ORCID Profile
0000-0003-4478-3601
Current Organisations
Rural Development Administration
,
Medical Research Council The Gambia Unit
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Publisher: Springer Science and Business Media LLC
Date: 03-06-2022
DOI: 10.1186/S12936-022-04176-9
Abstract: The development of resistance by Plasmodium falciparum to anti-malarial drugs impedes any benefits of the drug. In addition, absence or delayed availability of current anti-malarial drugs in remote areas has the potential to results to parasite escape and continuous transmission. The case of a 29-year old pregnant woman from Biase Local Government Area in Cross River State Nigeria presenting with febrile illness and high body temperature of 38.7 °C was reported. She looked pale and vomited twice on arrival at the health facility. Her blood smear on the first day of hospitalization was positive for P. falciparum by RDT, microscopy (21,960 parasite/µl) and real-time PCR, with a PCV of 18%. She was treated with 600 mg intravenous quinine in 500 ml of 5% Dextrose/0.9% Saline 8-hourly for 24 h. On the second day of hospitalization, she complained of weakness, persistent high-grade fever and vaginal bleeding. A bulging amnion from an extended cervix was observed. Following venous blood collection for laboratory investigations, 600 µg of misoprostol was inserted into the posterior fornix of her vagina as part of her obstetric care. Parenteral quinine was discontinued, and she was given full therapeutic regimen of artemether-lumefantrine 80/480 mg tablets to be taken for 3 days beginning from the second day. Her blood s les on the second and third day of hospitalization remained positive for P. falciparum by all three diagnostic methods. Single nucleotide polymorphism (SNP) assay on all three P. falciparum isolates revealed the presence of variants associated with multiple drug resistant markers. Infecting P. falciparum isolates may have been resistant to initial quinine treatment resulting from parasite cross-resistance with other quinoline associated resistant markers such as 86Y and 184 F. Therefore, the likely transmission of similarly resistant parasites in the study area calls for reinforcement of interventions and adherence to current World Health Organization guidelines in administering only approved drugs to in iduals in order to mitigate parasite escape and eventual transmission to other susceptible in iduals.
Publisher: Oxford University Press (OUP)
Date: 03-1993
Publisher: Springer Science and Business Media LLC
Date: 03-2015
Publisher: Oxford University Press (OUP)
Date: 21-11-2014
Publisher: American Society for Microbiology
Date: 12-2014
DOI: 10.1128/AAC.02746-14
Abstract: Reduced susceptibility of Plasmodium falciparum toward artemisinin derivatives has been reported from the Thai-Cambodian and Thai-Myanmar borders. Following increasing reports from central Vietnam of delayed parasite clearance after treatment with dihydroartemisinin-piperaquine (DHA-PPQ), the current first-line treatment, we carried out a study on the efficacy of this treatment. Between September 2012 and February 2013, we conducted a 42-day in vivo and in vitro efficacy study in Quang Nam Province. Treatment was directly observed, and blood s les were collected twice daily until parasite clearance. In addition, genotyping, quantitative PCR (qPCR), and in vitro sensitivity testing of isolates was performed. The primary endpoints were parasite clearance rate and time. The secondary endpoints included PCR-corrected and uncorrected cure rates, qPCR clearance profiles, in vitro sensitivity results (for chloroquine, dihydroartemisinin, and piperaquine), and genotyping for mutations in the Kelch 13 propeller domain. Out of 672 screened patients, 95 were recruited and 89 available for primary endpoint analyses. The median parasite clearance time (PCT) was 61.7 h (interquartile range [IQR], 47.6 to 83.2 h), and the median parasite clearance rate had a slope half-life of 6.2 h (IQR, 4.4 to 7.5 h). The PCR-corrected efficacy rates were estimated at 100% at day 28 and 97.7% (95% confidence interval, 91.2% to 99.4%) at day 42. At day 3, the P. falciparum prevalence by qPCR was 2.5 times higher than that by microscopy. The 50% inhibitory concentrations (IC 50 s) of isolates with delayed clearance times (≥72 h) were significantly higher than those with normal clearance times for all three drugs. Delayed parasite clearance (PCT, ≥72 h) was significantly higher among day 0 s les carrying the 543 mutant allele (47.8%) than those carrying the wild-type allele (1.8% P = 0.048). In central Vietnam, the efficacy of DHA-PPQ is still satisfactory, but the parasite clearance time and rate are indicative of emerging artemisinin resistance. (This study has been registered at ClinicalTrials.gov under registration no. NCT01775592.)
Publisher: F1000 Research Ltd
Date: 13-07-2021
DOI: 10.12688/WELLCOMEOPENRES.16168.2
Abstract: MalariaGEN is a data-sharing network that enables groups around the world to work together on the genomic epidemiology of malaria. Here we describe a new release of curated genome variation data on 7,000 Plasmodium falciparum s les from MalariaGEN partner studies in 28 malaria-endemic countries. High-quality genotype calls on 3 million single nucleotide polymorphisms (SNPs) and short indels were produced using a standardised analysis pipeline. Copy number variants associated with drug resistance and structural variants that cause failure of rapid diagnostic tests were also analysed. Almost all s les showed genetic evidence of resistance to at least one antimalarial drug, and some s les from Southeast Asia carried markers of resistance to six commonly-used drugs. Genes expressed during the mosquito stage of the parasite life-cycle are prominent among loci that show strong geographic differentiation. By continuing to enlarge this open data resource we aim to facilitate research into the evolutionary processes affecting malaria control and to accelerate development of the surveillance toolkit required for malaria elimination.
Publisher: Public Library of Science (PLoS)
Date: 19-04-2012
Publisher: Springer Science and Business Media LLC
Date: 03-09-2019
Publisher: Public Library of Science (PLoS)
Date: 11-2012
Publisher: Elsevier BV
Date: 08-2021
Publisher: F1000 Research Ltd
Date: 16-01-2023
DOI: 10.12688/WELLCOMEOPENRES.18681.1
Abstract: We describe the MalariaGEN Pf7 data resource, the seventh release of Plasmodium falciparum genome variation data from the MalariaGEN network. It comprises over 20,000 s les from 82 partner studies in 33 countries, including several malaria endemic regions that were previously underrepresented. For the first time we include dried blood spot s les that were sequenced after selective whole genome lification, necessitating new methods to genotype copy number variations. We identify a large number of newly emerging crt mutations in parts of Southeast Asia, and show ex les of heterogeneities in patterns of drug resistance within Africa and within the Indian subcontinent. We describe the profile of variations in the C-terminal of the csp gene and relate this to the sequence used in the RTS,S and R21 malaria vaccines. Pf7 provides high-quality data on genotype calls for 6 million SNPs and short indels, analysis of large deletions that cause failure of rapid diagnostic tests, and systematic characterisation of six major drug resistance loci, all of which can be freely downloaded from the MalariaGEN website.
Publisher: Springer Science and Business Media LLC
Date: 30-12-2023
Publisher: Springer Science and Business Media LLC
Date: 17-01-2019
Publisher: Springer Science and Business Media LLC
Date: 28-04-2013
DOI: 10.1038/NG.2624
Location: Korea, Republic of
No related grants have been discovered for Alfred Amambua-Ngwa.