ABSTRACT
Objective: To analyze data on socio-demographic and clinical characteristics of SARS-CoV-2 infected population whose samples were received from Medical Research Institute, Sri Lanka. Method(s): Laboratory based retrospective study was done on patient samples which were tested positive for SARS-CoV-2 by National Reference Virology Laboratory at the Medical Research Institute, Sri Lanka, from November, 2020 to November, 2021. Data on socio-demographic characteristics and clinical presentation of 13 126 patients were examined. Result(s): The mean age of the study population was (36.0+/-7.2) years and the majority were men (64.0%). The highest number of positive cases were found in the 21-30 years-of-age group. Two distinct peaks were noted in the incidence of SARS-CoV-2 positive individuals. In addition, 42.5% of the positive samples tested positive (42.5%) were from Medical Officer of Health collection centres. Furthermore, 60.6% (7 951) of the infected subjects were asymptomatic whereas the remaining were symptomatic. The highest percentage of symptomatic patients were observed in the 91-100 years-of-age group while the highest asymptomatic subjects were found in the 31-40 years-of-age group. The percentage of asymptomatic children (65.3%) was significantly (P<0.05) higher than that of adults (43.4%). Conclusion(s): The findings of this study aid decision makers to focus on the vulnerable groups, and geographic and temporal distribution of patients in the public health strategies that aim at preventing the spread of the disease and reducinig its mortalities.Copyright © 2023 Wolters Kluwer Medknow Publications. All rights reserved.
ABSTRACT
The development of an extensive toolkit for potential point-of-care diagnostics that is expeditiously adaptable to new emerging pathogens is of critical public health importance. Recently, a number of novel CRISPR-based diagnostics have been developed to detect SARS-CoV-2. Herein, we outline the development of an alternative CRISPR nucleic acid diagnostic utilizing a Cas13d ribonuclease derived from Ruminococcus flavefaciens XPD3002 (CasRx) to detect SARS-CoV-2, an approach we term SENSR (sensitive enzymatic nucleic acid sequence reporter) that can detect attomolar concentrations of SARS-CoV-2. We demonstrate 100% sensitivity in patient-derived samples by lateral flow and fluorescence readout with a detection limit of 45 copy/µL. This technology expands the available nucleic acid diagnostic toolkit, which can be adapted to combat future pandemics.
Subject(s)
COVID-19 , SARS-CoV-2 , Humans , Nucleic Acid Amplification Techniques , RNA, Viral , RuminococcusABSTRACT
The COVID-19 pandemic has illustrated the global demand for rapid, low-cost, widely distributable and point-of-care nucleic acid diagnostic technologies. Such technologies could help disrupt transmission, sustain economies and preserve health and lives during widespread infection. In contrast, conventional nucleic acid diagnostic procedures require trained personnel, complex laboratories, expensive equipment, and protracted processing times. In this work, lyophilized cell-free protein synthesis (CFPS) and toehold switch riboregulators are employed to develop a promising paper-based nucleic acid diagnostic platform activated simply by the addition of saliva. First, to facilitate distribution and deployment, an economical paper support matrix is identified and a mass-producible test cassette designed with integral saliva sample receptacles. Next, CFPS is optimized in the presence of saliva using murine RNase inhibitor. Finally, original toehold switch riboregulators are engineered to express the bioluminescent reporter NanoLuc in response to SARS-CoV-2 RNA sequences present in saliva samples. The biosensor generates a visible signal in as few as seven minutes following administration of 15 µL saliva enriched with high concentrations of SARS-CoV-2 RNA sequences. The estimated cost of this test is less than 0.50 USD, which could make this platform readily accessible to both the developed and developing world. While additional research is needed to decrease the limit of detection, this work represents important progress toward developing a diagnostic technology that is rapid, low-cost, distributable and deployable at the point-of-care by a layperson.