Q fever is a zoonotic illness caused by the bacterium Coxiella burnetii.1-3 A zoonotic illness is a human infection which occurs when the pathogen (e.g. Coxiella burnetii) is either directly or indirectly transmitted from an infected animal.2

Coxiella burnetii can infect both wild and domestic animals and their ticks. Cattle, sheep and goats are the main sources of human infection, but certain native and feral mammals (e.g. kangaroos, bandicoots, rats, horses, camels), as well as domestic animals such as cats and dogs, may also be implicated.1-3

Most commonly, people become infected after inhaling contaminated aerosols, such as dust particles.1

Less commonly, infection occurs following consumption of unpasteurised milk or milk products from infected animals.2

Infection may also occur by subcutaneous inoculation, possibly through cuts/abrasions, and is associated with a shorter incubation period than inhalation.2

Q fever is often described as an occupational zoonotic disease.2 This is because the people most at risk of developing the illness tend to be those whose work puts them at risk of exposure to the causative pathogen, although the general population may also be infected (refer to Q fever: Can it be prevented and who is at risk?).1,2

In Australia, any case of Q fever needs to be reported to Health Authorities.1

Further information about Q fever can also be obtained from the various State/Territory public health authorities.

NSW Health

QLD Health

VIC Health

SA Health

WA Health

ACT Health

NT Gov

Q fever presentations are non-specific, variable and often misdiagnosed.3,10 History of exposure to animals can be useful although indirect routes of infection may be unrecognised.3 In at least 50% of cases, people infected with Coxiella burnetii may remain asymptomatic and not even realise that they have the infection.1 Symptomatic patients may present with ‘acute’ Q fever symptoms.1,2

In total, up to 1 in 5 acute cases may develop post-Q fever fatigue syndrome or chronic Q fever (e.g. endocarditis) which can have incapacitating, long-lasting and serious consequences.1,4

The characteristic manifestations of acute Q fever are often described as ‘flu-like’, highly variable and non specific1-3 and may include:1-3,5

  • Rapid onset of fever and chills that can last several weeks
  • Profuse sweating
  • Severe headache
  • Aching muscles and joints
  • Extreme fatigue and mental confusion
  • Nausea and diarrhoea
  • Photophobia or blurred vision
  • Pneumonia
  • Weight loss
  • Hepatitis (with or without jaundice)
  • Rash

In most cases, acute Q fever is a self-resolving illness, symptoms appear 2-4 weeks after infection and symptoms can last up to 3-6 weeks.1,2 A post notification survey in the NSW Hunter region, reported that as a result of their Q fever illness, 93% of patients took time off work or school for a median 21 days (range 2-296 days).6

Click to learn about Jason’s experience with acute Q fever

Post-Q fever fatigue syndrome

A substantial proportion of patients with acute Q fever – up to about 15% – will go on to experience a post-Q fever fatigue syndrome, where symptoms continue to persist for more than 12 months after the acute illness.1,2 Symptoms associated with post-Q fever fatigue syndrome (fatigue and other symptoms), can last for years and have the potential to be highly incapacitating.1,7

Click to learn about Geoff’s experience with post Q fever fatigue syndrome

Chronic Q fever is the result of a persistent, focal Coxiella burnetii infection at one or more anatomical sites.2 It occurs in up to 5% of acute Q fever cases.4 Chronic Q fever may appear months or even years after the development of acute Q fever, even if this initial episode of Q fever was asymptomatic.2-4,8 The most common1,3 – and most serious2 – manifestation of chronic Q fever is endocarditis, which occurs in about 60–70% of chronic Q fever cases and nearly always occurs in patients with underlying immunosuppression or cardiac valve abnormalities.8 Chronic Q fever endocarditis is a condition with high morbidity and mortality if left untreated.2,9 Other manifestations of chronic Q fever include recrudescent granulomatous lesions in bone, joints, soft tissue or organs (liver, lung, testis etc.), vascular infections, late stage pregnancy infection, hepatitis and osteomyelitis.1-3

Click to learn about Geoff’s experience with chronic Q fever