Where did mononucleosis come from?

Infectious mononucleosis (mono) or glandular fever is often called the kissing disease. The label is only partly true. Kissing can spread the virus that causes this disease, but more commonly coughing, sneezing, or sharing a glass or cup transmits mononucleosis. It's not highly contagious.

Mononucleosis is caused by the Epstein-Barr virus, although similar signs and symptoms are sometimes caused by cytomegalovirus. Full-blown mono is most common in adolescents and young adults. Young children usually have minimal symptoms, and the infection often goes unrecognized. In lesser developed countries, mononucleosis is more frequently acquired at a young age, so classic mono signs and symptoms aren't as common as in developed nations.

Mono usually isn't very serious, although the virus remains in your body for life. Most people have been exposed to the Epstein-Barr virus by the time they're 35 years old and have built up antibodies. They're immune and won't get mononucleosis again. Treatment mostly involves bed rest and getting adequate fluids.

IT IS CAUSED BY A HERPESVIRUS, KNOWN AS EIPSTEIN--BARR VIURS OR HUMAN HERPESVIRUS 4. IT COMES FROM AN ANIMAL, BUT NOBODY IS SURE WHICH. VIRUSES CLOSELY RELATED TO THE HUMAN EIPSTEIN BARR VIRUS IS FOUND IN MANY NEW AND OLD PRIMATES.
THIS COULD MEAN THAT THE VIRUS CAME FROM SOME OTHER ANIMAL INTO PRIMATES TENS OF MILLIONS OF YEARS AGO.