Mononucleosis Support Group

Infectious mononucleosis (also known in North America as mono, the kissing disease or Pfeiffer's disease, and more commonly known as glandular fever in other English-speaking countries) is a disease seen most commonly in adolescents and young adults, characterized by fever, sore throat and fatigue. It is caused by the Epstein-Barr virus (EBV) or the cytomegalovirus (CMV). It is typically transmitted from asymptomatic individuals through saliva or blood, or by sharing a drinking glass, eating utensils, or needles. The disease is far less contagious than is commonly thought. Since the causative virus is also found in the mucus of the infected person, it can also spread through coughing or sneezing.

It is estimated that 90% of adults in the world have EBV-antibodies, having been infected with the Epstein-Barr virus at some point in their lives. The vast majority of infections do not result in the development of mononucleosis. The virus infects B cells (B-lymphocytes), producing a reactive lymphocytosis and the atypical T cells (T-lymphocytes). Early childhood infections often cause no symptoms. In developed countries with less crowded conditions and better hygiene, children do not commonly become infected until adolescence. Since they also typically begin dating at that age, the co-occurrence of mono and kissing have led to its being called the "kissing disease," although this is but one of its modes of transmission.

The disease is so-named because the count of mononuclear leukocytes (white blood cells with a one-lobed nucleus) rises significantly. There are two main types of mononuclear leukocytes: monocytes and lymphocytes. They normally account for about 35% of all white blood cells. With Mono, it can become 50-70% Also, the total white blood count increases 10000-20000 per cubic millimeter.

A person can be infected with the virus for weeks or months before any symptoms appear. Symptoms usually appear 4-7 weeks after infection, and may resemble strep throat or other bacterial or viral respiratory infections. These first signs of the disease are commonly confused with cold and flu symptoms. The typical symptoms and signs of mononucleosis are:

• Fever - this varies from mild to severe, but is seen in nearly all cases.
• Enlarged and tender lymph nodes - particularly the posterior cervical lymph nodes, on both sides of the neck.
• Sore throat - seen in nearly all patients with EBV-mononucleosis
• Fatigue (sometimes extreme fatigue)

Some patients also display:

• Enlarged spleen (splenomegaly, which may lead to rupture) or liver (hepatomegaly)
• Abdominal pain
• Aching muscles
• Headache
• Loss of appetite
• Jaundice
• Depression
• Weakness
• Skin rash

After an initial prodrome of 1-2 weeks, the fatigue of mono often lasts from 1-2 months. The virus can remain dormant in the B cells indefinitely after symptoms have disappeared, and resurface at a later date. Many people exposed to the Epstein-Barr virus do not show symptoms of the disease, but carry the virus and can transmit it to others. This is especially true in children, in whom infection seldom causes more than a very mild illness which often goes undiagnosed. This feature, along with mono's long incubation period, makes epidemiological control of the disease impractical. About 6% of people who have had mono will relapse.

Mononucleosis can cause the spleen to swell, which in rare cases may lead to a ruptured spleen. Rupture may occur without trauma, but impact to the spleen is usually a factor. Other complications include hepatitis (inflammation of the liver) causing jaundice, and anemia (a deficiency of red blood cells). In rare cases, death may result from severe hepatitis or splenic rupture.