Q Fever - the Bug from the Bush!

  by Dr Toby Ford, Ford Health

Published Newsletter Article:  Agforce, July 2006

What is Q fever?

Q fever is a serious disease with about 600 cases notified in Australia each year.  The illness may last 1 to 6 weeks.  Though rare, its complications may involve the liver, heart and bones.  A small number of people may develop a fever fatigue syndrome after this illness, which can last for a number of years.

Most acute cases of Q fever begin with sudden onset of one or more of the following:

  • high fevers (up to 40 degrees)
  • severe headaches
  • general tiredness
  • sore muscles
  • confusion
  • sore throat
  • chills, sweats
  • non-productive cough
  • nausea, vomiting
  • diarrhoea
  • abdominal pain
  • chest pain

Fever usually lasts for 1 to 2 weeks.  Weight loss can occur and persist for some time.  Thirty to fifty percent of people with a symptomatic infection will develop pneumonia.  Also, most patients have abnormal liver function tests and some will develop hepatitis.  In general, most people will recover to good health within several months without any treatment.  Only 1% - 2% of people with acute Q fever die of the disease.

Q fever is a 'zoonotic' disease, which means it passes from animals to humans.  While animals such as cows, sheep and goats can carry the Coxiella burnetii without becoming sick, humans contracting the bacteria sometimes develop a sudden and sever illness.

Q fever is passed on via infected animals' urine, milk, faeces and birth products.  You become infected when you breathe in infected droplets from these products or that are produced during the slaughter of animals, or by breathing in dust from materials that have been in touch with the bacteria.

Not all animals carry and transmit the disease to humans.  The animals that are the main source of this disease are kangaroos, wallabies, cattle, sheep, dogs, cats and goats.  Of these animals, cattle, sheep and goats are often the major source for human infection.

Q fever mainly affects workers from the meat and livestock industries.  A new worker in the meat processing or livestock industry may particularly be at risk as they may not have had precious exposure to animals.  Other people at risk of infection include sheep and cattle livestock farmers, dairy workers, vets, tanners, and shearer's.

The National Q Fever Management Program started in 2001 in Queensland has extended in until June 30 2007.  This Program screens and vaccinates people at risk of Q fever.  In Queensland, the Program provides specially trained immunisers to do skin and blood tests to check for previous exposure to Q fever and then vaccinate those without immunity one week later.  The Program covers abattoir workers, those contracted to abattoirs, sheep shearer's, sheep, dairy and beef cattle farmers, their employees and unpaid family members working on farms.  People who want to be vaccinated should first have a skin test to check they have a history of previous exposure.

Unfortunately, the company that makes the vaccine for Q fever in Australia, CSL, has stopped making it and will only re-start production in March 2007.  With supplies limited, Queensland Health is supplying it only to those workers who are at the highest risk.

For more information on the Q fever Program in Queensland please contact Dominic Ricini in the Communicable Diseases Unit at Queensland Health on (07) 3234 1155.

Some ways to prevent and control Q fever:

  • educate people on sources of infection
  • dispose of placenta, birth products, fetal membranes, and aborted fetuses carefully at facilities housing sheep and goats
  • restrict access to barns and laboratories housing potentially infected animals
  • use only pasteurized milk and milk products
  • vaccinate (where possible) people doing research with pregnant sheep or live C. burnetii
  • quarantine imported animals
  • make sure that holding facilities for sheep are located away from populated areas. Animals should be routinely tested for antibodies to C. burnetii, and prevent airflow to other occupied areas
  • managers should counsel workers at highest risk for developing chronic Q fever, especially if they have pre-existing heart valve disease or people who have had grafts in their veins
 

Sources:

The Australian Government Department of Health and Ageing, Population Health Division (2006) URL: http://immunise.health.gov.au/qfever/index.htm

Centre for Disease Control Atlanta

http://www.cdc.gov/ncidod/dvrd/qfever/index/htm