Thursday, July 31, 2014

Epstein-Barr Virus

Definition

Epstein-Barr Virus (EBV) is a common human virus that causes infectious mononucleosis and plays a role in the emergence of two rare forms of cancer: Burkitt's lymphoma, and nasopharyngeal carcinoma.

Some doctors and medical textbooks describe and diagnose EBV as infectious mononucleosis and vise-versa. To accommodate this association, this health profile will use EBV and mononucleosis ("mono") interchangeably.

Description

Epstein-Barr virus is in the herpes family of viruses and most people will become infected with EBV sometimes during their lives. In the United States, as many as 95 percent of adults between 35 and 40 years of age have been infected. Infants become susceptible to EBV as soon as maternal protection present at birth disappears.

Causes

Infectious mononucleosis, or "mono," is a contagious viral illness that initially attacks the lymph nodes in the neck and throat. When these tissues become less effective in fighting infection, sore throats, swelling of the nodes and fever may result.

Mono is caused by the Epstein-Barr virus, which is named after the scientists who first identified it in the mid-1960s. The virus enters the lymph nodes and attacks the lymphocytes (the white blood cells manufactured there). As the white blood cells come into contact with the virus, they change shape and multiply. At first, there are no symptoms because it takes several weeks before enough of the altered cells can accumulate to generate infection.

The virus can affect anyone, but the infection most often occurs in people between the ages of 10 and 35, especially teenagers. It can occur as an epidemic or in single cases, and it is believed to be spread by infectious saliva.

The incubation period for the disease is usually seven to 14 days in children and adolescents. The incubation period in adults is longer; at times it may be 30 to 50 days.

If the virus lasts more than six months, it is frequently called chronic EBV infection. Some doctors think EBV is the cause of a chronic condition called Chronic Fatigue Syndrome (CFS), although this has not been definitively proven.

Mononucleosis spreads by contact with moisture from the mouth and throat of a person who is infected with the virus. Kissing, sharing drinking glasses, eating utensils, and toothbrushes, or touching anything that has been near the mouth of an infected person, may result in transmission of the disease.

Symptoms

The infection develops slowly with such mild symptoms that it may initially be indistinguishable from a cold or the flu. As the condition progresses the symptoms may include:

  • A sore throat that lasts two weeks or more
  • Swollen lymph nodes in the neck, armpits, and groin
  • A persistent fever (usually about 102 degrees F)
  • Fatigue
  • Malaise (a vague feeling of discomfort)

These symptoms can be mild or so severe that throat pain impedes swallowing and fever reaches 105 degrees F. Some people also experience a rash, eye pain, photophobia (discomfort with bright light), a swollen spleen or liver infection.

Although the symptoms of infectious mononucleosis usually resolve in one or two months, the EBV remains dormant in cells in the throat and blood for the rest of the person's life. Periodically, the virus can reactivate and can be 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.

Diagnosis

Diagnosis is suggested on the basis of the clinical symptoms of fever, sore throat, swollen lymph glands and the age of the patient. A physical examination may reveal an enlarged liver and/or enlarged spleen. The liver and spleen may also be tender. Laboratory tests may be needed for confirmation.

Blood findings with infectious mononucleosis may include an elevated white blood cell count, an increased percentage of certain white blood cells and a positive reaction to a "monospot test." The monospot test relies on clumping of horse red blood cells by mononucleosis antibodies presumed to be in a person's serum.

Antibody tests for EBV measure the presence and/or the concentration of specific EBV antibodies. Different laboratory tests can measure specific EBV antibodies. Some of these tests can be performed on a single sample of blood, while others compare different samples of blood over a period of time.

Treatment

In most cases of mononucleosis, no specific treatment is necessary. The illness is usually self-limited. Since it is a viral infection and viruses do not respond to antibiotics, they are ineffective against mono. Doctors will recommend bedrest and drinking plenty of fluids.

When the patient's temperature returns to normal, he or she may gradually resume normal activities as strength returns. However, mono can be accompanied by a streptococcal infection of the throat, in which case an antibiotic will be prescribed to treat that condition.

In severe cases, corticosteroid drugs that reduce swelling are prescribed. If the spleen is swollen, the doctor may recommend avoiding strenuous activities, such as lifting and pushing, as well as any contact sports, which may cause sudden rupture of the spleen. Hospitalization is necessary if there is a serious complication, such as rupture of the spleen.

Questions

Could these symptoms be mimicking any other infectious disease?

Does any lab work need to be done to confirm EBV?

What are the chances this could lead to some other major complication or illness?

How will you know if the spleen has been affected?

How long is bedrest recommended?

When do the symptoms usually subside?

How long does the contagious period last?

What precautions should be taken to minimize this disease being passed on to others?

What are the chances that family members will be affected by this virus?