Mononucleosis

Mononucleosis, also known as infectious mononucleosis (IM), mono, or glandular fever is a contagious disease most common in teenagers and young adults. It is most commonly spread through bodily fluids, especially saliva.

Causative agents
Epstein-Barr virus (EBV) is the most common cause of infectious mononucleosis (IM), making up approximately 90% of those diagnosed, but other infectious agents, such as cytomegalovirus, toxoplasmosis gondii parasite, HIV (human immunodeficiency virus), rubella virus, hepatitis A, B, or C viruses, and adenovirus can cause this disease.

Although Epstein-Barr virus is the most common cause of infectious mononucleosis, the majority of people infected with EBV never develop mononucleosis. It is estimated that 80% - 90% of the worldwide population is infected with EBV.

Symptomology
Illness duration can vary from several weeks to several months and may include the following symptoms:
 * extreme fatigue and malaise
 * fever, sweating and chills
 * sore throat
 * head and body aches
 * swollen lymph nodes in the neck and armpits
 * swollen liver or spleen or both
 * rash, usually resolving in several days

Treatment
Treatment is mainly supportive: rest, plenty of fluids, analgesics, and antipyretics. A vaccine for the prevention of Epstein-Barr virus is being explored.

Trigger for chronic fatigue syndrome
A minority of infectious mononucleosis patients develop postviral fatigue syndrome and meet the criteria for chronic fatigue syndrome (CFS). Research studies cite figures from 12% to 24% of healthy people who contract infectious mononucleosis will have the illness progress into chronic fatigue syndrome (CFS). In a 2013 study by Jason and Katz, thirteen percent of adolescents (mainly female) met the criteria for CFS 6 months following infectious mononucleosis; the figure was 7% at 12 months and 4% at 24 months. A year later, Jason and Katz looked at numerous medical, demographic, and psychological factors in an effort to find predictors of which infectious mononucleosis patients would develop chronic fatigue syndrome. They found the best predictor was the illness severity of the case of infectious mononucleosis.

In 2019, Katz et al. found that severity of mononucleosis predicted risk of CFS six months post-infection.

Studies relating to infectious mononucleosis and ME/CFS

 * 2000, Acute infectious mononucleosis: Characteristics of patients who report failure to recover
 * 2006, Post-infective and chronic fatigue syndromes precipitated by viral and non-viral pathogens: Prospective cohort study
 * 2007, Gene expression correlates of postinfective fatigue syndrome after infectious mononucleosis
 * 2009, Chronic fatigue syndrome after infectious mononucleosis in adolescents. (Full Text)
 * 2014, Predictors of post-infectious chronic fatigue syndrome in adolescents
 * 2016, Tracking post-infectious fatigue in clinic using routine Lab tests
 * 2017, A Prospective Study of Infectious Mononucleosis in College Students
 * 2019, A Validated Scale for Assessing the Severity of Acute Infectious Mononucleosis (Abstract)