Last updated:
06 September 2004
1. Reason for surveillance
- To monitor the epidemiology and so inform the development of better prevention strategies.
2. Case definition
- A confirmed case requires laboratory definitive evidence, or
- Laboratory suggestive evidence and clinical evidence.
Laboratory definitive evidence
- Detection of Coxiella burnetii by nucleic acid testing, or
- Seroconversion or significant increase in antibody level to Phase II antigen in paired sera tested in parallel in the absence of recent Q fever vaccination, or
- Detection of C. burnetii by culture (note this practice should be strongly discouraged except where appropriate facilities and training exist.)
Laboratory suggestive evidence
Detection of specific IgM in the absence of recent Q fever vaccination. Clinical evidence
Clinically compatible disease.
3. Notification criteria and procedure
Q fever is to be notified by:
- Laboratories on microbiological confirmation (ideal reporting by routine mail).
Confirmed cases should be entered onto NDD.
4. The disease
Infectious agent
The rickettsia Coxiella burnetti. Mode of transmission
Q fever is transmitted by airborne dissemination of the organism from placental tissues, birth fluids and excreta of infected animals and by direct contact with infected animals and other contaminated materials such as wool, straw or clothing. Person to person transmission of Q fever has not been documented. Direct transmission by blood and bone marrow transfusion has been reported. Timeline
The typical incubation period depends on the size of the infecting dose, but is usually 14 to 21 days. Clinical presentation
The usual clinical presentation is fever of variable duration, sweating and chills, headache, weakness and malaise. Abnormal liver function tests are common. Chronic endocarditis can occur, and, if untreated, can cause significant morbidity.
5. Managing single notifications
Response times
Investigation
Within 3 working days of a confirmed case begin followup investigation. Data entry
Within 5 working days of notification enter confirmed cases on NDD. Ensure that the "occupation" and "vaccinated" fields are completed. Response procedure
The response to a notification will normally be carried out in collaboration with the case's health carers. But regardless of who does the follow-up, PHU staff should ensure that action has been taken to:
- Confirm the onset date and symptoms of the illness
- Confirm results of relevant pathology tests, or recommend the tests be done
- Find out if the case or relevant care-giver has been told what the diagnosis is before beginning the interview
- Seek the doctor's permission to contact the case or relevant care-giver
- Determine likely source of infection
- Consider prevention initiatives.
Case management
Treatment and investigation
Refer to: Therapeutic Guidelines: Antibiotic. Education
The case or relevant caregiver should be informed about the nature of the infection and the mode of transmission. In particular, emphasis should be placed on careful handling of products of conception from potentially infected animals. Exposure investigation
A history of possible exposures should be sought. Attempt to identify the source of infection, such as exposure to products of animal conception. Isolation and restriction
None. Environmental evaluation
When a cluster of cases occurs:
- Initiate an investigation to identify risk factors for infection
- Liaise with the Senior Animal Regulatory Officer at the Department of Primary Industries (formerly Agriculture) and WorkCover regarding prevention strategies in the workplace.
Contact management
Identification of contacts
Contacts are those who may have been exposed to the same source as the case. In occupational settings action to detect cases among defined contacts should be considered. Non-immune abattoir workers and others in hazardous occupations should be encouraged to ensure they are vaccinated against Q fever.
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