| Description |
The influenza a virus (IAV) is a major source of human mortality and both recent and anticipated pandemics make understanding this major human pathogen of paramount importance1,2. The use of mouse models allows us to experimentally manipulate critical variables to more fully understand the dynamics that govern the evolution of influenza virulence and transimissibility3-5. It is generally accepted that host genetic makeup plays an important role in susceptibility to viral infection. We investigated how different mouse stains (BALB/c, C57BL/6, and DBA/2) interact with IAV under different modes of infection by inoculating mice with and without anesthesia, to assess how variable genetic backgrounds affect IAV infection under natural conditions. We also evaluated experimenter transmission versus natural transmission efficiency (infected mouse transmitting to "contact" mouse) by measuring viral titers and virulence (weight loss). Our findings unexpectedly indicate that after inoculation without anesthesia, DBA/2 mice-previously shown to be more susceptible to influenza - had lower titers than BALB/c and C57BL/6 mice under the same treatment6-8. Moreover, while most contact BALB/c and C57BL/6 mice had detectable titers, no contact DBA/2 mice showed signs of infection. Additionally, our results indicate unanticipated discordance between weight loss measurements and viral titers. We propose that the DBA/2 mice response could be due to its characteristic overactive immune system, which may be protective against low doses of IAV, despite these effects being detrimental at high doses; furthermore the lack of correlation between weight loss and viral titers could be attributed to variable host genetic backgrounds, which permit different viral replication rates and trajectories over time6. |
