Community-based surveys for Plasmodium falciparum pfhrp2 and pfhrp3 gene deletions in selected regions of mainland Tanzania.
Malar J
; 19(1): 391, 2020 Nov 04.
Article
en En
| MEDLINE
| ID: mdl-33148255
ABSTRACT
BACKGROUND:
Histidine-rich protein 2 (HRP2)-based malaria rapid diagnostic tests (RDTs) are effective and widely used for the detection of wild-type Plasmodium falciparum infections. Although recent studies have reported false negative HRP2 RDT results due to pfhrp2 and pfhrp3 gene deletions in different countries, there is a paucity of data on the deletions of these genes in Tanzania.METHODS:
A community-based cross-sectional survey was conducted between July and November 2017 in four regions Geita, Kigoma, Mtwara and Ruvuma. All participants had microscopy and RDT performed in the field and provided a blood sample for laboratory multiplex antigen detection (for Plasmodium lactate dehydrogenase, aldolase, and P. falciparum HRP2). Samples showing RDT false negativity or aberrant relationship of HRP2 to pan-Plasmodium antigens were genotyped to detect the presence/absence of pfhrp2/3 genes.RESULTS:
Of all samples screened by the multiplex antigen assay (n = 7543), 2417 (32.0%) were positive for any Plasmodium antigens while 5126 (68.0%) were negative for all antigens. The vast majority of the antigen positive samples contained HRP2 (2411, 99.8%), but 6 (0.2%) had only pLDH and/or aldolase without HRP2. Overall, 13 samples had an atypical relationship between a pan-Plasmodium antigen and HRP2, but were positive by PCR. An additional 16 samples with negative HRP2 RDT results but P. falciparum positive by microscopy were also chosen for pfhrp2/3 genotyping. The summation of false negative RDT results and laboratory antigen results provided 35 total samples with confirmed P. falciparum DNA for pfhrp2/3 genotyping. Of the 35 samples, 4 (11.4%) failed to consistently amplify positive control genes; pfmsp1 and pfmsp2 and were excluded from the analysis. The pfhrp2 and pfhrp3 genes were successfully amplified in the remaining 31 (88.6%) samples, confirming an absence of deletions in these genes.CONCLUSIONS:
This study provides evidence that P. falciparum parasites in the study area have no deletions of both pfhrp2 and pfhrp3 genes. Although single gene deletions could have been missed by the multiplex antigen assay, the findings support the continued use of HRP2-based RDTs in Tanzania for routine malaria diagnosis. There is a need for the surveillance to monitor the status of pfhrp2 and/or pfhrp3 deletions in the future.Palabras clave
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Plasmodium falciparum
/
Proteínas Protozoarias
/
Eliminación de Gen
/
Pruebas Diagnósticas de Rutina
/
Antígenos de Protozoos
Tipo de estudio:
Observational_studies
/
Prevalence_studies
/
Risk_factors_studies
Límite:
Adolescent
/
Adult
/
Child
/
Child, preschool
/
Female
/
Humans
/
Male
/
Middle aged
País/Región como asunto:
Africa
Idioma:
En
Revista:
Malar J
Asunto de la revista:
MEDICINA TROPICAL
Año:
2020
Tipo del documento:
Article
País de afiliación:
Kenia