Microbe TV (A continuous video presentation introduces visitors to the variety of microbes.) Microbe is a word that means "small life." And that's just what microbes are: tiny bits of life, so tiny they're invisible to the naked eye. Different kinds of microbes include bacteria, protozoa viruses, and fungi. People sometimes call microbes "germs," because microbes cause diseases such as AIDS, tuberculosis, the flu, the common cold, and many more. But 'germ' doesn't do microbes justice, because they're much, much more than just agents of disease.