- Reason for surveillance
- Case definition
- Notification criteria and procedure
- The disease
- Managing single notifications
1. Reason for surveillance
To identify cases, and so prevent further spread.
2. Case definition
A confirmed case requires laboratory definitive evidence only.
Isolation of Yersinia pestis.
3. Notification criteria and procedure
Plague is to be notified by:
- Hospital CEOs on clinical diagnosis (ideal reporting by telephone immediately on diagnosis)
- Laboratories on confirmation (ideal reporting by telephone immediately on diagnosis).
Only confirmed cases should be entered onto NCIMS.
Note that plague is subject to the Commonwealth Quarantine Act 1908.
4. The disease
The bacillus Yersinia pestis.
Mode of transmission
In countries where it is endemic (not Australia) plague is transmitted mainly from rodents (or occasionally other animals such as cats or foxes) to humans by the bite of an infected flea or by handling tissues of infected animals. Human-to-human transmission can occur by droplet infection from coughing cases with plague pneumonia or pharyngitis. There is a theoretical concern that plague could be transmitted deliberately via the airborne route, e.g., for the purposes of terrorism.
The typical incubation period is 1 to 7 days, but shorter (1 to 4 days) for primary pneumonic plague.
Bubonic plague is communicable as long as fleas remain infective. It is not usually transmitted from person to person unless there is contact with pus from suppurating buboes.
Pneumonic plague can be highly communicable via respiratory droplets.
The usual clinical presentation is bubonic plague, which presents as a sudden onset of fever and chills, with enlarged lymph nodes (buboes), which may suppurate. The inguinal nodes are most commonly affected; less commonly the axillary and cervical nodes are affected. Bacteraemia can result in spread to a range of organs including the meninges and the lungs, where it causes a rapidly progressing pneumonia. Primary respiratory infection resulting from exposure to a patient with pneumonic plague or to materials that have been deliberately aerosolized would present as a pneumonia or pharyngitis. Early symptoms of pneumonic plague include fever and productive cough which may produce blood stained sputum.
5. Managing single notifications
Immediately on notification of a case begin follow-up investigation and notify the Communicable Diseases Branch.
Within 1 working day of notification enter confirmed cases on NCIMS.
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 and contact management
- Identify the likely source of infection
- Control further spread.
Investigation and treatment
Cases should be investigated and treated under the supervision of an Infectious Diseases physician. Recommended antibiotic treatment includes gentamicin, doxycycline or ciprofloxacin. All are highly effective if used early. For further guidance on treatment see Therapeutic Guidelines: Antibiotic.
The case or relevant care giver should be informed about the nature of the infection and the mode of transmission and the reason for and duration of isolation.
For bubonic plague, identify the source of infection, such as a locations visited during any recent overseas travel. In particular ask about:
- Contact with wild rodents or other animals or fleas.
For pneumonic plague, the possibility of the case being deliberately infected should be excluded, and expert advice sought through the Communicable Disease Branch.
Isolation and restriction
Strict isolation with airborne precautions is required for cases of pneumonic plague for 48 hours after commencing appropriate antibiotic therapy.
Patients with bubonic plague - with no respiratory symptoms and a clear chest x-ray - require appropriate handling of secretions, particularly suppurative discharge from buboes, for 48 hours after commencing appropriate antibiotic therapy.
The actual or probable source of infection must be determined and preventive measures undertaken. Treat clothes, habitation and domestic pets for fleas if a possible source of infection.
Identification of contacts
A close contact is defined as a person with face-to-face exposure to an infectious case of pneumonic plague, including health care workers, in the previous 7 days. people who have had direct, unprotected exposure to suppurative discharge from a case of bubonic plague in the previous 7 days may also be considered as a close contact.
In endemic areas overseas, close contacts also include persons who are likely to have been exposed to infected rodents or fleas in the same household as the case in the last seven days.
Determine whether any contacts have any symptoms consistent with plague and, if so, organise appropriate clinical review and investigation.
Close contacts should be strongly recommended to take appropriate antibiotic prophylaxis for 7 days. For further guidance on post-exposure prophylaxis see Therapeutic Guidelines: Antibiotic.
Advise susceptible contacts (or parents/guardians) of the risk of infection, the need for close symptom surveillance, and quarantine (if required).
Isolation and restriction
Close contacts receiving appropriate chemoprophylaxis should be placed under daily symptom surveillance for 7 days but do not require quarantine.
Close contacts cases who refuse chemoprophylaxis require strict home (or equivalent) quarantine for 7 days together with daily symptom surveillance.
For further information please call your local Public Health Unit on 1300 066 055