The Epstein-Barr virus (EBV) causes infectious mononucleosis, also referred to as "mono" and the "kissing disease." The viral infection transfers from person to person through saliva or through close contact with an infected individual. The most common age group to have mono is between the ages of 15 and 25, according to KidsHealth, a service provided by The Nemours Foundation. Treatment for the virus includes rest and focuses on relieving symptoms. Physicians may suspect mono based on symptoms, but a blood test helps diagnose the condition.
Most individuals infected with mono experience general feelings of sickness and extreme fatigue. These symptoms begin about a month to six weeks after exposure to the virus, according to the American Academy of Family Physicians. Although an individual with fatigue feels the need to sleep, the condition includes more than just feeling tired. A person with fatigue lacks motivation to participate in activities and may experience weakness. The fatigue may last for several weeks or months with a mono infection.
After several days to a week of general illness and fatigue, an individual with mono may develop a fever. The fever can reach 103 degrees F, according to the Merck Manual of Medical Information. The fever is most common in the late afternoon and early evening.
A sore throat typically accompanies the fever and fatigue. Some people may mistake the mono virus for the flu virus based on the initial symptoms. Pus in the back of the throat and swollen tonsils may accompany the pain. A physician may prescribe antibiotics based on these symptoms, but the sore throat will not clear up with medication. A sore throat may last for several weeks with the virus.
Swollen Lymph Nodes
Lymph nodes, small masses of lymphatic tissue, help signify an infection in the body. The lymph nodes in the neck may swell and become painful during a mono infection. Although the neck lymph nodes swell most often with a mononucleosis infection, any lymph node in the body may swell during the course of the virus. For some individuals, swollen lymph nodes in the body are the only symptom of mono. Swollen lymph nodes may last for a few weeks or longer.
About 50 percent of individuals infected with mononucleosis experience an enlarged spleen, according to the Merck Manual. The function of the spleen is to destroy old red blood cells, trap white blood cells and store extra blood for the body. The spleen, located under the left side of the ribcage, has a greater chance of rupture once enlarged. An enlarged spleen may cause tenderness when pressed, or it may not cause any symptoms.