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Andagalu B, Watson OJ, Onyango I, Opot B, Okoth R, Chemwor G, Sifuna P, Juma D, Cheruiyot A, Yeda R, Okudo C, Wafubwa J, Yalwala S, Abuom D, Ogutu B, Cowden J, Akala HM, Kamau E. Malaria Transmission Dynamics in a High-Transmission Setting of Western Kenya and the Inadequate Treatment Response to Artemether-Lumefantrine in an Asymptomatic Population. Clin Infect Dis 2023; 76:704-712. [PMID: 35767269 PMCID: PMC9938745 DOI: 10.1093/cid/ciac527] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 06/13/2022] [Accepted: 06/24/2022] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Assessing the infectious reservoir is critical in malaria control and elimination strategies. We conducted a longitudinal epidemiological study in a high-malaria-burden region in Kenya to characterize transmission in an asymptomatic population. METHODS 488 study participants encompassing all ages in 120 households within 30 clusters were followed for 1 year with monthly sampling. Malaria was diagnosed by microscopy and molecular methods. Transmission potential in gametocytemic participants was assessed using direct skin and/or membrane mosquito feeding assays, then treated with artemether-lumefantrine. Study variables were assessed using mixed-effects generalized linear models. RESULTS Asexual and sexual parasite data were collected from 3792 participant visits, with 903 linked with feeding assays. Univariate analysis revealed that the 6-11-year-old age group was at higher risk of harboring asexual and sexual infections than those <6 years old (odds ratio [OR] 1.68, P < .001; and OR 1.81, P < .001), respectively. Participants with submicroscopic parasitemia were at a lower risk of gametocytemia compared with microscopic parasitemia (OR 0.04, P < .001), but they transmitted at a significantly higher rate (OR 2.00, P = .002). A large proportion of the study population who were infected at least once remained infected (despite treatment) with asexual (71.7%, 291/406) or sexual (37.4%, 152/406) parasites. 88.6% (365/412) of feeding assays conducted in individuals who failed treatment the previous month resulted in transmissions. CONCLUSIONS Individuals with asymptomatic infection sustain the transmission cycle, with the 6-11-year age group serving as an important reservoir. The high rates of artemether-lumefantrine treatment failures suggest surveillance programs using molecular methods need to be expanded for accurate monitoring and evaluation of treatment outcomes.
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Affiliation(s)
- Ben Andagalu
- Department of Emerging and Infectious Diseases (DEID), US Army Medical Research Directorate-Africa (USAMRD-A), Kenya Medical Research Institute (KEMRI)/Walter Reed Project, Kisumu, Kenya
| | - Oliver J Watson
- Medical Research Council, Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
| | - Irene Onyango
- Department of Emerging and Infectious Diseases (DEID), US Army Medical Research Directorate-Africa (USAMRD-A), Kenya Medical Research Institute (KEMRI)/Walter Reed Project, Kisumu, Kenya
| | - Benjamin Opot
- Department of Emerging and Infectious Diseases (DEID), US Army Medical Research Directorate-Africa (USAMRD-A), Kenya Medical Research Institute (KEMRI)/Walter Reed Project, Kisumu, Kenya
| | - Raphael Okoth
- Department of Emerging and Infectious Diseases (DEID), US Army Medical Research Directorate-Africa (USAMRD-A), Kenya Medical Research Institute (KEMRI)/Walter Reed Project, Kisumu, Kenya
| | - Gladys Chemwor
- Department of Emerging and Infectious Diseases (DEID), US Army Medical Research Directorate-Africa (USAMRD-A), Kenya Medical Research Institute (KEMRI)/Walter Reed Project, Kisumu, Kenya
| | - Peter Sifuna
- Department of Emerging and Infectious Diseases (DEID), US Army Medical Research Directorate-Africa (USAMRD-A), Kenya Medical Research Institute (KEMRI)/Walter Reed Project, Kisumu, Kenya
| | - Dennis Juma
- Department of Emerging and Infectious Diseases (DEID), US Army Medical Research Directorate-Africa (USAMRD-A), Kenya Medical Research Institute (KEMRI)/Walter Reed Project, Kisumu, Kenya
| | - Agnes Cheruiyot
- Department of Emerging and Infectious Diseases (DEID), US Army Medical Research Directorate-Africa (USAMRD-A), Kenya Medical Research Institute (KEMRI)/Walter Reed Project, Kisumu, Kenya
| | - Redemptah Yeda
- Department of Emerging and Infectious Diseases (DEID), US Army Medical Research Directorate-Africa (USAMRD-A), Kenya Medical Research Institute (KEMRI)/Walter Reed Project, Kisumu, Kenya
| | - Charles Okudo
- Department of Emerging and Infectious Diseases (DEID), US Army Medical Research Directorate-Africa (USAMRD-A), Kenya Medical Research Institute (KEMRI)/Walter Reed Project, Kisumu, Kenya
| | - Jackline Wafubwa
- Department of Emerging and Infectious Diseases (DEID), US Army Medical Research Directorate-Africa (USAMRD-A), Kenya Medical Research Institute (KEMRI)/Walter Reed Project, Kisumu, Kenya
| | - Santos Yalwala
- Department of Emerging and Infectious Diseases (DEID), US Army Medical Research Directorate-Africa (USAMRD-A), Kenya Medical Research Institute (KEMRI)/Walter Reed Project, Kisumu, Kenya
| | - David Abuom
- Department of Emerging and Infectious Diseases (DEID), US Army Medical Research Directorate-Africa (USAMRD-A), Kenya Medical Research Institute (KEMRI)/Walter Reed Project, Kisumu, Kenya
| | | | - Jessica Cowden
- Department of Emerging and Infectious Diseases (DEID), US Army Medical Research Directorate-Africa (USAMRD-A), Kenya Medical Research Institute (KEMRI)/Walter Reed Project, Kisumu, Kenya
| | - Hoseah M Akala
- Department of Emerging and Infectious Diseases (DEID), US Army Medical Research Directorate-Africa (USAMRD-A), Kenya Medical Research Institute (KEMRI)/Walter Reed Project, Kisumu, Kenya
| | - Edwin Kamau
- Department of Emerging and Infectious Diseases (DEID), US Army Medical Research Directorate-Africa (USAMRD-A), Kenya Medical Research Institute (KEMRI)/Walter Reed Project, Kisumu, Kenya.,US Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, Maryland, USA.,Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California, USA
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Rakotoarisoa MA, Fenomanana J, Dodoson BT, Andrianaranjaka VHI, Ratsimbasoa A. Comparative effect of artemether-lumefantrine and artesunate-amodiaquine on gametocyte clearance in children with uncomplicated Plasmodium falciparum malaria in Madagascar. Malar J 2022; 21:331. [PMID: 36376921 PMCID: PMC9664793 DOI: 10.1186/s12936-022-04369-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Accepted: 11/05/2022] [Indexed: 11/16/2022] Open
Abstract
Background Gametocytes are the sexual stages ensuring continuity of the development cycle of the parasite, as well as its transmission to humans. The efficacy of artemisinin-based anti-malarials against asexual stages of Plasmodium has been reported in Madagascar, but their effects on gametocytes are not well documented. The present study aims to determine the emergence of gametocyte and gametocyte clearance after artesunate-amodiaquine (ASAQ) or artemether-lumefantrine (AL) treatment in children with uncomplicated Plasmodium falciparum malaria in 5 regions of Madagascar. Methods 558 children with uncomplicated P. falciparum malaria, aged between 1 and 15 years, were assigned randomly to AL or ASAQ treatment. They come from 5 regions of Madagascar with different epidemiological facies related to malaria: Ankilivalo, Benenitra, Ampanihy, Ankazomborona and Matanga. Gametocytes were identified by microscopy, from t blood smears at day 1, day 2, day 3, day 7, day 14, day 21 and day 28 after treatment. Results At baseline, 9.7% (54/558) children [95% CI: 7.4–12.5%] had detectable gametocyte by microscopy. Among the 54 enrolled children, gametocytes emergence rate was high during the first days of treatment in both treatment arms (AL and ASAQ), especially on day 1. Gametocytes were undetectable from day 14 for AL arm while for ASAQ arm, gametocyte carriage was gradually decreased but persisted until day 21. Conclusion This study demonstrates that AL has a more rapid effect on gametocyte clearance compared to ASAQ in children with uncomplicated Plasmodium falciparum malaria. Supplementary Information The online version contains supplementary material available at 10.1186/s12936-022-04369-2.
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Assefa DG, Yismaw G, Makonnen E. Comparative effect of dihydroartemisinin-piperaquine and artemether-lumefantrine on gametocyte clearance and haemoglobin recovery in children with uncomplicated Plasmodium falciparum malaria in Africa: a systematic review and meta-analysis of randomized control trials. Int J Infect Dis 2021; 113:136-47. [PMID: 34653658 DOI: 10.1016/j.ijid.2021.10.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 09/04/2021] [Accepted: 10/06/2021] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND Plasmodium falciparum gametocytaemia has been associated with anaemia. The aim of this review was to synthesize available evidence on the comparative effect of dihydroartemisinin-piperaquine (DHA-PQ) and artemether-lumefantrine (AL) on gametocyte clearance and haemoglobin recovery in children with uncomplicated P. falciparum malaria in Africa. METHODS A systematic literature search was undertaken to identify relevant articles from online databases. The search was performed from August 2020 to 30 April 2021. Extracted data from eligible studies were pooled as risk ratios with 95% confidence intervals (CI). RESULTS Gametocyte carriage was reduced in both treatment groups, with no significant difference found between the groups. However, on days 28 and 42, a significant increase in serum haemoglobin level from baseline was observed in the DHA-PQ group (standardized mean difference 0.15, 95% CI 0.05-0.26; participants=2715; studies=4; I2=32%, high quality of evidence) compared with the AL group (mean difference 0.35, 95% CI 0.12-0.59; participants=1434; studies=3; I2=35%, high quality of evidence). CONCLUSION DHA-PQ had a greater impact on haemoglobin recovery than AL on days 28 and 42; this difference was significant.
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Touray AO, Mobegi VA, Wamunyokoli F, Butungi H, Herren JK. Prevalence of asymptomatic P. falciparum gametocyte carriage among school children in Mbita, Western Kenya and assessment of the association between gametocyte density, multiplicity of infection and mosquito infection prevalence. Wellcome Open Res 2021; 5:259. [PMID: 33959684 PMCID: PMC8078214 DOI: 10.12688/wellcomeopenres.16299.2] [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] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/29/2021] [Indexed: 12/02/2022] Open
Abstract
Background: Asymptomatic Plasmodium falciparum gametocyte carriers are reservoirs for sustaining transmission in malaria endemic regions. Gametocyte presence in the host peripheral blood is a predictor of capacity to transmit malaria. However, it does not always directly translate to mosquito infectivity. Factors that affect mosquito infectivity include, gametocyte sex-ratio and density, multiplicity of infection (MOI), and host and vector anti-parasite immunity. We assess the prevalence of gametocyte carriage and some of its associated risk factors among asymptomatic schoolchildren in Western Kenya and to further analyse the association between gametocyte density, multiplicity of infection (MOI) and mosquito infection prevalence. Methods: P. falciparum parasite infections were detected by RDT (Rapid Diagnostic Test) and microscopy among schoolchildren (5-15 years old). Blood from 37 microscopy positive gametocyte carriers offered to laboratory reared An. gambiae s.l. mosquitoes. A total of 3395 fully fed mosquitoes were screened for Plasmodium sporozoites by ELISA. P. falciparum was genotyped using 10 polymorphic microsatellite markers. The association between MOI and gametocyte density and mosquito infection prevalence was investigated. Results: A significantly higher prevalence of P. falciparum infection was found in males 31.54% (764/2422) ( p-value < 0.001) compared to females 26.72% (657/2459). The microscopic gametocyte prevalence among the study population was 2% (84/4881). Children aged 5-9 years have a higher prevalence of gametocyte carriage (odds ratios = 2.1 [95% CI = 1.3-3.4], P = 0.002) as compared to children aged 10-15 years. After offering gametocyte positive blood to An. gambiae s.l. by membrane feeding assay, our results indicated that 68.1% of the variation in mosquito infection prevalence was accounted for by gametocyte density and MOI (R-SQR. = 0.681, p < 0.001). Conclusions: We observed a higher risk of gametocyte carriage among the younger children (5-9 years). Gametocyte density and MOI significantly predicted mosquito infection prevalence.
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Affiliation(s)
- Abdoulie O. Touray
- Department of Molecular Biology and Biotechnology, Institute of Basic Sciences, Technology and Innovation, Pan African University (PAUSTI), Nairobi, Kenya
- International Centre of Insect Physiology and Ecology (icipe), Nairobi, Kenya
| | - Victor A. Mobegi
- Department of Biochemistry, School of Medicine, University of Nairobi, Nairobi, Kenya
| | - Fred Wamunyokoli
- Department of Biochemistry, Jomo Kenyatta University of Agriculture and Technology (JKUAT), Nairobi, Kenya
| | - Hellen Butungi
- International Centre of Insect Physiology and Ecology (icipe), Nairobi, Kenya
- Wits Research Institute for Malaria, School of Pathology, Faculty of Health Sciences, University of the Witswatersrand, Johannesburg, South Africa
| | - Jeremy K. Herren
- International Centre of Insect Physiology and Ecology (icipe), Nairobi, Kenya
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Assefa DG, Zeleke ED, Bekele D, Tesfahunei HA, Getachew E, Joseph M, Manyazewal T. Efficacy and safety of dihydroartemisinin-piperaquine versus artemether-lumefantrine for treatment of uncomplicated Plasmodium falciparum malaria in Ugandan children: a systematic review and meta-analysis of randomized control trials. Malar J 2021; 20:174. [PMID: 33794897 PMCID: PMC8017896 DOI: 10.1186/s12936-021-03711-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Accepted: 03/24/2021] [Indexed: 12/02/2022] Open
Abstract
Background The emergence of artemisinin resistance in Southeast Asia and Plasmodium falciparum kelch13 propeller gene mutations in sub-Saharan African pose the greatest threat to global efforts to control malaria. This is a critical concern in Uganda, where artemisinin-based combination therapy (ACT) is the first-line treatment for uncomplicated falciparum. The objective of this study was to compare the efficacy and safety of dihydroartemisinin–piperaquine (DHA–PQ) and artemether–lumefantrine (AL) for the treatment of uncomplicated falciparum malaria in Ugandan children. Methods A search of PubMed and the Cochrane Central Register of Controlled Trials for retrieving randomized controlled trials comparing the efficacy and safety of DHA–PQ and AL for treatment of uncomplicated falciparum malaria in Ugandan children was done. The search was performed up to 31 August 2020. The data extracted from eligible studies and pooled as risk ratio (RR) with a 95% confidence interval (CI), using Rev Man Software (5.4). The protocol was registered in PROSPERO, ID: CRD42020182354. Results Eleven trials were included in this review and two of them only included under safety outcome. Total 3798 participants were enrolled. The PCR unadjusted treatment failure was significantly lower with DHA–PQ at day 28 (RR 0.30, 95% CI 0.19–0.49; participants = 7863; studies = 5; I2 = 93%, low quality evidence) and at day 42 (RR 0.53, 95% CI 0.38–0.76; participants = 1618; studies = 4; I2 = 79%, moderate quality of evidence). The PCR adjusted treatment failure at day 42 was significantly lower with DHA–PQ treatment group (RR 0.45, 95% CI 0.28 to 0.72; participants = 1370; studies = 5, high quality of evidence), and it was below 5% in both arms at day 28 (moderate quality of evidence). AL showed a longer prophylactic effect on new infections which may last for up to 63 days (PCR-adjusted treatment failure: RR 2.04, 95% CI 1.13–3.70; participants = 1311; studies = 2, moderate quality of evidence). Compared to AL, DHA–PQ was associated with a slightly higher frequency of cough (RR 1.07, 95% CI 1.01 to 1.13; 2575 participants; six studies; high quality of evidence). In both treatment groups, the risk of recurrent parasitaemia due to possible recrudescence was less than 5% at day 28. The appearance of gametocyte between 29 and 42 days was also significantly lower in DHA–PQ than AL (RR 0.26, 95% CI 0.12 to 0.56; participants = 623; studies = 2; I2 = 0%). Conclusion Compared to AL, DHA–PQ appeared to reduce treatment failure and gametocyte carriage in Ugandan children. This may trigger DHA–PQ to become the first-line treatment option. Both treatments were safe and well-tolerated. Supplementary Information The online version contains supplementary material available at 10.1186/s12936-021-03711-4.
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Affiliation(s)
- Dawit Getachew Assefa
- College of Health Sciences, Center for Innovative Drug Development and Therapeutic Trials for Africa (CDT-Africa), Addis Ababa University, P.O. Box 9086, Addis Ababa, Ethiopia. .,Department of Nursing, College of Health Science and Medicine, Dilla University, Dilla, Ethiopia.
| | - Eden Dagnachew Zeleke
- College of Health Sciences, Center for Innovative Drug Development and Therapeutic Trials for Africa (CDT-Africa), Addis Ababa University, P.O. Box 9086, Addis Ababa, Ethiopia.,Department of Midwifery, College of Health Science, Bule-Hora University, Bule-Hora, Ethiopia
| | - Delayehu Bekele
- College of Health Sciences, Center for Innovative Drug Development and Therapeutic Trials for Africa (CDT-Africa), Addis Ababa University, P.O. Box 9086, Addis Ababa, Ethiopia.,Department of Obstetrics and Gynecology, Saint Paul's Hospital Millennium Medical College, Addis Ababa, Ethiopia
| | - Hanna Amanuel Tesfahunei
- College of Health Sciences, Center for Innovative Drug Development and Therapeutic Trials for Africa (CDT-Africa), Addis Ababa University, P.O. Box 9086, Addis Ababa, Ethiopia.,Hager Biomedical Research Institute, Asmara, Eritrea
| | - Emnet Getachew
- College of Health Sciences, Center for Innovative Drug Development and Therapeutic Trials for Africa (CDT-Africa), Addis Ababa University, P.O. Box 9086, Addis Ababa, Ethiopia.,Arsi University, Asella, Ethiopia
| | - Michele Joseph
- College of Health Sciences, Center for Innovative Drug Development and Therapeutic Trials for Africa (CDT-Africa), Addis Ababa University, P.O. Box 9086, Addis Ababa, Ethiopia
| | - Tsegahun Manyazewal
- College of Health Sciences, Center for Innovative Drug Development and Therapeutic Trials for Africa (CDT-Africa), Addis Ababa University, P.O. Box 9086, Addis Ababa, Ethiopia
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Abstract
Malaria is one of the most devastating infectious diseases of humans. It is problematic clinically and economically as it prevails in poorer countries and regions, strongly hindering socioeconomic development. The causative agents of malaria are unicellular protozoan parasites belonging to the genus Plasmodium. These parasites infect not only humans but also other vertebrates, from reptiles and birds to mammals. To date, over 200 species of Plasmodium have been formally described, and each species infects a certain range of hosts. Plasmodium species that naturally infect humans and cause malaria in large areas of the world are limited to five—P. falciparum, P. vivax, P. malariae, P. ovale and P. knowlesi. The first four are specific for humans, while P. knowlesi is naturally maintained in macaque monkeys and causes zoonotic malaria widely in South East Asia. Transmission of Plasmodium species between vertebrate hosts depends on an insect vector, which is usually the mosquito. The vector is not just a carrier but the definitive host, where sexual reproduction of Plasmodium species occurs, and the parasite’s development in the insect is essential for transmission to the next vertebrate host. The range of insect species that can support the critical development of Plasmodium depends on the individual parasite species, but all five Plasmodium species causing malaria in humans are transmitted exclusively by anopheline mosquitoes. Plasmodium species have remarkable genetic flexibility which lets them adapt to alterations in the environment, giving them the potential to quickly develop resistance to therapeutics such as antimalarials and to change host specificity. In this article, selected topics involving the Plasmodium species that cause malaria in humans are reviewed.
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Affiliation(s)
- Shigeharu Sato
- Borneo Medical and Health Research Centre, Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, Jalan UMS, 88400 Kota Kinabalu, Sabah, Malaysia. .,Department of Pathobiology and Medical Diagnostics, Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, Jalan UMS, 88400, Kota Kinabalu, Sabah, Malaysia.
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Kishoyian G, Njagi ENM, Orinda GO, Kimani FT, Thiongo K, Matoke-Muhia D. Efficacy of artemisinin-lumefantrine for treatment of uncomplicated malaria after more than a decade of its use in Kenya. Epidemiol Infect 2021; 149:e27. [PMID: 33397548 PMCID: PMC8057502 DOI: 10.1017/s0950268820003167] [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] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 12/22/2020] [Accepted: 12/22/2020] [Indexed: 11/06/2022] Open
Abstract
BACKGROUND The resistance of Plasmodium falciparum to antimalarial drugs remains a major impairment in the treatment and eradication of malaria globally. Following the introduction of artemisinin-based combination therapy (ACT), there have been reports of delayed parasite clearance. In Kenya, artemether-lumefantrine (AL) is the recommended first-line treatment of uncomplicated malaria. This study sought to assess the efficacy of AL after a decade of use as the preferred method of managing malarial infections in Kenya. We assessed clinical and parasitological responses of children under 5 years between May and November 2015 in Chulaimbo sub-County, Kisumu, Kenya. Patients aged between 6 and 60 months with uncomplicated P. falciparum mono-infection, confirmed through microscopy, were enrolled in the study. The patients were admitted at the facility for 3 days, treated with a standard dose of AL, and then put under observation for the next 28 days for the assessment of clinical and parasitological responses. Of the 90 patients enrolled, 14 were lost to follow-up while 76 were followed through to the end of the study period. Seventy-five patients (98.7%) cleared the parasitaemia within a period of 48 h while one patient (1.3%) cleared on day 3. There was 100% adequate clinical and parasitological response. All the patients cleared the parasites on day 3 and there were no re-infections observed during the stated follow-up period. This study, therefore, concludes that AL is highly efficacious in clearing P. falciparum parasites in children aged ≥6 and ≤60 months. The study, however, underscores the need for continued monitoring of the drug to forestall both gradual ineffectiveness and possible resistance to the drug in all target users.
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Affiliation(s)
- Gabriel Kishoyian
- Department of Medical Laboratory Sciences, Kenya Medical Training College, P.O. Box2268-40100, Kisumu, Kenya
| | - Eliud N. M. Njagi
- Department of Biochemistry and Biotechnology, Kenyatta University, P.O.BOX 43844-00100, Nairobi, Kenya
| | - George O. Orinda
- Department of Biochemistry and Biotechnology, Kenyatta University, P.O.BOX 43844-00100, Nairobi, Kenya
| | - Francis T. Kimani
- Centre for Biotechnology Research and Development, Kenya Medical Research Institute, P.O. Box 54840-00200, Nairobi, Kenya
| | - Kevin Thiongo
- Centre for Biotechnology Research and Development, Kenya Medical Research Institute, P.O. Box 54840-00200, Nairobi, Kenya
| | - Damaris Matoke-Muhia
- Centre for Biotechnology Research and Development, Kenya Medical Research Institute, P.O. Box 54840-00200, Nairobi, Kenya
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Touray AO, Mobegi VA, Wamunyokoli F, Butungi H, Herren JK. Prevalence of asymptomatic P. falciparum gametocyte carriage in schoolchildren and assessment of the association between gametocyte density, multiplicity of infection and mosquito infection prevalence. Wellcome Open Res 2020; 5:259. [PMID: 33959684 PMCID: PMC8078214 DOI: 10.12688/wellcomeopenres.16299.1] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/22/2020] [Indexed: 07/22/2023] Open
Abstract
Background: Malaria is a major public health threat in sub-Saharan Africa. Asymptomatic Plasmodium falciparum gametocyte carriers are potential infectious reservoirs for sustaining transmission in many malaria endemic regions. The aim of the study was to assess the prevalence of gametocyte carriage and some of its associated risk factors among asymptomatic schoolchildren in Western Kenya and further analyse the association between gametocyte density, multiplicity of infection (MOI) and mosquito infection prevalence. Methods: Rapid diagnostic tests were used to screen for P. falciparum parasite infection among schoolchildren (5-15 years old) and the results were verified using microscopy. Microscopy positive gametocyte carriers were selected to feed laboratory reared An. gambiae s.l. mosquitoes using membrane feeding method. Genomic DNA was extracted from dry blood spot samples and P. falciparum populations were genotyped using 10 polymorphic microsatellite markers. Assessment of the association between MOI and gametocyte density and mosquito infection prevalence was conducted. Results: A significantly higher prevalence of P. falciparum infection was found in males 31.54% (764/2422) ( p-value < 0.001) compared to females 26.72% (657/2459). The microscopy gametocyte prevalence among the study population was 2% (84/4881). Children aged 5-9 years have a higher prevalence of gametocyte carriage (odds ratios = 2.1 [95% CI = 1.3-3.4], P = 0.002) as compared to children aged 10-15 years. After challenging An. gambiae s.l. by membrane feeding assay on gametocyte positive patient blood, our results indicate that 68.1% of the variation in mosquito infection prevalence is accounted for by gametocyte density and MOI (R-SQR. = 0.681, p < 0.001). Conclusions: Age was a significant risk factor for gametocyte carriage, as indicated by the higher risk of gametocyte carriage among the younger children (5-9 years). Gametocyte density and MOI statistically significantly predicted mosquito infection prevalence. Both of the variables added significantly to the prediction ( p < 0.05).
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Affiliation(s)
- Abdoulie O. Touray
- Department of Molecular Biology and Biotechnology, Institute of Basic Sciences, Technology and Innovation, Pan African University (PAUSTI), Nairobi, Kenya
- International Centre of Insect Physiology and Ecology (icipe), Nairobi, Kenya
| | - Victor A. Mobegi
- Department of Biochemistry, School of Medicine, University of Nairobi, Nairobi, Kenya
| | - Fred Wamunyokoli
- Department of Biochemistry, Jomo Kenyatta University of Agriculture and Technology (JKUAT), Nairobi, Kenya
| | - Hellen Butungi
- International Centre of Insect Physiology and Ecology (icipe), Nairobi, Kenya
- Wits Research Institute for Malaria, School of Pathology, Faculty of Health Sciences, University of the Witswatersrand, Johannesburg, South Africa
| | - Jeremy K. Herren
- International Centre of Insect Physiology and Ecology (icipe), Nairobi, Kenya
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Amoah LE, Acquah FK, Nyarko PB, Cudjoe E, Donu D, Ayanful-Torgby R, Sey F, Williamson KC, Awandare GA. Comparative analysis of asexual and sexual stage Plasmodium falciparum development in different red blood cell types. Malar J 2020; 19:200. [PMID: 32503587 PMCID: PMC7275330 DOI: 10.1186/s12936-020-03275-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2020] [Accepted: 05/29/2020] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Red blood cell (RBC) polymorphisms are suggested to influence the course of Plasmodium falciparum malaria. Whereas some variants have been found to be protective, others have been found to enhance parasite development. This study evaluated the effect of variant haemoglobin (Hb) and ABO blood groups on P. falciparum merozoite invasion, multiplication rates as well as gametocyte development. METHODS Approximately 2.5 mL of venous blood was collected from each participant. Flow cytometry was used to determine the in vitro merozoite invasion rates of NF54 parasites into the blood of 66 non-parasitaemic individuals with variant Hb genotypes (HbSS, HbSC) and blood groups (A, B, O), which were then compared with invasion into HbAA blood. The ex vivo asexual parasite multiplication and gametocyte production rates of parasites from 79 uncomplicated malaria patients with varying Hb genotypes (HbAS, HbAC and HbAA) were also estimated using microscopy. RESULTS Merozoite invasion rates were significantly reduced by about 50% in RBCs containing HbSS and HbSC relative to HbAA cells. The presence of blood group O and B reduced the invasion rates of HbSS by about 50% and 60%, respectively, relative to HbSC but the presence of blood group A removed the inhibitory effect of HbSS. The initial parasite densities in uncomplicated malaria patients with Hb genotypes HbAS and HbAC cells were similar but significantly lower than those with genotype HbAA. The ex vivo parasite multiplication rate, gametocytaemia and gametocyte conversion rates followed a similar trend but did not reach statistical significance (p > 0.05). CONCLUSIONS Parasite invasion rate into erythrocytes is dependent on both erythrocyte blood group antigen and haemoglobin genotype as blood group O and B provided protection via reduced merozoite invasion in RBCs containing HbSS relative to HbSC. Regardless of haemoglobin type, greater than 70% malaria patients had circulating ring stage parasites that differentiated into stage II gametocytes in 4 days.
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Affiliation(s)
- Linda E Amoah
- Department of Immunology, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana. .,West African Centre for Cell Biology of Infectious Pathogens, University of Ghana, Accra, Ghana.
| | - Festus K Acquah
- Department of Immunology, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana.,West African Centre for Cell Biology of Infectious Pathogens, University of Ghana, Accra, Ghana
| | - Prince B Nyarko
- West African Centre for Cell Biology of Infectious Pathogens, University of Ghana, Accra, Ghana
| | - Elizabeth Cudjoe
- Department of Immunology, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | - Dickson Donu
- Department of Immunology, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | - Ruth Ayanful-Torgby
- Department of Immunology, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | - Fredericka Sey
- Ghana Institute of Clinical Genetics, Korle-Bu, Accra, Ghana
| | - Kim C Williamson
- Microbiology and Immunology Department, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Gordon A Awandare
- West African Centre for Cell Biology of Infectious Pathogens, University of Ghana, Accra, Ghana
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