Mononucleosis Mononucleosis is an infectious disease found in humans, in which the blood and tissues contain mononuclear leukocytes. These are white blood cells with only one nucleus, either monocytes or lymphocytes. An infectious disease is a disease that can give you an infec...

A virus is an ultramicroscopic infectious organism that, having no independent metabolic activity, can replicate only within a cell of another host organism. A virus consists of a core of nucleic acid, either RNA or DNA, surrounded by a coating of antigenic protein and sometimes a lipid layer surr...