Author Interviews, Biomarkers, Flu - Influenza, Infections / 01.11.2017
Defective Viral Genomes May Indicate Greater Flu Virus Severity
MedicalResearch.com Interview with:
Ana Falcón
Department of Molecular and Cellular Biology
National Center for Biotechnology
Spanish National Research Council (CNB-CSIC)
Madrid, Spain
MedicalResearch.com: What is the background for this study?
Response: Influenza A virus (IAV) infection can be severe or even lethal in toddlers, the elderly and patients with certain medical conditions. Infection of apparently healthy individuals nonetheless accounts for many severe disease cases and deaths, suggesting that viruses with increased pathogenicity co-circulate with pandemic or epidemic viruses.
IAV virulence and pathogenesis are dependent on complex, multigenic mechanisms involving the viral genetic characteristics, the host conditions, the virus-host interactions, and the host response to the infection. Influenza virus pathogenicity has been studied in depth for many years, and several amino acid changes have been identified as virulence determinants, however, a general pathogenicity determinant has not been characterized.
A proportion of influenza virus particles have defective genome RNAs (Defective Viral Genomes-DVGs) due to internal deletions of viral segments. The DVGs have the 3’ and 5’ ends of the parental RNA segments, and most have a single, large central deletion that generates viral RNAs of 180–1000 nucleotides. The presence of DVGs potentiates the host response in cultured cells and in animal models and leads to attenuated infection, possibly through recognition of double-stranded RNA by receptors that activate antiviral signaling cascades.
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