Last updated:
06 September 2004
1. Reason for surveillance
• To identify any resurgence of animal disease in NSW
• To monitor the epidemiology and so inform the development of better prevention strategies.
2. Case definition
A confirmed case requires laboratory definitive evidence. Laboratory evidence
• Isolation of Brucella species, OR
• IgG seroconversion or a significant increase in antibody level or a fourfold rise in titre in Brucella agglutination titres or complement fixation titres between acute and convalescent phase serum samples. (Where possible both tests should be conducted at the same laboratory) OR
• A single high Brucella agglutination titre. Clinical evidence
Not applicable. Epidemiological evidence
Not applicable.
3. Notification criteria and procedure
Brucellosis is to be notified by:
• Laboratories on microbiological confirmation (ideal reporting by routine mail). Only confirmed cases should be entered onto NDD.
4. The disease
Infectious agents
Brucella species. Mode of transmission
Brucellosis is transmitted by direct contact with tissues, blood, urine, vaginal discharges, aborted foetuses and placentas of infected animals, and by ingestion of raw milk and dairy products from infected animals. Person-to-person transmission of brucellosis has not been documented. Ultimate control of human brucellosis will depend on the elimination of the disease in animals. Acute human cases may act as a marker of animal disease. Brucella suis is endemic in feral pigs, especially in Queensland and northern NSW. Brucella ovis is common in sheep flocks. Brucella abortus has been eradicated from NSW. Brucella melitensis is enzootic in goats in many parts of the world and imported cases of human infection and laboratory-acquired infections may occasional occur in Australia. Timeline
The typical incubation period is difficult to determine, probably 5 to 60 days, but more commonly 30 to 60 days. Clinical presentation
The usual clinical presentation is characterised by fever of variable duration, sweating and chills, headache, weakness, arthralgia, depression and weight loss. Suppurative infections of organs can occur, as can osteoarticular complications and genitourinary involvement. Where endocarditis occurs, there is a high case-fatality rate. Relapses of the original illness may occur.
5. Managing Single Notifications
Response times
Investigation
Within 3 working days of notification begin follow-up investigation. Where transmission from animals or their products is suspected, notify the Department of Primary Industry's Senior Field Vet for the Area and CDB on the same day. Data entry
Within 5 working days of notification enter confirmed cases on NDD. 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
• Review case management
• Identify and help control the likely source. Case management
Investigation and treatment
See the latest edition of the Therapeutic Guidelines: Antibiotic. Education
The case or relevant care-giver should be informed about the nature of the infection and the mode of transmission. In particular, emphasis should be placed on careful handling of carcasses and products of potentially infected animals. Exposure investigation
Obtain a history of possible exposures to dairy products, animals, farms, overseas travel, or potentially contaminated imported products in the previous two months. Isolation and restriction
None. Environmental evaluation
May be recommended in conjunction with the Senior Animal Regulatory Officer at the Department of Primary Industry, who may initiate animal control measures. Contact management
Identification of contacts
Contacts are those who may have been exposed to the same source as the case. Identify possible cases among co-exposed persons, provide them with information about the disease, and advise to seek medical attention should symptoms develop.
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