Tools to Detect Influenza Virus

Abstract

In 2009, pandemic influenza A (H1N1) virus (H1N1 09) started to spread quickly in many countries. It causes respiratory infection with signs and symptoms of common infectious agents. Thus, clinicians sometimes may miss the H1N1 patient. Clinical laboratory tests are important for the diagnosis of the H1N1 infection. There are several tests available, however, the rapid test and direct fluorescence antigen test are unable to rule out the influenza virus infection and viral culture test is time consuming. Therefore, nucleic acid amplification techniques based on reverse transcription polymerase chain reaction assays are regarded as a specific diagnosis to confirm the influenza virus infection. Although the nucleic acid-based techniques are highly sensitive and specific, the high mutation rate of the influenza RNA-dependent RNA polymerase could limit the utility of the techniques. In addition, their use depends on the availability, cost and throughput of the diagnostic techniques. To overcome these drawbacks, evaluation and development of the techniques should be continued. This review provides an overview of various techniques for specific diagnosis of influenza infection.

Diagnostic Methods of Influenza a From Clinical Specimens: A Critical Review of Literature

“…Antibodies are produced after the onset of influenza virus illness and can be detected using serological diagnostic tech¬niques like hemagglutination inhibition assay (HIA), en-zyme immunoassay (EIA), complement fixation, and neu¬tralization tests (Kim and Poudel 2013). Serological diagnosis of influenza is based on the detection of a four-fold or greater rise in specific antibody titre in paired serum samples, measured by haemagglutination inhibition, EIA, complement fixation, or neutralisation tests.…”

“…Many test manufacturers highlights the use of cell culture to confirm the cases in which patients displaying clinical illness that were negative for influenza in rapid diagnostic tests (Kim & Poudel 2013).…”

“…The first PCR based assay in detecting influenza virus was described in 1991 by Zhang and Evans (Kim & Poudel 2013). Since then, many modifications and highly sensitive methods based on PCR have been developed.…”

“…When the H1N1 outbreak occurred in 2009, CDC recommended the use of one step RT-PCR technique targeting the matrix gene of H1N1 09, this technique involves the use of oligo-dT or randon primers for reverse transcription and using the HA gene as target in a single tube, which minimized the cost and time required to analyze the sample for each type and subtype of the influenza virus (Kim & Poudel 2013).…”

“…The oseltamivir is one of the most widely used drugs against influenza infec¬tion and the resistance arises due to histidine to tyro¬sine substitution in the neuraminidase active site (H275Y) (Kim and Poudel, 2013). It was noted that the H275Y mutation caused impaired growth of the viral strains leading to compromised viral fitness and hence, was of little clinical significance.…”