It was shown that the interaction of microglia with amyloid-beta plaques enhances the microglial reactivity (Mandrekar-Colucci and Landreth, 2010), therefore to identify the association between increased microglial activation in the H3N2 IAV infected APP/PS1 mice and amyloid-β accumulation during the progression of AD, the amyloid-β plaque load was examined using Congo-red staining (Figures 2D,E). This evidence concerns the gene APP and Alzheimer disease.