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Malar J ; 20(1): 32, 2021 Jan 09.
Artículo en Inglés | MEDLINE | ID: mdl-33422080


BACKGROUND: Malaria remains highly endemic in Cameroon. The rapid emergence and spread of drug resistance was responsible for the change from monotherapies to artemisinin-based combinations. This systematic review and meta-analysis aimed to determine the prevalence and distribution of Plasmodium falciparum drug resistance markers within an evolving efficacy of anti-malarial drugs in Cameroon from January 1998 to August 2020. METHODS: The PRISMA-P and PRISMA statements were adopted in the inclusion of studies on single nucleotide polymorphisms (SNPs) of P. falciparum anti-malarial drug resistance genes (Pfcrt, Pfmdr1, Pfdhfr, Pfdhps, Pfatp6, Pfcytb and Pfk13). The heterogeneity of the included studies was evaluated using the Cochran's Q and I2 statistics. The random effects model was used as standard in the determination of heterogeneity between studies. RESULTS: Out of the 902 records screened, 48 studies were included in this aggregated meta-analysis of molecular data. A total of 18,706 SNPs of the anti-malarial drug resistance genes were genotyped from 47,382 samples which yielded a pooled prevalence of 35.4% (95% CI 29.1-42.3%). Between 1998 and 2020, there was significant decline (P < 0.0001 for all) in key mutants including Pfcrt 76 T (79.9%-43.0%), Pfmdr1 86Y (82.7%-30.5%), Pfdhfr 51I (72.2%-66.9%), Pfdhfr 59R (76.5%-67.8%), Pfdhfr 108 N (80.8%-67.6%). The only exception was Pfdhps 437G which increased over time (30.4%-46.9%, P < 0.0001) and Pfdhps 540E that remained largely unchanged (0.0%-0.4%, P = 0.201). Exploring mutant haplotypes, the study observed a significant increase in the prevalence of Pfcrt CVIET mixed quintuple haplotype from 57.1% in 1998 to 57.9% in 2020 (P < 0.0001). In addition, within the same study period, there was no significant change in the triple Pfdhfr IRN mutant haplotype (66.2% to 67.3%, P = 0.427). The Pfk13 amino acid polymorphisms associated with artemisinin resistance were not detected. CONCLUSIONS: This review reported an overall decline in the prevalence of P. falciparum gene mutations conferring resistance to 4-aminoquinolines and amino alcohols for a period over two decades. Resistance to artemisinins measured by the presence of SNPs in the Pfk13 gene does not seem to be a problem in Cameroon. Systematic review registration PROSPERO CRD42020162620.

Malar J ; 18(1): 73, 2019 Mar 12.
Artículo en Inglés | MEDLINE | ID: mdl-30866947


BACKGROUND: Accurate diagnosis of malaria is important for effective disease management and control. In Cameroon, presumptive clinical diagnosis, thick-film microscopy (TFM), and rapid diagnostic tests (RDT) are commonly used to diagnose cases of Plasmodium falciparum malaria. However, these methods lack sensitivity to detect low parasitaemia. Polymerase chain reaction (PCR), on the other hand, enhances the detection of sub-microscopic parasitaemia making it a much-needed tool for epidemiological surveys, mass screening, and the assessment of interventions for malaria elimination. Therefore, this study sought to determine the frequency of cases missed by traditional methods that are detected by PCR. METHODS: Blood samples, collected from 551 febrile Cameroonian patients between February 2014 and February 2015, were tested for P. falciparum by microscopy, RDT and PCR. The hospital records of participants were reviewed to obtain data on the clinical diagnosis made by the health care worker. RESULTS: The prevalence of malaria by microscopy, RDT and PCR was 31%, 45%, and 54%, respectively. However, of the 92% of participants diagnosed as having clinical cases of malaria by the health care worker, 38% were malaria-negative by PCR. PCR detected 23% and 12% more malaria infections than microscopy and RDT, respectively. A total of 128 (23%) individuals had sub-microscopic infections in the study population. The sensitivity of microscopy, RDT, and clinical diagnosis was 57%, 78% and 100%; the specificity was 99%, 94%, and 17%; the positive predictive values were 99%, 94%, and 59%; the negative predictive values were 66%, 78%, and 100%, respectively. Thus, 41% of the participants clinically diagnosed as having malaria had fever caused by other pathogens. CONCLUSIONS: Malaria diagnostic methods, such as TFM and RDT missed 12-23% of malaria cases detected by PCR. Therefore, traditional diagnostic approaches (TFM, RDT and clinical diagnosis) are not adequate when accurate epidemiological data are needed for monitoring malaria control and elimination interventions.

Sangre/parasitología , Pruebas Diagnósticas de Rutina/métodos , Inmunoensayo/métodos , Malaria Falciparum/diagnóstico , Microscopía/métodos , Plasmodium falciparum/aislamiento & purificación , Reacción en Cadena de la Polimerasa/métodos , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Camerún , Niño , Preescolar , Estudios Transversales , Femenino , Humanos , Lactante , Recién Nacido , Masculino , Persona de Mediana Edad , Plasmodium falciparum/citología , Plasmodium falciparum/genética , Plasmodium falciparum/inmunología , Sensibilidad y Especificidad , Encuestas y Cuestionarios , Adulto Joven
BMC Infect Dis ; 16(1): 658, 2016 11 08.
Artículo en Inglés | MEDLINE | ID: mdl-27825318


BACKGROUND: The current roll-out of rapid diagnostic tests (RDTs) in many endemic countries has resulted in the reporting of fewer cases of malaria-attributed illnesses. However, lack of knowledge of the prevalence of other febrile illnesses and affordable diagnostic tests means that febrile patients are not managed optimally. This study assessed the prevalence of commonly treatable or preventable febrile illnesses in children between 6 months and 15 years using rapid diagnostic tests at the point-of-care. METHODS: Febrile children were enrolled between February-April 2014 at a health facility after obtaining informed consent from parent. Eligible participants were aged 6 months-15 years with a history of fever in the last 24 h or axillary temperature ≥38 °C at consultation. All participants were tested using RDTs for malaria, typhoid, toxoplasmosis and rubella. Malaria parasites were further identified by microscopy and PCR. Clinical and household characteristics were recorded and association with pathogens determined. RESULTS: Of the 315 children enrolled, the mean age was 5.8 ± 3.8 years. Stomach pain (41.2 %) was the most reported symptom. Prior to attending the health facility, 70.8 % had taken antipyretics, 27.9 % antimalarials, 11.4 % antibiotics and 13.3 % antifungal drugs. Among 315 children with fever, based on RDTs, 56.8 % were infected with malaria, 4.4 % with typhoid, 3.2 % with acute toxoplasmosis, and 1.3 % with rubella (all positive for rubella were in the same family and not vaccinated). All non-malarial infections were co-infections and approximately 30 % of the fever cases went un-diagnosed. Malaria prevalence by microscopy and PCR was 43.4 and 70.2 % respectively. The sensitivity and specificity of RDTs for the diagnosis of malaria were 75.98 and 100 % respectively, with 0.73 measurement agreement between RDTs and microscopy while that of RDT and PCR were 81 and 100 % respectively with a K value of 0.72. The use of Insecticide Treated Bednets was 44 %. There was a significant association between ITN non-usage and malaria (p = 0. 029) as well as drinking water and presence of typhoid (p = 0.047). No association was observed between type of housing and malaria, or toxoplasmosis and raising cats. CONCLUSION: Though malaria still remains the major cause of fever in children, using RDTs for other treatable febrile illnesses like typhoid and toxoplasmosis could facilitate the optimal management of febrile illnesses in children especially when these occur as co-infections with malaria.

Malaria/epidemiología , Rubéola (Sarampión Alemán)/epidemiología , Toxoplasmosis/epidemiología , Fiebre Tifoidea/epidemiología , Adolescente , Animales , Antimaláricos/uso terapéutico , Camerún/epidemiología , Gatos , Niño , Preescolar , Coinfección/tratamiento farmacológico , Pruebas Diagnósticas de Rutina/métodos , Femenino , Fiebre/etiología , Instituciones de Salud , Humanos , Lactante , Mosquiteros Tratados con Insecticida , Malaria/diagnóstico , Malaria/tratamiento farmacológico , Masculino , Microscopía , Sistemas de Atención de Punto , Reacción en Cadena de la Polimerasa , Rubéola (Sarampión Alemán)/diagnóstico , Sensibilidad y Especificidad , Toxoplasmosis/diagnóstico , Toxoplasmosis/tratamiento farmacológico , Fiebre Tifoidea/diagnóstico