Mononucleosis is a contagious viral illness caused by the Epstein Barr virus that initially attacks on the lymph nodes in the neck and throat. In this disease unusual proliferation of lymphocytes takes place; causing high temperature, sore throat, and swollen lymph glands, especially in the neck (when causedby the cytomegalovirus).

Mononucleosis is caused due to the Epstein-Barr virus. The disease develops if the virus is encountered for the first time at early adult life. The peak incidence of illness occurs around ages of 15 and 17. Mononucleosis spreads by moisture contact with mouth and throat in case if person is infected with the virus, also due to kissing; sharing drinking glasses, eating utensils, and toothbrushes, or touching anything that has been near the mouth of an infected person, may result in transmission of the disease.

Infectious mononucleosis can be contagious if the infected person comes in close or intimate contact with another person. Avoid kissing or sharing utensils  for preventing the disease.Since the infection is probably spread by saliva or through sexual contact, kissing or other transfer of oral secretions and sexual contact with an infected person should be avoided.