Publications by authors named "David S Boyle"

Lipoarabinomannan (LAM) is a promising target biomarker for diagnosing subclinical and clinical tuberculosis (TB). Urine LAM (uLAM) testing using rapid diagnostic tests (RDTs) has been approved for people living with HIV (PLWH), however there is limited data regarding uLAM levels in HIV-negative (HIV-ve) adults with clinical TB. We conducted a clinical study of adults presenting with clinical TB-related symptoms at the National Lung Hospital in Hanoi, Vietnam.

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  • Salmonella enterica serovar Typhi (S. Typhi) causes Typhoid fever, and while blood cultures are the best way to diagnose it, they're hard to use in resource-limited areas.* -
  • Researchers developed a novel process control organism (PCO) as a biosafe surrogate to test various environmental surveillance methods for detecting S. Typhi in water.* -
  • The PCO successfully mimicked S. Typhi in lab tests and was consistently detected in wastewater samples from India and Malawi, making it a reliable tool for validating environmental detection methods for this pathogen.*
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  • * The new assay developed combines duplexed reverse transcriptase recombinase polymerase amplification with MS2 bacteriophage as a process control, allowing for internal verification of the testing steps.
  • * This assay provides highly sensitive detection of SARS-CoV-2 with results in under 25 minutes, visual readout options, and requires minimal equipment, making it more accessible and reducing the chances of false negatives.
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Diagnostics are critical tools that guide clinical decision-making for patient care and support disease surveillance. Despite its importance, developers and manufacturers often note that access to specimen panels and essential reagents is one of the key challenges in developing quality diagnostics, particularly in low-resource settings. A recent example, as the COVID-19 pandemic unfolded there was a need for clinical samples across the globe to support the rapid development of diagnostics.

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  • The study investigates the effectiveness of rapid diagnostic tests (RDTs) in detecting N-antigen levels and viral load in various specimen types among individuals exposed to confirmed COVID-19 cases.
  • The results show that antigen concentration correlates with viral load within the same specimen type but differs across types, with symptomatic individuals showing higher antigen levels.
  • Saliva samples had lower antigen concentrations than nasal swabs, suggesting that saliva-based RDTs need enhanced sensitivity to match the performance of nasal tests.
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Rapid diagnostic tests (RDTs) that detect antigen indicative of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection can help in making quick health care decisions and regularly monitoring groups at risk of infection. With many RDT products entering the market, it is important to rapidly evaluate their relative performance. Comparison of clinical evaluation study results is challenged by protocol design variations and study populations.

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  • - The typhoid conjugate vaccine is deemed safe and effective for preventing typhoid fever, but many countries struggle with clinical surveillance systems to determine its implementation due to ongoing transmission of the disease.
  • - This study estimated the costs of setting up an environmental surveillance program to track typhoid transmission across thirteen protocols, using Monte Carlo simulations to assess financial uncertainties related to the costs of equipment and operational expenses.
  • - Total costs per sample can range significantly based on the number of sites involved, with potential to be affordable at larger scales; however, careful consideration of operational costs, sensitivity evaluations, and leveraging existing resources is essential for effective implementation.
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Processing and storing blood samples for future analysis of biomarkers can be challenging in resource limited environments. The preparation of dried blood spots (DBS) from finger-stick collection of whole blood is a widely used and established method as DBS are biosafe, and allow simpler field processing, storage, and transport protocols than serum or plasma. Therefore, DBS are commonly used in population surveys to assess infectious disease and/or micronutrient status.

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  • * New direct-acting antivirals (DAAs) have high cure rates in under 12 weeks, but access to HCV RNA testing is limited to certain labs, creating a need for more decentralized testing options.
  • * A new rapid and accurate HCV RNA detection assay using reverse transcription recombinase polymerase amplification (RT-RPA) shows 100% sensitivity and specificity, making it a promising option for point-of-care testing and improving access to treatment.
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Lipoarabinomannan (LAM), a component of the Mycobacterium tuberculosis (MTB) cell wall, is detectable in the urine of MTB infected patients with active tuberculosis (TB). LAM-specific antibodies (Igs) have been developed by a variety of traditional and recombinant methods for potential use in a rapid diagnostic test (RDT). We evaluated the analytical performance of the TB LAM Igs to identify pairs that offer superior performance over existing urine LAM tests.

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  • The study compares different swab types and collection sites for testing SARS-CoV-2, focusing on the effectiveness of self-collected swabs from the anterior nares and tongue compared to standard nurse-collected nasopharyngeal swabs.
  • Results show that anterior nares swabs had higher diagnostic sensitivity using RT-PCR and antigen testing than tongue swabs, with sensitivities of 91-100% against viral culture.
  • The findings suggest that self-collection of anterior nares specimens could serve as a viable alternative for SARS-CoV-2 testing in certain situations.
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  • Eradicating poliovirus is crucial for global public health, and as cases drop, understanding its persistence in the environment becomes increasingly important.
  • This study focused on how poliovirus types 2 and 3 persist in wastewater and sediment under different temperatures, exploring factors that influence their decay over time.
  • Findings revealed that temperature and the presence of sediment significantly affect how long the viruses remain viable, highlighting the need for ongoing environmental surveillance as poliovirus eradication efforts continue.
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Inexpensive, simple, rapid diagnostics are necessary for efficient detection, treatment, and mitigation of COVID-19. Assays for SARS-CoV2 using reverse transcription polymerase chain reaction (RT-PCR) offer good sensitivity and excellent specificity, but are expensive, slowed by transport to centralized testing laboratories, and often unavailable. Antigen-based assays are inexpensive and can be rapidly mass-produced and deployed at point-of-care, with lateral flow assays (LFAs) being the most common format.

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A lack of comparative data across laboratories is often a barrier to the uptake and adoption of new technologies. Furthermore, data generated by different immunoassay methods may be incomparable due to a lack of harmonization. In this multicenter study, we describe validation experiments conducted in a single lab and cross-lab comparisons of assay results to assess the performance characteristics of the Q-plex™ 7-plex Human Micronutrient Array (7-plex), an immunoassay that simultaneously quantifies seven biomarkers associated with micronutrient (MN) deficiencies, inflammation and malarial antigenemia using plasma or serum; alpha-1-acid glycoprotein, C-reactive protein, ferritin, histidine-rich protein 2, retinol binding protein 4, soluble transferrin receptor, and thyroglobulin.

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The global COVID-19 pandemic has created an urgent demand for large numbers of inexpensive, accurate, rapid, point-of-care diagnostic tests. Analyte-based assays are suitably rapid and inexpensive and can be rapidly mass-produced, but for sufficiently accurate performance, they require highly optimized antibodies and assay conditions. We used an automated liquid handling system, customized to handle arrays of lateral flow (immuno)assays (LFAs) in a high-throughput screen, to identify anti-nucleocapsid antibodies that will perform optimally in an LFA.

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Severe acute respiratory coronavirus-2 (SARS-CoV-2) is a novel viral pathogen and therefore a challenge to accurately diagnose infection. Asymptomatic cases are common and so it is difficult to accurately identify infected cases to support surveillance and case detection. Diagnostic test developers are working to meet the global demand for accurate and rapid diagnostic tests to support disease management.

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  • * There are challenges in improving access to HIV testing in low- and middle-income countries due to high costs and complicated testing procedures, particularly the RNA extraction process.
  • * A new microfluidic paper-based device (μPAD) has been developed for easy RNA extraction and HIV detection in serum, using cost-effective materials and techniques to deliver quick results in just 45 minutes.
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  • * The FDA’s CLIA-waiver allows simple and low-risk testing in laboratories, leading to the deployment of various NAT systems since 2015, enhancing infectious disease detection capabilities.
  • * This review discusses the regulatory processes by the FDA and WHO for NATs, as well as the technological advancements and challenges, aiming to inform future developments and commercialization strategies.
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Enteric viruses, such as poliovirus, are a leading cause of gastroenteritis, which causes 2-3 million deaths annually. Environmental surveillance of wastewater supplements clinical surveillance for monitoring enteric virus circulation. However, while many environmental surveillance methods require liquid samples, some at-risk locations utilize pit latrines with waste characterized by high solids content.

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Background: Salmonella enterica remains a leading cause of food-borne diseases worldwide. Serotype information is important in food safety and public health activities to reduce the burden of salmonellosis. In the current study, two methods were used to determine serotypes of 111 strains of Salmonella isolated from poultry feces in Burkina Faso.

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To facilitate treatment and limit transmission of tuberculosis (TB), new methods are needed to enable rapid and affordable diagnosis of the disease in high-burden low-resource settings. We have developed a prototype integrated nucleic acid testing device to detect Mycobacterium tuberculosis (M.tb) in sputum.

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Environmental enteric dysfunction (EED) is an intestinal disorder common among children in low-resource settings and is associated with increased risk of growth stunting, cognitive deficits, and reduced oral vaccine immunogenicity. The Micronutrient and EED Assessment Tool (MEEDAT) is a multiplexed immunoassay that measures biomarkers previously associated with child growth faltering and/or oral vaccine immunogenicity: intestinal fatty acid-binding protein (I-FABP), soluble CD14 (sCD14), insulin-like growth factor 1 (IGF-1), and fibroblast growth factor 21 (FGF21). MEEDAT also measures systemic inflammation (α1-acid glycoprotein, C-reactive protein), ferritin, soluble transferrin receptor, retinol binding protein 4, thyroglobulin, and Plasmodium falciparum antigenemia (histidine-rich protein 2).

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The SARS-CoV-2 pandemic has created an unprecedented need for rapid diagnostic testing to enable the efficient treatment and mitigation of COVID-19. The primary diagnostic tool currently employed is reverse transcription polymerase chain reaction (RT-PCR), which can have good sensitivity and excellent specificity. Unfortunately, implementation costs and logistical problems with reagents during the global SARS-CoV-2 pandemic have hindered its universal on demand adoption.

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  • - The bag-mediated filtration system (BMFS) was created to improve the environmental surveillance of poliovirus (PV) and complements traditional methods focused on acute flaccid paralysis to help with PV eradication efforts in Nairobi, Kenya, from April to September 2015.
  • - During the study, environmental samples were collected and processed using two methods: BMFS (which filtered over 3 liters) and a grab sample method (collecting 1 liter). The samples were then analyzed for poliovirus presence using various techniques, including rRT-PCR.
  • - Results showed that BMFS detected Sabin polioviruses more frequently than the other method, especially Sabin-like PV type 3, indicating its effectiveness for environmental monitoring, while no
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