# name
Ultra-Sensitive Detection of Plasmodium falciparum by
                Amplification of Multi-Copy Subtelomeric Targets

# metadata.dc.description.abstract[].value
BACKGROUND: Planning and evaluating malaria control strategies
                relies on accurate definition of parasite prevalence in the
                population. A large proportion of asymptomatic parasite
                infections can only be identified by surveillance with molecular
                methods, yet these infections also contribute to onward
                transmission to mosquitoes. The sensitivity of molecular
                detection by PCR is limited by the abundance of the target
                sequence in a DNA sample; thus, detection becomes imperfect at
                low densities. We aimed to increase PCR diagnostic sensitivity
                by targeting multi-copy genomic sequences for reliable detection
                of low-density infections, and investigated the impact of these
                PCR assays on community prevalence data. METHODS AND FINDINGS:
                Two quantitative PCR (qPCR) assays were developed for
                ultra-sensitive detection of Plasmodium falciparum, targeting
                the high-copy telomere-associated repetitive element 2 (TARE-2,
                approximately 250 copies/genome) and the var gene acidic
                terminal sequence (varATS, 59 copies/genome). Our assays reached
                a limit of detection of 0.03 to 0.15 parasites/mul blood and
                were 10x more sensitive than standard 18S rRNA qPCR. In a
                population cross-sectional study in Tanzania, 295/498 samples
                tested positive using ultra-sensitive assays. Light microscopy
                missed 169 infections (57%). 18S rRNA qPCR failed to identify 48
                infections (16%), of which 40% carried gametocytes detected by
                pfs25 quantitative reverse-transcription PCR. To judge the
                suitability of the TARE-2 and varATS assays for high-throughput
                screens, their performance was tested on sample pools. Both
                ultra-sensitive assays correctly detected all pools containing
                one low-density P. falciparum-positive sample, which went
                undetected by 18S rRNA qPCR, among nine negatives. TARE-2 and
                varATS qPCRs improve estimates of prevalence rates, yet other
                infections might still remain undetected when absent in the
                limited blood volume sampled. CONCLUSIONS: Measured malaria
                prevalence in communities is largely determined by the
                sensitivity of the diagnostic tool used. Even when applying
                standard molecular diagnostics, prevalence in our study
                population was underestimated by 8% compared to the new assays.
                Our findings highlight the need for highly sensitive tools such
                as TARE-2 and varATS qPCR in community surveillance and for
                monitoring interventions to better describe malaria epidemiology
                and inform malaria elimination efforts.

# metadata.dc.relation.isformatof[].value
Reproducció del document publicat a:               http://dx.doi.org/10.1371/journal.pmed.1001788

# metadata.dc.source[].value
Articles publicats en revistes (ISGlobal)

# metadata.dc.title[].value
Ultra-Sensitive Detection of Plasmodium falciparum by
                Amplification of Multi-Copy Subtelomeric Targets