Diagnostic tests are used to confirm infectious mononucleosis, but the disease should be suspected from symptoms prior to the results from hematology. Infectious mononucleosis occurs with infection by the Epstein-Barr virus. A similar condition can be caused by cytomegalovirus, but that one gives a negative on the heterophile antibody test.
Infectious mononucleosis (mono) is a contagious illness caused by the Epstein-Barr virus (EBV).
The infection can be spread by saliva, and the incubation period for mono is four to eight weeks.
Most adults have laboratory evidence (antibodies against the EBV) indicative of a previous infection with EBV and are immune to further infection.