Fluorescence In Situ Hybridization (FISH) probes have been used to detect specific viral sequences in fixed and permeabilized viral preparations . However, such probes are not fluorogenic and need wash steps which limits their applicability for real-time tracking studies. Molecular beacons are fluorogenic oligonucleotide probes which turn on in fluorescence upon hybridizing with target nucleic acid sequences . But it is not obvious whether the complementary sites on the viral RNA will be accessible to such probes since the viral RNA typically remains bound to proteins. Moreover, to encapsulate even a few (<10) copies of molecular beacons inside target vesicles (~100 nm in diameter), one needs to start with at least tens of micromolar of the probe in the hydration solution which may pose practical challenges such as high cost. Simple nucleic acid-binding fluorogenic dyes may be advantageous in situations where detection of any viral nucleic acid is desirable. In this work, we systematically screened many commercially available nucleic-acid binding dyes to evaluate the feasibility of their use in microscopy-based viral content transfer experiment as illustrated in Figure . The RNAbinding dye QuantiFluor offered the most optimal physico-chemical (brightness and photostability) characteristics for this experiment. Using fluorescence microscopy, we probed the kinetic aspects of virus-vesicle fusion events on a single particle level. Using super-localization microscopy and a novel fusion geometry introduced below, we probed the pattern of distribution of viral contents within the fused volume to determine the efficiency of content transfer through the fusion pore. Taken together, we show that our method is applicable for semi-quantitative estimation of viral infectivity and efficiency of endosomal escape in a straightforward, cell-free manner.