Trial reportMalaria journal2014
Measurement of parasitological data by quantitative real-time PCR from controlled human malaria infection trials at the Walter Reed Army Institute of Research.
Trial report in Malaria journal, 2014. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 16 papers, 1 of them a synthesis that pooled it.
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Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
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Who cites it
16 citing papers in PubMed, 1 synthesis or guideline pooled it, 27 citations in OpenAlex.
- Reproducibility of malaria sporozoite challenge model in humans for evaluating efficacy of vaccines and drugs: a systematic review.BMC infectious diseases · 2021Pooled it
- Safety and protective efficacy of PfSPZ Vaccine administered to HIV-negative and -positive Tanzanian adults.The Journal of clinical investigation · 2024Trial
- Diagnosis of Plasmodium falciparum malaria at very low parasitaemias using a commercially available LAMP assay and RDT.Transactions of the Royal Society of Tropical Medicine and Hygiene · 2025Article
- The Dantu blood group prevents parasite growtheLife · 2023Article
- Controlled Human Infection Models To Accelerate Vaccine Development.Clinical microbiology reviews · 2022Review
- Analysis of nucleic acids extracted from rapid diagnostic tests reveals a significant proportion of false positive test results associated with recent malaria treatment.Malaria journal · 2022Article
- Article
- Analytical validation of a real-time hydrolysis probe PCR assay for quantifying Plasmodium falciparum parasites in experimentally infected human adults.Malaria journal · 2021Article
- Molecular malaria surveillance using a novel protocol for extraction and analysis of nucleic acids retained on used rapid diagnostic tests.Scientific reports · 2020Article
- Safety Considerations for Malaria Volunteer Infection Studies: A Mini-Review.The American journal of tropical medicine and hygiene · 2020Review
- Beyond Blood Smears: Qualification ofThe American journal of tropical medicine and hygiene · 2019Article
- Molecular monitoring of the diversity of human pathogenic malaria species in blood donations on Bioko Island, Equatorial Guinea.Malaria journal · 2019Article
- Detection of Malaria Parasites After Treatment in Travelers: A 12-months Longitudinal Study and Statistical Modelling Analysis.EBioMedicine · 2017Article
- Diagnosis and treatment based on quantitative PCR after controlled human malaria infection.Malaria journal · 2016Article
- Considerations for the use of human participants in vector biology research: a tool for investigators and regulators.Vector borne and zoonotic diseases (Larchmont, N.Y.) · 2015Review
- Increased sample volume and use of quantitative reverse-transcription PCR can improve prediction of liver-to-blood inoculum size in controlled human malaria infection studies.Malaria journal · 2015Article
Corrections and comments
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Authors and funding
7 authors at 1 institution in 1 country.
Funding
No grant is acknowledged in the PubMed record.
Abstract
backgroundThe use of quantitative real-time PCR (qPCR) has allowed for precise quantification of parasites in the prepatent period and greatly improved the reproducibility and statistical power of controlled human malaria infection (CHMI) trials. Parasitological data presented here are from non-immunized, control-challenged subjects who participated in two CHMI trials conducted at the Walter Reed Army Institute of Research (WRAIR).
methodsStandardized sporozoite challenge was achieved through the bite of five Anopheles stephensi mosquitoes infected with the 3D7clone of the NF54 strain of Plasmodium falciparum. Blood smears were scored positive when two unambiguous parasites were found. Analysis of parasitological PCR data was performed on log-transformed data using an independent sample t-test when comparing the two studies. The multiplication rate of blood-stage parasites was estimated using the linear model.
resultsOn average, parasites were detected 4.91 days (95% CI = 4.190 to 5.627) before smears. The earliest parasites were detected within 120 hours (5.01 days) after challenge. Parasite densities showed consistent cyclic patterns of blood-stage parasite growth in all volunteers. The parasite multiplication rates for both studies was 8.18 (95% CI = 6.162 to 10.20). Data showed that at low parasite densities, a combination of sequestration and stochastic effects of low copy number DNA may impact qPCR detection and the parasite detection limit.
conclusionSmear positive is an endpoint which antimalarial rescue is imperative whereas early detection of parasitological data by qPCR can allow for better anticipation of the endpoint. This would allow for early treatment to reduce clinical illness and risk for study participants. To use qPCR as the primary endpoint in CHMI trials, an algorithm of two positives by qPCR where one of the positives must have parasite density of at least 2 parasites/μL is proposed.
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