The disease known colloquially as “mono” or the “kissing disease” has probably been around since antiquity but was only recognized more recently. In 1880 Nil Filatov, a Russian pediatrician, described it as “idiopathic adenitis”. In 1888 Emil Pfeiffer reported it as an acute benign illness with characteristic lymphadenopathy in children and called it glandular fever or Drüsenfieber. The term “infectious mononucleosis” was coined by Thomas Sprunt and Frank Evans, published in the Bulletin of the Johns Hopkins Hospital in 1920, and characterized by the presence of atypical mononuclear cells in the blood. In 1932 Paul and Bunnell discovered that a serum from patients with infectious mononucleosis contains antibodies that cause erythrocytes of horses and sheep to clump, a finding of diagnostic utility. The disease, usually manifested as a syndrome of fever, pharyngitis, and adenopathy, it is still occasionally misdiagnosed as bacterial tonsillitis or pharyngitis. Unusual complications are legion. They include splenic rupture or infarction, abdominal pain, hepatitis, diarrhea, hemolytic anemia, thrombocytopenia, encephalitis, meningitis, cranial nerve palsies including Bell’s palsy, Guillain-Barré syndrome, airway obstruction, pneumonia, cardiomyopathy, and arrhythmias.

The discovery of the Epstein-Barr (EB) virus in 1964 by the British virologists Michael Anthony Epstein and Yvonne Barr allowed for more accurate diagnosis and management, as well as for further research. About 5–7% of cases of infectious mononucleosis are due to human cytomegalovirus (CMV), another type of herpes virus. In recent years, there has been increased interest in the use of vaccines to prevent this disease and other viral diseases.

While the Epstein-Barr virus is now recognized as the cause of infectious mononucleosis, the virus itself is believed to have been present in human populations for thousands of years. It is particularly prevalent in sub-Saharan Africa, where up to 90% of adults have been infected with the virus, which is also associated with other diseases such as Burkitt’s lymphoma and nasopharyngeal carcinoma. These diseases are more common in areas where the virus is endemic, and are thought to be also related to genetic and environmental factors.

Infectious mononucleosis can have a significant social impact due to its manner of transmission. It can be spread through the exchange of saliva, leading to concerns about its transmission in settings such as schools and universities, where close contact among students is common. By one month, most symptoms and signs and all laboratory tests will usually have returned to normal. Fatigue, cervical lymphadenopathy, pharyngitis, and functional health status may improve more slowly. Prolonged fatigue and malaise can last for months, leading to missed school or work, disrupted social plans, and significantly impacting a person’s quality of life.