Public health priority: Urgent.
PHU response time: Respond to cases immediately on notification. Enter confirmed cases on NCIMS within 1 working day. Notify the One Health Branch (OHB) on same day of notification of a suspect case.
Case management: Determine source of infection and take measures to prevent transmission. Airborne precautions should be maintained until pneumonic plague has been ruled out. For cases of pneumonic plague, airborne precautions are required until at least 48 hours after the start of appropriate antibiotics.
Contact management: Contact tracing is required for pneumonic and bubonic plague cases. Chemoprophylaxis or isolation is required for contacts of pneumonic plague.
The bacillus Yersina pestis
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 may occur via inhalation of respiratory droplets from an infected person, less commonly via direct contact with pus from suppurating buboes, or during a post-mortem examination/laboratory handling and testing.
There is also a theoretical concern that plague could be transmitted deliberately via airborne route, e.g. for purposes of bioterrorism.
The typical incubation period is 1 to 7 days, but shorter (1 to 4 days) for primary pneumonic plague (see clinical manifestations for description of the different plague clinical presentations)
Cases with either pneumonic and bubonic plague are considered infectious from the onset of symptoms and until at least 48 hours after commencement of appropriate antibiotic therapy.
There are three main presentations of plague depending on the route of infection.
Bubonic plague is the most common form of plague, in which bacteria are inoculated through the bite of a flea and spread via the lymphatic system. Bubonic plagues presents as a sudden onset of fever and chills, with enlarged painful lymph nodes (buboes), which may suppurate in the second week of illness. The inguinal nodes are most affected, and less commonly the axillary and cervical nodes.
If untreated bubonic plague may result in blood stream infection (septicaemic plague) and spread to range of organs including the meninges and the lungs, causing a rapidly progressing pneumonia, known as secondary pneumonic plague and meningitis.
Untreated bubonic plague has a mortality rate of 30-60%
Pneumonic plague may result from secondary pulmonary spread of bubonic plague, or via direct inhalation of bacteria from exposure to a patient with pneumonic plague or aerosolised infectious materials. Symptoms of fever, headache and weakness rapidly progress to dyspnoea, chest pain and cough, with increasing haemoptysis. Buboes may also be seen.
Pneumonic plague is the most severe form and is almost always fatal without treatment, or when treatment is delayed beyond 24 hours.
Septicaemic plague occurs with blood stream infection, either on its own (primary) or as a progression of bubonic or pneumonic plague. Cases present with fever, shock, purpura, distal gangrene, and may have gastrointestinal symptoms and progression to disseminated intravascular coagulation.
Rarely, other presentations of plague infection may be seen. For example, pharyngeal plague results from ingesting of the Yersinia pestis (plague bacilli) through contaminated food or drink. This form of plague can lead to sore throat, fever and painful lymph nodes.
A confirmed case requires laboratory definitive evidence only.
Isolation of Yersinia pestis.
A case may be suspected with the appropriate clinical presentation (see Clinical manifestations and epidemiological link). The most plague-endemic countries in the world are Democratic Republic of Congo, Madagascar and Peru, but distribution is global. The NSW Early Response to High Consequences Infectious Diseases policy can direct operational response to High Consequence Infectious Diseases such as plague and the NSW Specialist Service for HCID can provide expert infectious disease advice.
If suspected cases are not confirmed with laboratory testing and have an alternative diagnosis, they should be excluded.
Plague is to be notified by:
Suspect and confirmed cases should be entered into NCIMS.
Upon notification of a suspect case, notify the NSW Specialist Services for High Consequence Infectious Diseases (SSHCID) on 1800 424 300.
Suspect and confirmed cases must be notified to the One Health Branch (or After Hours CD on Call) immediately upon notification.
The One Health Branch or (After Hours CD on Call) must notify the NSW Chief Human Biosecurity Officer (HBO) (or on call HBO) of all suspected and confirmed cases. The Human Biosecurity Officer Guideline provides further details for required HBO actions.
Plague is a Listed Human Disease under and regulated by the Commonwealth Biosecurity Act 2015 and requires urgent national notification.
Upon notification of a suspect case notify NSW Specialist Services for High Consequences Infectious Diseases (SSHCID) on 1800 424 300 and the One Health Branch (or After Hours CD On Call).
Plague is a High Consequence Infectious Diseases (HCID). The SSHCID has a 24/7 hotline to an on-call HCID physician to provide advice to clinicians on assessment, diagnosis, and management of HCIDs. Due to potential for person-to-person spread, cases of pneumonic plague should be considered for transfer to the NSW Biocontainment Centre at Westmead Hospital. The NSW Early Response to HCID policy directive provides further details on case management for HCIDs. SSHCID risk assessment will determine hospitalisation requirements and appropriate precautions including PPE and negative pressure.
All patients with suspected plague should be managed with airborne precautions and in a single room until pneumonic plague has been excluded. If pneumonic plague is present, airborne precautions should continue until at least 48 hours of appropriate antibiotics have been administered and there is clinical improvement.
Determine source of infection and identify any other potentially co-exposed and undertake contact tracing (see Contact Management)
The following should be entered on NCIMS
When entering potential exposures on NCIMS, the following variables are considered minimum data requirements.
The response to a notification will normally be carried out in collaboration with the case's treating clinical team and HCID service. Regardless of who does the follow-up, PHU staff should ensure that action has been taken to:
SSHCID will support advice on testing and can support sample coordination.
Blood, and other clinical materials such as bubo aspirates, sputum, tracheal washes, swabs of skin lesions or pharyngeal mucosa, and CSF as indicated should be collected for culture.
If plague is strong suspected, specimens should be sent to the PC4 laboratory at NSW Health Pathology - Institute of Clinical Pathology and Medical Research (ICPMR) at Westmead Hospital.
The laboratory should be notified prior to sending specimens, and can be advise appropriate specimen type, collection and transport.
Y.pestis is classified as a Security Sensitive Biological Agent (SSBA). If a clinical laboratory isolates an organism, immediate notification to the SSBA Regulatory Scheme is required and the isolate should be forwarded immediately to the PC4 laboratory at NSW Health Pathology - Institute Of Clinical Pathology And Medical Research (ICMPR) at Westmead Hospital for confirmation. Isolates require Category A packaging and transport. Note that MALDI-TOF may be misidentify Y. pestis as Y. pseudotuberculosis.
When a patient's condition allows, collection of multiple blood culture samples taken prior to treatment will increase likelihood of successful isolation of the bacterium. Airborne precautions should be used for all procedures that could potentially produce aerosols e.g. tracheal washes and aspirate.
Cases should be investigated and treated under the supervision of an Infectious Diseases physician.
Every effort should be made to trace the source of the infection by collection of detailed travel and risk history.
Contact tracing is required for anyone who has had close and unprotected exposure to infectious material (sputum, aerosols or pus) from a person who has had less than 48h of appropriate antibiotics (See Contact Management).
Antibiotic treatment is highly effective if used early. Antibiotic therapy should be provided in line with the Therapeutic Guidelines and further guidance is available from the US Centers for Disease Control and Prevention (CDC)
Risk assessments and decisions on isolation and transmission-based precautions should be made in conjunction with SSHCID, an infectious disease specialist and infection prevention and control.
Airborne precautions including isolation in a single room are required for all cases of plague until pneumonic plague has been excluded. If confirmed pneumonic plague, airborne precautions are required until at least 48 hours after commencing appropriate antibiotic therapy and in the presence of clinical improvement. SSHCID risk assessment will determine whether negative pressure is required.
Patients with bubonic plague and with no respiratory symptoms and a clear chest x-ray can be managed with standard precautions. The use of gloves and gowns will be required for handling infectious secretions, particularly suppurative discharge from buboes for 48 hours after commencing appropriate antibiotic therapy.
The case or relevant care giver should be informed about the nature of the infection and the mode of transmission, management and duration of isolation.
The case and/or relevant care giver should be provided with the NSW Plague Factsheet.
The actual or probable source of infection must be determined, and preventive measures undertaken to prevent further transmission.
Treat clothes, habitation, and domestic pets for fleas if a possible source of infection. The One Health Branch will coordinate the response to potential local acquisition with the NSW Department of Primary Industries and Regional Development (DPIRD) for any animal treatment/ involvement and notify the Environmental Health Branch to coordinate any required environmental risk assessment.
Plague is found in all continents, except Oceania. There is a risk of human plague wherever there is presence of plague natural foci (the bacteria, an animal reservoir, and a vector).
Plague is primarily associated with rural settings with cases often in agricultural areas and small towns/villages due to increased exposure to infected rodents where the disease circulates.
Plague epidemics have occured in Africa, Asia and South America; since 1990, most human cases have occured in Africa. Three most endemic countries are The Democratic Republic of Congo, Madagascar and Peru. Global and US Distribution Maps are available from the US Centers for Diseases Control and Prevention.
For all cases of plague, identify the source of infection, such as a locations visited during any recent overseas travel.
Ask about:
For any case of plague (regardless of type) that is potentially acquired in Australia (unless clearly laboratory acquired) or for which there are no clear indications of relevant exposure or source acquisition, an investigation into whether the case may have been deliberately infected (i.e. bioterrorism) should commence. Notify the One Health Branch (or After Hours CD On Call), who will coordinate with relevant investigation authorities (e.g. NSW Police) where required.
A close contact is defined as:
Laboratory staff who have handled or processed infectious specimens will need to be risk assessed.
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. Risk assessment may be needed for travel companions who fulfill these criteria or may have been co-exposed.
Determine whether any contacts have any symptoms consistent with plague and, if so manage as a suspect case in consultation with SSHCID and organise appropriate clinical review and investigation.
Household pets can be susceptible to plague. If any pets or other animals have had contact with a confirmed plague case, notify Department of Primary Industries and Regional Development via the One Health Branch.
Close contacts should be strongly recommended to take appropriate antibiotic prophylaxis for 7 days. SSHCID can provide advice regarding appropriate prophylaxis with guidance available from the Therapeutic Guidelines and US Center of Disease Control and Prevention.
PHUs should ensure appropriate (daily) monitoring for contacts to identify any illness compatible with plague while contacts are receiving prophylaxis, or for 7 days after exposure. Consultation with an Infectious Disease physician should be undertaken. For any symptoms compatible with plague, medical assessment and exclusion of active infection is required.
Advise susceptible contacts (or parents/guardians) of the risk of infection, the need for symptom monitoring, post-exposure prophylaxis (where recommended) and isolation (if required).
Contacts should be provided with the NSW Plague Factsheet.
Close contacts receiving appropriate chemoprophylaxis should be placed under daily symptom surveillance for 7 days but do not require isolation.
Close contacts cases who refuse chemoprophylaxis require strict home (or equivalent) isolation for 7 days from last exposure in addition to daily symptom monitoring.
For close contacts who require isolation, admission to the NSW Biocontainment Centre may be appropriate, which would be decided in conjunction with advice from SSHCID.