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Si us plau utilitzeu sempre aquest identificador per citar o enllaçar aquest document: https://hdl.handle.net/2445/183414
Utility of ultra-sensitive qPCR to detect Plasmodium falciparum and Plasmodium vivax infections under different transmission intensities
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Background: The use of molecular diagnostics has revealed an unexpectedly large number of asymptomatic
low-density malaria infections in many malaria endemic areas. This study compared the gains in parasite prevalence
obtained by the use of ultra-sensitive (us)-qPCR as compared to standard qPCR in cross-sectional surveys conducted
in Thailand, Brazil and Papua New Guinea (PNG). The compared assays differed in the copy number of qPCR targets in
the parasite genome.
Methods: Plasmodium falciparum (Pf) and Plasmodium vivax (Pv) parasites were quantified by qPCR amplifying the
low-copy Pf_ and Pv_18S rRNA genes or the multi-copy targets Pf_varATS and Pv_mtCOX1. Cross-sectional surveys at
the three study sites included 2252 participants of all ages and represented different transmission intensities.
Results: In the two low-transmission areas, P. falciparum positivity was 1.3% (10/773) (Thailand) and 0.8% (5/651) (Bra-
zil) using standard Pf_18S rRNA qPCR. In these two countries, P. falciparum positivity by Pf_varATS us-qPCR increased
to 1.9% (15/773) and 1.7% (11/651). In PNG, an area with moderate transmission intensity, P. falciparum positivity
significantly increased from 8.6% (71/828) by standard qPCR to 12.2% (101/828) by us-qPCR. The proportions of P.
falciparum infections not detected by standard qPCR were 33%, 55% and 30% in Thailand, Brazil and PNG. Plasmodium
vivax was the predominating species in Thailand and Brazil, with 3.9% (30/773) and 4.9% (32/651) positivity by Pv_18S
rRNA qPCR. In PNG, P. vivax positivity was similar to P. falciparum, at 8.0% (66/828). Use of Pv_mtCOX1 us-qPCR led to
a significant increase in positivity to 5.1% (39/773), 6.4% (42/651) and 11.5% (95/828) in Thailand, Brazil, and PNG. The
proportions of P. vivax infections missed by standard qPCR were similar at all three sites, with 23%, 24% and 31% in
Thailand, Brazil and PNG.
Conclusion: The proportional gains in the detection of P. falciparum and P. vivax infections by ultra-sensitive diag-
nostic assays were substantial at all three study sites. Thus, us-qPCR yields more precise prevalence estimates for
both P. falciparum and P. vivax at all studied levels of endemicity and represents a significant diagnostic improvement.
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GRUENBERG, Maria, ANTUNES MONIZ, Clara, HOFMANN, Natalie e., KOEPFLI, Cristian, ROBINSON, Leanne j., NATE, Elma, MONTEIRO, Wuelton marcelo, CARDOSO DE MELO, Gisely, KUEHN, Andrea, SIQUEIRA, Andre m., NGUITRAGOOL, Wang, BASSAT ORELLANA, Quique, LACERDA, Marcus, SATTABONGKOT, Jetsumon, MUELLER, Ivo, FELGER, Ingrid. Utility of ultra-sensitive qPCR to detect Plasmodium falciparum and Plasmodium vivax infections under different transmission intensities. _Malaria Journal_. 2020. Vol. 19, núm. 1, pàgs. 319. [consulta: 15 de gener de 2026]. ISSN: 1475-2875. [Disponible a: https://hdl.handle.net/2445/183414]