| dc.creator |
Hofmann, Natalie |
|
| dc.creator |
Mwingira, Felista |
|
| dc.creator |
Shekalaghe, Seif |
|
| dc.creator |
Robison, Leanne |
|
| dc.creator |
Muller, Ivo |
|
| dc.creator |
Felger, Ingrid |
|
| dc.date |
2020-08-31T10:37:33Z |
|
| dc.date |
2020-08-31T10:37:33Z |
|
| dc.date |
2015-03-03 |
|
| dc.date.accessioned |
2021-05-07T09:43:38Z |
|
| dc.date.available |
2021-05-07T09:43:38Z |
|
| dc.identifier |
Hofmann N, Mwingira F, Shekalaghe S, Robinson LJ, Mueller I, Felger I (2015) UltraSensitive Detection of Plasmodium falciparum by Amplification of Multi-Copy Subtelomeric Targets. PLoS Med 12(3): e1001788. doi:10.1371/journal. pmed.1001788 |
|
| dc.identifier |
http://hdl.handle.net/20.500.11810/5491 |
|
| dc.identifier |
doi:10.1371/journal. pmed.1001788 |
|
| dc.identifier.uri |
http://hdl.handle.net/20.500.11810/5491 |
|
| dc.description |
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, *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/μl blood
and were 10× 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. |
|
| dc.publisher |
PLOS |
|
| dc.relation |
12;3 |
|
| dc.subject |
Plasmodium falciparum, Quantitative PCR, TARE-2 and varATS qPCR |
|
| dc.title |
Ultra-Sensitive Detection of Plasmodium falciparum by Amplification of Multi-Copy Subtelomeric Targets |
|