Virus that infects almost all Americans can trigger devastating health condition

Stanford scientists claim to have solved a longstanding medical mystery about what causes a well-known chronic autoimmune disease - and it is a virus that affects nine in every ten Americans at some point in their life.

Often called the 'kissing disease', a contagious bug known for spreading by saliva and causing 'mono', the Epstein-Barr virus (EBV) is incredibly widespread and can lay dormant in your system for years before reactivating to trigger swollen glands, a fever, and a headache.

But a Stanford study claims this common infection, which infects half of us by the time we are five, could in fact be the cause for lupus, a debilitating chronic condition that causes extreme fatigue, aches, and rashes, and counts Lady Gaga and Nick Cannon among its sufferers.

This autoimmune condition has long perplexed the medical community, with many of its symptoms mimicking other diseases which also makes it difficult to diagnose. Despite being first identified in 1904, there is no known cure or specific lupus treatment.

A facial rash is one of lupus' visible symptoms (Olga Shefer/Getty Images)

In their groundbreaking study, Stanford Medicine investigators examined whether EBV was working as a trigger for the condition, changing the function of a small number of immune cells that help to fight off infection, called B cells.

Through complicated genetic analysis, they found that EBV infects these B cells, effectively commandeering them and causing them to attack tissue in every part of the body, in ever greater numbers - potentially solving the century-long mystery of lupus' origins.

The Stanford team managed to trace the source of EBV's effect on the immune cells to a viral protein called EBNA2, which they believe plays a role in triggering lupus' extreme autoimmune response.

The study's senior author, immunology Professor William Robinson MD, called it 'the single most impactful finding to emerge from my lab in my entire career,' and confidently added that the team thinks that it 'applies to 100% of lupus cases'.

Around one million Americans are thought to live with lupus, which results in damage throughout the body, causing particular issues with your skin, joints, kidneys, heart and nerves.

Lupus can make every day activities more difficult due to joint and muscle pain (Olga Pankova/Getty Images)

This is a result of rogue B cells creating antibodies that target and destroy the nuclei of your own cells, rather than the dangerous pathogens they are meant to fight off. This becomes a systemic problem as basically all cells in your body contain a nucleus.

Most people will experience extreme fatigue as a primary symptom of lupus which, along with joint pain and a rash, are often the first signs of the condition. This can develop into wider inflammation of the internal organs.

While the condition can be painful, the vast majority of sufferers can live a normal life, though one in 20 will experience life threatening consequences.

However, while this new study might explain something of the function and origin of lupus, people wanting to avoid the condition might be out of luck. Due to the extreme prevalence of EBV and its under diagnosis, you likely have it already.

Professor Robinson said the odds are '20 to 1' that you already have the virus and there is no way of getting rid of it, adding that 'practically the only way to not get EBV is to live in a bubble'.