Hi!
Actually cytomegalovirus can spread even from hand to mouth contact, by kissing, etc. It is one of the diseases that are known to be transmissible by kissing, or by other direct or indirect oral contact, like sharing a glass or cigarette. It can cause illness even in immune-competent people. Once infected, the virus remains in body for life and usually remains dominant. The infection flares when the immunity is compromised due to any illness or dieting, stress etc. So, while you may be immune-competent, the CMV infection can flare during above mentioned conditions. Also positive IgG indicates past infection. If your IgM for CMV is normal, it should mean that the current symptoms are not due to CMV. Please also discuss with your doctor. Take care!
The medical advice given should not be considered a substitute for medical care provided by a doctor who can examine you. The advice may not be completely correct for you as the doctor cannot examine you and does not know your complete medical history. Hence this reply to your post should only be considered as a guiding line and you must consult your doctor at the earliest for your medical problem.