A point-of-care test for measles diagnosis: detection of measles-specific IgM antibodies and viral nucleic acid

Implementing effective monitoring strategies is fundamental to protect crops from pathogens and to ensure the food supply as the world population continues to grow. This is especially important for emergent plant pathogens such as tomato brown rugose fruit virus (ToBRFV), which overcomes the genetic resistance resources used in tomato breeding against tobamoviruses and has become pandemic in less than a decade. Here we report the development of a CRISPR/Cas12a-based test to detect ToBRFV in the laboratory and potentially in a field setting. Using different tobamoviruses to assess specificity, our test showed a clear positive signal for ToBRFV-infected samples, while no cross-reactivity was observed for closely related viruses. Next, we compared the limit of detection of our CRISPR-based test with a reference real-time quantitative PCR test widely used, revealing similar sensitivities for both tests. Finally, to reduce complexity and achieve field-applicability, we used a fast nucleic acid purification step and compared its results side-to-side with those of a commonly used column-mediated protocol. The rapid protocol saved time and resources but at the expense of sensitivity. However, it still may be useful to confirm ToBRFV detection in samples with incipient symptoms of infection. Although there is room for improvement, to our knowledge this is the first field-compatible CRISPR-based test to detect ToBRFV which combines isothermal amplification with a simplified nucleic acid extraction protocol.

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The diagnosis of hepatitis C viral infection

Orvosi Hetilap ◽

10.1556/oh.2014.29972 ◽

2014 ◽

Vol 155 (26) ◽

pp. 1019-1023

Author(s):

Judit Gervain

Keyword(s):

Hepatitis C ◽

Nucleic Acid ◽

Viral Infection ◽

Structural Changes ◽

Viral Infections ◽

Transient Elastography ◽

Viral Nucleic Acid ◽

Length Of Treatment ◽

Subtype B

The successful therapy of hepatitis C viral infection requires that the illness is diagnosed before the development of structural changes of the liver. Testing is stepwise consisting of screening, diagnosis, and anti-viral therapy follow-up. For these steps there are different biochemical, serological, histological and molecular biological methods available. For screening, alanine aminotransferase and anti-HCV tests are used. The diagnosis of infection is confirmed using real-time polymerase chain reaction of the viral nucleic acid. Before initiation of the therapy liver biopsy is recommended to determine the level of structural changes in the liver. Alternatively, transient elastography or blood biomarkers may be also used for this purpose. Differential diagnosis should exclude the co-existence of other viral infections and chronic hepatitis due to other origin, with special attention to the presence of autoantibodies. The outcome of the antiviral therapy and the length of treatment are mainly determined by the viral genotype. In Hungary, most patients are infected with genotype 1, subtype b. The polymorphism type that occurs in the single nucleotide located next to the interleukin 28B region in chromosome 19 and the viral polymorphism type Q80K for infection with HCV 1a serve as predictive therapeutic markers. The follow-up of therapy is based on the quantitative determination of viral nucleic acid according to national and international protocols and should use the same method and laboratory throughout the treatment of an individual patient. Orv. Hetil., 2014, 155(26), 1019–1023.

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Testing for resistance: Point-of-care testing as a communicational tool in antibiotic prescribing

Communication & Medicine ◽

10.1558/cam.32191 ◽

2018 ◽

Vol 14 (3) ◽

pp. 229-240

Author(s):

Johanna Lindell

Keyword(s):

Point Of Care ◽

Rapid Test ◽

Antibiotic Use ◽

Treatment Recommendation ◽

Antibiotic Prescribing ◽

Communicative Practices ◽

Effective Strategies ◽

Reactive Protein ◽

Point Of Care Test ◽

Test Result

As antibiotic resistance becomes a growing health emergency, effective strategies are needed to reduce inappropriate antibiotic use. In this article, one such strategy – communicative practices associated with the C-reactive protein point-of care test – is investigated. Building on a collection of 31 videorecorded consultations from Danish primary care, and using conversation analysis, this study finds that the rapid test can be used throughout the consultation to incrementally build the case for a nonantibiotic treatment recommendation, both when the test result is forecast and reported. The study also finds that the format of reports of elevated results differs from that of ‘normal’ results, resulting in a subtle shift of authority from doctor to test.

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Gold-Aptamer-Nanoconstructs Engineered to Detect Conserved Enteroviral Nucleic Acid Sequences

10.26434/chemrxiv.8312324.v1 ◽

2019 ◽

Author(s):

Veeren Chauhan ◽

Mohamed M Elsutohy ◽

C Patrick McClure ◽

Will Irving ◽

Neil Roddis ◽

...

Keyword(s):

Nucleic Acid ◽

In Silico ◽

Point Of Care ◽

Lateral Flow ◽

Nucleic Acid Sequence ◽

In Silico Screening ◽

Lateral Flow Assays ◽

Life Threatening ◽

Software And Hardware ◽

Nucleic Acid Sequences

Enteroviruses are a ubiquitous mammalian pathogen that can produce mild to life-threatening disease. Bearing this in mind, we have developed a rapid, accurate and economical point-of-care biosensor that can detect a nucleic acid sequences conserved amongst 96% of all known enteroviruses. The biosensor harnesses the physicochemical properties of gold nanoparticles and aptamers to provide colourimetric, spectroscopic and lateral flow-based identification of an exclusive enteroviral RNA sequence (23 bases), which was identified through in silico screening. Aptamers were designed to demonstrate specific complementarity towards the target enteroviral RNA to produce aggregated gold-aptamer nanoconstructs. Conserved target enteroviral nucleic acid sequence (≥ 1x10-7 M, ≥1.4×10-14 g/mL), initiates gold-aptamer-nanoconstructs disaggregation and a signal transduction mechanism, producing a colourimetric and spectroscopic blueshift (544 nm (purple) > 524 nm (red)). Furthermore, lateral-flow-assays that utilise gold-aptamer-nanoconstructs were unaffected by contaminating human genomic DNA, demonstrated rapid detection of conserved target enteroviral nucleic acid sequence (< 60 s) and could be interpreted with a bespoke software and hardware electronic interface. We anticipate our methodology will translate in-silico screening of nucleic acid databases to a tangible enteroviral desktop detector, which could be readily translated to related organisms. This will pave-the-way forward in the clinical evaluation of disease and complement existing strategies at overcoming antimicrobial resistance.

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