Q fever

Cause

Coxiella burnetii

Description

This bacterium can be carried by a variety of domestic and wild animals, especially cattle, sheep, goats, bandicoots, kangaroos and wallabies. Clinical disease is not common in domestic livestock but animals are a source of infection for people.

Where the disease occurs

The disease occurs in most parts of the world and throughout Queensland. It has not been detected in New Zealand.

The disease in animals

Coxiella burnetii can cause abortion in sheep and goats and rarely in cattle. The organism is present in high concentrations in the placenta, foetal fluids, urine and faeces of infected animals. While Q fever has significant implications for human health, control strategies in livestock are not usually required.

How people can get the disease

About half of Australian cases of Q fever occur in Queensland, with around nine people affected each year per 100,000 population. This can be as high as 200 per 100,000 people in some rural shires. Q fever is one of the most common diseases that humans contract from animals.

Q fever can spread from animals to people by the inhalation of infective material from placental tissues and fluids. Human infection can also occur through the ingestion of un-pasteurised milk and by contact with infected animals, their waste products, or contaminated straw, wool, hair and hides. The bacterium resists drying and can live in dust for many months. It has been spread up to one kilometre by the wind. Ticks may also spread it between animals, but rarely, if ever, spread to people.

Animal handlers, farmers, veterinarians, abattoir workers, meat inspectors and biological researchers working with pregnant animals are most at risk. Goats are probably the greatest risk to people.

Those most at risk include:

  • Veterinarians, veterinary nurses and students
  • Farmers
  • Meat inspectors
  • Abattoir workers - including contractors visiting the site
  • Animal handlers/transporters
  • Laboratory staff
  • Researchers working with pregnant animals

Not all people infected with C. burnetii show signs of clinical illness. In acute cases, it produces a sudden, severe flu-like illness. Symptoms can include; high fevers, chills, severe headache, muscle and joint pain and extreme fatigue. Approximately one third of people develop a chronic form of Q fever. These people may be hospitalised due to endocarditis (inflammation of the heart). People with a pre-existing heart valve condition are at an increased risk.  Deaths are rare. Between 10 and 20% of people have prolonged fatigue and, in a few cases, this is severe enough to prevent people working for the rest of their lives.

Treatments for people

People with Q fever are treated with appropriate antibiotics and may be admitted to hospital.

Preventing the disease in people
  • People who work with animals or materials that may carry Q fever bacteria should use protective equipment and carry out procedures to prevent infection. These procedures include washing hands and arms thoroughly in soapy water after handling animals and carcasses.
  • Strict hygienic practices must be followed when pregnant animals, hides, wool, straw, or other contaminated material is handled. This involves the prevention of inhalation of contaminated dust or fluid droplets, adequate disinfection and disposal of material, and prompt treatment of cuts and abrasions.
  • Placental and other birth material should be burnt or buried. Contaminated litter should be burnt.
  • Milk should be pasteurised or boiled.
  • There is a vaccine available for Q fever which was developed in Australia. People who are occupationally or recreationally exposed to potentially infectious animals and/or materials should seek information on vaccination from local doctor.
  • It is most important for anyone with flu-like symptoms who is likely to have had contact with infected animals to seek medical advice, stating clearly that contact with the Q fever organisms has possibly occurred.

Last updated 27 September 2012