Epstein–Barr virus About 90% of cases of<unk>  are caused by the Epstein–Barr virus, a member of the Herpesviridae family of DNA viruses. It is one of the most commonly found viruses throughout the world. Contrary to common belief, the Epstein–Barr virus is not highly contagious. It can only be contracted through direct contact with an infected person's saliva, such as through kissing or sharing toothbrushes. About 95% of the population has been exposed to this virus by the age of 40, but only 15–20% of teenagers and about 40% of exposed adults actually become infected. Cytomegalovirus About 5% to 7% of cases of<unk>  is caused by human cytomegalovirus (CMV), another type of herpes virus. This virus is found in body fluids including saliva, urine, blood, and tears. A person becomes infected with this virus by direct contact with infected body fluids. Cytomegalovirus is most commonly transmitted through kissing and sexual intercourse. It can also be transferred from an infected mother to her unborn child. This virus is often "silent" because the signs and symptoms cannot be felt by the person infected. However, it can cause life-threatening illness in infants, people with HIV, transplant recipients, and those with weak<unk> mune systems. For those with weak<unk> mune systems, cytomegalovirus can cause more serious illnesses such as pneumonia and inflammations of the retina, esophagus, liver, large intestine, and brain. Approximately 90% of the human population has been infected with cytomegalovirus by the time they reach adulthood, but most are unaware of the infection. Once a person becomes infected with cytomegalovirus, the virus stays in their body fluids throughout the person's lifetime. Transmission Epstein–Barr virus infection is spread via saliva, and has an incubation period of four to seven weeks. The length of time that an individual remains contagious is unclear, but the chances of passing the illness to someone else may be the highest during the first six weeks following infection. Some studies indicate that a person can spread the infection for many months, possibly up to a year and a half.
Infectious mononucleosis
Chronic lymphocytic leukemia
Adult-onset Still's disease
Streptococcal pharyngitis
Post-Ebola virus syndrome
Acute lymphoblastic leukemia
Typhoid fever
Peritonsillar abscess