, Faculty of Science, University of Dschang, Dschang 00237, Cameroon
| | - Ornella Laetitia Oben Ayem
- Biotechnology Center, University of Yaoundé I, Messa, Yaoundé P.O. Box 3851, Cameroon; (L.N.N.); (P.T.N.N.); (I.M.A.); (O.L.O.A.); (J.P.K.C.); (C.T.F.); (A.H.M.E.); (C.M.M.)
- Department of Biochemistry, Faculty of Science, University of Yaoundé I, Messa, Yaoundé P.O. Box 3851, Cameroon
| | - Jean Paul Kengne Chedjou
- Biotechnology Center, University of Yaoundé I, Messa, Yaoundé P.O. Box 3851, Cameroon; (L.N.N.); (P.T.N.N.); (I.M.A.); (O.L.O.A.); (J.P.K.C.); (C.T.F.); (A.H.M.E.); (C.M.M.)
- Department of Biochemistry, Faculty of Science, University of Buea, Buea P.O. Box 63, Cameroon
| | - Calvino Tah Fomboh
- Biotechnology Center, University of Yaoundé I, Messa, Yaoundé P.O. Box 3851, Cameroon; (L.N.N.); (P.T.N.N.); (I.M.A.); (O.L.O.A.); (J.P.K.C.); (C.T.F.); (A.H.M.E.); (C.M.M.)
- Department of Biochemistry, Faculty of Science, University of Yaoundé I, Messa, Yaoundé P.O. Box 3851, Cameroon
| | - Aristid Herve Mbange Ekollo
- Biotechnology Center, University of Yaoundé I, Messa, Yaoundé P.O. Box 3851, Cameroon; (L.N.N.); (P.T.N.N.); (I.M.A.); (O.L.O.A.); (J.P.K.C.); (C.T.F.); (A.H.M.E.); (C.M.M.)
- Institut Universitaire de Technologie, University of Ngoundere, Ngoundere BP 61207, Cameroon
| | - Cyrille Mbanwi Mbu’u
- Biotechnology Center, University of Yaoundé I, Messa, Yaoundé P.O. Box 3851, Cameroon; (L.N.N.); (P.T.N.N.); (I.M.A.); (O.L.O.A.); (J.P.K.C.); (C.T.F.); (A.H.M.E.); (C.M.M.)
- Department of Microbiology, Faculty of Science, University of Yaoundé I, Yaoundé P.O. Box 3851, Cameroon
| | - Wilfred Fon Mbacham
- Biotechnology Center, University of Yaoundé I, Messa, Yaoundé P.O. Box 3851, Cameroon; (L.N.N.); (P.T.N.N.); (I.M.A.); (O.L.O.A.); (J.P.K.C.); (C.T.F.); (A.H.M.E.); (C.M.M.)
- Department of Biochemistry, Faculty of Science, University of Yaoundé I, Messa, Yaoundé P.O. Box 3851, Cameroon
- Department of Biochemistry, Faculty of Medicine and Biomedical Science, University of Yaoundé I, Messa, Yaoundé P.O. Box 3851, Cameroon
- Correspondence: (N.M.A.); (W.F.M.); Tel.: +237-675354405 (N.M.A.); +237-677579180 (W.F.M.)
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Jafari-Guemouri S, Courtois L, Mama A, Rouas B, Neto Braga G, Accrombessi M, Massougbodji A, Ding XC, Tuikue Ndam N, Fievet N, Briand V. A Genotyping Study in Benin Comparing the Carriage of Plasmodium falciparum Infections Before Pregnancy and in Early Pregnancy: Story of a Persistent Infection. Clin Infect Dis 2021; 73:e355-e361. [PMID: 32569359 PMCID: PMC8282262 DOI: 10.1093/cid/ciaa841] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [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: 03/30/2020] [Accepted: 06/17/2020] [Indexed: 12/16/2022] Open
Abstract
Background Malaria infections in the first trimester of pregnancy are frequent and deleterious for both mother and child health. To investigate if these early infections are newly acquired or already present in the host, we assessed whether parasites detected before pregnancy and those detected in early pregnancy are the same infection. Methods We used data from the preconceptional “RECIPAL” study (Benin, 2014–2017). Sixty-three pregnant women of 411 included who had a malaria infection detected by quantitative polymerase chain reaction both before pregnancy and at the first antenatal care (ANC) visit were selected for this study. Two highly polymorphic markers, msp-2 and glurp, and a fragment-analysis method were used to enumerate the Plasmodium falciparum genotypes and to quantify their proportions within isolates. An infection was considered as persistent when identical msp-2 and glurp genotypes were found in the corresponding prepregnancy and early-pregnancy samples. Results The median time between the 2 malaria screenings was 3 months. The median gestational age at the first ANC visit was 6.4 weeks. Most infections before pregnancy were submicroscopic infections. Based on both msp-2 and glurp genotyping, the infection was similar before and in early pregnancy in 46% (29/63) of cases. Conclusions Almost half of P. falciparum infections detected in the first trimester originate before pregnancy. Protecting young women from malaria infection before pregnancy might reduce the prevalence of malaria in early pregnancy and its related poor maternal and birth outcomes.
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Affiliation(s)
- Sayeh Jafari-Guemouri
- Université de Paris, UMR261-MERIT, Institut de Recherche pour le Développement, Paris, France
| | - Laura Courtois
- Université de Paris, UMR261-MERIT, Institut de Recherche pour le Développement, Paris, France
| | - Atika Mama
- Clinical Research Institute of Benin (IRCB), Abomey-Calavi, Benin
| | - Baptiste Rouas
- Université de Paris, UMR261-MERIT, Institut de Recherche pour le Développement, Paris, France
| | - Gabriel Neto Braga
- Université de Paris, UMR261-MERIT, Institut de Recherche pour le Développement, Paris, France
| | - Manfred Accrombessi
- Clinical Research Institute of Benin (IRCB), Abomey-Calavi, Benin.,Faculty of Infectious and Tropical Diseases, Disease Control Department, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | | | | | - Nicaise Tuikue Ndam
- Université de Paris, UMR261-MERIT, Institut de Recherche pour le Développement, Paris, France
| | - Nadine Fievet
- Université de Paris, UMR261-MERIT, Institut de Recherche pour le Développement, Paris, France
| | - Valérie Briand
- Université de Paris, UMR261-MERIT, Institut de Recherche pour le Développement, Paris, France.,University of Bordeaux, Inserm, Institut de Recherche pour le Développement, Inserm, University of Bordeaux, UMR, Bordeaux, France
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Ventimiglia NT, Stucke EM, Coulibaly D, Berry AA, Lyke KE, Laurens MB, Bailey JA, Adams M, Niangaly A, Kone AK, Takala-Harrison S, Kouriba B, Doumbo OK, Felgner PL, Plowe CV, Thera MA, Travassos MA. Malian adults maintain serologic responses to virulent PfEMP1s amid seasonal patterns of fluctuation. Sci Rep 2021; 11:14401. [PMID: 34257318 PMCID: PMC8277812 DOI: 10.1038/s41598-021-92974-7] [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: 02/06/2021] [Accepted: 06/08/2021] [Indexed: 12/03/2022] Open
Abstract
Plasmodium falciparum erythrocyte membrane protein-1s (PfEMP1s), diverse malaria proteins expressed on the infected erythrocyte surface, play an important role in pathogenesis, mediating adhesion to host vascular endothelium. Antibodies to particular non-CD36-binding PfEMP1s are associated with protection against severe disease. We hypothesized that given lifelong P. falciparum exposure, Malian adults would have broad PfEMP1 serorecognition and high seroreactivity levels during follow-up, particularly to non-CD36-binding PfEMP1s such as those that attach to endothelial protein C receptor (EPCR) and intercellular adhesion molecule-1 (ICAM-1). Using a protein microarray, we determined serologic responses to 166 reference PfEMP1 fragments during a dry and subsequent malaria transmission season in Malian adults. Malian adult sera had PfEMP1 serologic responses throughout the year, with decreased reactivity to a small subset of PfEMP1 fragments during the dry season and increases in reactivity to a different subset of PfEMP1 fragments during the subsequent peak malaria transmission season, especially for intracellular PfEMP1 domains. For some individuals, PfEMP1 serologic responses increased after the dry season, suggesting antigenic switching during asymptomatic infection. Adults were more likely to experience variable serorecognition of CD36-binding PfEMP1s than non-CD36-binding PfEMP1s that bind EPCR or ICAM-1, which remained serorecognized throughout the year. Sustained seroreactivity to non-CD36-binding PfEMP1s throughout adulthood amid seasonal fluctuation patterns may reflect underlying protective severe malaria immunity and merits further investigation.
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Affiliation(s)
| | - Emily M Stucke
- University of Maryland School of Medicine, Baltimore, MD, USA
| | - Drissa Coulibaly
- University of Sciences, Techniques and Technologies, Bamako, Mali
| | - Andrea A Berry
- University of Maryland School of Medicine, Baltimore, MD, USA
| | - Kirsten E Lyke
- University of Maryland School of Medicine, Baltimore, MD, USA
| | | | - Jason A Bailey
- University of Maryland School of Medicine, Baltimore, MD, USA
| | - Matthew Adams
- University of Maryland School of Medicine, Baltimore, MD, USA
| | - Amadou Niangaly
- University of Sciences, Techniques and Technologies, Bamako, Mali
| | - Abdoulaye K Kone
- University of Sciences, Techniques and Technologies, Bamako, Mali
| | | | - Bourema Kouriba
- University of Sciences, Techniques and Technologies, Bamako, Mali
| | - Ogobara K Doumbo
- University of Sciences, Techniques and Technologies, Bamako, Mali
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Hounkonnou CPA, Briand V, Fievet N, Accrombessi M, Yovo E, Mama A, Sossou D, Vianou B, Massougbodji A, Ndam NT, Cot M, Cottrell G. Dynamics of Submicroscopic Plasmodium falciparum Infections Throughout Pregnancy: A Preconception Cohort Study in Benin. Clin Infect Dis 2021; 71:166-174. [PMID: 32215629 PMCID: PMC7312237 DOI: 10.1093/cid/ciz748] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [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: 06/03/2019] [Accepted: 08/05/2019] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND In the context of global malaria elimination efforts, special attention is being paid to submicroscopic Plasmodium falciparum infections. In pregnant, sub-Saharan African women, such infections are more prevalent than microscopic infections, and are thought to have adverse effects on both mothers' and newborns' health. However, no study has studied the dynamics and determinants of these infections throughout pregnancy. Retard de Croissance Intra-uterin et Paludisme (RECIPAL), a preconception cohort study carried out in Benin between 2014 and 2017, represented a unique opportunity to assess this issue. METHODS We used data from 273 pregnant Beninese women who were followed-up from preconception to delivery. We studied the dynamics of and factors influencing submicroscopic (and microscopic) P. falciparum infections during the 3 trimesters of pregnancy, using an ordinal logistic mixed model. RESULTS The incidence rate of submicroscopic P. falciparum infections during pregnancy was 12.7 per 100 person-months (95% confidence interval [CI] 10.8-14.9), compared to 6.7 per 100 person-months (95% CI 5.5-8.1) for microscopic infections. The prevalences were highest in the first trimester for both submicroscopic and microscopic infections. After adjustment for potential confounding factors, we found that those of young age and those with a submicroscopic P. falciparum infection prior to pregnancy were at significantly higher risks of submicroscopic and microscopic infections throughout pregnancy, with a more pronounced effect in the first trimester of pregnancy. CONCLUSIONS The first trimester of pregnancy is a particularly high-risk period for P. falciparum infection during pregnancy, especially for the youngest women. Malaria prevention tools covering the preconception period and early pregnancy are urgently needed to better protect pregnant women and their newborns.
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Affiliation(s)
- Cornélia P A Hounkonnou
- Université de Paris, Mère et enfant en milieu tropical: pathogènes, système de santé et transition épidémiologique, Institut de Recherche pour le Développement, Paris, France.,Sorbonne Université, Université Pierre et Marie-Curie, Paris, France
| | - Valérie Briand
- Université de Paris, Mère et enfant en milieu tropical: pathogènes, système de santé et transition épidémiologique, Institut de Recherche pour le Développement, Paris, France
| | - Nadine Fievet
- Université de Paris, Mère et enfant en milieu tropical: pathogènes, système de santé et transition épidémiologique, Institut de Recherche pour le Développement, Paris, France
| | | | - Emmanuel Yovo
- Centre d'Etude et de Recherche sur le Paludisme Associé à la Grossesse et à l'Enfance (CERPAGE), Cotonou, Bénin
| | - Atikatou Mama
- Centre d'Etude et de Recherche sur le Paludisme Associé à la Grossesse et à l'Enfance (CERPAGE), Cotonou, Bénin
| | - Darius Sossou
- Centre d'Etude et de Recherche sur le Paludisme Associé à la Grossesse et à l'Enfance (CERPAGE), Cotonou, Bénin
| | - Bertin Vianou
- Centre d'Etude et de Recherche sur le Paludisme Associé à la Grossesse et à l'Enfance (CERPAGE), Cotonou, Bénin
| | - Achille Massougbodji
- Centre d'Etude et de Recherche sur le Paludisme Associé à la Grossesse et à l'Enfance (CERPAGE), Cotonou, Bénin
| | - Nicaise Tuikue Ndam
- Université de Paris, Mère et enfant en milieu tropical: pathogènes, système de santé et transition épidémiologique, Institut de Recherche pour le Développement, Paris, France
| | - Michel Cot
- Université de Paris, Mère et enfant en milieu tropical: pathogènes, système de santé et transition épidémiologique, Institut de Recherche pour le Développement, Paris, France
| | - Gilles Cottrell
- Université de Paris, Mère et enfant en milieu tropical: pathogènes, système de santé et transition épidémiologique, Institut de Recherche pour le Développement, Paris, France.,Centre d'Etude et de Recherche sur le Paludisme Associé à la Grossesse et à l'Enfance (CERPAGE), Cotonou, Bénin
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8
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Sallah K, Giorgi R, Ba EH, Piarroux M, Piarroux R, Cisse B, Gaudart J. Targeting Malaria Hotspots to Reduce Transmission Incidence in Senegal. Int J Environ Res Public Health 2020; 18:E76. [PMID: 33374228 DOI: 10.3390/ijerph18010076] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 12/15/2020] [Accepted: 12/16/2020] [Indexed: 11/16/2022]
Abstract
In central Senegal, malaria incidence declined in response to scaling-up of control measures from 2000 to 2010 and has since remained stable, making elimination unlikely in the short term. Additional control measures are needed to reduce transmission. We simulated chemoprophylaxis interventions targeting malaria hotspots using a metapopulation mathematical model, based on a differential-equation framework and incorporating human mobility. The model was fitted to weekly malaria incidence from 45 villages. Three approaches for selecting intervention targets were compared: (a) villages with malaria cases during the low transmission season of the previous year; (b) villages with highest incidence during the high transmission season of the previous year; (c) villages with highest connectivity with adjacent populations. Our results showed that intervention strategies targeting hotspots would be effective in reducing malaria incidence in both targeted and untargeted areas. Regardless of the intervention strategy used, pre-elimination (1-5 cases per 1000 per year) would not be reached without simultaneously increasing vector control by more than 10%. A cornerstone of malaria control and elimination is the effective targeting of strategic locations. Mathematical tools help to identify those locations and estimate the impact in silico.
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9
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Hounkonnou CPA, Ndam NT, Fievet N, Accrombessi M, Yovo E, Mama A, Sossou D, Vianou B, Massougbodji A, Briand V, Cot M, Cottrell G. Sub-optimal Intermittent Preventive Treatment in pregnancy (IPTp) is associated with an increased risk of submicroscopic P. falciparum infection in pregnant women: a prospective cohort study in Benin. Clin Infect Dis 2020; 73:e3759-e3767. [PMID: 32901806 PMCID: PMC8662796 DOI: 10.1093/cid/ciaa1355] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [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: 05/29/2020] [Indexed: 01/07/2023] Open
Abstract
Background Harmful maternal and neonatal health outcomes result from malaria in pregnancy, the prevention of which primarily relies on intermittent preventive treatment in pregnancy (IPTp) with sulfadoxine-pyrimethamine (SP). The World Health Organization recommends IPTp-SP in sub-Saharan Africa, but implementation is highly heterogeneous and often suboptimal in terms of the number of doses and their timing. In this study, we assessed the impact of this heterogeneity on malaria in pregnancy, mainly with respect to submicroscopic Plasmodium falciparum infections. Methods We used data from 273 Beninese women followed throughout pregnancy. Screening for P. falciparum infections, using both microscopy-based and polymerase chain reaction (PCR)–based methods, was performed monthly, and information on IPTp-SP doses was collected. Gestational age was estimated by repeated ultrasound scans. Using a negative binomial model, we investigated the effect of IPTp-SP doses and timing after 17 weeks of gestation on the number of P. falciparum infections, focusing on submicroscopic infections detectable only by PCR. Results At least 2 IPTp-SP doses were taken by 77.3% of the women. The median gestational age at the first IPTp-SP dose was 22 weeks. A late first IPTp-SP dose (>21.2 weeks) was marginally associated with an increased number of P. falciparum infections (adjusted incidence rate ratio [aIRR] = 1.3; P = .098). The number of IPTp-SP doses was not associated with the number of submicroscopic infections (aIRR = 1.2, P = .543). Conclusions A late first IPTp-SP dose failed to provide optimal protection against P. falciparum, especially submicroscopic infections. This highlights the need for a new antimalarial drug for IPTp that could be taken early in pregnancy.
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Affiliation(s)
- Cornélia P A Hounkonnou
- Université de Paris, MERIT, IRD, Paris, France.,Sorbonne Université, Université Pierre et Marie-Curie, Paris, France
| | | | | | - Manfred Accrombessi
- Institut de Recherche Clinique du Bénin, Abomey-Calavi, Bénin.,Faculty of Infectious and Tropical Diseases, Disease Control Department, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Emmanuel Yovo
- Institut de Recherche Clinique du Bénin, Abomey-Calavi, Bénin
| | - Atikatou Mama
- Institut de Recherche Clinique du Bénin, Abomey-Calavi, Bénin
| | - Darius Sossou
- Institut de Recherche Clinique du Bénin, Abomey-Calavi, Bénin
| | - Bertin Vianou
- Institut de Recherche Clinique du Bénin, Abomey-Calavi, Bénin
| | | | - Valérie Briand
- IRD, Inserm, Université de Bordeaux, IDLIC team, UMR, Bordeaux, France
| | - Michel Cot
- Université de Paris, MERIT, IRD, Paris, France
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10
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Briand V, Cottrell G, Tuike Ndam N, Martiáñez-Vendrell X, Vianou B, Mama A, Kouwaye B, Houzé S, Bailly J, Gbaguidi E, Sossou D, Massougbodji A, Accrombessi M, Mayor A, Ding XC, Fievet N. Prevalence and clinical impact of malaria infections detected with a highly sensitive HRP2 rapid diagnostic test in Beninese pregnant women. Malar J 2020; 19:188. [PMID: 32448310 PMCID: PMC7247134 DOI: 10.1186/s12936-020-03261-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [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: 10/24/2019] [Accepted: 05/15/2020] [Indexed: 02/07/2023] Open
Abstract
Background While sub-microscopic malarial infections are frequent and potentially deleterious during pregnancy, routine molecular detection is still not feasible. This study aimed to assess the performance of a Histidine Rich Protein 2 (HRP2)-based ultrasensitive rapid diagnostic test (uRDT, Alere Malaria Ag Pf) for the detection of infections of low parasite density in pregnant women. Methods This was a retrospective study based on samples collected in Benin from 2014 to 2017. A total of 942 whole blood samples collected in 327 women in the 1st and 3rd trimesters and at delivery were tested by uRDT, conventional RDT (cRDT, SD BIOLINE Malaria Ag Pf), microscopy, quantitative polymerase chain-reaction (qPCR) and Luminex-based suspension array technology targeting P. falciparum HRP2. The performance of each RDT was evaluated using qPCR as reference standard. The association between infections detected by uRDT, but not by cRDT, with poor maternal and birth outcomes was assessed using multivariate regression models. Results The overall positivity rate detected by cRDT, uRDT, and qPCR was 11.6% (109/942), 16.2% (153/942) and 18.3% (172/942), respectively. Out of 172 qPCR-positive samples, 68 were uRDT-negative. uRDT had a significantly better sensitivity (60.5% [52.7–67.8]) than cRDT (44.2% [36.6–51.9]) and a marginally decreased specificity (93.6% [91.7–95.3] versus 95.7% [94.0–97.0]). The gain in sensitivity was particularly high (33%) and statistically significant in the 1st trimester. Only 28 (41%) out of the 68 samples which were qPCR-positive, but uRDT-negative had detectable but very low levels of HRP2 (191 ng/mL). Infections that were detected by uRDT but not by cRDT were associated with a 3.4-times (95%CI 1.29–9.19) increased risk of anaemia during pregnancy. Conclusions This study demonstrates the higher performance of uRDT, as compared to cRDTs, to detect low parasite density P. falciparum infections during pregnancy, particularly in the 1st trimester. uRDT allowed the detection of infections associated with maternal anaemia.
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Affiliation(s)
- Valérie Briand
- Institut de Recherche Pour le Développement (IRD), University of Bordeaux, Inserm, UMR 1219, 146 rue Léo-Saignat, 33076, Bordeaux Cedex, France. .,Université de Paris, MERIT, IRD, 75006, Paris, France.
| | | | | | | | - Bertin Vianou
- Institut de Recherche Clinique du Bénin (IRCB), Cotonou, Benin
| | - Atika Mama
- Institut de Recherche Clinique du Bénin (IRCB), Cotonou, Benin
| | | | - Sandrine Houzé
- Université de Paris, MERIT, IRD, 75006, Paris, France.,AP-HP, Centre National de Référence sur le paludisme, hôpital Bichat-Claude-Bernard, 75017, Paris, France
| | - Justine Bailly
- AP-HP, Centre National de Référence sur le paludisme, hôpital Bichat-Claude-Bernard, 75017, Paris, France
| | - Erasme Gbaguidi
- Institut de Recherche Clinique du Bénin (IRCB), Cotonou, Benin
| | - Darius Sossou
- Institut de Recherche Clinique du Bénin (IRCB), Cotonou, Benin
| | | | - Manfred Accrombessi
- Institut de Recherche Clinique du Bénin (IRCB), Cotonou, Benin.,Faculty of Infectious and Tropical Diseases, Disease Control Department, London School of Hygiene and Tropical Medicine, WC1E 7HT, London, UK
| | - Alfredo Mayor
- ISGlobal, Hospital Clínic of Barcelona, Universitat de Barcelona, Barcelona, 08036, Spain
| | | | - Nadine Fievet
- Université de Paris, MERIT, IRD, 75006, Paris, France
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11
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Tornyigah B, Coppée R, Houze P, Kusi KA, Adu B, Quakyi I, Coleman N, Mama A, Deloron P, Anang AK, Clain J, Tahar R, Ofori MF, Tuikue Ndam N. Effect of Drug Pressure on Promoting the Emergence of Antimalarial-Resistant Parasites among Pregnant Women in Ghana. Antimicrob Agents Chemother 2020; 64:e02029-19. [PMID: 32179528 DOI: 10.1128/AAC.02029-19] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Accepted: 03/08/2020] [Indexed: 11/20/2022] Open
Abstract
The continuous spread of antimalarial drug resistance is a threat to current chemotherapy efficacy. Therefore, characterizing the genetic diversity of drug resistance markers is needed to follow treatment effectiveness and further update control strategies. Here, we genotyped Plasmodium falciparum resistance gene markers associated with sulfadoxine-pyrimethamine (SP) and artemisinin-based combination therapy (ACT) in isolates from pregnant women in Ghana. The prevalence of the septuple IRN I- A/FG K GS/T pfdhfr/pfdhps haplotypes, including the pfdhps A581G and A613S/T mutations, was high at delivery among post-SP treatment isolates (18.2%) compared to those of first antenatal care (before initiation of intermittent preventive treatment of malaria in pregnancy with sulfadoxine-pyrimethamine [IPTp-SP]; 6.1%; P = 0.03). Regarding the pfk13 marker gene, two nonsynonymous mutations (N458D and A481C) were detected at positions previously related to artemisinin resistance in isolates from Southeast Asia. These mutations were predicted in silico to alter the stability of the pfk13 propeller-encoding domain. Overall, these findings highlight the need for intensified monitoring and surveillance of additional mutations associated with increased SP resistance as well as emergence of resistance against artemisinin derivatives.
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12
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Bridges DJ, Chishimba S, Mwenda M, Winters AM, Slawsky E, Mambwe B, Mulube C, Searle KM, Hakalima A, Mwenechanya R, Larsen DA. The use of spatial and genetic tools to assess Plasmodium falciparum transmission in Lusaka, Zambia between 2011 and 2015. Malar J 2020; 19:20. [PMID: 31941493 PMCID: PMC6964105 DOI: 10.1186/s12936-020-3101-7] [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] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Accepted: 01/07/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Zambia has set itself the ambitious target of eliminating malaria by 2021. To continue tracking transmission to zero, new interventions, tools and approaches are required. METHODS Urban reactive case detection (RCD) was performed in Lusaka city from 2011 to 2015 to better understand the location and drivers of malaria transmission. Briefly, index cases were followed to their home and all consenting individuals living in the index house and nine proximal houses were tested with a malaria rapid diagnostic test and treated if positive. A brief survey was performed and for certain responses, a dried blood spot sample collected for genetic analysis. Aggregate health facility data, individual RCD response data and genetic results were analysed spatially and against environmental correlates. RESULTS Total number of malaria cases remained relatively constant, while the average age of incident cases and the proportion of incident cases reporting recent travel both increased. The estimated R0 in Lusaka was < 1 throughout the study period. RCD responses performed within 250 m of uninhabited/vacant land were associated with a higher probability of identifying additional infections. CONCLUSIONS Evidence suggests that the majority of malaria infections are imported from outside Lusaka. However there remains some level of local transmission occurring on the periphery of urban settlements, namely in the wet season. Unfortunately, due to the higher-than-expected complexity of infections and the small number of samples tested, genetic analysis was unable to identify any meaningful trends in the data.
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Affiliation(s)
- Daniel J Bridges
- PATH MACEPA, National Malaria Elimination Centre, Gt East Rd, Lusaka, Zambia. .,Akros, 45A Roan Road, Lusaka, Zambia.
| | - Sandra Chishimba
- PATH MACEPA, National Malaria Elimination Centre, Gt East Rd, Lusaka, Zambia.,Akros, 45A Roan Road, Lusaka, Zambia
| | - Mulenga Mwenda
- PATH MACEPA, National Malaria Elimination Centre, Gt East Rd, Lusaka, Zambia.,Akros, 45A Roan Road, Lusaka, Zambia
| | - Anna M Winters
- Akros, 45A Roan Road, Lusaka, Zambia.,School of Public and Community Health Sciences, University of Montana, Missoula, MT, USA
| | - Erik Slawsky
- Department of Public Health, Syracuse University, Syracuse, NY, USA
| | - Brenda Mambwe
- PATH MACEPA, National Malaria Elimination Centre, Gt East Rd, Lusaka, Zambia
| | - Conceptor Mulube
- PATH MACEPA, National Malaria Elimination Centre, Gt East Rd, Lusaka, Zambia
| | - Kelly M Searle
- School of Public Health, University of Minnesota, Minneapolis, MN, USA
| | - Aves Hakalima
- Lusaka District Health Management Team, Ministry of Health, Lusaka, Zambia
| | - Roy Mwenechanya
- Akros, 45A Roan Road, Lusaka, Zambia.,Department of Biomedical Sciences, School of Veterinary Medicine, University of Zambia, Lusaka, Zambia
| | - David A Larsen
- Akros, 45A Roan Road, Lusaka, Zambia.,Department of Public Health, Syracuse University, Syracuse, NY, USA
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13
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Quakyi I, Tornyigah B, Houze P, Kusi KA, Coleman N, Escriou G, Laar A, Cot M, Fobil J, Asare GQ, Deloron P, Anang AK, Cottrell G, Ofori MF, Ndam NT. High uptake of Intermittent Preventive Treatment of malaria in pregnancy is associated with improved birth weight among pregnant women in Ghana. Sci Rep 2019; 9:19034. [PMID: 31836735 PMCID: PMC6911095 DOI: 10.1038/s41598-019-55046-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [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: 07/18/2019] [Accepted: 11/20/2019] [Indexed: 11/09/2022] Open
Abstract
Despite the clinically proven advantages of intermittent preventive treatment of malaria in pregnancy (IPTp) with sulfadoxine-pyrimethamine (SP), utilisation has been low in many African countries. To increase uptake and achieve the desired effect, the World Health Organization revised the policy to a monthly administration. Assessing the coverage and impact of the revised policy on pregnancy and neonatal outcomes is, therefore, a necessity. A 2-parallel cross-sectional hospital-based study was carried out among pregnant women attending first antenatal care (ANC) and delivery. Maternal and cord blood samples were assayed for malaria parasites by quantitative PCR targeting both the 18S rDNA and the acidic terminal segment of Plasmodium falciparum var genes, and plasma SP levels were measured by liquid chromatography coupled to tandem mass spectrometry. Parasite prevalence was similar between the two study sites but decreased significantly between the first ANC (9% or 43%) and delivery (4% or 11%) based on the qPCR target. At delivery, 64.5% of women received ≥3 IPTp-SP dose, 15.5% received 2 doses and 6% had 1 dose. Taking ≥3 IPTp-SP doses was associated with an average birth weight increase of more than 0.165 kg. IPTp-SP uptake was associated with plasma SP level at delivery (OR = 32.3, p ≤ 0.005, 95% CI (13.3;78.4) for those that reported ≥3 IPTp-SP doses) while the same trend of improved birth weight was observed with high plasma SP levels. The new IPTp policy is well implemented and well utilised by women in the sites considered in this study and translates to the improved birth weight observed. This study confirms the interest and the clinical benefit expected from this policy change.
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Affiliation(s)
- Isabella Quakyi
- Université de Paris, MERIT, IRD, F-75006, Paris, France.,Department of Biological Environmental and Occupational Health Sciences, School of Public Health, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Bernard Tornyigah
- Université de Paris, MERIT, IRD, F-75006, Paris, France.,Department of Immunology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, Legon, Ghana
| | - Pascal Houze
- Service de biochimie générale, Hôpital universitaire Necker-Enfants Malades, AP-HP, 149 rue de Sèvres, 75015, Paris, France.,Unité de Technologies Biologiques et Chimiques pour la Santé (UTCBS), Paris 5-CNRS UMR8258 Inserm U1022, Faculté de Pharmacie, Université Paris Descartes, Paris, France.,Department of Parasitology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Kwadwo A Kusi
- Department of Immunology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, Legon, Ghana
| | - Nathaniel Coleman
- Department of Biological Environmental and Occupational Health Sciences, School of Public Health, College of Health Sciences, University of Ghana, Legon, Ghana
| | | | - Amos Laar
- Department of Biological Environmental and Occupational Health Sciences, School of Public Health, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Michel Cot
- Université de Paris, MERIT, IRD, F-75006, Paris, France
| | - Julius Fobil
- Department of Biological Environmental and Occupational Health Sciences, School of Public Health, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Gloria Quansah Asare
- Department of Biological Environmental and Occupational Health Sciences, School of Public Health, College of Health Sciences, University of Ghana, Legon, Ghana
| | | | - Abraham K Anang
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | | | - Michael F Ofori
- Department of Immunology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, Legon, Ghana
| | - Nicaise Tuikue Ndam
- Université de Paris, MERIT, IRD, F-75006, Paris, France. .,Department of Immunology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, Legon, Ghana.
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14
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Tuikue Ndam N, Tornyigah B, Dossou AY, Escriou G, Nielsen MA, Salanti A, Issifou S, Massougbodji A, Chippaux JP, Deloron P. Persistent Plasmodium falciparum Infection in Women With an Intent to Become Pregnant as a Risk Factor for Pregnancy-associated Malaria. Clin Infect Dis 2019; 67:1890-1896. [PMID: 29733338 DOI: 10.1093/cid/ciy380] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Accepted: 05/03/2018] [Indexed: 02/04/2023] Open
Abstract
Background Pregnant women are more susceptible to Plasmodium falciparum than before pregnancy, and infection has consequences for both mother and offspring. The World Health Organization recommends that pregnant woman in areas of transmission receive intermittent preventive treatment (IPTp) starting in the second trimester. Consequently, women are not protected during the first trimester, although P. falciparum infections are both frequent and harmful. Methods A cohort of nulligravid women was followed up during subsequent pregnancy. Malaria was diagnosed by means of microscopy and polymerase chain reaction. Parasites were genotyped at polymorphic loci. Results Among 275 nulligravidae enrolled, 68 women became pregnant and were followed up during pregnancy. Before pregnancy, P. falciparum prevalence rates were 15% by microscopy and 66% by polymerase chain reaction. Microscopic infection rates increased to 29% until IPTp administration, and their density increased by 20-fold. Conversely, submicroscopic infection rates decreased. After IPTp administration, all types of infections decreased, but they increased again late in pregnancy. The risk of infection during pregnancy was higher in women with a microscopic (odds ratio, 6.5; P = .047) or submicroscopic (3.06; P = .05) infection before pregnancy and was not related to the season of occurrence. Most infections during pregnancy were persistent infections acquired before pregnancy. Conclusions Microscopic and submicroscopic malaria infections were frequent in nulligravid women from south Benin. During the first trimester of pregnancy, microscopic infections were more frequent, with a higher parasite density, and mainly derived from parasites infecting the woman before conception. Preventive strategies targeting nonpregnant women with a desire for conception need to be designed.
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Affiliation(s)
- Nicaise Tuikue Ndam
- Mère et Enfant face aux Infections Tropicales, Institut de Recherche pour le Développement, Université Paris 5, Sorbonne Paris Cité, France.,Department of Parasitology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon
| | - Bernard Tornyigah
- Mère et Enfant face aux Infections Tropicales, Institut de Recherche pour le Développement, Université Paris 5, Sorbonne Paris Cité, France.,Department of Parasitology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon
| | | | - Guillaume Escriou
- Mère et Enfant face aux Infections Tropicales, Institut de Recherche pour le Développement, Université Paris 5, Sorbonne Paris Cité, France
| | - Morten A Nielsen
- Centre for Medical Parasitology at Department of Immunology and Microbiology, Faculty of Health and Medical Science, University of Copenhagen.,Department of Infectious Diseases, Copenhagen University Hospital (Rigshospitalet), Denmark
| | - Ali Salanti
- Centre for Medical Parasitology at Department of Immunology and Microbiology, Faculty of Health and Medical Science, University of Copenhagen.,Department of Infectious Diseases, Copenhagen University Hospital (Rigshospitalet), Denmark
| | - Saadou Issifou
- Centre de Recherche sur le Paludisme Associé à la Grossesse et l'Enfance, Cotonou, Benin
| | - Achille Massougbodji
- Centre de Recherche sur le Paludisme Associé à la Grossesse et l'Enfance, Cotonou, Benin
| | - Jean-Philippe Chippaux
- Mère et Enfant face aux Infections Tropicales, Institut de Recherche pour le Développement, Université Paris 5, Sorbonne Paris Cité, France.,Centre de Recherche sur le Paludisme Associé à la Grossesse et l'Enfance, Cotonou, Benin
| | - Philippe Deloron
- Mère et Enfant face aux Infections Tropicales, Institut de Recherche pour le Développement, Université Paris 5, Sorbonne Paris Cité, France
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Bottazzi P, Winkler M, Boillat S, Diagne A, Maman Chabi Sika M, Kpangon A, Faye S, Speranza C. Measuring Subjective Flood Resilience in Suburban Dakar: A Before–After Evaluation of the “Live with Water” Project. Sustainability 2018; 10:2135. [DOI: 10.3390/su10072135] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Gbalégba CGN, Ba H, Silué KD, Ba O, Tia E, Chouaibou M, Tian-Bi NTY, Yapi GY, Koné B, Utzinger J, Koudou BG. Distribution of Plasmodium spp. infection in asymptomatic carriers in perennial and low seasonal malaria transmission settings in West Africa. Infect Dis Poverty 2018; 7:39. [PMID: 29690913 PMCID: PMC5926534 DOI: 10.1186/s40249-018-0412-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [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: 09/17/2017] [Accepted: 03/24/2018] [Indexed: 11/24/2022] Open
Abstract
Background Since 2000, substantial progress has been made in reducing malaria worldwide. However, some countries in West Africa remain a hotspot for malaria with all age groups at risk. Asymptomatic carriers of Plasmodium spp. are important sources of infections for malaria vectors and thus contribute to the anchoring of the disease in favourable eco-epidemiological settings. The objective of this study was to assess the asymptomatic malaria case rates in Korhogo and Kaedi, two urban areas in northern Côte d’Ivoire and southern Mauritania, respectively. Methods Cross-sectional surveys were carried out during the rainy season in 2014 and the dry season in 2015 in both settings. During each season, 728 households were randomly selected and a household-based questionnaire was implemented to collect demographic and epidemiological data, including of malaria preventive methods used in communities. Finger-prick blood samples were obtained for biological examination using microscopy and rapid diagnostic tests (RDTs). Results Overall, 2672 households and 15 858 consenting participants were surveyed. Plasmodium spp. infection was confirmed in 12.4% (n = 832) and 0.3% (n = 22) of the assessed individuals in Korhogo and Kaedi, respectively. In Korhogo, the prevalence of asymptomatic malaria was 10.5% (95% CI: 9.7–11.2) as determined by microscopy and 9.3% (95% CI: 8.6–10.0%) when assessed by RDT. In Kaedi, asymptomatic malaria prevalence was 0.2% (95% CI: 0.1–0.4%) according to microscopy, while all RDTs performed were negative (n = 8372). In Korhogo, asymptomatic malaria infection was significantly associated with age and season, with higher risk within the 5–14 years-old, and during the rainy season. In Kaedi, the risk of asymptomatic malaria infection was associated with season only (higher during the dry season; crude OR (cOR): 6.37, 95% CI: 1.87–21.63). P. falciparum was the predominant species identified in both study sites representing 99.2% (n = 825) in Korhogo and 59.1% (n = 13) in Kaedi. Gametocytes were observed only in Korhogo and only during the rainy season at 1.3% (95% CI: 0.7–2.4%). Conclusions Our findings show a low prevalence of clinical malaria episodes with a significant proportion of asymptomatic carriers in both urban areas. National policies for malaria infections are focused on treatment of symptomatic cases. Malaria control strategies should be designed for monitoring and managing malaria infections in asymptomatic carriers. Additional measures, including indoor residual spraying, effective use of long-lasting insecticidal nets is strongly needed to reduce the number of Plasmodium spp. infections in Korhogo and Kaedi. Electronic supplementary material The online version of this article (10.1186/s40249-018-0412-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Constant G N Gbalégba
- Unité de Formation et de Recherche Sciences de la Nature, Université Nangui Abrogoua, 02 B.P. 801, Abidjan, 02, Côte d'Ivoire. .,Centre Suisse de Recherches Scientifiques en Côte d'Ivoire , 01 B.P. 1303, Abidjan, 01, Côte d'Ivoire.
| | - Hampâté Ba
- Laboratoire de Parasitologie - Mycologie, Institut National de Recherches en Santé Publique , B.P. 695, Nouakchott, Mauritania
| | - Kigbafori D Silué
- Centre Suisse de Recherches Scientifiques en Côte d'Ivoire , 01 B.P. 1303, Abidjan, 01, Côte d'Ivoire.,Unité de Formation et de Recherche Biosciences, Université Félix Houphouët-Boigny, 22 B.P. 582, Abidjan, 22, Côte d'Ivoire
| | - Ousmane Ba
- Laboratoire de Parasitologie - Mycologie, Institut National de Recherches en Santé Publique , B.P. 695, Nouakchott, Mauritania
| | - Emmanuel Tia
- Centre d'Entomologie Médicale et Vétérinaire, Université Alassane Ouattara, 27 B.P. 529, Abidjan, 27, Côte d'Ivoire
| | - Mouhamadou Chouaibou
- Centre Suisse de Recherches Scientifiques en Côte d'Ivoire , 01 B.P. 1303, Abidjan, 01, Côte d'Ivoire
| | - Nathan T Y Tian-Bi
- Centre Suisse de Recherches Scientifiques en Côte d'Ivoire , 01 B.P. 1303, Abidjan, 01, Côte d'Ivoire.,Unité de Formation et de Recherche Biosciences, Université Félix Houphouët-Boigny, 22 B.P. 582, Abidjan, 22, Côte d'Ivoire
| | - Grégoire Y Yapi
- Centre d'Entomologie Médicale et Vétérinaire, Université Alassane Ouattara, 27 B.P. 529, Abidjan, 27, Côte d'Ivoire
| | - Brama Koné
- Centre Suisse de Recherches Scientifiques en Côte d'Ivoire , 01 B.P. 1303, Abidjan, 01, Côte d'Ivoire.,Université Péléforo Gon Coulibaly, B.P. 1328, Korhogo, Côte d'Ivoire
| | - Jürg Utzinger
- Swiss Tropical and Public Health Institute , P.O. Box, CH- 4002, Basel, Switzerland.,University of Basel, P.O. Box, CH-4003, Basel, Switzerland
| | - Benjamin G Koudou
- Unité de Formation et de Recherche Sciences de la Nature, Université Nangui Abrogoua, 02 B.P. 801, Abidjan, 02, Côte d'Ivoire.,Centre Suisse de Recherches Scientifiques en Côte d'Ivoire , 01 B.P. 1303, Abidjan, 01, Côte d'Ivoire.,Centre for Neglected Tropical Diseases, Liverpool School of Tropical Medicine , Pembroke Place, Liverpool, L3 5QA, UK
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Atelu GR, Duah NO, Wilson MD. Carriage of sub-microscopic sexual and asexual Plasmodium falciparum stages in the dry season at Navrongo, Ghana. Ghana Med J 2018; 50:220-227. [PMID: 28579627 DOI: 10.4314/gmj.v50i4.4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND We investigated the prevalence of sub-microscopic Plasmodium falciparum infections and gametocyte carriage in asymptomatic individuals in Navrongo in northern Ghana, an area of seasonal malaria transmission. DESIGN A cross sectional study of 209 randomly selected participants of all age-groups was conducted in February and March, 2015. METHODS Capillary blood samples collected from these individuals were used for the detection of both asexual and gametocyte stage parasites by microscopy, reverse transcriptase polymerase chain reaction (RT-PCR) and conventional nested PCR methods. The prevalence data as determined by microscopy and molecular methods were compared using chi-square tests. RESULTS Parasitaemia from these asymptomatic infections ranged from 40 to 3,520 parasites/µl of blood (geometric mean parasitaemia = 732 parasites/µl). The prevalence of asymptomatic P. falciparum carriage was 4.8% (10/209) and 13.9% (29/209) using microscopy and RT-PCR respectively. The overall prevalence of sub-microscopic infections in the total number of samples analysed was 9.1% (19/209) and 66% (19/29) of the asymptomatic infections. P. falciparum gametocytemia detected by microscopy was 1% (2/209) and 3.8% (8/209) by PCR. CONCLUSION This is the first report of sub-microscopic asexual and gametocytes infections in the dry season in a seasonal malaria transmission area in Ghana. It has established that persistent latent malaria infections occur and that these could supply the source of parasites for the next transmission season. The findings highlight the presence of sub-microscopic infections and therefore the need for active case detection surveillance to eliminate "asymptomatic reservoir" parasites and consequently break the transmission of the disease in Ghana. FUNDING Bill and Melinda Gates Foundation grant awarded to Noguchi Memorial Institute for Medical Research Postdoctoral and Postgraduate Training in Infectious Diseases Research (Global Health Grant # OPP52155); National Institutes of Health grant (NIH-NIAID RO1 # 1RO1AI099623) to MDW; European Developing Countries Clinical Trials Partnership (EDCTP)-West African Network of Excellence for Clinical Trials in TB, AIDS and Malaria (WANETAM) (Project code CB.07.41700.007).
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Affiliation(s)
- Geoffrey R Atelu
- Ghana Field Epidemiology and Laboratory Training Program, School of Public Health, College of Health Sciences, University of Ghana, Legon, Ghana.,Ghana Health Service, Accra, Ghana
| | - Nancy O Duah
- Epidemiology Department, Noguchi Memorial Institute for Medical Research, University of Ghana, P. O. Box LG 581, Legon, Ghana
| | - Michael D Wilson
- Parasitology Department, Noguchi Memorial Institute for Medical Research, University of Ghana, P. O. Box LG 581, Legon, Ghana
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18
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Adomako-Ankomah Y, Chenoweth MS, Tocker AM, Doumbia S, Konate D, Doumbouya M, Keita AS, Anderson JM, Fairhurst RM, Diakite M, Miura K, Long CA. Host age and Plasmodium falciparum multiclonality are associated with gametocyte prevalence: a 1-year prospective cohort study. Malar J 2017; 16:473. [PMID: 29162100 PMCID: PMC5696713 DOI: 10.1186/s12936-017-2123-2] [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: 07/17/2017] [Accepted: 11/15/2017] [Indexed: 11/19/2022] Open
Abstract
Background Since Plasmodium falciparum transmission relies exclusively on sexual-stage parasites, several malaria control strategies aim to disrupt this step of the life cycle. Thus, a better understanding of which individuals constitute the primary gametocyte reservoir within an endemic population, and the temporal dynamics of gametocyte carriage, especially in seasonal transmission settings, will not only support the effective implementation of current transmission control programmes, but also inform the design of more targeted strategies. Methods A 1-year prospective cohort study was initiated in June 2013 with the goal of assessing the longitudinal dynamics of P. falciparum gametocyte carriage in a village in Mali with intense seasonal malaria transmission. A cohort of 500 individuals aged 1–65 years was recruited for this study. Gametocyte prevalence was measured monthly using Pfs25-specific RT-PCR, and analysed for the effects of host age and gender, seasonality, and multiclonality of P. falciparum infection over 1 year. Results Most P. falciparum infections (51–89%) in this population were accompanied by gametocytaemia throughout the 1-year period. Gametocyte prevalence among P. falciparum-positive individuals (proportion of gametocyte positive infections) was associated with age (p = 0.003) but not with seasonality (wet vs. dry) or gender. The proportion of gametocyte positive infections were similarly high in children aged 1–17 years (74–82% on median among 5 age groups), while older individuals had relatively lower proportion, and those aged > 35 years (median of 43%) had significantly lower than those aged 1–17 years (p < 0.05). Plasmodium falciparum-positive individuals with gametocytaemia were found to have significantly higher P. falciparum multiclonality than those without gametocytaemia (p < 0.033 in two different analyses). Conclusions Taken together, these results suggest that a substantial proportion of Pf-positive individuals carries gametocytes throughout the year, and that age is a significant determinant of gametocyte prevalence among these P. falciparum-positive individuals. Furthermore, the presence of multiple P. falciparum genotypes in an infection, a common feature of P. falciparum infections in high transmission areas, is associated with gametocyte prevalence. Electronic supplementary material The online version of this article (10.1186/s12936-017-2123-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Yaw Adomako-Ankomah
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
| | - Matthew S Chenoweth
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
| | - Aaron M Tocker
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
| | - Saibou Doumbia
- Malaria Research and Training Center, Faculty of Medicine, Pharmacy, and Odontostomatology, University of Sciences, Techniques, and Technologies of Bamako, Bamako, Mali
| | - Drissa Konate
- Malaria Research and Training Center, Faculty of Medicine, Pharmacy, and Odontostomatology, University of Sciences, Techniques, and Technologies of Bamako, Bamako, Mali
| | - Mory Doumbouya
- Malaria Research and Training Center, Faculty of Medicine, Pharmacy, and Odontostomatology, University of Sciences, Techniques, and Technologies of Bamako, Bamako, Mali
| | - Abdoul S Keita
- Malaria Research and Training Center, Faculty of Medicine, Pharmacy, and Odontostomatology, University of Sciences, Techniques, and Technologies of Bamako, Bamako, Mali
| | - Jennifer M Anderson
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
| | - Rick M Fairhurst
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
| | - Mahamadou Diakite
- Malaria Research and Training Center, Faculty of Medicine, Pharmacy, and Odontostomatology, University of Sciences, Techniques, and Technologies of Bamako, Bamako, Mali
| | - Kazutoyo Miura
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA.
| | - Carole A Long
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
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Niang M, Thiam LG, Sane R, Diagne N, Talla C, Doucoure S, Faye J, Diop F, Badiane A, Diouf B, Camara D, Diene-Sarr F, Sokhna C, Richard V, Toure-Balde A. Substantial asymptomatic submicroscopic Plasmodium carriage during dry season in low transmission areas in Senegal: Implications for malaria control and elimination. PLoS One 2017; 12:e0182189. [PMID: 28771615 PMCID: PMC5542561 DOI: 10.1371/journal.pone.0182189] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Accepted: 07/13/2017] [Indexed: 11/19/2022] Open
Abstract
Background In the progress towards malaria elimination, the accurate diagnosis of low-density asymptomatic infections is critical. Low-density asymptomatic submicroscopic malaria infections may act as silent reservoirs that maintain low-level residual malaria transmission in the community. Light microscopy, the gold standard in malaria diagnosis lacks the sensitivity to detect low-level parasitaemia. In this study, the presence and prevalence of submicroscopic Plasmodium carriage were investigated to estimate the parasites reservoir among asymptomatic individuals living in low transmission areas in Dielmo and Ndiop, Senegal during the dry season. Methods A total of 2,037 blood samples were collected during cross-sectional surveys prior the malaria transmission season in July 2013 (N = 612), June 2014 (N = 723) and June 2015 (N = 702) from asymptomatic individuals living in Dielmo and Ndiop, Senegal. Samples were used to determine the prevalence of submicroscopic Plasmodium carriage by real time PCR (qPCR) in comparison to microscopy considered as gold standard. Results The prevalence of submicroscopic Plasmodium carriage was 3.75% (23/612), 12.44% (90/723) and 6.41% (45/702) in 2013, 2014 and 2015, respectively. No Plasmodium carriage was detected by microscopy in 2013 while microscopy-based prevalence of Plasmodium carriage accounted for only 0.27% (2/723) and 0.14% (1/702) in 2014 and 2015, respectively. Plasmodium falciparum accounted for the majority of submicroscopic infections and represented 86.95% (20/23), 81.11% (73/90) and 95.55 (43/45) of infections in 2013, 2014 and 2015 respectively. Conclusion Low-density submicroscopic asymptomatic Plasmodium carriage is common in the study areas during the dry season indicating that traditional measures are insufficient to assess the scale of parasite reservoir when transmission reaches very low level. Control and elimination strategies may wish to consider using molecular methods to identify parasites carriers to guide Mass screening and Treatment strategies.
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Affiliation(s)
- Makhtar Niang
- Immunology Unit, Institut Pasteur Dakar, Dakar, Sénégal
- * E-mail:
| | | | - Rokhaya Sane
- Immunology Unit, Institut Pasteur Dakar, Dakar, Sénégal
| | - Nafissatou Diagne
- French National Research Institute for Sustainable Development, URMITE, URMITE UMR 198, Dakar, Sénégal
| | - Cheikh Talla
- Epidemiology Unit, Institut Pasteur Dakar, Dakar, Sénégal
| | - Souleymane Doucoure
- French National Research Institute for Sustainable Development, URMITE, URMITE UMR 198, Dakar, Sénégal
| | - Joseph Faye
- Epidemiology Unit, Institut Pasteur Dakar, Dakar, Sénégal
| | - Fode Diop
- Immunology Unit, Institut Pasteur Dakar, Dakar, Sénégal
| | | | - Babacar Diouf
- Immunology Unit, Institut Pasteur Dakar, Dakar, Sénégal
| | - Diogop Camara
- Immunology Unit, Institut Pasteur Dakar, Dakar, Sénégal
| | | | - Cheikh Sokhna
- French National Research Institute for Sustainable Development, URMITE, URMITE UMR 198, Dakar, Sénégal
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20
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Gbédandé K, Fievet N, Viwami F, Ezinmegnon S, Issifou S, Chippaux JP, Dossou Y, Moutairou K, Massougbodji A, Ndam N, de Jongh WA, Søgaard TMM, Salanti A, Nielsen MA, Esen M, Mordmüller B, Deloron P, Luty AJF. Clinical development of a VAR2CSA-based placental malaria vaccine PAMVAC: Quantifying vaccine antigen-specific memory B & T cell activity in Beninese primigravidae. Vaccine 2017; 35:3474-3481. [PMID: 28527688 DOI: 10.1016/j.vaccine.2017.05.027] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Revised: 05/04/2017] [Accepted: 05/06/2017] [Indexed: 11/18/2022]
Abstract
BACKGROUND The antigen VAR2CSA plays a pivotal role in the pathophysiology of pregnancy-associated malaria (PAM) caused by Plasmodium falciparum. A VAR2CSA-based vaccine candidate, PAMVAC, is under development by an EU-funded multi-country consortium (PlacMalVac project). As part of PAMVAC's clinical development, we quantified naturally acquired vaccine antigen-specific memory B and T cell responses in Beninese primigravidae recruited at the beginning of pregnancy and followed up to delivery and beyond. METHODS Clinical and parasitological histories were compiled from monthly clinic visits. On 4 occasions (first and fifth month of pregnancy, delivery, 6months post-delivery) peripheral blood mononuclear cells were isolated for in vitro assays. PAMVAC-specific memory B cells as well as those specific for a PAM unrelated P. falciparum antigen (PfEMP1-CIDR1a) and for tetanus toxoid were quantified by ELISpot. Memory T cell responses were assessed by quantifying cytokines (IL-5, IL-6, IL-10, IL-13, IFN-γ, TNF-α) in supernatants of cells stimulated in vitro either with PAMVAC, or mitogen (PHA). RESULTS Both tetanus toxoid- and PAMVAC-specific memory B cell frequencies increased to reach peak levels in the 5th month and at delivery, respectively and persisted post-delivery. The frequency of CIDR1a-specific memory B cells was stable during pregnancy, but declined post-delivery. The cumulated prevalence of infection with P. falciparum during pregnancy was 61% by microscopy. In women with a history of such infections, a significantly higher frequency of PAMVAC-specific memory B cells was observed at delivery. PAMVAC-specific pro-inflammatory (IFN-γ, TNF) responses tended to be higher at delivery in those with a history of infection. Mitogen-induced IL-5/IL-13 responses were significantly enhanced in the same women. CONCLUSIONS PAMVAC-specific memory B cells are induced during first pregnancies and are maintained post-delivery. Women with a T helper cell profile biased towards production of Th2-type cytokines have a greater risk of infection with P. falciparum.
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Affiliation(s)
- Komi Gbédandé
- Centre d'Etude et de Recherche sur le Paludisme Associé à la Grossesse et à l'Enfance (CERPAGE), Faculté des Sciences de la Santé, Université d'Abomey-Calavi, Benin; Département de Biochimie et de Biologie Cellulaire, Faculté des Sciences et Techniques, Université d'Abomey-Calavi, Benin; MERIT UMR D216, Institut de Recherche pour le Développement, Université Paris Descartes, COMUE Sorbonne Paris Cité, 75006 Paris, France.
| | - Nadine Fievet
- Centre d'Etude et de Recherche sur le Paludisme Associé à la Grossesse et à l'Enfance (CERPAGE), Faculté des Sciences de la Santé, Université d'Abomey-Calavi, Benin; MERIT UMR D216, Institut de Recherche pour le Développement, Université Paris Descartes, COMUE Sorbonne Paris Cité, 75006 Paris, France.
| | - Firmine Viwami
- Centre d'Etude et de Recherche sur le Paludisme Associé à la Grossesse et à l'Enfance (CERPAGE), Faculté des Sciences de la Santé, Université d'Abomey-Calavi, Benin.
| | - Sem Ezinmegnon
- Centre d'Etude et de Recherche sur le Paludisme Associé à la Grossesse et à l'Enfance (CERPAGE), Faculté des Sciences de la Santé, Université d'Abomey-Calavi, Benin.
| | - Saadou Issifou
- Centre d'Etude et de Recherche sur le Paludisme Associé à la Grossesse et à l'Enfance (CERPAGE), Faculté des Sciences de la Santé, Université d'Abomey-Calavi, Benin.
| | - Jean-Philippe Chippaux
- Centre d'Etude et de Recherche sur le Paludisme Associé à la Grossesse et à l'Enfance (CERPAGE), Faculté des Sciences de la Santé, Université d'Abomey-Calavi, Benin; MERIT UMR D216, Institut de Recherche pour le Développement, Université Paris Descartes, COMUE Sorbonne Paris Cité, 75006 Paris, France.
| | - Yannelle Dossou
- Centre d'Etude et de Recherche sur le Paludisme Associé à la Grossesse et à l'Enfance (CERPAGE), Faculté des Sciences de la Santé, Université d'Abomey-Calavi, Benin.
| | - Kabirou Moutairou
- Département de Biochimie et de Biologie Cellulaire, Faculté des Sciences et Techniques, Université d'Abomey-Calavi, Benin.
| | - Achille Massougbodji
- Centre d'Etude et de Recherche sur le Paludisme Associé à la Grossesse et à l'Enfance (CERPAGE), Faculté des Sciences de la Santé, Université d'Abomey-Calavi, Benin.
| | - Nicaise Ndam
- MERIT UMR D216, Institut de Recherche pour le Développement, Université Paris Descartes, COMUE Sorbonne Paris Cité, 75006 Paris, France.
| | | | - T Max M Søgaard
- ExpreS(2)ion Biotechnologies SCION-DTU Science Park DK-2970, Hoersholm, Denmark.
| | - Ali Salanti
- Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark.
| | - Morten A Nielsen
- Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark.
| | - Meral Esen
- Institut für Tropenmedizin, Eberhard Karls Universität Tübingen, Tübingen, Germany.
| | - Benjamin Mordmüller
- Institut für Tropenmedizin, Eberhard Karls Universität Tübingen, Tübingen, Germany.
| | - Philippe Deloron
- MERIT UMR D216, Institut de Recherche pour le Développement, Université Paris Descartes, COMUE Sorbonne Paris Cité, 75006 Paris, France.
| | - Adrian J F Luty
- Centre d'Etude et de Recherche sur le Paludisme Associé à la Grossesse et à l'Enfance (CERPAGE), Faculté des Sciences de la Santé, Université d'Abomey-Calavi, Benin; MERIT UMR D216, Institut de Recherche pour le Développement, Université Paris Descartes, COMUE Sorbonne Paris Cité, 75006 Paris, France.
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21
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Held J, Supan C, Salazar CLO, Tinto H, Bonkian LN, Nahum A, Sié A, Abdulla S, Cantalloube C, Djeriou E, Bouyou-Akotet M, Ogutu B, Mordmüller B, Kreidenweiss A, Siribie M, Sirima SB, Kremsner PG. Safety and efficacy of the choline analogue SAR97276 for malaria treatment: results of two phase 2, open-label, multicenter trials in African patients. Malar J 2017; 16:188. [PMID: 28472957 PMCID: PMC5418711 DOI: 10.1186/s12936-017-1832-x] [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: 01/30/2017] [Accepted: 04/23/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Malaria remains one of the most important infectious diseases. Treatment options for severe malaria are limited and the choline analogue SAR97276A is a novel chemical entity that was developed primarily as treatment for severe malaria. Before starting clinical investigations in severely ill malaria patients, safety and efficacy of SAR97276A was studied in patients with uncomplicated malaria. Here, we summarize two open-label, multi-center phase 2 trials assessing safety and efficacy of parenterally administered SAR97276A in African adults and children with falciparum malaria. RESULTS Study 1 was conducted in Burkina Faso, Gabon, Benin and Tanzania between August 2008 and July 2009 in malaria patients in an age de-escalating design (adults, children). A total of 113 malaria patients received SAR97276A. Adults were randomized to receive a single dose SAR97296A given either intramuscularly (IM) (0.18 mg/kg) or intravenously (IV) (0.14 mg/kg). If a single dose was not efficacious a second adult group was planned to test a three dose regimen administered IM once daily for 3 days. Single dose SAR97276A showed insufficient efficacy in adults (IM: 20 of 34 cured, 59%; and IV: 23/30 cured, 77%). The 3-day IM regimen showed acceptable efficacy in adults (27/30, 90%) but not in children (13/19, 68%). SAR97276A was well tolerated but no further groups were recruited due lack of efficacy. Study 2 was conducted between October 2011 and January 2012 in Burkina Faso, Gabon and Kenya. SAR97276A administered at a higher dose given IM was compared to artemether-lumefantrine. The study population was restricted to underage malaria patients to be subsequently enrolled in two age cohorts (teenagers, children). Rescue therapy was required in all teenaged malaria patients (8/8) receiving SAR97276A once daily (0.5 mg/kg) for 3 days and in 5 out of 8 teenaged patients treated twice daily (0.25 mg/kg) for 3 days. All patients (4/4) in the control group were cured. The study was stopped, before enrollment of children, due to lack of efficacy but the overall safety profile was good. CONCLUSIONS Monotherapy with SAR97276A up to twice daily for 3 days is not an efficacious treatment for falciparum malaria. SAR97276A will not be further developed for the treatment of malaria. Trial registration at clinicaltrials.gov: NCT00739206, retrospectively registered August 20, 2008 for Study 1 and NCT01445938 registered September 26, 2011 for Study 2.
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Affiliation(s)
- Jana Held
- Institut für Tropenmedizin, Universitätsklinikum Tübingen, Wilhelmstraße 27, 72074, Tübingen, Germany. .,Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon. .,German Centre for Infection Research, Partner Site Tübingen, Tübingen, Germany.
| | - Christian Supan
- Institut für Tropenmedizin, Universitätsklinikum Tübingen, Wilhelmstraße 27, 72074, Tübingen, Germany.,Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
| | - Carmen L Ospina Salazar
- Institut für Tropenmedizin, Universitätsklinikum Tübingen, Wilhelmstraße 27, 72074, Tübingen, Germany.,Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
| | | | | | - Alain Nahum
- Centre de Recherche Entomologique de Cotonou, Cotonou, Benin
| | - Ali Sié
- Centre de Recherche en Santé de Nouna, Nouna, Burkina Faso
| | - Salim Abdulla
- Ifakara Health Research Center, Bagamoyo, United Republic of Tanzania
| | | | | | - Marielle Bouyou-Akotet
- Département de Parasitologie, Mycologie, Médecine Tropicale, Université des Sciences de la Santé, Libreville, Gabon
| | | | - Benjamin Mordmüller
- Institut für Tropenmedizin, Universitätsklinikum Tübingen, Wilhelmstraße 27, 72074, Tübingen, Germany.,Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon.,German Centre for Infection Research, Partner Site Tübingen, Tübingen, Germany
| | - Andrea Kreidenweiss
- Institut für Tropenmedizin, Universitätsklinikum Tübingen, Wilhelmstraße 27, 72074, Tübingen, Germany.,Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon.,German Centre for Infection Research, Partner Site Tübingen, Tübingen, Germany
| | | | - Sodiomon B Sirima
- Groupe de Recherche Action en Santé, Ouagadougou, Burkina Faso.,Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Peter G Kremsner
- Institut für Tropenmedizin, Universitätsklinikum Tübingen, Wilhelmstraße 27, 72074, Tübingen, Germany. .,Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon. .,German Centre for Infection Research, Partner Site Tübingen, Tübingen, Germany.
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Diédhiou SM, Konaté L, Doucouré S, Samb B, Niang EA, Sy O, Thiaw O, Konaté A, Wotodjo AN, Diallo M, Gadiaga L, Sokhna C, Faye O. [Effectiveness of three biological larvicides and of an insect growth regulator against Anopheles arabiensis in Senegal]. ACTA ACUST UNITED AC 2016; 110:102-115. [PMID: 27942991 DOI: 10.1007/s13149-016-0531-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Accepted: 07/07/2016] [Indexed: 11/30/2022]
Abstract
Urban malaria is a major public health problem in Africa. In Senegal, the environmental changes seem to favor the persistence of malaria transmission in Dakar suburbs by creating, throughout the year, potential breeding sites of malaria vectors. In such a situation and in a context of a growing threat of insecticide resistance in anopheline vectors, the larval control making use of products from biological origin or growth regulators could represent an additional tool to the current strategies developed against anophelines. In this study conducted in 2012, the efficiency and residual effect of three biological larvicides (VectoBac® WG, Vecto-Max® CG, and VectoBac® GR) and an insect growth regulator (MetaLarv™) were evaluated on Anopheles gambiae s.l. larvae in seminatural conditions (experimental station) and natural breeding sites in the suburbs of Dakar. The formulations were tested according to the manufacturer recommendations, namely 0.03 g/m2 for VectoBac® WG, 0.5 g/m2 for VectoBac® GR, 0.75 g/m2 for VectoMax® CG, and 0.5 g/m2 for MetaLarv™. In experimental station, the treatment with larvicides was effective over a period of 14 days with a mortality ranging between 92% and 100%. The insect growth regulator remained effective up to 55 days with a single emergence recorded in the 27th day after treatment. In natural conditions, a total effectiveness (100% mortality) of larvicides was obtained 48 hours after treatment, then a gradual recolonization of breeding sites was noted. However, the insect growth regulator has reduced adult emergence higher than 80% until the end of follow-up (J28). This study showed a good efficiency of the larvicides and of the growth regulator tested. These works provide current data on potential candidates for the implementation of larval control interventions in addition to that of chemical adulticide for control of urban malaria.
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Affiliation(s)
- S M Diédhiou
- Laboratoire d'écologie vectorielle et parasitaire, faculté des sciences et techniques, université Cheikh-Anta-Diop de Dakar, Dakar, Sénégal. .,Unité de recherche sur les maladies infectieuses et tropicales émergentes (Urmite), IRD, UMR 198, CNRS 6236, Inserm 1095, Aix-Marseille-Université Campus UCAD-IRD, BP 1386, CP 18524, Dakar, Sénégal.
| | - L Konaté
- Laboratoire d'écologie vectorielle et parasitaire, faculté des sciences et techniques, université Cheikh-Anta-Diop de Dakar, Dakar, Sénégal
| | - S Doucouré
- Unité de recherche sur les maladies infectieuses et tropicales émergentes (Urmite), IRD, UMR 198, CNRS 6236, Inserm 1095, Aix-Marseille-Université Campus UCAD-IRD, BP 1386, CP 18524, Dakar, Sénégal
| | - B Samb
- Laboratoire d'écologie vectorielle et parasitaire, faculté des sciences et techniques, université Cheikh-Anta-Diop de Dakar, Dakar, Sénégal
| | - E A Niang
- Laboratoire d'écologie vectorielle et parasitaire, faculté des sciences et techniques, université Cheikh-Anta-Diop de Dakar, Dakar, Sénégal
| | - O Sy
- Laboratoire d'écologie vectorielle et parasitaire, faculté des sciences et techniques, université Cheikh-Anta-Diop de Dakar, Dakar, Sénégal
| | - O Thiaw
- Laboratoire d'écologie vectorielle et parasitaire, faculté des sciences et techniques, université Cheikh-Anta-Diop de Dakar, Dakar, Sénégal.,Unité de recherche sur les maladies infectieuses et tropicales émergentes (Urmite), IRD, UMR 198, CNRS 6236, Inserm 1095, Aix-Marseille-Université Campus UCAD-IRD, BP 1386, CP 18524, Dakar, Sénégal
| | - A Konaté
- Laboratoire d'écologie vectorielle et parasitaire, faculté des sciences et techniques, université Cheikh-Anta-Diop de Dakar, Dakar, Sénégal
| | - A N Wotodjo
- Unité de recherche sur les maladies infectieuses et tropicales émergentes (Urmite), IRD, UMR 198, CNRS 6236, Inserm 1095, Aix-Marseille-Université Campus UCAD-IRD, BP 1386, CP 18524, Dakar, Sénégal
| | - M Diallo
- Laboratoire d'écologie vectorielle et parasitaire, faculté des sciences et techniques, université Cheikh-Anta-Diop de Dakar, Dakar, Sénégal
| | - L Gadiaga
- Programme national de lutte contre le paludisme, Dakar, Sénégal
| | - C Sokhna
- Unité de recherche sur les maladies infectieuses et tropicales émergentes (Urmite), IRD, UMR 198, CNRS 6236, Inserm 1095, Aix-Marseille-Université Campus UCAD-IRD, BP 1386, CP 18524, Dakar, Sénégal
| | - O Faye
- Laboratoire d'écologie vectorielle et parasitaire, faculté des sciences et techniques, université Cheikh-Anta-Diop de Dakar, Dakar, Sénégal
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23
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Coalson JE, Walldorf JA, Cohee LM, Ismail MD, Mathanga D, Cordy RJ, Marti M, Taylor TE, Seydel KB, Laufer MK, Wilson ML. High prevalence of Plasmodium falciparum gametocyte infections in school-age children using molecular detection: patterns and predictors of risk from a cross-sectional study in southern Malawi. Malar J 2016; 15:527. [PMID: 27809907 PMCID: PMC5096312 DOI: 10.1186/s12936-016-1587-9] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [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: 07/20/2016] [Accepted: 10/28/2016] [Indexed: 01/11/2023] Open
Abstract
Background In endemic areas, many people experience asymptomatic Plasmodium infections, particularly older children and adults, but their transmission contribution is unknown. Though not the exclusive determinant of infectiousness, transmission from humans to mosquitoes requires blood meals containing gametocytes. Gametocytes often occur at submicroscopic densities, challenging measurement in human populations. More sensitive molecular techniques allow better characterization of gametocyte epidemiologic patterns. Methods Approximately 30 households were selected from each of eight sites in southern Malawi during two cross-sectional surveys. Blood was sampled from 623 people during the dry season and 896 the following rainy season. Among people PCR-positive for Plasmodium falciparum, mature gametocytes were detected by qRT-PCR. Regression models evaluated predictors of gametocyte carriage and density in the total population and among those with PCR-positive infections. Results The prevalence of gametocyte carriage by molecular testing was 3.5% during the dry season and 8.6% during the rainy season, and by microscopy 0.8 and 3.3%, respectively. Nearly half of PCR-positive infections carried gametocytes, regardless of recent symptom status. Among P. falciparum-infected people, only living in unfinished houses and age were significantly associated with gametocyte presence. Infected people in unfinished houses had higher odds of carrying gametocytes (OR 2.24, 95% CI 1.16–4.31), and 31% (95% CI 3–65%) higher gametocyte density than those in finished houses. School-age children (5–15 years), had higher odds than adults (≥16 years) of having gametocytes when infected (OR 2.77, 95% CI 1.47–5.19), but 31% (95% CI 11–47%) lower gametocyte density. Children <5 years did not have significantly higher odds of gametocyte carriage or density when infected than adults. Conclusions School-age children frequently carry gametocytes in communities of southern Malawi and represent an under-recognized reservoir of infection. Malaria elimination strategies should address these frequently asymptomatic reservoirs, especially in highly endemic areas. Improved household construction may also reduce the infectious reservoir. Electronic supplementary material The online version of this article (doi:10.1186/s12936-016-1587-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jenna E Coalson
- Department of Epidemiology, University of Michigan School of Public Health, Ann Arbor, MI, USA.
| | - Jenny A Walldorf
- Division of Malaria Research, Institute for Global Health, University of Maryland, Baltimore, MD, USA
| | - Lauren M Cohee
- Division of Malaria Research, Institute for Global Health, University of Maryland, Baltimore, MD, USA
| | - Miriam D Ismail
- Department of Epidemiology, University of Michigan School of Public Health, Ann Arbor, MI, USA
| | - Don Mathanga
- Malaria Alert Centre, College of Medicine, University of Malawi, Blantyre, Malawi
| | - Regina Joice Cordy
- Department of Immunology and Infectious Disease, The Harvard School of Public Health, Boston, MA, USA
| | - Matthias Marti
- Department of Immunology and Infectious Disease, The Harvard School of Public Health, Boston, MA, USA
| | - Terrie E Taylor
- Department of Osteopathic Medical Specialties, College of Osteopathic Medicine, Michigan State University, East Lansing, MI, USA
| | - Karl B Seydel
- Department of Osteopathic Medical Specialties, College of Osteopathic Medicine, Michigan State University, East Lansing, MI, USA
| | - Miriam K Laufer
- Division of Malaria Research, Institute for Global Health, University of Maryland, Baltimore, MD, USA
| | - Mark L Wilson
- Department of Epidemiology, University of Michigan School of Public Health, Ann Arbor, MI, USA
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24
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Gbédandé K, Cottrell G, Vianou B, Ibitokou S, Fernando A, Troye-Blomberg M, Salanti A, Moutairou K, Massougbodji A, Ndam NT, Deloron P, Luty AJF, Fievet N. Infections with Plasmodium falciparum during pregnancy affect VAR2CSA DBL-5 domain-specific T cell cytokine responses. Malar J 2016; 15:485. [PMID: 27653505 PMCID: PMC5031276 DOI: 10.1186/s12936-016-1525-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [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: 06/22/2016] [Accepted: 09/06/2016] [Indexed: 01/15/2023] Open
Abstract
Background Current knowledge of human immunological responses to pregnancy-associated malaria-specific Plasmodium falciparum protein VAR2CSA concerns almost exclusively B cell-driven
antibody-mediated activity. Knowledge of VAR2CSA-specific T cell-mediated activity is minimal by comparison, with only a single published report of a study investigating VAR2CSA-derived peptide-specific T cell responses. The study described here represents an attempt to redress this balance. Methods Within the framework of a cohort study of 1037 pregnant Beninese, sub-groups were selected on the basis of the documented presence/absence of infection with P. falciparum and conducted detailed immunological assessments both at inclusion into the study and at delivery. Peripheral blood mononuclear cells were isolated, stimulated in vitro, and VAR2CSA DBL-5 domain-specific, IFN-γ-secreting T-cell frequencies and cytokine responses were quantified using flow cytometric techniques. Multivariate analyses were used to determine primarily whether the T cell-mediated DBL5-specific activity measured was associated with infection by P. falciparum adjusted for gravidity, anaemia and other cofactors. Results Infections with P. falciparum detected at inclusion were associated with enhanced non-specific TNF responses, whilst diminished non-specific and DBL-5-specific IL-10 responses were associated with infections detected at delivery. Infections during pregnancy led to enhanced non-specific and DBL-5-specific IFN-γ responses detectable at delivery but to concomitantly lower DBL-5-specific CD8+ IFN-γ responses. Prospective assessments indicated that non-specific pro-inflammatory responses detectable at inclusion in the study were associated with the occurrence of infections subsequently during pregnancy. Conclusions The findings represent a first step in elucidating the quantity and quality of cellular immunological responses to VAR2CSA, which will help in the development of the primary vaccine candidate for prevention of pregnancy-associated malaria. Electronic supplementary material The online version of this article (doi:10.1186/s12936-016-1525-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Komi Gbédandé
- Centre d'Etude et de Recherche sur le Paludisme Associé à la Grossesse et à l'Enfance (CERPAGE), Faculté des Sciences de la Santé, Université d'Abomey-Calavi, Cotonou, Benin.,Département de Biochimie et de Biologie Cellulaire, Faculté des Sciences et Techniques, Université d'Abomey-Calavi, Cotonou, Benin.,Institut de Recherche pour le Développement, MERIT UMR D216 Mère et enfant face aux infections tropicales, Paris, France
| | - Gilles Cottrell
- Centre d'Etude et de Recherche sur le Paludisme Associé à la Grossesse et à l'Enfance (CERPAGE), Faculté des Sciences de la Santé, Université d'Abomey-Calavi, Cotonou, Benin.,Institut de Recherche pour le Développement, MERIT UMR D216 Mère et enfant face aux infections tropicales, Paris, France.,COMUE Sorbonne Paris Cité, Faculté de Pharmacie, Université Paris Descartes, Paris, France
| | - Bertin Vianou
- Centre d'Etude et de Recherche sur le Paludisme Associé à la Grossesse et à l'Enfance (CERPAGE), Faculté des Sciences de la Santé, Université d'Abomey-Calavi, Cotonou, Benin
| | - Samad Ibitokou
- Centre d'Etude et de Recherche sur le Paludisme Associé à la Grossesse et à l'Enfance (CERPAGE), Faculté des Sciences de la Santé, Université d'Abomey-Calavi, Cotonou, Benin
| | - Aurax Fernando
- Centre d'Etude et de Recherche sur le Paludisme Associé à la Grossesse et à l'Enfance (CERPAGE), Faculté des Sciences de la Santé, Université d'Abomey-Calavi, Cotonou, Benin
| | - Marita Troye-Blomberg
- Department of Molecular Biosciences, the Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Ali Salanti
- Department of International Health, Institute of International Health, Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - Kabirou Moutairou
- Département de Biochimie et de Biologie Cellulaire, Faculté des Sciences et Techniques, Université d'Abomey-Calavi, Cotonou, Benin
| | - Achille Massougbodji
- Centre d'Etude et de Recherche sur le Paludisme Associé à la Grossesse et à l'Enfance (CERPAGE), Faculté des Sciences de la Santé, Université d'Abomey-Calavi, Cotonou, Benin
| | - Nicaise Tuikue Ndam
- Centre d'Etude et de Recherche sur le Paludisme Associé à la Grossesse et à l'Enfance (CERPAGE), Faculté des Sciences de la Santé, Université d'Abomey-Calavi, Cotonou, Benin.,Institut de Recherche pour le Développement, MERIT UMR D216 Mère et enfant face aux infections tropicales, Paris, France.,COMUE Sorbonne Paris Cité, Faculté de Pharmacie, Université Paris Descartes, Paris, France
| | - Philippe Deloron
- Institut de Recherche pour le Développement, MERIT UMR D216 Mère et enfant face aux infections tropicales, Paris, France.,COMUE Sorbonne Paris Cité, Faculté de Pharmacie, Université Paris Descartes, Paris, France
| | - Adrian J F Luty
- Institut de Recherche pour le Développement, MERIT UMR D216 Mère et enfant face aux infections tropicales, Paris, France.,COMUE Sorbonne Paris Cité, Faculté de Pharmacie, Université Paris Descartes, Paris, France
| | - Nadine Fievet
- Centre d'Etude et de Recherche sur le Paludisme Associé à la Grossesse et à l'Enfance (CERPAGE), Faculté des Sciences de la Santé, Université d'Abomey-Calavi, Cotonou, Benin. .,Institut de Recherche pour le Développement, MERIT UMR D216 Mère et enfant face aux infections tropicales, Paris, France. .,COMUE Sorbonne Paris Cité, Faculté de Pharmacie, Université Paris Descartes, Paris, France.
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25
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Briand V, Le Hesran JY, Mayxay M, Newton PN, Bertin G, Houzé S, Keomany S, Inthavong Y, Vannavong N, Chindavongsa K, Hongvanthong B, Fievet N. Prevalence of malaria in pregnancy in southern Laos: a cross-sectional survey. Malar J 2016; 15:436. [PMID: 27566274 PMCID: PMC5002160 DOI: 10.1186/s12936-016-1492-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [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: 06/09/2016] [Accepted: 08/16/2016] [Indexed: 11/28/2022] Open
Abstract
Background There are no data on the burden of malaria in pregnancy (MiP) in Laos, where malaria still remains prevalent in the south. Methods Two cross-sectional surveys were conducted in 2014 to assess the prevalence of MiP in Vapi District, Salavan Province, southern Laos: the first consisted of screening 204 pregnant women during pregnancies [mean (95 % CI) gestational age: 23 (22–25) weeks] living in 30 randomly selected villages in Vapi District; the second was conducted among 331 pregnant women, who delivered during the study period in Vapi and Toumlane District Hospitals and in Salavan Provincial Hospital. Peripheral and placental malaria was detected using rapid diagnostic tests (RDT), thick blood smears (TBS) and real-time quantitative polymerase chain reactions (RT-qPCR). Factors associated with low birth weight (LBW) and maternal anaemia were assessed. Results In the villages, 12/204 women (5.9 %; 95 % CI 3.1–10.0) were infected with malaria as determined by RT-qPCR: 11 were Plasmodium vivax infections and 1 was mixed Plasmodium vivax/Plasmodium falciparum infection, among which 9 were sub-microscopic (as not detected by TBS). History of malaria during current pregnancy tended to be associated with a higher risk of MiP (aIRR 3.05; 95 % CI 0.94–9.88). At delivery, two Plasmodium falciparum sub-microscopic infections (one peripheral and one placental) were detected (4.5 %; 0.6–15.5) in Vapi District. In both surveys, all infected women stated they had slept under a bed net the night before the survey, and 86 % went to the forest for food-finding 1 week before the survey in median. The majority of infections (94 %) were asymptomatic and half of them were associated with anaemia. Overall, 24 % of women had LBW newborns. Factors associated with a higher risk of LBW were tobacco use (aIRR 2.43; 95 % CI 1.64–3.60) and pre-term delivery (aIRR 3.17; 95 % CI 2.19–4.57). Factors associated with a higher risk of maternal anaemia were no iron supplementation during pregnancy, Lao Theung ethnicity and place of living. Conclusions The prevalence of MiP in this population was noticeable. Most infections were asymptomatic and sub-microscopic vivax malaria, which raises the question of reliability of recommended national strategies for the screening and prevention of MiP in Laos. Electronic supplementary material The online version of this article (doi:10.1186/s12936-016-1492-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Valérie Briand
- Faculté de Pharmacie, Institut de Recherche pour le Développement (IRD), Mère et enfant face aux infections tropicales (UMR216), 4 avenue de l'Observatoire, 75006, Paris, France. .,COMUE Sorbonne Paris Cité, Faculté de Pharmacie, Université Paris Descartes, Paris, France.
| | - Jean-Yves Le Hesran
- Faculté de Pharmacie, Institut de Recherche pour le Développement (IRD), Mère et enfant face aux infections tropicales (UMR216), 4 avenue de l'Observatoire, 75006, Paris, France.,COMUE Sorbonne Paris Cité, Faculté de Pharmacie, Université Paris Descartes, Paris, France
| | - Mayfong Mayxay
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Vientiane, Lao People's Democratic Republic.,Faculty of Postgraduate Studies, University of Health Sciences, Vientiane, Lao People's Democratic Republic.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Paul N Newton
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Vientiane, Lao People's Democratic Republic.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Gwladys Bertin
- Faculté de Pharmacie, Institut de Recherche pour le Développement (IRD), Mère et enfant face aux infections tropicales (UMR216), 4 avenue de l'Observatoire, 75006, Paris, France.,COMUE Sorbonne Paris Cité, Faculté de Pharmacie, Université Paris Descartes, Paris, France
| | - Sandrine Houzé
- Faculté de Pharmacie, Institut de Recherche pour le Développement (IRD), Mère et enfant face aux infections tropicales (UMR216), 4 avenue de l'Observatoire, 75006, Paris, France.,COMUE Sorbonne Paris Cité, Faculté de Pharmacie, Université Paris Descartes, Paris, France.,Laboratoire de Parasitologie, CNR du Paludisme, AP-HP, Hôpital Bichat, Paris, France
| | - Sommay Keomany
- Salavan Provincial Hospital, Salavan, Salavan Province, Lao People's Democratic Republic
| | - Yom Inthavong
- Vapi District Hospital, Vapi, Salavan Province, Lao People's Democratic Republic
| | - Nanthasane Vannavong
- Champasack Provincial Health Office, Champasack, Champasack Province, Lao People's Democratic Republic
| | | | - Bouasy Hongvanthong
- Center of Malariology, Parasitology and Entomology, Vientiane, Lao People's Democratic Republic
| | - Nadine Fievet
- Faculté de Pharmacie, Institut de Recherche pour le Développement (IRD), Mère et enfant face aux infections tropicales (UMR216), 4 avenue de l'Observatoire, 75006, Paris, France.,COMUE Sorbonne Paris Cité, Faculté de Pharmacie, Université Paris Descartes, Paris, France
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26
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Ibitokou SA, Denoeud-Ndam L, Ezinmegnon S, Ladékpo R, Zannou DM, Massougbodji A, Girard PM, Cot M, Luty AJF, Ndam NT. Insights Into Circulating Cytokine Dynamics During Pregnancy in HIV-Infected Beninese Exposed to Plasmodium falciparum Malaria. Am J Trop Med Hyg 2015; 93:287-92. [PMID: 26101276 DOI: 10.4269/ajtmh.14-0653] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2014] [Accepted: 01/20/2015] [Indexed: 11/07/2022] Open
Abstract
We investigated the circulating plasma levels of Th1- (Interleukin-2 [IL-2], tumor necrosis factor-α [TNF-α], interferon-gamma [IFN-γ]) and Th2-type (IL-4, IL-5, IL-10) cytokines in human immunodeficiency virus (HIV)-infected pregnant women living in a malaria-endemic area. We analyzed samples from 200 pregnant women included in the prevention of pregnancy-associated malaria in HIV-infected women: cotrimoxazole prophylaxis versus mefloquine (PACOME) clinical trial who were followed until delivery. Cytokine concentrations were measured by flow cytometry-based multiplex bead array. Significantly elevated levels of IL-10 and lower levels of TNF-α were observed at delivery compared with inclusion (P = 0.005). At inclusion, the presence of circulating IFN-γ, a higher CD4(+) T cell count and having initiated intermittent preventive treatment of malaria with sulfadoxine pyrimethamine (SP-IPTp) were all associated with a lower likelihood of Plasmodium falciparum infection. At delivery, the inverse relationship between the presence of infection and circulating IFN-γ persisted, although there was a positive association between the likelihood of infection and the presence of circulating TNF-α. Initiation of antiretroviral therapy was associated with elevated IL-5 production. Consistent with our own and others' observations in HIV seronegative subjects, this study shows circulating IL-10 to be a marker of infection with P. falciparum during pregnancy even in HIV-infected women, although plasma IFN-γ may be a marker of anti-malarial protection in such women.
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Affiliation(s)
- Samad A Ibitokou
- Centre d'étude et de Recherche sur le Paludisme Associé à la Grossesse et à l'enfance (CERPAGE), Faculté des Sciences de la Santé, Université d'Abomey-Calavi, Benin; Institut de Recherche pour le Développement, UMR 216, Mère et enfant face aux Infections Tropicales, Paris, France; Service des Maladies Infectieuses et Tropicales, Hôpital Saint-Antoine, Paris, France
| | - Lise Denoeud-Ndam
- Centre d'étude et de Recherche sur le Paludisme Associé à la Grossesse et à l'enfance (CERPAGE), Faculté des Sciences de la Santé, Université d'Abomey-Calavi, Benin; Institut de Recherche pour le Développement, UMR 216, Mère et enfant face aux Infections Tropicales, Paris, France; Service des Maladies Infectieuses et Tropicales, Hôpital Saint-Antoine, Paris, France
| | - Sèm Ezinmegnon
- Centre d'étude et de Recherche sur le Paludisme Associé à la Grossesse et à l'enfance (CERPAGE), Faculté des Sciences de la Santé, Université d'Abomey-Calavi, Benin; Institut de Recherche pour le Développement, UMR 216, Mère et enfant face aux Infections Tropicales, Paris, France; Service des Maladies Infectieuses et Tropicales, Hôpital Saint-Antoine, Paris, France
| | - Rodolphe Ladékpo
- Centre d'étude et de Recherche sur le Paludisme Associé à la Grossesse et à l'enfance (CERPAGE), Faculté des Sciences de la Santé, Université d'Abomey-Calavi, Benin; Institut de Recherche pour le Développement, UMR 216, Mère et enfant face aux Infections Tropicales, Paris, France; Service des Maladies Infectieuses et Tropicales, Hôpital Saint-Antoine, Paris, France
| | - Djimon-Marcel Zannou
- Centre d'étude et de Recherche sur le Paludisme Associé à la Grossesse et à l'enfance (CERPAGE), Faculté des Sciences de la Santé, Université d'Abomey-Calavi, Benin; Institut de Recherche pour le Développement, UMR 216, Mère et enfant face aux Infections Tropicales, Paris, France; Service des Maladies Infectieuses et Tropicales, Hôpital Saint-Antoine, Paris, France
| | - Achille Massougbodji
- Centre d'étude et de Recherche sur le Paludisme Associé à la Grossesse et à l'enfance (CERPAGE), Faculté des Sciences de la Santé, Université d'Abomey-Calavi, Benin; Institut de Recherche pour le Développement, UMR 216, Mère et enfant face aux Infections Tropicales, Paris, France; Service des Maladies Infectieuses et Tropicales, Hôpital Saint-Antoine, Paris, France
| | - Pierre-Marie Girard
- Centre d'étude et de Recherche sur le Paludisme Associé à la Grossesse et à l'enfance (CERPAGE), Faculté des Sciences de la Santé, Université d'Abomey-Calavi, Benin; Institut de Recherche pour le Développement, UMR 216, Mère et enfant face aux Infections Tropicales, Paris, France; Service des Maladies Infectieuses et Tropicales, Hôpital Saint-Antoine, Paris, France
| | - Michel Cot
- Centre d'étude et de Recherche sur le Paludisme Associé à la Grossesse et à l'enfance (CERPAGE), Faculté des Sciences de la Santé, Université d'Abomey-Calavi, Benin; Institut de Recherche pour le Développement, UMR 216, Mère et enfant face aux Infections Tropicales, Paris, France; Service des Maladies Infectieuses et Tropicales, Hôpital Saint-Antoine, Paris, France
| | - Adrian J F Luty
- Centre d'étude et de Recherche sur le Paludisme Associé à la Grossesse et à l'enfance (CERPAGE), Faculté des Sciences de la Santé, Université d'Abomey-Calavi, Benin; Institut de Recherche pour le Développement, UMR 216, Mère et enfant face aux Infections Tropicales, Paris, France; Service des Maladies Infectieuses et Tropicales, Hôpital Saint-Antoine, Paris, France
| | - Nicaise Tuikue Ndam
- Centre d'étude et de Recherche sur le Paludisme Associé à la Grossesse et à l'enfance (CERPAGE), Faculté des Sciences de la Santé, Université d'Abomey-Calavi, Benin; Institut de Recherche pour le Développement, UMR 216, Mère et enfant face aux Infections Tropicales, Paris, France; Service des Maladies Infectieuses et Tropicales, Hôpital Saint-Antoine, Paris, France
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Bickersmith SA, Lainhart W, Moreno M, Chu VM, Vinetz JM, Conn JE. A sensitive, specific and reproducible real-time polymerase chain reaction method for detection of Plasmodium vivax and Plasmodium falciparum infection in field-collected anophelines. Mem Inst Oswaldo Cruz 2015; 110:573-6. [PMID: 26061150 PMCID: PMC4501424 DOI: 10.1590/0074-02760150031] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [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: 02/20/2015] [Accepted: 04/30/2015] [Indexed: 12/31/2022] Open
Abstract
We describe a simple method for detection of Plasmodium vivax and Plasmodium falciparum infection in anophelines using a triplex TaqMan real-time polymerase chain reaction (PCR) assay (18S rRNA). We tested the assay on Anopheles darlingi and Anopheles stephensi colony mosquitoes fed with Plasmodium-infected blood meals and in duplicate on field collected An. darlingi. We compared the real-time PCR results of colony-infected and field collected An. darlingi, separately, to a conventional PCR method. We determined that a cytochrome b-PCR method was only 3.33% as sensitive and 93.38% as specific as our real-time PCR assay with field-collected samples. We demonstrate that this assay is sensitive, specific and reproducible.
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Affiliation(s)
| | - William Lainhart
- Department of Biomedical Sciences, School of Public Health, State University of New York, Albany, NY, USA
| | - Marta Moreno
- Division of Infectious Diseases, Department of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Virginia M Chu
- Department of Biomedical Sciences, School of Public Health, State University of New York, Albany, NY, USA
| | - Joseph M Vinetz
- Division of Infectious Diseases, Department of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Jan E Conn
- Wadsworth Center, New York State Department of Health, Albany, NY, USA
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Lo E, Zhou G, Oo W, Afrane Y, Githeko A, Yan G. Low parasitemia in submicroscopic infections significantly impacts malaria diagnostic sensitivity in the highlands of Western Kenya. PLoS One 2015; 10:e0121763. [PMID: 25816298 PMCID: PMC4376713 DOI: 10.1371/journal.pone.0121763] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [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: 06/11/2014] [Accepted: 02/11/2015] [Indexed: 11/30/2022] Open
Abstract
Asymptomatic malaria infections represent a major challenge in malaria control and elimination in Africa. They are reservoirs of malaria parasite that can contribute to disease transmission. Therefore, identification and control of asymptomatic infections are important to make malaria elimination feasible. In this study, we investigated the extent and distribution of asymptomatic malaria in Western Kenya and examined how varying parasitemia affects performance of diagnostic methods including microscopy, conventional PCR, and quantitative PCR. In addition, we compared parasite prevalence rates and parasitemia levels with respect to topography and age in order to explore factors that influence malaria infection. Over 11,000 asymptomatic blood samples from children and adolescents up to 18 years old representing broad areas of Western Kenya were included. Quantitative PCR revealed the highest parasite positive rate among all methods and malaria prevalence in western Kenya varied widely from less than 1% to over 50%. A significantly lower parasitemia was detected in highland than in lowland samples and this contrast was also observed primarily among submicroscopic samples. Although we found no correlation between parasitemia level and age, individuals of younger age group (aged <14) showed significantly higher parasite prevalence. In the lowlands, individuals of aged 5–14 showed significantly higher prevalence than those under age 5. Our findings highlight the need for a more sensitive and time-efficient assay for asymptomatic malaria detection particularly in areas of low-transmission. Combining QPCR with microscopy can enhance the capacity of detecting submicroscopic asymptomatic malaria infections.
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Affiliation(s)
- Eugenia Lo
- Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, CA, 92697, United States of America
| | - Guofa Zhou
- Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, CA, 92697, United States of America
| | - Winny Oo
- Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, CA, 92697, United States of America
| | - Yaw Afrane
- Centre for Vector Biology and Control Research, Kenya Medical Research Institute, Kisumu, 40100, Kenya
| | - Andrew Githeko
- Centre for Vector Biology and Control Research, Kenya Medical Research Institute, Kisumu, 40100, Kenya
| | - Guiyun Yan
- Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, CA, 92697, United States of America
- * E-mail:
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Kone GK, Lalou R, Audibert M, Lafarge H, Dos Santos S, Ndonky A, Le Hesran JY. Use of health care among febrile children from urban poor households in Senegal: does the neighbourhood have an impact? Health Policy Plan 2015; 30:1307-19. [PMID: 25769739 DOI: 10.1093/heapol/czu144] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/31/2014] [Indexed: 11/12/2022] Open
Abstract
Urban malaria is considered a major public health problem in Africa. The malaria vector is well adapted in urban settings and autochthonous malaria has increased. Antimalarial treatments prescribed presumptively or after rapid diagnostic tests are also highly used in urban settings. Furthermore, health care strategies for urban malaria must comply with heterogeneous neighbourhood ecosystems where health-related risks and opportunities are spatially varied. This article aims to assess the capacity of the urban living environment to mitigate or increase individual or household vulnerabilities that influence the use of health services. The data are drawn from a survey on urban malaria conducted between 2008 and 2009. The study sample was selected using a two-stage randomized sampling. The questionnaire survey covered 2952 households that reported a case of fever episode in children below 10 years during the month before the survey.Self-medication is a widespread practice for children, particularly among the poorest households in Dakar. For rich households, self-medication for children is more a transitional practice enabling families to avoid opportunity costs related to visits to health facilities. For the poorest, it is a forced choice and often the only treatment option. However, the poor that live in well-equipped neighbourhoods inhabited by wealthy residents tend to behave as their rich neighbours. They grasp the opportunities provided by the area and adjust their behaviours accordingly. Though health care for children is strongly influenced by household socio-economic characteristics, neighbourhood resources (facilities and social networks) will promote health care among the poorest and reduce access inequalities. Without being a key factor, the neighbourhood of residence-when it provides resources-may be of some help to overcome the financial hurdle. Findings suggest that the neighbourhood (local setting) is a relevant scale for health programmes in African cities.
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Affiliation(s)
- Georges Karna Kone
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CR CHUM) et Université de Daloa (Cote d'ivoire), 850 rue saint Denis Montréal, Canada,
| | - Richard Lalou
- UMR 151 IRD/AMU, Laboratoire Population-Environnement-Développement, Aix-Marseille Université, centre Saint-Charles, Case 10, 3, place Victor-Hugo, 13331 Marseille cedex 3, France
| | - Martine Audibert
- CERDI, CNRS, 65 Boulevard François Mitterrand, 63000 Clermont-Ferrand, France
| | - Hervé Lafarge
- University of Paris Dauphine 32, avenue Henri Varagnat 93143 Bondy cedex, France
| | - Stéphanie Dos Santos
- UMR 151 IRD/AMU, Laboratoire Population-Environnement-Développement, Aix-Marseille Université, centre Saint-Charles, Case 10, 3, place Victor-Hugo, 13331 Marseille cedex 3, France
| | - Alphousseyni Ndonky
- UMR 151 IRD/AMU, Laboratoire Population-Environnement-Développement, Aix-Marseille Université, centre Saint-Charles, Case 10, 3, place Victor-Hugo, 13331 Marseille cedex 3, France
| | - Jean-Yves Le Hesran
- University of Paris Dauphine 32, avenue Henri Varagnat 93143 Bondy cedex, France
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Cottrell G, Moussiliou A, Luty AJF, Cot M, Fievet N, Massougbodji A, Deloron P, Tuikue Ndam N. Submicroscopic Plasmodium falciparum Infections Are Associated With Maternal Anemia, Premature Births, and Low Birth Weight. Clin Infect Dis 2015; 60:1481-8. [PMID: 25694651 DOI: 10.1093/cid/civ122] [Citation(s) in RCA: 106] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Accepted: 02/02/2015] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Molecular, as opposed to microscopic, detection measures the real prevalence of Plasmodium falciparum infections. Such occult infections are common during pregnancy but their impact on pregnancy outcomes is unclear. We performed a longitudinal study to describe that impact. METHODS In a cohort of 1037 Beninese pregnant women, we used ultrasound to accurately estimate gestational ages. Infection with P. falciparum, hemoglobin concentration, use of intermittent preventive treatment during pregnancy (IPTp) for malaria, and other parameters were recorded during pregnancy. Using multivariate analyses, we evaluated the impact of submicroscopic infections on maternal anemia, premature birth, and low birth weight. RESULTS At inclusion, polymerase chain reaction (PCR) and microscopy detected infection in 40% and 16% of women, respectively. The proportion infected declined markedly after 2 doses of IPTp but rebounded to 34% (by PCR) at delivery. Submicroscopic infections during pregnancy were associated with lower mean hemoglobin irrespective of gravidity, and with increased anemia risk in primigravidae (odds ratio [OR], 2.23; 95% confidence interval [CI], .98-5.07). Prospectively, submicroscopic infections at inclusion were associated with significantly increased risks of low birth weight in primigravidae (OR, 6.09; 95% CI, 1.16-31.95) and premature births in multigravidae (OR, 2.25; 95% CI, 1.13-4.46). CONCLUSIONS In this detailed longitudinal study, we document the deleterious impact of submicroscopic P. falciparum parasitemia during pregnancy on multiple pregnancy outcomes. Parasitemia occurs frequently during pregnancy, but routine microscopic and rapid diagnostic tests fail to detect the vast majority of episodes. Our findings imply caution in any revision of the current strategies for prevention of pregnancy-associated malaria.
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Affiliation(s)
- Gilles Cottrell
- PRES Sorbonne Paris Cité, Faculté de Pharmacie, Université Paris Descartes Institut de Recherche pour le Développement, UMR216-MERIT
| | - Azizath Moussiliou
- Institut de Recherche pour le Développement, UMR216-MERIT Université Pierre et Marie Curie, Paris, France
| | - Adrian J F Luty
- PRES Sorbonne Paris Cité, Faculté de Pharmacie, Université Paris Descartes Institut de Recherche pour le Développement, UMR216-MERIT
| | - Michel Cot
- PRES Sorbonne Paris Cité, Faculté de Pharmacie, Université Paris Descartes Institut de Recherche pour le Développement, UMR216-MERIT
| | - Nadine Fievet
- PRES Sorbonne Paris Cité, Faculté de Pharmacie, Université Paris Descartes Institut de Recherche pour le Développement, UMR216-MERIT
| | - Achille Massougbodji
- Centre d'Etude et de Recherche sur le paludisme associé à la Grossesse et à l'Enfance, Université d'Abomey-Calavi, Cotonou, Benin
| | - Philippe Deloron
- PRES Sorbonne Paris Cité, Faculté de Pharmacie, Université Paris Descartes Institut de Recherche pour le Développement, UMR216-MERIT
| | - Nicaise Tuikue Ndam
- PRES Sorbonne Paris Cité, Faculté de Pharmacie, Université Paris Descartes Institut de Recherche pour le Développement, UMR216-MERIT
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Zhou SS, Rietveld AEC, Velarde-Rodriguez M, Ramsay AR, Zhang SS, Zhou XN, Cibulskis RE. Operational research on malaria control and elimination: a review of projects published between 2008 and 2013. Malar J 2014; 13:473. [PMID: 25471215 PMCID: PMC4265439 DOI: 10.1186/1475-2875-13-473] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [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: 08/11/2014] [Accepted: 11/28/2014] [Indexed: 11/10/2022] Open
Abstract
A literature review for operational research on malaria control and elimination was conducted using the term 'malaria' and the definition of operational research (OR). A total of 15 886 articles related to malaria were searched between January 2008 and June 2013. Of these, 582 (3.7%) met the definition of operational research. These OR projects had been carried out in 83 different countries. Most OR studies (77%) were implemented in Africa south of the Sahara. Only 5 (1%) of the OR studies were implemented in countries in the pre-elimination or elimination phase. The vast majority of OR projects (92%) were led by international or local research institutions, while projects led by National Malaria Control Programmes (NMCP) accounted for 7.8%. With regards to the topic under investigation, the largest percentage of papers was related to vector control (25%), followed by epidemiology/transmission (16.5%) and treatment (16.3%). Only 19 (3.8%) of the OR projects were related to malaria surveillance. Strengthening the capacity of NMCPs to conduct operational research and publish its findings, and improving linkages between NMCPs and research institutes may aid progress towards malaria elimination and eventual eradication world-wide.
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Affiliation(s)
- Shui-sen Zhou
- />Global Malaria Programme, World Health Organization, 20 Avenue Appia, CH-1211 Geneva 27, Switzerland
- />National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, 207 Rui Jin Er Road, Shanghai, 200025 P. R. China
| | - Aafje EC Rietveld
- />Global Malaria Programme, World Health Organization, 20 Avenue Appia, CH-1211 Geneva 27, Switzerland
| | - Mar Velarde-Rodriguez
- />Global Malaria Programme, World Health Organization, 20 Avenue Appia, CH-1211 Geneva 27, Switzerland
- />Barcelona Institute for Global Health Hospital Clinic, Universidad de Barcelona, Carrer Rossello 132, 502a, E-08036 Barcelona, Spain
| | - Andrew R Ramsay
- />Special Programme for Research and Training in Tropical Diseases (TDR), 20 Avenue Appia, CH-1211 Geneva 27, Switzerland
| | - Shao-sen Zhang
- />National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, 207 Rui Jin Er Road, Shanghai, 200025 P. R. China
| | - Xiao-nong Zhou
- />National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, 207 Rui Jin Er Road, Shanghai, 200025 P. R. China
| | - Richard E Cibulskis
- />Global Malaria Programme, World Health Organization, 20 Avenue Appia, CH-1211 Geneva 27, Switzerland
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Torrentino-Madamet M, Fall B, Benoit N, Camara C, Amalvict R, Fall M, Dionne P, Ba Fall K, Nakoulima A, Diatta B, Diemé Y, Ménard D, Wade B, Pradines B. Limited polymorphisms in k13 gene in Plasmodium falciparum isolates from Dakar, Senegal in 2012-2013. Malar J 2014; 13:472. [PMID: 25471113 PMCID: PMC4289025 DOI: 10.1186/1475-2875-13-472] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Accepted: 11/28/2014] [Indexed: 11/21/2022] Open
Abstract
Background The emergence of Plasmodium falciparum resistance to artemisinin and its derivatives, manifested as delayed parasite clearance following the treatment, has developed in Southeast Asia. The spread of resistance to artemisinin from Asia to Africa may be catastrophic for malaria control and elimination worldwide. Recently, mutations in the propeller domain of the Kelch 13 (k13) gene (PF3D71343700) were associated with in vitro resistance to artemisinin and with delayed clearance after artemisinin treatment in southern Asia. The aim of the study was to characterize the genetic variability of k13 and to evaluate the molecular resistance to artemisinin for the first time in Senegal. Methods Plasmodium falciparum isolates were collected from 138 malaria patients in Dakar and its districts during the rainy season of October 2012 to January 2013 at the Hôpital Principal de Dakar. The k13 gene was amplified using nested PCR and sequenced. Results A very limited variability within the k13 gene in Senegalese P. falciparum isolates was identified. No polymorphism was detected in the six k13-propeller blades. Only two mutations, T149S (6.3%) and K189T (42.2%), and one (N) or two (NN) asparagine insertion at the codon 142 (4.7 and 6.3%, respectively) were detected in the Plasmodium/Apicomplexa-specific domain. None of the polymorphisms associated with artemisinin resistance in Southeast Asia was detected in the 138 P. falciparum from Dakar. Discussion The present data do not suggest widespread artemisinin resistance in Dakar in 2012–2013. Notably, the C580Y, R539T or Y493H substitutions that were associated with in vitro resistance or delayed parasite clearance in Southeast Asia were not observed in Dakar, nor were any of the polymorphisms observed in parasites from Southeast Asia, nor the M476I mutation that was selected in vitro with artemisinin pressure in a African parasite line.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | - Bruno Pradines
- Aix Marseille Université, Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes, UM 63, CNRS 7278, IRD 198, Inserm 1095, Marseille, France.
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Bouba Djourdebbé F, Dos Santos S, Legrand TK, Soura AB. Environmental factors and childhood Fever in areas of the Ouagadougou Health and Demographic Surveillance System, Burkina Faso. J Biosoc Sci 2015; 47:536-53. [PMID: 25392191 DOI: 10.1017/S0021932014000479] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Using data on 825 under-5 children from the Ouagadougou Health and Demographic Surveillance System collected in 2010, this article examines the effects of aspects of the immediate environment on childhood fever. Logit regression models were estimated to assess the effects of the quality of the local environment on the probability that a child is reported to have had a fever in the two weeks preceding the survey, after controlling for various demographic and socioeconomic variables. While the estimated impact of some environmental factors persisted in the full models, the effects of variables such as access to water and type of household waste management decreased in the presence of demographic, socioeconomic and neighbourhood factors. The management of waste water was found to significantly affect the occurrence of childhood fever. Overall, the results of the study call for more efforts to promote access to tap water to households at prices that are affordable for the local population, where the threats to child health appears to be greatest.
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Ibitokou SA, Boström S, Brutus L, Tuikue Ndam N, Vianou B, Agbowaï C, Amadoudji Zin M, Huynh BT, Massougbodji A, Deloron P, Troye-Blomberg M, Fievet N, Luty AJ. Submicroscopic infections with Plasmodium falciparum during pregnancy and their association with circulating cytokine, chemokine, and cellular profiles. Clin Vaccine Immunol 2014; 21:859-66. [PMID: 24717969 DOI: 10.1128/CVI.00009-14] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The immunological consequences of pregnancy-associated malaria (PAM) due to Plasmodium falciparum have been extensively investigated in cross-sectional studies conducted at delivery, but there have been very few longitudinal studies of changes due to PAM during pregnancy. We conducted a prospective study in Benin to investigate the changes associated with PAM in groups of 131 and 111 women at inclusion in the second trimester and at delivery, respectively. Infected women were identified by standard microscopic examinations of blood smears and by quantitative PCR (qPCR) assays and were matched to uninfected control women by age, gestational age, and gravidity. We quantified plasma levels of a panel of soluble immunological mediators and other mediators, as well as the frequencies of peripheral blood mononuclear cell types. Comparisons of these variables in infected and uninfected women used multivariate analyses, and we also assessed the predictive value of variables measured at inclusion for pregnancy outcomes at delivery. In multivariate analyses, peripheral plasma interleukin 10 (IL-10) and gamma interferon-inducible protein 10 (IP-10) levels were associated with PAM at inclusion and at delivery, while higher IL-10 levels distinguished qPCR-detectable submicroscopic infections at inclusion but not at delivery. Maternal anemia at delivery was associated with markers of proinflammatory (increased frequency of monocytes) and anti-inflammatory (increased IL-10 levels and increased activation of regulatory T cells) activity measured at inclusion. Elevated concentrations of IL-10 are associated with the majority of P. falciparum infections during pregnancy, but this marker alone does not identify all submicroscopic infections. Reliably identifying such occult infections will require more sensitive and specific methods.
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Strøm GEA, Moyo S, Fataki M, Langeland N, Blomberg B. PCR targeting Plasmodium mitochondrial genome of DNA extracted from dried blood on filter paper compared to whole blood. Malar J 2014; 13:137. [PMID: 24708551 PMCID: PMC3983671 DOI: 10.1186/1475-2875-13-137] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Accepted: 04/02/2014] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND Monitoring mortality and morbidity attributable to malaria is paramount to achieve elimination of malaria. Diagnosis of malaria is challenging and PCR is a reliable method for identifying malaria with high sensitivity. However, blood specimen collection and transport can be challenging and obtaining dried blood spots (DBS) on filter paper by finger-prick may have advantages over collecting whole blood by venepuncture. METHODS DBS and whole blood were collected from febrile children admitted at the general paediatric wards at a referral hospital in Dar es Salaam, Tanzania. DNA extracted from whole blood and from DBS was tested with a genus-specific PCR targeting the mitochondrial Plasmodium genome. Positive samples by PCR of DNA from whole blood were tested with species-specific PCR targeting the 18S rRNA locus, or sequencing if species-specific PCR was negative. Rapid diagnostic test (RDT) and thin blood smear microscopy was carried out on all patients where remnant whole blood and a blood slide, respectively, were available. RESULTS Positivity of PCR was 24.5 (78/319) and 11.2% (52/442) by whole blood and DBS, respectively. All samples positive on DBS were also positive on Plasmodium falciparum species-specific PCR. All RDT positive cases were also positive by DBS PCR. All but three cases with positive blood slides were also positive by DBS. CONCLUSIONS In this study, PCR for malaria mitochondrial DNA extracted from whole blood was more sensitive than from DBS. However, DBS are a practical alternative to whole blood and detected approximately the same number of cases as RDTs and, therefore, remain relevant for research purposes.
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Affiliation(s)
- Gro E A Strøm
- Department of Clinical Science, University of Bergen, Bergen, Norway.
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Hamainza B, Moonga H, Sikaala CH, Kamuliwo M, Bennett A, Eisele TP, Miller J, Seyoum A, Killeen GF. Monitoring, characterization and control of chronic, symptomatic malaria infections in rural Zambia through monthly household visits by paid community health workers. Malar J 2014; 13:128. [PMID: 24678631 PMCID: PMC4113135 DOI: 10.1186/1475-2875-13-128] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [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: 01/24/2014] [Accepted: 03/23/2014] [Indexed: 11/29/2022] Open
Abstract
Background Active, population-wide mass screening and treatment (MSAT) for chronic Plasmodium falciparum carriage to eliminate infectious reservoirs of malaria transmission have proven difficult to apply on large national scales through trained clinicians from central health authorities. Methodology Fourteen population clusters of approximately 1,000 residents centred around health facilities (HF) in two rural Zambian districts were each provided with three modestly remunerated community health workers (CHWs) conducting active monthly household visits to screen and treat all consenting residents for malaria infection with rapid diagnostic tests (RDT). Both CHWs and HFs also conducted passive case detection among residents who self-reported for screening and treatment. Results Diagnostic positivity was higher among symptomatic patients self-reporting to CHWs (42.5%) and HFs (24%) than actively screened residents (20.3%), but spatial and temporal variations of diagnostic positivity were highly consistent across all three systems. However, most malaria infections (55.6%) were identified through active home visits by CHWs rather than self-reporting to CHWs or HFs. Most (62%) malaria infections detected actively by CHWs reported one or more symptoms of illness. Most reports of fever and vomiting, plus more than a quarter of history of fever, headache and diarrhoea, were attributable to malaria infection. The minority of residents who participated >12 times had lower rates of malaria infection and associated symptoms in later contacts but most residents were tested <4 times and high malaria diagnostic positivity (32%) in active surveys, as well as incidence (1.7 detected infections per person per year) persisted in the population. Per capita cost for active service delivery by CHWs was US$5.14 but this would rise to US$10.68 with full community compliance with monthly testing at current levels of transmission, and US$6.25 if pre-elimination transmission levels and negligible treatment costs were achieved. Conclusion Monthly active home visits by CHWs equipped with RDTs were insufficient to eliminate the human infection reservoir in this typical African setting, despite reasonably high LLIN/IRS coverage. However, dramatic impact upon infection and morbidity burden might be attainable and cost-effective if community participation in regular testing could be improved and the substantial, but not necessarily prohibitive, costs are affordable to national programmes.
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Affiliation(s)
- Busiku Hamainza
- Ministry of Health, National Malaria Control Centre, Chainama Hospital College Grounds, off Great East road, P,O, Box 32509, Lusaka, Zambia.
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Denoeud-Ndam L, Zannou DM, Fourcade C, Taron-Brocard C, Porcher R, Atadokpede F, Komongui DG, Dossou-Gbete L, Afangnihoun A, Ndam NT, Girard PM, Cot M. Cotrimoxazole prophylaxis versus mefloquine intermittent preventive treatment to prevent malaria in HIV-infected pregnant women: two randomized controlled trials. J Acquir Immune Defic Syndr 2014; 65:198-206. [PMID: 24220287 DOI: 10.1097/qai.0000000000000058] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Malaria during pregnancy has serious consequences that are worsened by HIV infection. Malaria preventive measures for HIV-infected pregnant women include cotrimoxazole (CTX) prophylaxis given to prevent HIV-related opportunistic infections and also protective against malaria, or intermittent preventive treatment (IPTp) with an antimalarial drug. Here, we present the first study evaluating CTX efficacy versus mefloquine (MQ)-IPTp, alone and in combination, in HIV-infected pregnant women. METHODS We conducted 2 randomized, open-label, noninferiority trials in Benin. In the CTX-mandatory trial, HIV-infected women with CD4 counts of <350 per cubic millimeter received CTX either alone or with MQ-IPTp (N = 292). In the CTX-not-mandatory trial (CD4 count >350/mm), CTX was compared with MQ-IPTp (N = 140). In both the trials, the primary end point was microscopic placental parasitemia. RESULTS At delivery, 1 woman in each CTX-alone treatment group exhibited placental parasitemia, versus no women in the groups receiving MQ. CTX alone demonstrated noninferiority in the CTX-mandatory trial. However, polymerase chain reaction-detected placental parasitemia was markedly reduced in the CTX + MQ group compared with CTX alone (0/105 vs. 5/103, P = 0.03). Because of insufficient recruitment in the CTX-not-mandatory trial, noninferiority could not be conclusively assessed. Dizziness and vomiting of moderate intensity were reported by 34%-37% of women receiving MQ in both the trials, versus 0%-3% in CTX groups (P < 0.0001). No serious adverse events related to these drugs were found. CONCLUSIONS CTX alone provided adequate protection against malaria in HIV-infected pregnant women, although MQ-IPTp showed higher efficacy against placental infection. Although more frequently associated with dizziness and vomiting, MQ-IPTp may be an effective alternative given concerns about parasite resistance to CTX.
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Affiliation(s)
- Lise Denoeud-Ndam
- *UMR 216, Institut de Recherche pour le Développement, Paris, France; †Faculté de Pharmacie, Université Paris Descartes, Paris, France; ‡Centre de Traitement Ambulatoire, Centre National Hospitalier Universitaire Hubert Koutoukou Maga, Cotonou, Benin; §Faculté des Sciences de la Santé, Université d'Abomey-Calavi, Abomey-Calavi, Benin; ‖Inserm U717, Hôpital Saint-Louis, Paris, France; ¶Service de Médecine Interne, Hôpital d'Instructions des Armées, Cotonou, Benin; #Service de gynécologie, Hôpital de la Mère et de l'Enfant Lagune, Cotonou, Benin; **Clinique Louis Pasteur, Porto-Novo, Benin; ††Centre de Traitement Ambulatoire, Hôpital de zone de Suru Léré, Cotonou, Benin; ‡‡Service des Maladies Infectieuses et Tropicales, Hôpital Saint-Antoine, APHP, Paris, France; §§Inserm U707, Université Pierre et Marie Curie, Paris, France
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Lindblade KA, Steinhardt L, Samuels A, Kachur SP, Slutsker L. The silent threat: asymptomatic parasitemia and malaria transmission. Expert Rev Anti Infect Ther 2014; 11:623-39. [PMID: 23750733 DOI: 10.1586/eri.13.45] [Citation(s) in RCA: 334] [Impact Index Per Article: 33.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Scale-up of malaria control interventions has resulted in a substantial decline in global malaria morbidity and mortality. Despite this achievement, there is evidence that current interventions alone will not lead to malaria elimination in most malaria-endemic areas and additional strategies need to be considered. Use of antimalarial drugs to target the reservoir of malaria infection is an option to reduce the transmission of malaria between humans and mosquito vectors. However, a large proportion of human malaria infections are asymptomatic, requiring treatment that is not triggered by care-seeking for clinical illness. This article reviews the evidence that asymptomatic malaria infection plays an important role in malaria transmission and that interventions to target this parasite reservoir may be needed to achieve malaria elimination in both low- and high-transmission areas.
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Affiliation(s)
- Kim A Lindblade
- Malaria Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, 1600 Clifton Rd. NE, MS A-06, Atlanta, GA 30333, USA.
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Golassa L, Enweji N, Erko B, Aseffa A, Swedberg G. Detection of a substantial number of sub-microscopic Plasmodium falciparum infections by polymerase chain reaction: a potential threat to malaria control and diagnosis in Ethiopia. Malar J 2013; 12:352. [PMID: 24090230 PMCID: PMC3850638 DOI: 10.1186/1475-2875-12-352] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [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] [Received: 07/23/2013] [Accepted: 09/18/2013] [Indexed: 12/05/2022] Open
Abstract
Background Prompt and effective malaria diagnosis not only alleviates individual suffering, but also decreases malaria transmission at the community level. The commonly used diagnostic methods, microscopy and rapid diagnostic tests, are usually insensitive at very low-density parasitaemia. Molecular techniques, on the other hand, allow the detection of low-level, sub-microscopic parasitaemia. This study aimed to explore the presence of sub-microscopic Plasmodium falciparum infections using polymerase chain reaction (PCR). The PCR-based parasite prevalence was compared against microscopy and rapid diagnostic test (RDT). Methods This study used 1,453 blood samples collected from clinical patients and sub-clinical subjects to determine the prevalence of sub-microscopic P. falciparum carriages. Subsets of RDT and microscopy negative blood samples were tested by PCR while all RDT and microscopically confirmed P. falciparum-infected samples were subjected to PCR. Finger-prick blood samples spotted on filter paper were used for parasite genomic DNA extraction. Results The prevalence of sub-microscopic P. falciparum carriage was 19.2% (77/400) (95% CI = 15. 4–23.1). Microscopy-based prevalence of P. falciparum infection was 3.7% (54/1,453) while the prevalence was 6.9% (100/1,453) using RDT alone. Using microscopy and PCR, the estimated parasite prevalence was 20.6% if PCR were performed in 1,453 blood samples. The prevalence was estimated to be 22.7% if RDT and PCR were used. Of 54 microscopically confirmed P. falciparum-infected subjects, PCR detected 90.7% (49/54). Out of 100 RDT-confirmed P. falciparum infections; PCR detected 80.0% (80/100). The sensitivity of PCR relative to microscopy and RDT was, therefore, 90.7% and 80%, respectively. The sensitivity of microscopy and RDT relative to PCR was 16.5 (49/299) and 24.2% (80/330), respectively. The overall PCR-based prevalence of P. falciparum infection was 5.6- and 3.3 fold higher than that determined by microscopy and RDT, respectively. None of the sub-microscopic subjects had severe anaemia, though 29.4% had mild anaemia (10–11.9 g/dl). Conclusions Asymptomatic, low-density malaria infection was common in the study area and PCR may be a better tool for measuring Plasmodium prevalence than microscopy and RDT. The inadequate sensitivity of the diagnostic methods to detect substantial number of sub-microscopic parasitaemia would undoubtedly affect malaria control efforts, making reduction of transmission more difficult. RDT and microscopy-based prevalence studies and subsequent reports of reduction in malaria incidence underestimate the true pictures of P. falciparum infections in the community. PCR, on the other hand, seems to have reasonable sensitivity to detect a higher number of infected subjects with low and sub-microscopic parasite densities than RDTs or microscopy.
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Affiliation(s)
- Lemu Golassa
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia.
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Moussiliou A, De Tove YSS, Doritchamou J, Luty AJF, Massougbodji A, Alifrangis M, Deloron P, Ndam NT. High rates of parasite recrudescence following intermittent preventive treatment with sulphadoxine-pyrimethamine during pregnancy in Benin. Malar J 2013; 12:195. [PMID: 23758883 PMCID: PMC3686599 DOI: 10.1186/1475-2875-12-195] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Accepted: 06/04/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Despite widespread parasite resistance to sulphadoxine-pyrimethamine (SP) its use for intermittent preventative treatment during pregnancy remains the policy in Benin and throughout most of sub-Saharan Africa. METHODS In a prospective study, 982 pregnant women were recruited in Benin and followed until delivery. The prevalence of point mutations in the pfdhfr and pfdhps genes associated with Plasmodium falciparum resistance to SP during consecutive antenatal visits was determined. Parasites clearance among women infected at SP intake was assessed by microscopy and PCR. Association between the persistence of parasites and malaria consequences, were investigated. Recurrent parasites were genotyped to identify recrudescences from re-infections. RESULTS The prevalence of pfdhfr/pfdhps quadruple mutants (triple pfdhfr + single pfdhps) was consistently above 80% while quintuple and sextuple mutants remained low. Importantly the higly mutated parasites apparently never included the two key mutations, pfdhfr 164 L or pfdhps 540E. Based on PCR results, SP failed to clear existing parasitaemia in half (48%) of the women who were infected at IPTp schedule. The frequency of recrudescence reached 76% after the second dose. Women with persistent parasitaemia had an increased prevalence of anaemia (P = 0.03). CONCLUSION The data presented here, highlight the inability of SP to ensure optimal antiplasmodial protection in late pregnancy, and invite urgent consideration of an alternative drug or strategy.
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Affiliation(s)
- Azizath Moussiliou
- Institut de Recherche pour le Développement, UMR216 Mère et enfant face aux infections tropicales, Faculté des sciences biologiques et pharmaceutiques, 4, avenue de l’observatoire, Paris 75006, France
- Faculté de Pharmacie, Université Paris Descartes, PRES Sorbonne Paris Cité, Paris 75270, France
- Centre d’Etude et de Recherche sur le Paludisme associé à la Grossesse et à l’Enfance, Faculté des Science de Santé, Université d’Abomey-Calavi, Cotonou 01 BP 188, Benin
| | - Yolande Sissinto-Savi De Tove
- Centre d’Etude et de Recherche sur le Paludisme associé à la Grossesse et à l’Enfance, Faculté des Science de Santé, Université d’Abomey-Calavi, Cotonou 01 BP 188, Benin
| | - Justin Doritchamou
- Institut de Recherche pour le Développement, UMR216 Mère et enfant face aux infections tropicales, Faculté des sciences biologiques et pharmaceutiques, 4, avenue de l’observatoire, Paris 75006, France
- Faculté de Pharmacie, Université Paris Descartes, PRES Sorbonne Paris Cité, Paris 75270, France
- Centre d’Etude et de Recherche sur le Paludisme associé à la Grossesse et à l’Enfance, Faculté des Science de Santé, Université d’Abomey-Calavi, Cotonou 01 BP 188, Benin
| | - Adrian JF Luty
- Institut de Recherche pour le Développement, UMR216 Mère et enfant face aux infections tropicales, Faculté des sciences biologiques et pharmaceutiques, 4, avenue de l’observatoire, Paris 75006, France
- Faculté de Pharmacie, Université Paris Descartes, PRES Sorbonne Paris Cité, Paris 75270, France
| | - Achille Massougbodji
- Centre d’Etude et de Recherche sur le Paludisme associé à la Grossesse et à l’Enfance, Faculté des Science de Santé, Université d’Abomey-Calavi, Cotonou 01 BP 188, Benin
| | - Michael Alifrangis
- Department of International Health, Immunology and Microbiology, Centre for Medical Parasitology Faculty of Health, Medical Sciences, University of Copenhagen, Copenhagen K 1014, Denmark
- Department of Infectious Diseases, Copenhagen University Hospital (Rigshospitalet), Copenhagen K 1014, Denmark
| | - Philippe Deloron
- Institut de Recherche pour le Développement, UMR216 Mère et enfant face aux infections tropicales, Faculté des sciences biologiques et pharmaceutiques, 4, avenue de l’observatoire, Paris 75006, France
- Faculté de Pharmacie, Université Paris Descartes, PRES Sorbonne Paris Cité, Paris 75270, France
| | - Nicaise Tuikue Ndam
- Institut de Recherche pour le Développement, UMR216 Mère et enfant face aux infections tropicales, Faculté des sciences biologiques et pharmaceutiques, 4, avenue de l’observatoire, Paris 75006, France
- Faculté de Pharmacie, Université Paris Descartes, PRES Sorbonne Paris Cité, Paris 75270, France
- Centre d’Etude et de Recherche sur le Paludisme associé à la Grossesse et à l’Enfance, Faculté des Science de Santé, Université d’Abomey-Calavi, Cotonou 01 BP 188, Benin
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Alout H, Ndam NT, Sandeu MM, Djégbe I, Chandre F, Dabiré RK, Djogbénou LS, Corbel V, Cohuet A. Insecticide resistance alleles affect vector competence of Anopheles gambiae s.s. for Plasmodium falciparum field isolates. PLoS One 2013; 8:e63849. [PMID: 23704944 PMCID: PMC3660590 DOI: 10.1371/journal.pone.0063849] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Accepted: 04/06/2013] [Indexed: 11/19/2022] Open
Abstract
The widespread insecticide resistance raises concerns for vector control implementation and sustainability particularly for the control of the main vector of human malaria, Anopheles gambiae sensu stricto. However, the extent to which insecticide resistance mechanisms interfere with the development of the malignant malaria parasite in its vector and their impact on overall malaria transmission remains unknown. We explore the impact of insecticide resistance on the outcome of Plasmodium falciparum infection in its natural vector using three An. gambiae strains sharing a common genetic background, one susceptible to insecticides and two resistant, one homozygous for the ace-1(R) mutation and one for the kdr mutation. Experimental infections of the three strains were conducted in parallel with field isolates of P. falciparum from Burkina Faso (West Africa) by direct membrane feeding assays. Both insecticide resistant mutations influence the outcome of malaria infection by increasing the prevalence of infection. In contrast, the kdr resistant allele is associated with reduced parasite burden in infected individuals at the oocyst stage, when compared to the susceptible strain, while the ace-1 (R) resistant allele showing no such association. Thus insecticide resistance, which is particularly problematic for malaria control efforts, impacts vector competence towards P. falciparum and probably parasite transmission through increased sporozoite prevalence in kdr resistant mosquitoes. These results are of great concern for the epidemiology of malaria considering the widespread pyrethroid resistance currently observed in Sub-Saharan Africa and the efforts deployed to control the disease.
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Affiliation(s)
- Haoues Alout
- Institut de recherche pour le développement (IRD), Maladies Infectieuses et Vecteurs, Ecologie, Génétique, Evolution et Contrôle (MIVEGEC), UM1-UM2-CNRS 5290 IRD 224, Montpellier, France
- Institut de Recherche en Sciences de la Santé (IRSS), 01 BP 545 Bobo-Dioulasso 01, Burkina Faso
| | - Nicaise Tuikue Ndam
- Institut des Sciences Biomédicale et Appliquées, Cotonou, Bénin
- IRD, UMR 216, Mère et Enfant face aux Infections Tropicales, Université Paris Descartes, Paris, France
| | - Marcel Maurice Sandeu
- IRD, UMR 216, Mère et Enfant face aux Infections Tropicales, Université Paris Descartes, Paris, France
- Centre de Recherche Entomologique de Cotonou, Cotonou, Bénin
| | - Innocent Djégbe
- Centre de Recherche Entomologique de Cotonou, Cotonou, Bénin
| | - Fabrice Chandre
- Institut de recherche pour le développement (IRD), Maladies Infectieuses et Vecteurs, Ecologie, Génétique, Evolution et Contrôle (MIVEGEC), UM1-UM2-CNRS 5290 IRD 224, Montpellier, France
| | - Roch Kounbobr Dabiré
- Institut de Recherche en Sciences de la Santé (IRSS), 01 BP 545 Bobo-Dioulasso 01, Burkina Faso
| | | | - Vincent Corbel
- Institut de recherche pour le développement (IRD), Maladies Infectieuses et Vecteurs, Ecologie, Génétique, Evolution et Contrôle (MIVEGEC), UM1-UM2-CNRS 5290 IRD 224, Montpellier, France
- Department of Entomology, Faculty of Agriculture, Kasetsart University, Bangkok, Thailand
| | - Anna Cohuet
- Institut de recherche pour le développement (IRD), Maladies Infectieuses et Vecteurs, Ecologie, Génétique, Evolution et Contrôle (MIVEGEC), UM1-UM2-CNRS 5290 IRD 224, Montpellier, France
- Institut de Recherche en Sciences de la Santé (IRSS), 01 BP 545 Bobo-Dioulasso 01, Burkina Faso
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Fall B, Pascual A, Sarr FD, Wurtz N, Richard V, Baret E, Diémé Y, Briolant S, Bercion R, Wade B, Tall A, Pradines B. Plasmodium falciparum susceptibility to anti-malarial drugs in Dakar, Senegal, in 2010: an ex vivo and drug resistance molecular markers study. Malar J 2013; 12:107. [PMID: 23510258 PMCID: PMC3606842 DOI: 10.1186/1475-2875-12-107] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2012] [Accepted: 03/10/2013] [Indexed: 11/18/2022] Open
Abstract
Background In 2006, the Senegalese National Malaria Control Programme recommended artemisinin-based combination therapy (ACT) as the first-line treatment for uncomplicated malaria. Since the introduction of ACT, there have been very few reports on the level of resistance of P. falciparum to anti-malarial drugs. To determine whether parasite susceptibility has been affected by the new anti-malarial policies, an ex vivo susceptibility and drug resistance molecular marker study was conducted on local isolates obtained from the Centre de santé Elizabeth Diouf (Médina, Dakar, Senegal). Methods The prevalence of genetic polymorphisms in genes associated with anti-malarial drug resistance, i.e., pfcrt, pfdhfr, pfdhps and pfmdr1, were evaluated for a panel of 165 isolates collected from patients recruited from 17 August 2010 to 6 January 2011. The malaria isolates were assessed for susceptibility to chloroquine (CQ); quinine (QN); monodesethylamodiaquine (MDAQ), the active metabolite of amodiaquine; mefloquine (MQ); lumefantrine (LMF); dihydroartemisinin (DHA), the active metabolite of artemisinin derivatives; and doxycycline (DOX) using the Plasmodium lactate dehydrogenase (pLDH) ELISA. Results The prevalence of the in vitro resistant isolates, or isolates with reduced susceptibility, was 62.1% for MQ, 24.2% for CQ, 10.3% for DOX, 11.8% MDAQ, 9.7% for QN, 2.9% for LMF and 0% for DHA. The Pfcrt 76T mutation was identified in 43.6% of the samples. The pfmdr1 86Y, 184F and 1246Y mutations were found in 16.2%, 50.0% and 1.6% of the samples, respectively. The pfdhfr 108N, 51I and 59R mutations were identified in 81.9%, 77.4% and 79.4% of the samples, respectively. The double mutant (108N and 51I) was detected in 75.5% of the isolates, and the triple mutant (108N, 51I and 59R) was detected in 73.6% of the isolates. The pfdhps 437G, 436A and 613S mutations were found in 54.4%, 38.6% and 1.2% of the samples, respectively. There was only one double mutant, 437G and 540E, and one quintuple mutant, pfdhfr 108N, 51I and 59R and pfdhps 437G and 540E. The prevalence of the quadruple mutant (pfdhfr 108N, 51I and 59R and pfdhps 437G) was 36.7%. Conclusions The results of this study indicate that an intensive surveillance of the in vitro P. falciparum susceptibility to anti-malarial drugs must be conducted in Senegal.
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Affiliation(s)
- Bécaye Fall
- Laboratoire d'étude de la chimiosensibilité du paludisme, Fédération des laboratoires, Hôpital Principal de Dakar, Dakar, Sénégal
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Babiker HA, Gadalla AAH, Ranford-Cartwright LC. The role of asymptomatic P. falciparum parasitaemia in the evolution of antimalarial drug resistance in areas of seasonal transmission. Drug Resist Updat 2013; 16:1-9. [PMID: 23510592 DOI: 10.1016/j.drup.2013.02.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Accepted: 02/11/2013] [Indexed: 01/15/2023]
Abstract
In areas with seasonal transmission, proper management of acute malaria cases that arise in the transmission season can markedly reduce the disease burden. However, asymptomatic carriage of Plasmodium falciparum sustains a long-lasting reservoir in the transmission-free dry season that seeds cyclical malaria outbreaks. Clinical trials targeting asymptomatic parasitaemia in the dry season failed to interrupt the malaria epidemics that follow annual rains. These asymptomatic infections tend to carry multiple-clones, capable of producing gametocytes and infecting Anopheles mosquitoes. Different clones within an infection fluctuate consistently, indicative of interaction between clones during the long course of asymptomatic carriage. However, the therapy-free environment that prevails in the dry season dis-advantages the drug resistant lineages and favors the wild-type parasites. This review highlights some biological and epidemiological characteristics of asymptomatic parasitaemia and calls for consideration of policies to diminish parasite exposure to drugs "therapy-free" and allow natural selection to curb drug resistance in the above setting.
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Affiliation(s)
- Hamza A Babiker
- Biochemistry Department, Faculty of Medicine, Sultan Qaboos University, Oman.
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Sandeu MM, Moussiliou A, Moiroux N, Padonou GG, Massougbodji A, Corbel V, Ndam NT. Optimized Pan-species and speciation duplex real-time PCR assays for Plasmodium parasites detection in malaria vectors. PLoS One 2012; 7:e52719. [PMID: 23285168 DOI: 10.1371/journal.pone.0052719] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Accepted: 11/20/2012] [Indexed: 11/19/2022] Open
Abstract
Background An accurate method for detecting malaria parasites in the mosquito’s vector remains an essential component in the vector control. The Enzyme linked immunosorbent assay specific for circumsporozoite protein (ELISA-CSP) is the gold standard method for the detection of malaria parasites in the vector even if it presents some limitations. Here, we optimized multiplex real-time PCR assays to accurately detect minor populations in mixed infection with multiple Plasmodium species in the African malaria vectors Anopheles gambiae and Anopheles funestus. Methods Complementary TaqMan-based real-time PCR assays that detect Plasmodium species using specific primers and probes were first evaluated on artificial mixtures of different targets inserted in plasmid constructs. The assays were further validated in comparison with the ELISA-CSP on 200 field caught Anopheles gambiae and Anopheles funestus mosquitoes collected in two localities in southern Benin. Results The validation of the duplex real-time PCR assays on the plasmid mixtures demonstrated robust specificity and sensitivity for detecting distinct targets. Using a panel of mosquito specimen, the real-time PCR showed a relatively high sensitivity (88.6%) and specificity (98%), compared to ELISA-CSP as the referent standard. The agreement between both methods was “excellent” (κ = 0.8, P<0.05). The relative quantification of Plasmodium DNA between the two Anopheles species analyzed showed no significant difference (P = 0, 2). All infected mosquito samples contained Plasmodium falciparum DNA and mixed infections with P. malariae and/or P. ovale were observed in 18.6% and 13.6% of An. gambiae and An. funestus respectively. Plasmodium vivax was found in none of the mosquito samples analyzed. Conclusion This study presents an optimized method for detecting the four Plasmodium species in the African malaria vectors. The study highlights substantial discordance with traditional ELISA-CSP pointing out the utility of employing an accurate molecular diagnostic tool for detecting malaria parasites in field mosquito populations.
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Machault V, Vignolles C, Pagès F, Gadiaga L, Tourre YM, Gaye A, Sokhna C, Trape JF, Lacaux JP, Rogier C. Risk mapping of Anopheles gambiae s.l. densities using remotely-sensed environmental and meteorological data in an urban area: Dakar, Senegal. PLoS One 2012; 7:e50674. [PMID: 23226351 DOI: 10.1371/journal.pone.0050674] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2012] [Accepted: 10/23/2012] [Indexed: 11/19/2022] Open
Abstract
Introduction High malaria transmission heterogeneity in an urban environment is basically due to the complex distribution of Anopheles larval habitats, sources of vectors. Understanding 1) the meteorological and ecological factors associated with differential larvae spatio-temporal distribution and 2) the vectors dynamic, both may lead to improving malaria control measures with remote sensing and high resolution data as key components. In this study a robust operational methodology for entomological malaria predictive risk maps in urban settings is developed. Methods The Tele-epidemiology approach, i.e., 1) intensive ground measurements (Anopheles larval habitats and Human Biting Rate, or HBR), 2) selection of the most appropriate satellite data (for mapping and extracting environmental and meteorological information), and 3) use of statistical models taking into account the spatio-temporal data variability has been applied in Dakar, Senegal. Results First step was to detect all water bodies in Dakar. Secondly, environmental and meteorological conditions in the vicinity of water bodies favoring the presence of Anopheles gambiae s.l. larvae were added. Then relationship between the predicted larval production and the field measured HBR was identified, in order to generate An. gambiae s.l. HBR high resolution maps (daily, 10-m pixel in space). Discussion and Conclusion A robust operational methodology for dynamic entomological malaria predictive risk maps in an urban setting includes spatio-temporal variability of An. gambiae s.l. larval habitats and An. gambiae s.l. HBR. The resulting risk maps are first examples of high resolution products which can be included in an operational warning and targeting system for the implementation of vector control measures.
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Diallo A, Santos SD, Lalou R, Le Hesran JY. Perceived malaria in the population of an urban setting: a skipped reality in Dakar, Senegal. Malar J 2012; 11:340. [PMID: 23043538 PMCID: PMC3507665 DOI: 10.1186/1475-2875-11-340] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [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: 06/05/2012] [Accepted: 10/02/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Urban malaria remains a public health problem. Dakar is located in a low endemic area. However, anti-malarial drugs consumption is reported to be high despite the decline of malaria announced by health authorities. The objective of the present study was to assess the burden of reported malaria attacks (RMAs) in 2008 and to describe care-seeking behaviours in the population of Dakar, Senegal. METHODS In this cross-sectional study, 2,952 households selected from 50 sites were visited. In each household, a women and a child between two and 10 years old were interviewed about a malaria episode that occurred in 2008. The following information was recorded: age, education level, sex (for children), type of care seeking, method of diagnosis, use of anti-malarial treatment, place of medication purchase, bed net use, malaria-related deaths in the family, and perceptions of the frequency of mosquito bites. After a description of the variables in each subsample, a Pearson's chi-square test was used to compare proportions, and logistic regression was performed to identify the association between RMAs and other covariates. RESULTS Among women, 31.8% reported a malaria attack in 2008; among children, the rate of malaria attacks reported by mothers or caretakers was 39.0%. With regard to care-seeking, 79.5% of women and 81.5% of children with a RMA had visited health facilities (HFs). Younger women and children under five years old were more likely to visit a HF (P<0.001). Presumptive diagnosis was the primary method that was used to identify malaria in HFs. For those who had visited a HF, the rate of anti-malarial treatment was 77% in women and 60% in children. Finally, 43.6% of women and 42.0% of children declared the use of bed nets. In a multivariate analysis, the malaria-related death of a relative and perceptions of mosquito bites were significantly associated with RMAs in women. In children, age was associated with RMAs. CONCLUSION The frequent perceptions of the occurrence of malaria in the population were confirmed at the HF by the high presumptive diagnosis of health professionals. Despite the decline of malaria that has been announced by health authorities, the population will continue to complain of malaria and seek care directly at private pharmacies. This situation may sustain the circulation of anti-malarial drugs and increase the risk of an emergence of anti-malarial resistance.
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Affiliation(s)
- Abdoulaye Diallo
- Institut de Recherche pour le Développement, UMR 216, Mère et Enfant Face aux Infections Tropicales, 4 Avenue de l'Observatoire, Paris 75270 Cedex 06, France.
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