Mononucleosis risk factors

Overview
Majority of the population become infected with EBV at sometime during their lives with an estimated 90%-95% of adults demonstrating seropositivity by 21 years of age. Therefore, even individuals exposed to infected contacts have shown to be previously infected with EBV and hence are not at risk for the manifestation of mononucleosis.

However, once infected, the patient carries the virus for the rest of their life with the virus typically residing dormantly in the B lymphocytes. Independent infections of mononucleosis may be contracted multiple times, regardless of whether the patient is already carrying the virus dormantly.

Periodic reactivation of the virus may occur, during which time the patient is again infectious, but usually without any symptoms of illness. Therefore, in susceptible hosts under the appropriate environmental stressors, reactivation of the virus occurs to cause vague subclinical symptoms or remain mostly asymptomatic and diagnosed only by a positive serologic response. However, its imperative to note that during this phase the virus can spread to others.

By Epidemiology:

 * It is predominantly found in under-developed countries, and almost everyone is exposed to the ebstein barr virus by 18 months of age. Therefore, even individuals exposed to infected contacts are not at risk for the manifestation of the disease. Additionally, antibody to the virus is almost universally positive.


 * In the United States, roughly half of five-year-olds have been infected and up to 95% of adults between 35 and 40 years of age.

By Age:

 * Infants become susceptible to EBV as soon as maternal antibody protection which is present at birth starts to disappears.


 * Children if infected with EBV usually remain asymptomatic and hence are indistinguishable from the other mild, brief illnesses of childhood. However, when the infection occurs during adolescence or young adulthood, it causes acute infectious mononucleosis 35% to 50% of the time.


 * Among adults, increased risk of acquiring mononucleosis is observed among:
 * adolescents and young adults
 * patients who have intimate contact with the saliva of an infected person
 * contact with the airborne virus

By Immune system status:

 * Any condition that weakens the immune system is a predisposing factor for the development of mononucleosis secondary to EBV infection. Such states include:
 * Diabetes
 * Following solid organ transplant
 * Chemotherapy
 * HIV

Genetic susceptibility:

 * A recent twin study done to assess the genetic susceptibility to infectious mononucleosis demonstrated results compatible with a heritable contribution to the risk of acquiring mononucleosis.