Caused by a common virus called herpes simplex (HSV-1), cold sores are contagious and can spread from person to person through skin-to-skin contact or by sharing items (such as eating utensils, lip balm, towels, cosmetics, and food), even when they aren't visible.
Infectious mononucleosis, or mono, refers to a group of symptoms usually caused by the Epstein-Barr virus (EBV). It typically occurs in teenagers, but you can get it at any age. People with mono often have a high fever, swollen lymph glands, and a sore throat.
In many people, the illness is mild, and may never be diagnosed as mono. Infection by EBV generally results in lifelong immunityâyou can only have EBV mono once. Thereâs also a less common form of mononucleosis, caused by infection by cytomegalovirus (CMV).In one study of people with mono, about one out of seven had mono caused by CMV; the rest had typical EBV mononucleosis.nfection by EBV generally results in lifelong immunityâyou can only have EBV mono once. Thereâs also a less common form of mononucleosis, caused by infection by cytomegalovirus (CMV). In one study of people with mono, about one out of seven had mono caused by CMV; the rest had typical EBV mononucleosis.