Article
High-throughput Plasmodium falciparum hrp2 and hrp3 gene deletion typing by digital PCR to monitor malaria rapid diagnostic test efficacy
Registro en:
VERA-ARIAS, Claudia A. et al. High-throughput Plasmodium falciparum hrp2 and hrp3 gene deletion typing by digital PCR to monitor malaria rapid diagnostic test efficacy. eLife, v.11, e72083, p. 1 - 16, June 2022.
2050-084X
10.7554/eLife.72083
Autor
Vera-Arias, Claudia A.
Holzschuh, Aurel
Oduma, Colins O
Badu, Kingsley
Abdul-Hakim, Mutala
Yukich, Joshua
Hetzel, Manuel W
Fakih, Bakar S
Ali, Abdullah
Ferreira, Marcelo U
Ladeia-Andrade, Simone
Sáenz, Fabián E
Afrane, Yaw
Zemene, Endalew
Yewhalaw, Delenasaw
Kazura, James W
Yan, Guiyun
Koepfli, Cristian
Resumen
Most rapid diagnostic tests for Plasmodium falciparum malaria target the Histidine-Rich
Proteins 2 and 3 (HRP2 and HRP3). Deletions of the hrp2 and hrp3 genes result in false-negative
tests and are a threat for malaria control. A novel assay for molecular surveillance of hrp2/hrp3
deletions was developed based on droplet digital PCR (ddPCR). The assay quantifies hrp2, hrp3,
and a control gene with very high accuracy. The theoretical limit of detection was 0.33 parasites/μl.
The deletion was reliably detected in mixed infections with wild-type
and hrp2-deleted
parasites at
a density of >100 parasites/reaction. For a side-by-
side
comparison with the conventional nested
PCR (nPCR) assay, 248 samples were screened in triplicate by ddPCR and nPCR. No deletions were
observed by ddPCR, while by nPCR hrp2 deletion was observed in 8% of samples. The ddPCR assay
was applied to screen 830 samples from Kenya, Zanzibar/Tanzania, Ghana, Ethiopia, Brazil, and
Ecuador. Pronounced differences in the prevalence of deletions were observed among sites, with
more hrp3 than hrp2 deletions. In conclusion, the novel ddPCR assay minimizes the risk of false-negative
results (i.e., hrp2 deletion observed when the sample is wild type), increases sensitivity, and
greatly reduces the number of reactions that need to be run.