Could ME/CFS be caused by undiagnosed Lyme disease or other bacterial infections?


For many decades, ME/CFS has been linked to a number of viral infections, specifically Epstein Barr Virus (EBV) and Human Herpes Viruses (HHV). However, bacterial infections may be another possible source of infection in ME/CFS.

Lyme disease is a bacterial infection spread to humans by infected ticks. It is also known as Lyme borreliosis. Ticks are tiny spider-like creatures found in woodland and moorland areas that feed on the blood of birds and mammals, and can land on humans and transmit bacteria into the blood stream as they feed.

IACFS/ME conference: Lyme back on the agenda

At the recent IACFS/ME annual conference 2022 attended by ME Research UK, many of the scientists highlighted the role of viral infections like EBV/HHV, in terms of being either a clear risk for ME/CFS initiation or as a factor in how the illness presents or progresses afterwards, given the potential for viral reactivation.

In contrast, Prof. Kenny De Meirleir, medical director at the Whittemore Peterson Institute in Nevada, USA, and a doctor who has treated ME/CFS sufferers over the years at his private clinic in Belgium, claimed that tick-borne bacterial infections are often overlooked as a cause of ME/CFS, and could account for a significant percentage of cases.

Lyme cases in the media

Many Lyme sufferers have turned to social media to recount their arduous journey to diagnosis, often providing anecdotal evidence that doctors either dismissed their symptoms at first, or informed them they were suffering from chronic fatigue syndrome, or even multiple sclerosis in some cases.

John Caudwell, a celebrated British businessman and founder of Phones 4U, has a son who has suffered from Lyme disease for some years, and Mr Caudwell is a vocal advocate for better Lyme testing and treatment. He set up a charity, the Caudwell LymeCo, to promote awareness of Lyme. Numerous famous celebrities have reported Lyme disease experiences over the years – Justin Bieber in 2020, Shania Twain in 2005 – and other public figures have raised the public profile of the illness.

Lyme risk in the UK

The UK Health Security Agency reports around 1,500 laboratory-confirmed cases of Lyme disease in England and Wales each year, although it is estimated that the true number is closer to 3,000 to 4,000 new cases each year, as many suspected cases are treated without a laboratory test by GPs. Rates in Scotland number in the hundreds, but are also based on official records of known diagnosed cases.

The great imitator

Lyme disease is often characterised as ‘the great imitator’ – a name once given to syphilis (another spiral shaped/spirochete) during the 19th century, but now given to Lyme because it can generate a wide variety of medically unexplained symptoms that can mimic other disorders, such as fever, pain in the joints, arthritis-type presentation, heart palpitations, sleep disturbance, or neurological symptoms such as muscle twitches.

What’s most relevant to ME/CFS is that Lyme disease can produce profound fatigue and pain, meaning undiagnosed Lyme infection could easily fall under an ME/CFS type diagnosis.

Borrelia Burgdorferi and Borrelia Miyamotoi

The majority of cases of Lyme Disease in the UK and northern Europe are caused by spirochaetes (spiral shaped bacteria) with a genospecies called Borrelia burgdorferi.

Prof. De Meirleir suggested that many of his patients tested positive for B. miyamotoi, another genospecies more commonly found in the USA that originated in Japan. The controversial claim made by De Meirleir is that many ME/CFS patients test positive for B. miyamotoi, compared with healthy controls.

The exact details of these data remain unclear given they have not been fully published, nor has this finding been replicated in other studies looking at Lyme in ME/CFS patients. 

De Meirleir also reported that he found increased levels of toxins called lipopolysaccharides, produced by Lyme bacteria, in people with ME/CFS. He went on to say that Lyme bacteria may also invade the digestive system and disrupt the mucosal lining, leading to increased allergy, inflammatory bowel issues and disruption to the gut microbiome – gut dysbiosis.

Ongoing controversy

While many ME/CFS patients may be acutely aware of the controversy that surrounds ME/CFS science, chronic Lyme disease is yet another field of medicine that lacks clear consensus. Medical experts in the UK claim that most cases of so-called chronic or persistent Lyme disease are not Lyme cases, but rather patients with chronic fatigue syndrome (NewScientist 2019). However, some commentators suggest that this stance is wholly inaccurate, and that undiagnosed, persistent, post-treatment Lyme disease syndrome (PTLDS) is far more common than reported in official surveillance statistics (BJGP Open 2020).

In the UK there are few, if any, specialist NHS centres for the diagnosis or treatment of Lyme disease, and many sufferers end up paying for private treatment in the UK or abroad, some travelling as far as the USA or Germany for treatment.


Researchers continue to question whether ME/CFS is caused by one specific pathogen or even a combination of infections that shift the immune system and overwhelms the body’s control mechanisms. If we accept that viruses may trigger ME/CFS, perhaps we should also remain open-minded to the idea that stealth bacterial infections might also play some role in the disease for a subgroup of sufferers.

Doctors should remain vigilant to the fact that some ME/CFS patients may have undiagnosed Lyme or other bacterial infections that might be causing their symptoms.

ME Research UK will continue to monitor scientific publications in this area and report on possible links between Lyme disease and ME/CFS.

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