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==Cause==
==Cause==
*The name mononucleosis comes because the number of  [[white blood cells|mononuclear leukocytes]] (WBCs with one-lobed nucleus) rises significantly and is caused by [[EBV|Epstein Barr virus]].  
[[EBV|Epstein-Barr virus]] is ubiquitous across the globe and the strongest causative agent for the manifestation of [[infectious mononucleosis]]. Commonly, a person is first exposed to the virus during or after adolescence. Though once deemed ''The Kissing Disease,'' recent research has shown that transmission of mononucleosis not only occurs from intimate contact with infected saliva, but also from contact with the airborne virus.  


*There are two main types of mononuclear leukocytes: [[monocyte|monocytes]] and [[lymphocyte|lymphocytes]]. Normal [[Reference_ranges_for_blood_tests#Hematology|blood values]] are 35% of all [[white blood cells]]. With infectious mononucleosis, this can rise to 50-70%. Also, the total white blood count may increase to 10,000-20,000 per cubic millimeter (normally 4,000-11,000).
'''''For more information on the virus, click [[Epstein Barr virus|here]]'''''
 
*[[EBV]] infects [[B cell|B-lymphocytes]], producing a [[lymphocytosis|reactive lymphocytosis]] and [[T cell|atypical T-lymphocytes]] known as Downey bodies.


==Diagnosis==
==Diagnosis==

Revision as of 16:36, 19 December 2012

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Overview

Epstein-Barr virus, frequently referred to as EBV, is a member of the herpesvirus family and one of the most common human viruses.

Epidemiology and Demographics

Majority of mononucleosis syndromes are caused by Epstein-Barr virus, and most people become infected with EBV sometime during their lives with an estimated 90%-95% of persons greater than 21 years of age demonstrating antibody to EBV.[1][2]

In the United States, the disease occurs most often among older children and young adults; however, in certain socioeconomically depressed areas the infection affects young children who remain asymptomatic.

Additionally, the dormant feature combined with long (4 to 6 week) incubation period of the disease, makes epidemiological control of the disease impractical.

Pathophysiology

Epstein-Barr virus, frequently referred to as EBV, is a member of the herpesvirus family that targets oro-pharyngeal epithelium and B cells. Transmission of the EBV through the air or blood does not normally occur. The incubation period, or the time from infection to appearance of symptoms, ranges from 4 to 6 weeks. 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.

Cause

Epstein-Barr virus is ubiquitous across the globe and the strongest causative agent for the manifestation of infectious mononucleosis. Commonly, a person is first exposed to the virus during or after adolescence. Though once deemed The Kissing Disease, recent research has shown that transmission of mononucleosis not only occurs from intimate contact with infected saliva, but also from contact with the airborne virus.

For more information on the virus, click here

Diagnosis

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. Serologic results for persons with infectious mononucleosis include an elevated white blood cell count, an increased percentage of certain atypical white blood cells, and a positive reaction to a mono spot test.

History and Symptoms

  • Symptoms of infectious mononucleosis include:
  • 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.

Treatment

  • There is no specific treatment for infectious mononucleosis, other than treating the symptoms.
  • No antiviral drugs or vaccines are available.
  • 5-day course of steroids may be used to control the swelling of the throat and tonsils. The use of steroids has also been reported to decrease the overall length and severity of illness, but these reports have not been published.[2]

Prognosis

  • 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. This reactivation 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 that are not normally found in the United States. EBV appears to play an important role in these malignancies, but is probably not the sole cause of disease.
  • Symptoms related to infectious mononucleosis caused by EBV infection seldom last for more than 4 months. When such an illness lasts more than 6 months, it is frequently called chronic EBV infection. However, valid laboratory evidence for continued active EBV infection is seldom found in these patients. The illness should be investigated further to determine if it meets the criteria for chronic fatigue syndrome. This process includes ruling out other causes of chronic illness or fatigue.

Resources

CDC Mononucleosis

References

  1. Henle G, Henle W, Clifford P, Diehl V, Kafuko GW, Kirya BG, Klein G, Morrow RH, Munube GM, Pike P, Tukei PM, Ziegler JL (1969). "Antibodies to Epstein-Barr virus in Burkitt's lymphoma and control groups". Journal of the National Cancer Institute. 43 (5): 1147–57. PMID 5353242. Unknown parameter |month= ignored (help); |access-date= requires |url= (help)
  2. Pereira MS, Blake JM, Macrae AD (1969). "EB virus antibody at different ages". British Medical Journal. 4 (5682): 526–7. PMC 1630375. PMID 4902364. Unknown parameter |month= ignored (help); |access-date= requires |url= (help)


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