Q fever

see also:

• zoonoses
• NSW Govt fact sheet
• CDC Information Q Fever

• Q fever is a zoonosis caused by Coxiella burnetii, an obligate gram-negative intracellular bacterium which primarily infects cattle, sheep and goats as the primary reservoirs but other animals including wild animals may be reservoirs
• it can be found in the placenta and amniotic fluid, urine, faeces, blood or milk of animals who are infected with or carry the bacteria
• bacteria can survive in the soil and dust for many years and be spread over several kilometres by the wind
• resistant to heat, drying, and many common disinfectants

• transmission is usually via inhalation of dust or fluids from contaminated soil or animal waste
  • very high risk of infection if birthing, slaughtering or butchering infected animals or handling material or clothes used during this
  • mowing grass contaminated by infected animal excretions
  • herding, shearing or transporting animals
  • visiting, living or working in/near a high-risk industry
• rarely, transmission is via:
  • direct contact with infected animal tissue or fluids on broken skin (e.g. cuts or needlestick injuries when working with infected animals)
  • ingestion of unpasteurised milk or diary products
  • human to human via:
    • transplacental exposure
    • sexual contact
    • blood transfusion
    • transplantation
  • tick bites

• usually 2-3 weeks but ranges from 3 to 30 days

• many are relatively asymptomatic
• others may develop a severe flu-like illness:
  • high fevers, chills
  • severe ‘drenching’ sweats
  • severe headaches, often behind the eyes
  • myalgias
  • arthralgias
  • extreme fatigue
• some may develop hepatitis or pneumonia

• without treatment:
  • usually resolves with 2-6 weeks and most make a full recovery and become immune
  • some people have a chronic course over 2 years which may result in infective endocarditis (including SBE). especially if either:
    • pregnant
    • immunocompromised
    • underlying cardiac issues
  • 10% of symptomatic patients develop chronic fatigue which may last years

• diagnosis is based upon clinical features and serial serology (repeat in 14 days)
• early antibiotic Rx:
  • doxycycline 100 mg (child: 2 mg/kg up to 100 mg) orally, 12-hourly for 14 days
  • For children 8 years or younger who have mild or uncomplicated disease, treat with doxycycline for 5 days only. If fever does not resolved within 5 days, complete the 14-day treatment course with trimethoprim + sulfamethoxazole — seek expert advice.
  • For pregnant women:
    • trimethoprim+sulfamethoxazole 160+800 mg orally, 12-hourly, PLUS,
    • folic acid 5 mg orally, daily.
    • Treatment is recommended until 32 weeks' gestation, even if the patient has spontaneously recovered, to prevent fetal and maternal complications. Seek expert advice for the management of pregnant women beyond 32 weeks gestation.
    • Although trimethoprim + sulfamethoxazole can cause congenital abnormalities when used during pregnancy, the potential benefits of treatment outweigh the potential harms. The concomitant use of folic acid reduces the risk of congenital abnormalities.
  • People with life-threatening allergies to doxycycline may need to consider alternate antibiotics such as moxifloxacin, clarithromycin, trimethoprim/sulfamethoxazole and rifampicin.
• chronic Q fever
  • may require long term doxycycline + hydroxychloroquine
  • if endocarditis, cardiac surgery may also be required

• safe and effective vaccine (Q-VAX®) is the best way to prevent Q fever infection for high risk adults
• other precautions:
  • wear a properly fitted P2 mask (available from pharmacies and hardware stores) and gloves and cover wounds with waterproof dressings when handling or disposing of animal products, waste, placentas, and aborted foetuses.