CSF2 and viral infectious disease: Furthermore, many viral backbones are capable of accepting transgene insertions that can be used to facilitate real-time imaging (e.g., sodium iodide symporter [NIS]) to monitor viral infections or used to locally deliver a high concentration of a particular cytokine to augment the oncolytic effect (e.g., interferon alpha and granulocyte-macrophage colony-stimulating factor [GM-CSF]) [6,7,8].