Public health priority: Urgent
PHU response time: Respond to notification of laboratory suggestive evidence in order to identify confirmed cases on the same day. Report case details to One Health Branch (OHB) on same day. Enter on NCIMS within one working day.
Case management: Appropriate antibiotics under the direction of the treating doctor. Identify the likely source of infection.
Contact management: Assess and control risk in others exposed to the same source of infection.
Bacillus anthracis, a bacterium.
Anthrax is acquired in three ways: percutaneously, by inhalation, or by ingestion. B. anthracis spores can remain viable in soil for many years. Long term changes in climate and soil conditions may increase the risk of anthrax outbreaks
Humans can become infected with anthrax by handling products from infected animals, by inhaling anthrax spores (especially from contaminated animal products such as hides) or through cuts and abrasions when in contact with contaminated soil. Eating undercooked meat from infected animals can also transmit anthrax.
Transmission from person to person has not been reported. Articles and soil contaminated with spores may remain infective for decades.
The incidence of anthrax in animals in NSW is very low. Cases in animals most commonly occur in the 'anthrax belt', a region stretching from southern Queensland, through central NSW and into Victoria. In NSW, it lies approximately between Bourke and Inverell in the north, to Albury and Deniliquin in the south. Infections in animals have also occurred in Western Australia. Human cases rarely occur in NSW. In 2001, several people in the USA contracted anthrax from spores maliciously distributed through the mail.
For all three types of anthrax, symptoms can appear within seven days of coming into contact with the bacterium, although incubation periods of up to 60 days possible. The reported incubation period for cutaneous anthrax ranges from three to ten (commonly five to seven days). The incubation period for gastrointestinal anthrax is suspected to be three to seven and respiratory incubation for anthrax has been reported from one to 60 days (commonly one to five days).
The symptoms of the disease vary depending on how the disease was contracted. Anthrax meningitis may be a complication of cutaneous, inhalation, or gastrointestinal anthrax, and is almost invariably fatal.
About 95 per cent of reported anthrax infections occur when the bacterium (or spore) enters a cut or abrasion on the skin, (eg. when handling contaminated wool, hides, leather or hair products of infected animals). Skin infection begins as a small papule and progresses to a vesicle in one to two days. The vesicle then erodes, leaving a necrotic ulcer with a characteristic black centre - the typical anthrax eschar. Secondary vesicles are sometimes observed. The lesion is usually painless but can become painful if a secondary bacterial infection develops. Other symptoms can include oedema around the eschar, swelling of adjacent lymph glands, fever, malaise and headache. The case fatality rate of cutaneous anthrax can be up to 20% without antibiotic treatment and <1 per cent with antibiotic treatment.
Initial symptoms may resemble an influenza-like illness (ILI), which include a sore throat, mild fever and myalgia in the absence of rhinorrhoea. This prodromal phase is characteristically followed by partial resolution of symptoms, followed after several days by rapid progression to severe breathing problems and shock. The cardinal feature is a widening mediastinum on chest X-ray without pulmonary infiltrates. Meningitis frequently occurs. Inhalational anthrax is usually fatal even when treated, but commencement of antibiotics during the prodrome may be effective.
The gastrointestinal form of anthrax usually occurs after eating contaminated meat and is characterised by an acute inflammation of the intestinal tract. Initial signs of nausea, loss of appetite, vomiting, and fever are followed by abdominal pain, vomiting of blood and severe diarrhoea. Gastrointestinal anthrax results in death in 25% to 60% of cases.
People at greater risk of anthrax infection include:
Anyone who handles material potentially contaminated with anthrax should only do so under the guidance of NSW Health and NSW Department of Primary Industries and Regional Development (DPIRD). People handling potentially contaminated animals or materials should wear gloves, eye protection, overalls, and rubber boots and should ensure skin breaks are protected with sealed waterproof dressings.
Thorough hand washing and showering with soap are also very important to prevent infection.
There is no anthrax vaccine available in Australia to prevent infection for civilian use.
A confirmed case requires either:
Isolation of Bacillus anthracis-like organisms or spores confirmed by a reference laboratory.
Not applicable.
Anthrax is to be immediately notified by laboratories on suggestive or definitive laboratory evidence (ideally by telephone). Confirmed cases should be entered onto NCIMS.
On the same day of notification, begin follow-up investigation, and notify OHB of case details.
Within one working day of notification, enter confirmed cases 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 health carers, but regardless of who does the follow-up, PHU staff should ensure that action has been taken to:
Clinical samples from a patient with suspected anthrax should be sent directly to a specified reference laboratory. In NSW this is the PC4 laboratory at NSW Health Pathology - Institute of Clinical Pathology and Medical Research (ICPMR) at Westmead Hospital. The laboratory should be contacted for advice on the collection and preparation of specimens can be packaged and shipped using standard (category B) methods.
Based on clinical signs and symptoms, specimens to be taken from cases may include blood culture sputum, swabs from cutaneous lesions, faeces, swabs from oropharyngeal lesions, or cerebrospinal (CSF) fluid.
B. anthracis is classified as a Security Sensitive Biological Agent. If a clinical laboratory isolates an organism with growth features characteristic of this organism, immediate notification to the SSBA Regulatory Scheme is required and the isolate should be forwarded immediately to the PC4 laboratory NSW Health Pathology - Institute Of Clinical Pathology And Medical Research (ICPMR) at Westmead Hospital for confirmation. Isolates require Category A packaging and transport.
For treatment recommendations, consult an infectious disease physician and/or contact the High Consequence Infectious Disease (HCID) Specialist Service on 1800 4243 00 (1800 HCID 00). The HCID Specialist Service is a 24/7 hotline to reach an on-call HCID physician for advice to clinicians on assessment, diagnosis, and management of HCIDs.
Obtain a history of exposure to infected animals or animal products (e.g. contaminated hair, wool, hides, or products made from them), or anthrax vaccines given to livestock, and trace to the place of origin. In a manufacturing plant, consider the adequacy of preventative measures and refer to SafeWork NSW. Consider the possibility that the infection arose from deliberate exposure (see 10. Managing special situations).
In the event of a human case occurring from contact with animals or animal products, the PHU should notify OHB and immediately contact the 24/7 Emergency Animal Disease (EAD) hotline (1800 675 888).
Where an occupational or other exposure risk factor cannot be identified, consideration should be given to broadening the investigation in consultation with OHB and Reference Laboratories to assist with typing of the organism.
Hand hygiene should be performed using soap and water preferable to the use of alcohol-based hand rubs.
For cutaneous anthrax, the lesion is likely to be sterile after 24 hours following treatment, however dressings soiled with discharges from lesions should be burned and reusable surgical equipment must be sterilised.
Standard and contact infection control precautions apply for all direct clinical care of all types of anthrax. Soiled dressings should be disposed of as clinical waste (incineration).
Environmental cleaning should be performed with suitable sporicidal agent.
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 soiled dressings and contaminated clothing and Personal Protective Equipment (PPE). Education on the handling of carcasses and products of potentially infected animals should be a priority and should be referred to DPIRD to advise or assist.
Identify the likely source of infection in conjunction with the DPIRD, who may initiate animal control measures.
In the event of a deliberate release, environmental sampling for forensic purposes may be required (see 11. Managing special situations).
Contacts are those who may have been exposed to the same infection sources as a human case OR had direct contact with infectious animals/materials.
Where a person has been exposed to a suspicious substance, they should be advised to call 000 so that NSW Police can assess the incident.
Where an incident is deemed 'high risk' by NSW Police due to an actual threat to the health or safety of high-profile or other persons as a result of deliberate exposure to a suspicious substance, a Forensic Service specialist may attend the incident scene and collect environmental samples for testing.
The Chief Health Officer will be notified of any samples that test positive for anthrax and will inform the local Public Health Unit (PHU).
While efforts are made to adhere to this chain of communication, notification of a positive anthrax result may reach the PHU through different channels. Regardless, the PHU must ensure that both the Chief Health Officer and LHD Health Services Functional Area Coordinator (HSFAC) have been notified.
It is important to recognise that low to medium risk suspicious substance incidents (sometimes known as "white powder" incidents) occur relatively frequently and that in most situations notification to public health will not be required.
Other potential suspected or confirmed anthrax detections, such as livestock or soil, may involve coordination with DPIRD Animal Biosecurity and Local Land Services, SafeWork NSW
A preliminary or definitive finding of anthrax (preliminary or definitive) in an environmental sample to which people have been potentially exposed will prompt the State Public Health Controller to initiate an urgent meeting involving officials from NSW Ministry of Health, Health Protection NSW, and the local PHU. This meeting may also include infectious diseases specialists and laboratory experts.
The aims of the meeting will be: to assess the risk to exposed people and to determine whether interventions such as antibiotic prophylaxis and symptom monitoring will be recommended for them, and; to determine if any further public health actions or investigations are required, subject to advice from NSW Police.
The local PHU may be tasked with managing contacts identified by NSW Police as having been exposed to material that tested positive for anthrax. In conjunction with a specialist clinical service such as an Infectious Disease Department of the LHD, the PHU will inform contacts of the results, counselling them about the risk and, if recommended, arrange for antibiotic prophylaxis and symptoms monitoring. Contact details for exposed people will usually be accessed from NSW Police via the State HSFAC and State Public Health Controller
For guidance on deliberate release of anthrax, see Anthrax: Public Health response plan for Australia for guidelines for preparedness, response and management following the deliberate release of Bacillus anthracis (Second edition October 2012)