A sore throat accompanied by severe fatigue can be caused by an Epstein-Barr virus infection, an illness referred to as mononucleosis. Mononucleosis is often called "the kissing disease" because the virus is most often transmitted through contact with infected saliva. Mononucleosis can also be spread through airborne particles that are released during a cough or sneeze or by sharing utensils with an infected person. MayoClinic.com notes that mononucleosis is not as contagious as other infections, such as the common cold.
Symptoms of mononucleosis usually appear gradually and begin with severe fatigue, malaise, headache and a sore throat. As the infection spreads, the sore throat will become increasingly worse and the tonsils may develop a whitish covering on the surface. The lymph nodes also become swollen. Other symptoms of mononucleosis include drowsiness, fever, loss of appetite, muscle aches and rash.
Because antibiotics are ineffective against viruses, there is no specific treatment for mononucleosis. The infection is usually allowed to run its course. Home-care strategies focus on relieving symptoms until the infection goes away. Increased fluid intake, adequate bed rest, saltwater gargles, throat lozenges and popsicles may help reduce the severity of symptoms and speed up healing. Over-the-counter pain relievers and fever reducers may help relieve sore throat and reduce fever.
Most cases of mononucleosis go away without the development of any serious health problems. Medline Plus notes that fever associated with mononucleosis generally subsides in approximately 10 days. The sore throat and swollen lymph nodes heal in about 4 weeks. Other symptoms, such as fatigue, can last for 2 to 3 months.
Mononucleosis can cause the spleen to become enlarged. In some cases, the spleen can rupture, which causes intense pain and requires immediate medical attention. Mononucleosis can also cause inflammation of the liver and jaundice, which is a yellow tint of the skin and whites of the eyes. Less commonly, mononucleosis can lead to anemia, inflammation of the heart, or thrombocytopenia, which is a decrease in the number of blood platelets.
Because mononucleosis causes enlargement of the spleen, it is important to avoid sports, exercise and physical activity. Partaking in these activities puts the affected individual at an increased risk of rupturing the spleen. The American Academy of Family Physicians notes that physical activity should be avoided for approximately 3 to 4 weeks after mononucleosis.