scholarly journals Study protocol for a cluster-randomized split-plot design trial to assess the effectiveness of targeted active malaria case detection among high-risk populations in Southern Lao PDR (the AcME-Lao study)

2019 ◽  
Vol 3 ◽  
pp. 1730 ◽  
Author(s):  
Andrew A. Lover ◽  
Emily Dantzer ◽  
Sophia Hocini ◽  
Ronaldo Estera ◽  
Francois Rerolle ◽  
...  
Keyword(s):  
High Risk ◽  
Diagnostic Tests ◽  
Lao Pdr ◽  
High Sensitivity ◽  
Rapid Diagnostic Tests ◽  
Case Detection ◽  
Test And Treat ◽  
High Risk Populations ◽  
Cluster Randomized ◽  
Plot Design

Introduction: Novel interventions are needed to accelerate malaria elimination, especially in areas where asymptomatic parasitemia is common, and where transmission generally occurs outside of village-based settings. Testing of community members linked to a person with clinical illness (reactive case detection, RACD) has not shown effectiveness in prior studies due to the limited sensitivity of current point-of-care tests. This study aims to assess the effectiveness of active case finding in village-based and forested-based settings using novel high-sensitivity rapid diagnostic tests in Lao People’s Democratic Republic (Lao PDR). Methods and analysis: This study is a cluster-randomized split-plot design trial. The interventions include village-based mass test and treat (MTAT), focal test and treat in high-risk populations (FTAT), and the combination of these approaches, using high-sensitivity rapid diagnostic tests (HS-RDTs) to asses P. falciparum infection status. Within four districts in Champasak province, Lao PDR fourteen health center-catchment areas will be randomized to either FTAT or control; and within these HCCAs, 56 villages will be randomized to either MTAT or control. In intervention areas, FTAT will be conducted by community-based peer navigators on a routine basis, and three separate rounds of MTAT are planned. The primary study outcome will be PCR-based Plasmodium falciparum prevalence after one year of implementation. Secondary outcomes include malaria incidence; interventional coverage; operational feasibility and acceptability; and cost and cost- effectiveness. Ethics and dissemination: Findings will be reported on clinicaltrials.gov, in peer-reviewed publications and through stakeholder meetings with Ministry of Health and community leaders in Lao PDR and throughout the Greater Mekong Subregion. Trial registration: clinicaltrials.gov NCT03783299 (21/12/2018)

scholarly journals Laboratory evaluation of the Chembio Dual Path Platform HIV-Syphilis Assay

2016 ◽  
Vol 5 (1) ◽  
Author(s):  
Mireille B. Kalou ◽  
Arnold Castro ◽  
Amy Watson ◽  
Heather Jost ◽  
Stacy Clay ◽  
...  
Keyword(s):  
Sensitivity And Specificity ◽  
Diagnostic Tests ◽  
Treponema Pallidum ◽  
High Sensitivity ◽  
Rapid Diagnostic Tests ◽  
Laboratory Evaluation ◽  
Serum Samples ◽  
Operational Characteristics ◽  
High Risk Populations ◽  
Positive Results

Background: Use of rapid diagnostic tests for HIV and syphilis has increased remarkably in the last decade. As new rapid diagnostic tests become available, there is a continuous need to assess their performance and operational characteristics prior to use in clinical settings.Objectives: In this study, we evaluated the performance of the Chembio Dual Path Platform (DPP®) HIV–Syphilis Assay to accurately diagnose HIV, syphilis, and HIV/syphilis co-infection.Method: In 2013, 990 serum samples from the Georgia Public Health Laboratory in Atlanta, Georgia, United States were characterised for HIV and syphilis and used to evaluate the platform. HIV reference testing combined third-generation Enzyme Immunoassay and Western Blot, whereas reference testing for syphilis was conducted by the Treponema pallidum passive particle agglutination method and the TrepSure assay. We assessed the sensitivity and specificity of the DPP assay on this panel by comparing results with the HIV and syphilis reference testing algorithms.Results: For HIV, sensitivity was 99.8% and specificity was 98.4%; for syphilis, sensitivity was 98.8% and specificity was 99.4%. Of the 348 co-infected sera, 344 (98.9%) were detected accurately by the DPP assay, but 11 specimens had false-positive results (9 HIV and 2 syphilis) due to weak reactivity.Conclusion: In this evaluation, the Chembio DPP HIV–Syphilis Assay had high sensitivity and specificity for detecting both HIV and treponemal antibodies. Our results indicate that this assay could have a significant impact on the simultaneous screening of HIV and syphilis using a single test device for high-risk populations or pregnant women needing timely care and treatment.

scholarly journals Using risk-tracing snowball approach to increase HIV case detection among high-risk populations in Cambodia: an intervention study

2017 ◽  
Vol 17 (1) ◽  
Author(s):  
Srean Chhim ◽  
John Macom ◽  
Chettana Pav ◽  
Nirada Nim ◽  
Phearun Yun ◽  
...  
Keyword(s):  
High Risk ◽  
Intervention Study ◽  
Case Detection ◽  
High Risk Populations

scholarly journals Prozone-like phenomenon in travellers with fatal malaria: report of two cases

2015 ◽  
Vol 9 (03) ◽  
pp. 321-324 ◽  
Author(s):  
Lurdes Santos ◽  
Nuno Rocha Pereira ◽  
Paulo Andrade ◽  
Paulo Figueiredo Dias ◽  
Carlos Lima Alves ◽  
...  
Keyword(s):  
Diagnostic Tests ◽  
False Negative ◽  
Specific Antigen ◽  
Malaria Diagnosis ◽  
High Sensitivity ◽  
Rapid Diagnostic Tests ◽  
Microscopy Observation ◽  
Negative Results ◽  
False Negative Results ◽  
Potential Benefits

Malaria diagnosis remains a concern in non-endemic countries, with rapid diagnosis being crucial to improve patients’ outcome. Rapid diagnostic tests have high sensitivity but they also have flaws and false-negative results that might jeopardize malaria diagnosis. Some false-negative results might relate to a prozone-like effect. The authors describe two patients with false-negative rapid diagnostic tests in which a prozone-like effect might have been involved. The authors highlight that these tests should not be used without accompanying light microscopy observation of blood films and discuss potential benefits of using rapid diagnostic tests with more than one specific antigen for Plasmodium falciparum.

scholarly journals Comparative sensitivity evaluation for 122 CE-marked rapid diagnostic tests for SARS-CoV-2 antigen, Germany, September 2020 to April 2021

2021 ◽  
Vol 26 (44) ◽  
Author(s):  
Heinrich Scheiblauer ◽  
Angela Filomena ◽  
Andreas Nitsche ◽  
Andreas Puyskens ◽  
Victor M Corman ◽  
...  
Keyword(s):  
Diagnostic Tests ◽  
Market Access ◽  
High Sensitivity ◽  
Rapid Diagnostic Tests ◽  
Lower Sensitivity ◽  
Viral Loads ◽  
Sensitivity Evaluation ◽  
Wide Range ◽  
German Healthcare System ◽  
Minimum Sensitivity

Introduction Numerous CE-marked SARS-CoV-2 antigen rapid diagnostic tests (Ag RDT) are offered in Europe, several of them with unconfirmed quality claims. Aim We performed an independent head-to-head evaluation of the sensitivity of SARS-CoV-2 Ag RDT offered in Germany. Methods We addressed the sensitivity of 122 Ag RDT in direct comparison using a common evaluation panel comprised of 50 specimens. Minimum sensitivity of 75% for panel specimens with a PCR quantification cycle (Cq) ≤ 25 was used to identify Ag RDT eligible for reimbursement in the German healthcare system. Results The sensitivity of different SARS-CoV-2 Ag RDT varied over a wide range. The sensitivity limit of 75% for panel members with Cq ≤ 25 was met by 96 of the 122 tests evaluated; 26 tests exhibited lower sensitivity, few of which failed completely. Some RDT exhibited high sensitivity, e.g. 97.5 % for Cq < 30. Conclusions This comparative evaluation succeeded in distinguishing less sensitive from better performing Ag RDT. Most of the evaluated Ag RDT appeared to be suitable for fast identification of acute infections associated with high viral loads. Market access of SARS-CoV-2 Ag RDT should be based on minimal requirements for sensitivity and specificity.

scholarly journals Characterizing Mobility Patterns of Forest Goers in Southern Lao PDR using GPS Loggers.

2021 ◽  
Author(s):  
Francois Rerolle ◽  
Emily Dantzer ◽  
Toula Phimmakong ◽  
Andrew Lover ◽  
Bouasy Hongvanthong ◽  
...  
Keyword(s):  
High Risk ◽  
Clustering Algorithm ◽  
Lao Pdr ◽  
Malaria Vectors ◽  
Gradient Boosting ◽  
Mobility Patterns ◽  
Utilization Distribution ◽  
Control Programs ◽  
High Risk Populations ◽  
National Control

Abstract Background In the Greater Mekong Subregion (GMS), forest-going populations are considered high-risk populations for malaria and are increasingly targeted by national control programs’ elimination efforts. A better understanding of forest-going populations’ mobility patterns and risk associated with specific types of forest-going trips is necessary for countries in the GMS to achieve their objective of eliminating malaria by 2030. Methods Between March and November 2018, as part of a focal test and treat intervention (FTAT), we recruited 2,904 forest-goers in southern Lao PDR. A subset of forest-goers carried an “i-Got-U” GPS logger for roughly two months, configured to collect GPS coordinates every 15 to 30 minutes. The utilization distribution (UD) surface around each GPS trajectory was used to extract trips to the forest and forest-fringes. Trips with shared mobility characteristics in terms of duration, timing and forest penetration were identified by a hierarchical clustering algorithm. Then, clusters of trips with increased exposure to dominant malaria vectors in the region were further classified as high-risk. Finally, we used gradient boosting trees to assess which of the forest-goers’ socio-demographic and behavioral characteristics best predicted their likelihood to engage in such high-risk trips. Results A total of 122 forest-goers accepted carrying a GPS logger resulting in the collection of 803 trips to the forest or forest-fringes. Six clusters of trips emerged, helping to classify 385 (48%) trips with increased exposure to malaria vectors based on high forest penetration and whether the trip happened overnight. Age, outdoor sleeping structures and number of children were the best predictors of forest-goers’ probability of engaging in high-risk trips. The probability of engaging in high-risk trips was high (~33%) in all strata of the forest-going population. Conclusion This study characterized the heterogeneity within the mobility patterns of forest-goers and attempted to further segment their role in malaria transmission in southern Lao People’s Democratic Republic (PDR). National control programs across the region can leverage these results to tailor their interventions and messaging to high-risk populations and accelerate malaria elimination.

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