There are several forms of Epstein–Barr virus (EBV) infection. These include asymptomatic infections, the primary infection, infectious mononucleosis, and the progression of asymptomatic or primary infections to: 1) any one of various Epstein–Barr virus-associated lymphoproliferative diseases such as chronic active EBV infection, EBV+ hemophagocytic lymphohistiocytosis, Burkitt's lymphoma, and Epstein–Barr virus positive diffuse large B-cell lymphoma, not otherwise specified); 2) non-lymphoid cancers such as Epstein–Barr virus associated gastric cancer, soft tissue sarcomas, leiomyosarcoma, and nasopharyngeal cancers; and 3) Epstein–Barr virus-associated non-lymphoproliferative diseases such as some cases of the immune disorders of multiple sclerosis and systemic lupus erythematosis and the childhood disorders of Alice in Wonderland Syndrome and acute cerebellar ataxia.
Symptoms
Symptoms of infectious mononucleosis are fever, sore throat, and swollen lymph glands. Sometimes, a swollen spleen or liver involvement may develop. Heart problems or involvement of the central nervous system occurs only rarely, and infectious mononucleosis is almost never fatal. There are no known associations between active EBV infection and problems during pregnancy, such as miscarriages or birth defects. Although the symptoms of infectious mononucleosis usually resolve in 1 or 2 months, EBV remains dormant or latent in a few cells in the throat and blood for the rest of the person's life. Periodically, the virus can reactivate and is commonly found in the saliva of infected persons. Reactivated and post-latent virus may pass the placental barrier in (also seropositive) pregnant women via macrophages and therefore can infect the fetus. Also re-infection of prior seropositive individuals may occur. In contrast, reactivation in adults usually occurs without symptoms of illness.
EBV also establishes a lifelong dormant infection in some cells of the body's immune system. A late event in a very few carriers of this virus is the emergence of Burkitt's lymphoma and nasopharyngeal carcinoma, two rare cancers. EBV appears to play an important role in these malignancies, but is probably not the sole cause of disease.
Most individuals exposed to people with infectious mononucleosis have previously been infected with EBV and are not at risk for infectious mononucleosis. In addition, transmission of EBV requires intimate contact with the saliva (found in the mouth) of an infected person. Transmission of this virus through the air or blood does not normally occur. The incubation period, or the time from infection to appearance of symptoms, ranges from 2 to 6 weeks with 4 weeks being the most common. Persons with infectious mononucleosis may be able to spread the infection to others for a period of weeks. However, no special precautions or isolation procedures are recommended, since the virus is also found frequently in the saliva of healthy people. In fact, many healthy people can carry and spread the virus intermittently for life. These people are usually the primary reservoir for person-to-person transmission. For this reason, transmission of the virus is almost impossible to prevent.
The clinical diagnosis of infectious mononucleosis is suggested on the basis of the symptoms of fever, sore throat, swollen lymph glands, and the age of the patient. Usually, laboratory tests are needed for confirmation. Blood test results for persons with infectious mononucleosis include an elevated white blood cell count, an increased percentage of atypical mononuclear cells. Liver enzymes are often elevated. A positive "mono spot" test is useful in confirming the diagnosis but a negative result does not rule out primary EBV infection.
EBV-associated diseases
Chronic active EBV infection
Epstein–Barr virus-associated lymphoproliferative diseases
Hodgkin's disease
Acute kidney injury
Alice in Wonderland syndrome
Common variable immunodeficiency (CVID) Hairy leukoplakia Hepatitis Herpangina Infectious mononucleosis Kikuchi's disease Multiple sclerosis (higher risk in patients infected as teenagers than as children) Nasopharyngeal cancer Several Non-Hodgkin's lymphomas, including Burkitt's lymphoma and primary cerebral lymphoma Post-transplant lymphoproliferative disorder Smooth muscle tumors Stevens–Johnson syndrome Subepithelial Infiltrates New daily persistent headache (NDPH)
Since EBV is present in most adults, then most adult diseases can be "associated" with EBV. However, since "association" is not "causation" (http://rafalab.dfci.harvard.edu/dsbook/association-is-not-causation.html), this list long list need not be of great concern.