English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Background  The unexpected high proportion of submicroscopic malaria infections in areas with low transmission intensity challenges the control and elimination of malaria in the Americas. The current PCR-based assays present limitations as most protocols still rely on amplification of few-copies target gene. Here, the hypothesis was that amplification of different plasmodial targets—ribosomal ( 18S rRNA ) and non-ribosomal multi-copy sequences (Pvr47 for  Plasmodium vivax  and Pfr364 for  Plasmodium falciparum )—could increase the chances of detecting submicroscopic malaria infection.    Methods  A non-ribosomal real-time PCR assay targeting Pvr47/Pfr364 ( NR - qPCR ) was established and compared with three additional PCR protocols, two of them based on  18S rRNA  gene amplification ( Nested - PCR  and  R - qPCR ) and one based on Pvr47/Pfr364 targets ( NR - cPCR ). The limit of detection of each PCR protocol, at single and artificial mixed  P. vivax / P. falciparum  infections, was determined by end-point titration curves. Field samples from clinical (n = 110) and subclinical (n = 324) malaria infections were used to evaluate the impact of using multiple molecular targets to detect malaria infections.    Results  The results demonstrated that an association of ribosomal and non-ribosomal targets did not increase sensitivity to detect submicroscopic malaria infections. Despite of that, artificial mixed-malaria infections demonstrated that the NR-qPCR was the most sensitive protocol to detect low-levels of  P. vivax / P. falciparum  co-infections. Field studies confirmed that submicroscopic malaria represented a large proportion (up to 77%) of infections among asymptomatic Amazonian residents, with a high proportion of infections (~ 20%) identified only by the NR-qPCR.    Conclusions  This study presents a new species-specific non-ribosomal PCR assay with potential to identify low-density  P. vivax  and  P. falciparum  infections. As the majority of subclinical infections was caused by  P. vivax , the commonest form of malaria in the Amazon area, future studies should investigate the potential of Pvr47/Pfr364 to detect mixed-malaria infections in the field.    Electronic supplementary material  The online version of this article (10.1186/s12936-019-2781-3) contains supplementary material, which is available to authorized users.

Ribosomal and non-ribosomal PCR targets for the detection of low-density and mixed malaria infections