Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 4 de 4
Filtrar
Más filtros










Base de datos
Intervalo de año de publicación
1.
Sci Rep ; 14(1): 12620, 2024 06 01.
Artículo en Inglés | MEDLINE | ID: mdl-38824239

RESUMEN

Ivermectin (IVM) has been proposed as a new tool for malaria control as it is toxic on vectors feeding on treated humans or cattle. Nevertheless, IVM may have a direct mosquitocidal effect when applied on bed nets or sprayed walls. The potential for IVM application as a new insecticide for long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS) was tested in this proof-of-concept study in a laboratory and semi-field environment. Laboratory-reared, insecticide-susceptible Kisumu Anopheles gambiae were exposed to IVM on impregnated netting materials and sprayed plastered- and mud walls using cone bioassays. The results showed a direct mosquitocidal effect of IVM on this mosquito strain as all mosquitoes died by 24 h after exposure to IVM. The effect was slower on the IVM-sprayed walls compared to the treated nettings. Further work to evaluate possibility of IVM as a new insecticide formulation in LLINs and IRS will be required.


Asunto(s)
Anopheles , Mosquiteros Tratados con Insecticida , Insecticidas , Ivermectina , Control de Mosquitos , Animales , Anopheles/efectos de los fármacos , Ivermectina/farmacología , Insecticidas/farmacología , Control de Mosquitos/métodos , Malaria/prevención & control , Malaria/transmisión , Mosquitos Vectores/efectos de los fármacos
2.
Front Cell Infect Microbiol ; 14: 1366563, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38716192

RESUMEN

Background: Routine surveillance for antimalarial drug resistance is critical to sustaining the efficacy of artemisinin-based Combination Therapies (ACTs). Plasmodium falciparum kelch-13 (Pfkelch-13) and non-Pfkelch-13 artemisinin (ART) resistance-associated mutations are uncommon in Africa. We investigated polymorphisms in Plasmodium falciparum actin-binding protein (Pfcoronin) associated with in vivo reduced sensitivity to ART in Nigeria. Methods: Fifty-two P. falciparum malaria subjects who met the inclusion criteria were followed up in a 28-day therapeutic efficacy study of artemether-lumefantrine in Lagos, Nigeria. Parasite detection was done by microscopy and molecular diagnostic approaches involving PCR amplification of genes for Pf18S rRNA, varATS, telomere-associated repetitive elements-2 (TARE-2). Pfcoronin and Pfkelch-13 genes were sequenced bi-directionally while clonality of infections was determined using 12 neutral P. falciparum microsatellite loci and msp2 analyses. Antimalarial drugs (sulfadoxine-pyrimethamine, amodiaquine, chloroquine and some quinolones) resistance variants (DHFR_51, DHFR_59, DHFR_108, DHFR_164, MDR1_86, MDR1_184, DHPS_581 and DHPS_613) were genotyped by high-resolution melting (HRM) analysis. Results: A total of 7 (26.92%) cases were identified either as early treatment failure, late parasitological failure or late clinical failure. Of the four post-treatment infections identified as recrudescence by msp2 genotypes, only one was classified as recrudescence by multilocus microsatellites genotyping. Microsatellite analysis revealed no significant difference in the mean allelic diversity, He, (P = 0.19, Mann-Whitney test). Allele sizes and frequency per locus implicated one isolate. Genetic analysis of this isolate identified two new Pfcoronin SNVs (I68G and L173F) in addition to the P76S earlier reported. Linkage-Disequilibrium as a standardized association index, IAS, between multiple P. falciparum loci revealed significant LD (IAS = 0.2865, P=0.02, Monte-Carlo simulation) around the neutral microsatellite loci. The pfdhfr/pfdhps/pfmdr1 drug resistance-associated haplotypes combinations, (108T/N/51I/164L/59R/581G/86Y/184F), were observed in two samples. Conclusion: Pfcoronin mutations identified in this study, with potential to impact parasite clearance, may guide investigations on emerging ART tolerance in Nigeria, and West African endemic countries.


Asunto(s)
Antimaláricos , Artemisininas , Resistencia a Medicamentos , Malaria Falciparum , Proteínas de Microfilamentos , Plasmodium falciparum , Adulto , Femenino , Humanos , Masculino , Antimaláricos/farmacología , Antimaláricos/uso terapéutico , Combinación Arteméter y Lumefantrina/uso terapéutico , Artemisininas/farmacología , Artemisininas/uso terapéutico , Combinación de Medicamentos , Resistencia a Medicamentos/genética , Genotipo , Malaria Falciparum/tratamiento farmacológico , Malaria Falciparum/parasitología , Proteínas de Microfilamentos/genética , Repeticiones de Microsatélite/genética , Mutación , Nigeria , Plasmodium falciparum/genética , Plasmodium falciparum/efectos de los fármacos , Polimorfismo Genético , Proteínas Protozoarias/genética , Recurrencia
3.
BMC Res Notes ; 17(1): 129, 2024 May 09.
Artículo en Inglés | MEDLINE | ID: mdl-38725016

RESUMEN

OBJECTIVES: The study evaluated sub-microscopic malaria infections in pregnancy using two malaria Rapid Diagnostic Tests (mRDTs), microscopy and RT-PCR and characterized Plasmodium falciparum dihydrofolate reductase (Pfdhfr) and Plasmodium falciparum dihydropteroate synthase (Pfdhps) drug resistant markers in positive samples. METHODS: This was a cross sectional survey of 121 pregnant women. Participants were finger pricked, blood drops were collected for rapid diagnosis with P. falciparum histidine-rich protein 11 rapid diagnostic test kit and the ultra-sensitive Alere Pf malaria RDT, Blood smears for microscopy and dried blood spots on Whatman filter paper for molecular analysis were made. Real time PCR targeting the var acidic terminal sequence (varATS) gene of P. falciparum was carried out on a CFX 96 real time system thermocycler (BioRad) in discriminating malaria infections. For each run, laboratory strain of P. falciparum 3D7 and nuclease free water were used as positive and negative controls respectively. Additionally, High resolution melt analyses was employed for genotyping of the different drug resistance markers. RESULTS: Out of one hundred and twenty-one pregnant women sampled, the SD Bioline™ Malaria Ag P.f HRP2-based malaria rapid diagnostic test (mRDT) detected eight (0.06%) cases, the ultra-sensitive Alere™ malaria Ag P.f rapid diagnostic test mRDT had similar outcome in the same samples as detected by the HRP2-based mRDT. Microscopy and RT-PCR confirmed four out of the eight infections detected by both rapid diagnostic tests as true positive and RT-PCR further detected three false negative samples by the two mRDTs providing a sub-microscopic malaria prevalence of 3.3%. Single nucleotide polymorphism in Pfdhps gene associated with sulphadoxine resistance revealed the presence of S613 mutant genotypes in three of the seven positive isolates and isolates with mixed wild/mutant genotype at codon A613S. Furthermore, four mixed genotypes at the A581G codon were also recorded while the other Pfdhps codons (A436G, A437G and K540E) showed the presence of wild type alleles. In the Pfdhfr gene, there were mutations in 28.6%, 28.6%, and 85.7% at the I51, R59 and N108 codons respectively. Mixed wild and mutant type genotypes were also observed in 28.6% each of the N51I, and C59R codons. For the Pfcrt, two haplotypes CVMNK and CVIET were observed. The SVMNT was altogether absent. Triple mutant CVIET 1(14.3%) and triple mutant + wild genotype CVIET + CVMNK 1(14.3%) were observed. The Pfmdr1 haplotypes were single mutants YYND 1(14.3%); NFND 1(14.3%) and double mutants YFND 4(57.1%); YYDD 1(14.3%).


Asunto(s)
Malaria Falciparum , Plasmodium falciparum , Polimorfismo de Nucleótido Simple , Femenino , Humanos , Malaria Falciparum/parasitología , Malaria Falciparum/diagnóstico , Malaria Falciparum/epidemiología , Embarazo , Plasmodium falciparum/genética , Plasmodium falciparum/efectos de los fármacos , Adulto , Estudios Transversales , Polimorfismo de Nucleótido Simple/genética , Nigeria/epidemiología , Antimaláricos/farmacología , Antimaláricos/uso terapéutico , Alelos , Adulto Joven , Complicaciones Parasitarias del Embarazo/parasitología , Complicaciones Parasitarias del Embarazo/genética , Complicaciones Parasitarias del Embarazo/diagnóstico , Resistencia a Múltiples Medicamentos/genética , Dihidropteroato Sintasa/genética , Tetrahidrofolato Deshidrogenasa/genética , Proteínas Protozoarias/genética , Adolescente
4.
Am J Trop Med Hyg ; 110(2): 214-219, 2024 02 07.
Artículo en Inglés | MEDLINE | ID: mdl-38167431

RESUMEN

Despite marked progress in Senegal, three regions in the southeast part continue to have a high burden of malaria, but there have been no recent studies assessing the prevalence of malaria associated with pregnancy. This study aimed to determine the prevalence of malaria infection in pregnant women attending antenatal clinics in Senegal. During the malaria transmission season of 2019, pregnant women attending 11 health care facilities for a scheduled visit and those presenting unwell with signs of malaria were invited to participate in a malaria screening study. A finger prick blood sample was taken for malaria diagnosis by rapid diagnosis test (RDT) and polymerase chain reaction (PCR). A total of 877 pregnant women were enrolled, 787 for a scheduled antenatal consultation and 90 for an unscheduled consultation with signs of malaria. The prevalence of Plasmodium falciparum among the first group was 48% by PCR and 20% by RDT, and that among the second group was 86% by PCR and 83% by RDT. RDT sensitivity in capturing asymptomatic, PCR-positive infections was 9.2% but ranged from 83% to 94% among febrile women. The prevalence of infection by PCR in women who reported having received at least three doses of sulfadoxine pyrimethamine (SP) was 41.9% compared with 58.9% in women who reported they had not received any SP doses (prevalence ratio adjusted for gravidity and gestational age, 0.54; 95% CI, 0.41-0.73). The burden of P. falciparum infections remains high among pregnant women, the majority of which are not captured by RDT. More effective measures to prevent malaria infection in pregnancy are needed.


Asunto(s)
Antimaláricos , Malaria Falciparum , Malaria , Humanos , Femenino , Embarazo , Lactante , Antimaláricos/uso terapéutico , Mujeres Embarazadas , Prevalencia , Senegal/epidemiología , Sulfadoxina/uso terapéutico , Pirimetamina/uso terapéutico , Malaria/tratamiento farmacológico , Malaria Falciparum/diagnóstico , Malaria Falciparum/epidemiología , Malaria Falciparum/tratamiento farmacológico , Combinación de Medicamentos , Infecciones Asintomáticas/epidemiología , Instituciones de Atención Ambulatoria
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA