What is Epstein-Barr Virus (EBV) and how is it related to ME/CFS?
Many individuals with ME/CFS state that an episode of infectious mononucleosis, i.e. glandular fever, preceded the development of their ME/CFS. Hence, it is no surprise that Epstein-Barr virus (EBV), the virus that causes infectious mononucleosis, has generated much interest in ME/CFS research.
How common is it?
Infection with EBV is incredibly common with most people (over 90% globally) being infected at some point in their life. However, only a subset of people infected will develop symptoms of infectious mononucleosis (e.g. fever, fatigue, sore throat, swollen glands), and symptoms varying in severity. Furthermore, an even smaller subset will develop chronic illness, including ME/CFS, following EBV infection.
How does it spread?
EBV is often referred to as ‘kissing disease’ because a primary way it spreads is through exchange of saliva. However, it is important to note that other close contact situations, such as sharing food and drink and utensils, allow for exchange of saliva and other body fluids thus passing on virus. EBV is also known as human herpesvirus 4 as it is one of nine viruses within the herpes family.
What is the underlying mechanism of infection?
EBV is a DNA virus, which means it carries genetic information in the form of DNA – a molecule which contains instructions for making proteins which are crucial for the functioning of the body. DNA viruses essentially enter cells and hijack the cell machinery forcing the cell to replicate viral DNA and make new viral proteins which assemble into new virus particles which are ready to infect other cells and continue the disease process.
Management and prognosis
There is no specific treatment for or vaccine against EBV, however medication can be given to relieve symptoms such as pain and fever. Antiviral medications, whilst decreasing viral replication in vitro, have not been found to be effective clinically.
Infectious mononucleosis is a self-limiting disease, from which most patients recover. However, the virus does not typically disappear from the body, rather in most people it remains in a latent phase where it persists in a dormant state primarily in B-cells (white blood cells which make antibodies).
Theories of how EBV relates to ME/CFS
Whilst EBV is not the only virus that has been linked with ME/CFS, there are several theories as to how EBV could be involved in the disease mechanisms of ME/CFS. These include:
- Immune Dysfunction – An EBV infection could lead to chronic immune activation or autoimmune responses contributing to the symptoms associated with ME/CFS.
- Viral reactivation – In individuals with ME/CFS, EBV may periodically reactivate leading to ongoing symptoms
- Genetic predisposition – Some individuals may have certain genetic variations related to immune pathways which increase the likelihood of developing ME/CFS following an EBV infection.
It is important to acknowledge that these are theories that require more research, and furthermore many researchers consider ME/CFS to be a multifactorial condition involving a complex interplay of many factors.
Additional comment on viruses and ME/CFS.
Current ME Research UK virus-centred projects
- Dr Amy Proal – Identifying viruses in tissue and nerve samples from ME/CFS patients
- Dr Bhupesh Prusty – Infectious triggers and mitochondrial dysfunction in ME/CFS
- Prof Elisa Oltra – The effect of activated HERVs and the associated immune response in severe ME/CFS
