Cytomegalovirus (CMV) is a common human virus thought to affect over 50% of the population. It is common in childhood, and most people are unaware they have it. CMV is mainly spread through close contact with someone who already has the virus and is usually passed on through body fluids, including saliva, blood, and urine. Once you are infected, the virus will remain with you for the rest of your life but will usually be inactive. However, it can recur, especially in people with a weakened immune system. Some people may experience flu-like symptoms, but usually, the virus presents with no symptoms.