We know that pigs and people are quite capable of harbouring influenza A viruses of swine. human and avian origin in their respiratory tracts. This adaptability allows for a host carrying multiple viruses at the same time and this may facilitate the generation of “novel” influenza viruses with pandemic potential through genetic reassortment between the comingled viruses. These researchers wanted to investigate the effect of viral component sourcing on virulence of the newly generated influenza virus .
The researchers found the following:
- two distinct H1N2 swine influenza viruses containing avian-like or classical swine-like hemagglutinins with polymerase acidic (PA) and nucleoprotein (NP) genes from 2009 pandemic H1N1 influenza viruses were found to be circulating in Korean pigs in 2018.
- Swine H1N2 influenza virus containing an avian-like hemagglutinin gene produced enhanced pathogenicity and caused severe interstitial pneumonia in infected pigs and mice.
- The mortality rate of mice infected with swine H1N2 influenza virus containing an avian-like hemagglutinin gene was higher by 100% when compared to that of mice infected with swine H1N2 influenza virus harbouring classical swine-like hemagglutinin.
- Inflammatory messengers such as chemokines attracting inflammatory cells were strongly induced in lung tissues of pigs and mice infected by swine H1N2 influenza virus containing an avian-like hemagglutinin gene.
Take Home Messages:
- Comingling of muItiple influenza type A virus isolates has the potential to generate novel influenza viruses
- Certain combinations of genetic components of the influenza have the potential to increase the capability to cause disease when avian-like hemagglutinin with PA and NP genes from 2009 pandemic H1N1 influenza viruses are combined.
Ref: Jang Y, Seo T, Seo SH. Higher virulence of swine H1N2 influenza viruses containing avian-origin HA and 2009 pandemic PA and NP in pigs and mice. Arch Virol. 2020 Mar 28. doi: 10.1007/s00705-020-04572-z. [Epub ahead of print]