Science and curiosity: What is the kissing disease?

by Giuseppe Scarlata, Antonino Napoleone | November 18, 2021.
edited by Ivy Rose Sebastian.

Some memories remain etched in our minds despite the passage of time. Some of those unforgettable moments might include your first day of school, your first love and perhaps your first kiss. However, like these fleeting happy moments, we might have also shared a few unpleasant experiences as teenagers. Have you ever shared symptoms such as fever, sore throat, petechiae on the palate and swollen lymph nodes that resemble walnuts, with your partner? This would certainly not be a pleasant memory and that unpleasant experience could very well be the kissing disease. Why is it called the ‘kissing’ disease and how is it transmitted? Here are some interesting facts about infectious mononucleosis or otherwise commonly called the kissing disease.

It’s a virus!

The aetiological agent of infectious mononucleosis is the Epstein-Barr virus (EBV), a member of the gamma-herpesvirus family, which has a genome consisting of double-stranded DNA approximately 170 kilobases long (Figure 1). The primary transmission route of the virus is through direct contact with the saliva of an infected individual, which is why it’s called the kissing disease. It is estimated that EBV can infect 95% of the world’s population at some point in their lives. However, although EBV infection is generally asymptomatic, in 30-50% of cases it can present itself as infectious mononucleosis, which is a more prominent clinical syndrome, and predominantly affects adolescents and young adults between the ages of 15 and 24.

At a physiological level, the pivotal event that marks the beginning of the infectious process occurs at the ore-pharyngeal level when the virus binds to B lymphocytes, which are part of the leukocyte or white blood cell family and play a primary role in the immune system. Fortunately, the virus enters a latent phase, living in a dormant form within its host for its entire life and only reactivating itself in cases of severe stress. However, the uncontrolled proliferation of infected B lymphocytes can lead to rare but significant pathological events far more fatal than infectious mononucleosis, such as Burkitt’s lymphoma, meningitis, upper airway obstruction, encephalitis, or other neurological disorders. However, complications and more aggressive forms of infection mostly occur in immunocompromised individuals (e.g., cancer patients, HIV-positive individuals, hospitalised patients). Such patients also have a higher risk of developing fulminant EBV infection.

What are the symptoms of the kissing disease? 

The incubation period for infectious mononucleosis usually lasts around 4 to 6 weeks after exposure to the pathogen, leading to symptoms that are quite common with other infectious forms of herpes or influenza, such as fever, sore throat, fatigue, throat petechiae and especially swollen lymph nodes. The throat has a pus-like material in it (Figure 2), while 50% of subjects have hepatosplenomegaly (enlarged liver and spleen). Other rarer symptoms are meningitis, skin rashes, convulsions, anaemia, and airway obstruction.

Diagnosis and treatment

At the first sign of the symptoms, it is advisable to undergo a medical examination and then a simple blood test to detect the presence of specific antibodies to viral antigens by means of dedicated tests that can confirm the disease. For histopathological lesions, the in situ hybridization (ISH) of EBV-encoded RNA (EBER) in biopsy tissues remains the gold standard for detecting EBV. Methods such as the heterophile antibody test, immunofluorescence assays, enzyme immunoassays, Western blot, and polymerase chain reaction (PCR) are also employed in the detection of EBV in different types of samples. The determination of EBV viral load using PCR, however, is gaining more prominence in the diagnosis of EBV-associated diseases. Given the challenge of false positive/negative results that are sometimes experienced during the detection of EBV, variability in results from different laboratories, and the impact of factors such as sample type and the immunological status of patients, the need for further efforts from scientists is essential to optimise these present diagnostic methods. 

With regards to treatment, it is not necessary to break up with your partner, but it is true that there is no specific therapy. The patient must rest for the duration of the disease (about two to three weeks), hydrate and take painkillers to reduce pain. Although the symptoms of the disease are uncomfortable, the infection usually resolves on its own without long-term effects. In the presence of splenomegaly, it is highly recommended to minimise physical efforts and avoid sports or other activities that may cause the rupture of the spleen. The use of corticosteroids is recommended for more severe forms, while the use of antiviral drugs is still under investigation.

One last point

The spread of the virus can be prevented by avoiding contact with possible objects contaminated by the saliva of infected individuals and by practising good hygiene. Furthermore, since EBV is transmitted almost exclusively through saliva, it is advisable to avoid sharing cutlery or glasses with strangers in public places, restaurants, bars, or discos. It should be understood that this is not a sexually transmitted disease and that the main precautions to be taken are that one should be well informed and follow simple rules of personal hygiene. An important pointer: since it is not a bacterial infection, but a viral one, the kissing disease should not be treated with antibiotics!

References

1. https://www.cdc.gov/epstein-barr/about-mono.html 
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5. Bravender T. Epstein-Barr virus, cytomegalovirus, and infectious mononucleosis. Adolesc Med State Art Rev. 2010;21(2):251-ix.  
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7. AbuSalah, Mai Abdel Haleem et al. “Recent Advances in Diagnostic Approaches for Epstein-Barr Virus.” Pathogens (Basel, Switzerland) vol. 9,3 226. 18 Mar. 2020, doi:10.3390/pathogens9030226.