Visualizing Viral and Host Processes Using Fluorescence Microscopy

Virus infections unfold through spatially organized events whose timing and progression vary among individual cells. Imaging complements population-based approaches by preserving spatial context and, in live experiments, temporal progression at single-cell and tissue scales. This review examines how imaging has advanced our understanding of virus infection, using influenza A virus (IAV) as the principal example. The review is organized around three complementary perspectives: visualization of viral components throughout infection, analysis of virus-induced host-cell and tissue remodeling, and investigation of heterogeneous antiviral responses. Together, these perspectives show how imaging preserves the spatial, temporal, and cell-to-cell context needed to relate viral processes to host-cell responses across scales. Because imaging approaches differ in what they directly measure, this review considers their complementary strengths and limitations and distinguishes descriptive observations from mechanistic conclusions.