Medical Microbiology and Immunology - Hardcoverby Addison Boyd (Editor) Microbiology refers to the scientific study of microorganisms, such as viruses, fungi and bacteria. One of the subsets of microbiology is medical microbiology, which is focused on the prevention, diagnosis and treatment of various infectious diseases. It studies microbes for finding out their clinical applications to improve human health. Immunology is a branch of biology and medicine, which includes the study of immune