The Center for the Study of Complex Malaria in India (CSCMi 3.0): Hidden Plasmodium Infections: Reservoirs, Impact, and Biomarker Discovery
试验速览
- 阶段
- 不适用
- 状态
- 招募中
- 入组人数
- 3,000
- 试验地点
- 2
- 主要终点
- Prevalence and incidence of Plasmodium infection - Project 1
研究概览
简要总结
The goal of this prospective cohort study is to understand the factors responsible for the persistence of malaria transmission in some areas despite intensive control efforts. The study will measure the prevalence and incidence of asymptomatic and sub-patent Plasmodium infections and examine the factors that contribute to persistent transmission among residents of malaria-endemic areas of Odisha, India.
The main questions the study aims to answer are: Do asymptomatic and sub-patent Plasmodium infections contribute to persistent malaria transmission in endemic areas of Odisha? What is the frequency of false-negative results and incorrect species identification when microscopy and rapid diagnostic tests (RDTs) are compared with PCR? How is malaria epidemiology changing over time across areas with different transmission patterns, including shifts in Plasmodium species? What is the prevalence of asymptomatic gametocyte carriers, and how might they contribute to ongoing transmission? What are the characteristics and distribution of mosquito vectors in and around households, and how do they relate to transmission patterns? Can novel host- and parasite-derived biomarkers improve the detection of malaria infections, including asymptomatic cases?
Participants will provide blood samples for malaria testing by microscopy, RDT and PCR. A subset will provide additional samples for biomarker analysis as part of a nested sub-study. Participants will be followed over time to measure malaria infection prevalence, incidence and changes in transmission patterns. They will also take part in household-level assessments, including surveys and mosquito vector monitoring around their homes.
详细描述
Malaria transmission has declined in many parts of India as a result of expanded control efforts. However, persistent transmission continues in several regions despite high intervention coverage. Increasing evidence suggests that asymptomatic and subpatent Plasmodium infections may form an important hidden reservoir that sustains transmission and complicates malaria elimination. These infections are often missed by routine diagnostic methods such as microscopy and rapid diagnostic tests (RDTs), particularly in low-transmission or pre-elimination settings.
Local mosquito vector dynamics, including species composition, density and behaviour, are also likely to play a critical role in sustaining residual transmission, but remain insufficiently characterised in these settings.
This study is part of the Center for the Study of Complex Malaria in India 3 (CSCMi-3) and aims to characterise the epidemiology and biological determinants of hidden malaria infections in Odisha, India. It will also examine how vector, human and parasite factors interact to sustain transmission. The study is a prospective, community-based cohort conducted in selected rural villages across three endemic districts, representing different malaria transmission settings. Participants will be enrolled through household-based community surveys and followed longitudinally to monitor malaria infection dynamics over time.
The parent cohort study will enrol approximately 3,000 individuals, who will be followed through repeated visits to estimate the prevalence and incidence of asymptomatic malaria infections. The study will also assess the frequency of false-negative results and species misclassification by comparing routine diagnostic methods with molecular detection. In addition, it will evaluate Pfhrp2/Pfhrp3 gene deletions and explore potential shifts in Plasmodium species composition over time. Blood samples collected during study visits will be used for parasitological testing and laboratory analyses to better understand the persistence of malaria transmission.
Concurrent entomological surveys will be conducted in and around participant households to characterise mosquito vector species, density and seasonal patterns, and to examine their relationship with household-level infection patterns and ongoing transmission.
研究设计
- 研究类型
- Observational
- 观察模型
- Cohort
- 时间视角
- Prospective
入排标准
- 年龄范围
- 12 Months 至 69 Years（Child, Adult, Older Adult）
- 性别
- All
- 接受健康志愿者
- 是
入选标准
- •Individuals 12 months to 69 years, all social classes, and all types of health status will be enrolled
排除标准
- •Individuals unable or unwilling to provide informed consent (or parental consent/assent for minors) Individuals unable to comply with study procedures or follow-up visits according to investigator judgement
结局指标
主要结局
Prevalence and incidence of Plasmodium infection - Project 1
时间窗: Nine time points between Years 1 and 5, including one baseline visit and eight follow-up visits conducted every six months.
Prevalence and incidence of Plasmodium infection among study participants, determined by polymerase chain reaction (PCR)-based detection of Plasmodium species in finger-prick blood samples collected during longitudinal community surveys. The study will estimate the prevalence, incidence and persistence of asymptomatic, subpatent and submicroscopic infections, together with species-specific infections.
Diagnostic performance of malaria microscopy and rapid diagnostic tests compared with PCR - Project 1
时间窗: Baseline and follow-up visits conducted every six months over five years.
Diagnostic performance of malaria microscopy and rapid diagnostic tests (RDTs) compared with PCR, assessed by false-negative and false-positive results, positive and negative predictive values, and species concordance for Plasmodium detection.
Novel circulating infection biomarkers of host and parasite origin - Biomarker Sub-study, Project 2
时间窗: Sixteen time points between Years 1 and 5, with eight time points each for Groups A and B.
Identification and quantification of circulating host- and parasite-derived biomarkers associated with malaria infection, using multiplex and molecular assays in longitudinal blood samples collected from the biomarker sub-cohort
次要结局
未报告次要终点
研究者
Sam Wassmer
Professor of Malaria Pathogenesis
London School of Hygiene and Tropical Medicine