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Evaluation of InfluA&B Respi-Strip for the rapid detection of influenza A and B viruses in respiratory samples

Abstract number: 1733_664

Degallaix S., Denorme L., Lefèvre O., Labrune V., Laurent T., Leclipteux T., Mertens P.

Influenza virus is the causative agent of flu, a highly contagious infection of the upper respiratory tract. Flu is characterised by the antigen variability, the seasonality and the impact on the general population.

There are two main (A and B) types of influenza viruses. H1N1, H2N2 and H3N2 InfA subtypes as well as InfB strains can cause outbreaks of variable intensity annually in humans. Although influenza A are the most prevalent, type B viruses can represent up to 50% of circulating virus during one season, and is often more abundant at the end of the season.

Flu is most often a mild viral infection, but influenza can cause severe complications such as bronchitis or pneumonia, particularly in children and elderly people. Antivirals are available, but these treatments are effective only if administered early requiring a rapid diagnostic test. There are many other viral infections that can mimic influenza making laboratory tests necessary to distinguish it from other acute respiratory infections. The widespread of H5N1 wildbird strains that can infect humans and the threat of a pandemic makes the rapid diagnosis still more valuable.

We have developed a new rapid dipstick test (InfluA&B Respi-Strip) based on monoclonal antibodies (MAb) directed agaisnt non-variable proteins of influenza A and B viruses. The final device has two sides, one for the detection of influenza A and the opposite side for the detection of influenza B. For each virus, MAbs are coated on the nitrocellulose, while other Mabs are conjugated to colloidal gold particles. A build-in control is used as migration control.

An evaluation on 113 frozen nasopharyngeal samples has been conducted to compare the InfluA&B Respi-Strip to a market leader rapid immunochromatographic test (Test N), with RT-PCR as the reference method. Both tests showed excellent specificities for both InfA and InfB detection (98.6–100%). InfluA&B Respi-Strip was slightly more sensitive than Test N, for both InfA and InfB detection. InfluA&B Respi-Strip will be further validated on fresh samples during the epidemic season.

In conclusion, the Coris' Influ-A&B Respi-Strip shows sensitivity and specificity comparable to one of the bests currently available rapid tests. The use of this test for diagnosis of influenza disease should enhance patient healthcare by enabling rapid and appropriate use of antiviral treatments and lowering inappropriate use of preventive antibiotic treatment still often prescribed by mistake.

Session Details

Date: 31/03/2007
Time: 00:00-00:00
Session name: European Society of Clinical Microbiology and Infectious Diseases
Subject:
Location: ICC, Munich, Germany
Presentation type:
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