1. A computer software product, comprising a non-transitory computer-readable storage medium having fixed therein a sequence of instructions which, when executed by a computer, direct the performance of a method which comprises: acquiring a first signal emitted by a fluorescent dye, excited by an incoherent light source, said dye bound to an infectious agent of interest contained in a monolayer of a biological sample smeared across an area of a microscope slide; detecting, quantifying, and recording the abundance of said first signal emitted by said fluorescent dye across a defined area of said smeared area; and acquiring a second signal indicative of a cell in said biological sample known to be a target of said infectious agent; detecting, quantifying, and recording the abundance of said second signal emitted across said defined area of said smeared area; and comparing said abundance of said first signal with abundance of said second signal emitted over said defined area in using such comparative information in combination with information relating to the physical or physiological state of said patient to determine a prognosis of susceptibility or diagnosis of a disease or disorder associated with said infectious agent.