Products, compositions, systems, and methods for treating a subject carrying avirus or bacterium. The methods maybe performed in situ in a non-invasive manner by application of an initiationenergy to the subject thus producing an effect on orchange to a target structure of the subject directly or indirectly. Themethods may further be performed by application of an initiationenergy to a subject to activate within the subject a photoactivatable drugdirectly or indirectly, optionally in the presence of one ormore plasmonics active agents, thus treating the virus or bacterium. Alsoprovided are kits containing products or compositions formulatedor configured and systems for use in practicing these methods.
