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The purpose of the Southern Cross Medical Library is to provide information of a general nature to help you better understand certain medical conditions. Always seek specific medical advice for treatment appropriate to you. This information is not intended to relate specifically to insurance or healthcare services provided by Southern Cross. For more articles go to the Medical Library index page.

Chronic fatigue syndrome (Tapanui flu)

Chronic fatigue syndrome (CFS) is a complex condition characterised by debilitating fatigue. Its cause is not fully understood, although it frequently follows a viral infection.

In New Zealand, the condition is sometimes referred to as Tapanui flu, named after an Otago town where a number of people displayed debilitating fatigue in the early 1980s. The condition is also known as myalgic encephalomyelitis (ME), post viral fatigue syndrome (PVS), chronic fatigue immune dysfunction syndrome (CFIDS), and more recently systemic exertion intolerance disease (SEID).


CFS differs from the more typical types of fatigue in that it interferes with a person’s ability to participate in the activities of everyday life, sometimes for long periods of time. It can become disabling but does not appear to be progressive or life threatening.

Chronic fatigue syndrome can occur at any age; however, it most commonly affects people in their 40s and 50s. It occurs more commonly in women than in men.

The combination, nature, and severity of symptoms can vary between individuals. In some people, there may be periods of relative wellbeing and periods where symptoms are problematic. For others, symptoms may be constant and severe.

Symptoms may include:

  • Ongoing, flu-like fatigue
  • Exercise may increase symptoms
  • Impaired memory or concentration
  • Depression
  • Irritability
  • Muscle and joint pain
  • Sleep disturbances (eg: insomnia)
  • Swollen lymph nodes (glands)
  • Headaches
  • Sore throat
  • Gastrointestinal problems (eg: irritable bowel syndrome).


While the causes of CFS are not fully understood, it is known that as many as 60% of cases develop after a viral illness (eg: glandular fever, viral meningitis, gastroenteritis). However, a direct relationship between viral infection and CFS not yet been determined. Research studies have indicated that other factors may play a role in the development of the condition, including immune abnormalities, psychological disorders, and hormone imbalances.

There is some thought that CFS may be caused by multiple factors, rather than one single factor, although research studies have yet to conclusively confirm this.


There is no one laboratory test that can help make the diagnosis, though tests may be performed to rule out other medical conditions that have similar symptoms. For example, sleep studies can determine whether chronic fatigue is caused by a sleep disorder such as insomnia, obstructive sleep apnoea, or restless leg syndrome. Blood tests can determine whether fatigue is caused by medical conditions such as anaemia, diabetes, or hypothyroidism. Fatigue is also a symptom of mental health conditions, such as depression, anxiety, and schizophrenia, and a counsellor can determine whether one of these conditions is the cause of fatigue. Other chronic diseases such as HIV/AIDS and inflammatory bowel diseases (eg: Crohn’s disease, ulcerative colitis) also cause persistent fatigue.

Fibromyalgia, which has the primary symptoms of chronic muscle pain and fatigue, can be differentiated from CFS by the presence of trigger points, which are not a feature of CFS.

A diagnosis of CFS requires the presence of unexplained persistent fatigue for six months or more and at least four of the following other signs and symptoms:

  • Impaired memory or concentration
  • Sore throat
  • Enlarged or tender lymph nodes
  • Unexplained muscle pain
  • Pain in multiple joints
  • Headaches (new type, pattern, or severity)
  • Non-refreshing sleep
  • Feeling unwell for more than 24 hours after physical or mental exercise.


While there is no proven treatment or cure for CFS, the condition can be managed using a variety of measures. These include:

Conservation of energy
Unlike depression, where exercise may help to alleviate symptoms, in CFS sufferers it may worsen symptoms. This is not to say that exercise should be avoided in CFS sufferers. It should be done gently and not all at once. Prioritise activities so the most taxing are done at the best time of the day. Plan to have a quiet day after a busy one. Resting regularly during the day for even brief rest periods (such as 5 to 10 minutes) can be helpful.

Relaxation and stress management
Finding methods of relaxation and stress management can be helpful in reducing symptoms in some people. Stress reduction may be achieved through techniques such as meditation, biofeedback, yoga and tai chi. Some people with CFS find talking about the condition with family and friends, so they understand the implications of the condition, can also be helpful. Some people may find it helpful to work with a professional counsellor or psychologist to develop strategies to cope with CFS.

Eat a balanced diet with regular meals and avoid high sugar snacks. For some people with CFS, the elimination of problem foods and environmental chemicals is beneficial.

Non-steroidal anti-inflammatory drugs (NSAIDs) can be helpful in relieving pain and reducing fever. Low doses of antidepressant medications may be prescribed in some cases. As they tend to have slight sedative affects, they can assist with sleep as well as treating depression.

Alternative treatments
Nutritional supplements containing different vitamins (eg: vitamins A, E, C and B12) may be helpful in relieving symptoms in some cases. Herbal remedies such as Echinacea, garlic, ginseng, and evening primrose oil may also prove beneficial. Other treatments such as acupuncture and massage may also help.

The probability of finding an effective treatment increases as scientific knowledge of the syndrome increases. There are several studies in progress that may be useful in developing a treatment for CFS.

Support and information

The Associated New Zealand Myalgic Encephalomyelitis Society (ANZMES) is the national organisation providing information for sufferers of ME/CFS.

Phone: (09) 269 6374 or (03) 471 6203


O’Toole, M.T. (Ed.) (2013). Chronic fatigue syndrome (CFS). Mosby’s Dictionary of Medicine, Nursing & Health Professions (9th ed.). St Louis, MI: Elsevier Mosby.
Associated New Zealand ME Society (Date Unknown). What is ME? (Web Page). Auckland: Associated New Zealand ME Society. [Accessed: 09/05/17]
Cunha, B. A. (2016). Chronic fatigue syndrome (Web Page). Medscape Drugs and Diseases. New York, NY: WebMD LLC. [Accessed: 09/05/17].
Mayo Clinic (2016). Chronic fatigue syndrome (Web Page). Rochester, NY: Mayo Foundation for Medical Education and Research. [Accessed: 09/05/17]

Last Reviewed – May 2017


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