Epstein-Barr Virus.

The Epstein-Barr virus is a member of the Herpes family and
the most common human virus.
The virus is world wide with most people becoming infected at
some
point.
In the United States of America, 95% of adults aged between
35-40 years old become infected. When infection takes place
in adolescence or young adults it causes Infectious
mononucleosis (glandular fever).

Unlike Infectious mononucleosis EBV remains dormant or latent
in a few cells in the throat and also in the blood, for the
rest of that person's life.  EBV also establishes a life long
dormant infection in some cells of the bodies' immune system.
A late event in a very few carriers of this virus is the
emergence of Burkett's Lymphoma.

Burkett's Lymphoma

Burkett's lymphoma is a (non-Hodgkin's) cancer of the
lymphatic system.
The B-Cell which is involved in this case grows in the bone
marrow and continues to develop there (unlike the T-Cell).
This type of lymphoma is very common in children living in
Africa. Many of the children caught Chronic Malaria which
reduced their immunity towards E.B.V. and I.M.
In some cases the infected cells changed into cancerous
cells, leading to the development of the lymphoma.