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Anthrax (potential bioterrorism agent)

Queensland Health Guidelines for Public Health Units

Revision History

1.0July 2010Full revision of guideline
1.1March 2013Updated link to Anthrax. Public health reponse plan for Australia
2.0Feb 2015Full revision of guideline

Infectious Agent

The agent is Bacillus anthracis.

Notification Criteria

Laboratory definitive evidence

Isolation of Bacillus anthracis-like organisms or spores confirmed by a reference laboratory.

Laboratory suggestive evidence

Detection of Bacillus anthracis by microscopic examination of stained smears


Detection of Bacillus anthracis by nucleic acid testing.

NB: nucleic acid testing is suggestive evidence as it has only been validated on cultures due to the rarity of anthrax cases.

Clinical evidence

Cutaneous: painless skin lesion evolving over 1-6 days from a papular through a vesicular stage, to a depressed black eschar invariably accompanied by oedema that may be mild to extensive;


Gastrointestinal: abdominal distress characterised by nausea, vomiting, haematemesis, bloody diarrhoea, anorexia, abdominal pain, ascites and septicaemia, and followed by fever;


Oro-pharyngeal: painless, necrotic oral or oro-pharyngeal ulceration which may be pseudo-membranous, accompanied by dysphagia, dyspnoea, cervical adenopathy and cervical oedema and fever;


Inhalational: rapid onset of hypoxia, dyspnoea and high temperature, with radiological evidence of mediastinal widening;


Subcutaneous: severe soft tissue infection, including necrotising fasciitis or severe cellulitis and abscess formation or severe sepsis in association with intravenous drug use;


Meningeal: acute onset of high fever, convulsions, loss of consciousness and meningeal signs and symptoms in association with one of the other clinical syndromes.

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Notification Procedure

Pathology Laboratories

To notify urgently (i) on receipt of request for testing and (ii) on confirmation of diagnosis by telephone or facsimile.

The public health unit should immediately notify the Communicable Diseases Unit, Queensland Health. Communicable Diseases Unit should immediately notify Biosecurity Queensland of suspected or confirmed cases.

The inhalational form of anthrax infection is so unusual in industrialised countries that it warrants immediate reporting to law enforcement authorities for consideration of deliberate transmission. 

Laboratory Aspects

Anthrax is a Tier 1 Security Sensitive Biological Agent (SSBA), the handling of which is regulated under the National Health Security Act 2007 and National Health Security Regulations 2008.

If a clinical laboratory isolates an organism with growth features characteristic of Bacillus anthracis, the isolate should be forwarded immediately to Queensland Health Forensic and Scientific Services (FSS) and further work by the clinical laboratory should cease until identity is confirmed. The Public Health Microbiology Laboratory at FSS must be notified prior to transfer of the culture. 

NB: people infected with an SSBA and people or entities treating them, such as doctors, nurses or hospitals are exempt from the requirements of the SSBA Regulatory Scheme. This exemption applies while the SSBA is in the body of the person (or normal human and clinical waste) and to taking diagnostic samples for the purposes of treatment, but does not apply to handling samples once they are sent to a pathology laboratory or to taking samples for the purposes of research (see guideline at

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Reporting to NOCS

Report only confirmed cases

Confirmed case

A confirmed case requires either:

  1. Laboratory definitive evidence


  1. Laboratory suggestive evidence AND clinical evidence.

Objectives of Surveillance

  1. To define the epidemiology of anthrax in Queensland.
  2. To identify cases so that appropriate public health action can be taken.
  3. To identify possible bioterrorism events so that appropriate public health and law enforcement action can be taken.

Public Health Significance and Occurrence

Primarily a disease of herbivores; humans and carnivores are incidental hosts. In most industrialised countries, anthrax is an infrequent and sporadic human infection. It is an occupational hazard of workers who process hides, hair (especially from goats), bone, bone products and wool; and of veterinarians, agriculture and wildlife workers who handle infected animals. Human anthrax is endemic in the agricultural regions of the world where anthrax in animals is common, such as Africa, Asia, South and Central America and southern and Eastern Europe.

Bovine anthrax occurs sporadically in Australia. Human cases of anthrax are rare. In the 10 years to the end of May 2014 only 3 cases (all cutaneous) were reported in Australia - in 2006, 2007 and 2010. All had plausible exposure to anthrax spores. No case of either inhalational or gastrointestinal anthrax has ever been reported in this country.

Anthrax is a potential bioterrorism agent. Although production of material readily dispersible in an aerosolised form is technically difficult, lower grade material could also cause large numbers of infections if dispersed in sufficient quantities. In 2001, 22 cases of anthrax (11 inhalational, 11 cutaneous) were identified in the US linked to mail containing B. anthracis spores.

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Clinical Features

An acute bacterial disease that usually affects the skin, but may rarely involve the oropharynx, mediastinum or intestinal tract.  In cutaneous anthrax, itching of exposed skin surface occurs first, followed by a lesion that becomes papular, then vesicular and in 2-6 days develops into a depressed black eschar. Moderate to severe and very extensive oedema usually surrounds the eschar, sometimes with small secondary vesicles. Pain is unusual and, if present is due to oedema or secondary infection. Untreated infections may spread to regional lymph nodes and the bloodstream with overwhelming septicaemia.  Untreated cutaneous anthrax has a case fatality rate between 5% and 20%. With effective treatment very few deaths occur.

Initial symptoms of inhalational anthrax are mild and non-specific and may include fever, malaise and mild cough or chest pain. Acute symptoms of respiratory distress, X-ray evidence of mediastinal widening, fever and shock follow in 3-5 days, with death shortly thereafter. Inhalational anthrax has a high fatality rate. In 2001 in the USA about 50% of cases died.

Intestinal anthrax is rare and more difficult to recognise. It tends to occur in explosive food poisoning outbreaks where abdominal distress is typically followed by fever, and signs of septicaemia. It has a fatality rate of 25% - 50%.


Animals (normally herbivores, both domesticated and wild) shed the bacilli in terminal haemorrhages. On exposure to the air, vegetative cells sporulate and the B. anthracis spores, which resist adverse environmental conditions and disinfection, may remain viable in contaminated soil for years. Anthrax spores may be passively redistributed in the soil and adjacent vegetation through the action of water, wind and other environmental forces. Dried or otherwise-processed skins and hides of infected animals may harbour spores for years.

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Mode of Transmission

Cutaneous: contamination of the skin with the bacterial spores due to its mechanical abrasion or damage caused by insect bites.

Inhalational: inhalation of spores (which are then transported to and germinate in regional lymph nodes).

Source of spores may be:

  • Contact with tissues of animals (cattle, sheep, goats, horses, pigs and others) dying of the disease
  • Contact with contaminated hair, wool, hides or products made from them (eg. drums, brushes, rugs);
  • Contact with soil contaminated by infected animals or
  • Contact with contaminated bone meal used in gardening. 
  • Anthrax spores could be used in biological warfare or terrorism.
  • Accidental infections may occur among laboratory workers.

Gastrointestinal: ingestion of undercooked contaminated meat. There is no evidence that milk from infected animals transmits anthrax.

Person to person transmission is extremely rare and has been reported for the cutaneous form only. It requires direct contact with skin lesions.

Incubation Period

From 1 to 7 days, although incubation periods up to 60 days are possible. There is some minor variation depending on the form of the disease.

Period of Communicability

Person to person transmission is extremely rare.

Articles and soil contaminated with spores may remain infective for several years.

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Susceptibility and Resistance

There is some evidence of inapparent infection among people in frequent contact with the infectious agent. Second attacks can occur, but reports are rare.




Check case's occupation. Search for history of exposure to infected animals or animal products and trace to place of origin. If a workplace such as a manufacturing plant is involved, in conjunction with Workplace Health and Safety Queensland, check for adequacy of preventive measures.

A potential bioterrorist source needs to be ruled out for all human cases of anthrax with no obvious exposure. Inhalational anthrax should be considered a bioterrorist event until proven otherwise.


Anthrax is rarely transmitted from person to person. Standard precautions should be practised for the duration of illness for cutaneous and inhalation anthrax. Antibiotic therapy sterilises a skin lesion within 24-48 hours. Soiled articles require disinfection or sterilisation.

Cases should be treated with appropriate antibiotics. For treatment regimens refer to the current edition of the Therapeutic Guidelines:


The National Medical Stockpile (NMS) holds a range of medical countermeasures for the prevention and treatment of anthrax exposure in Australia and these include: BioThrax - anthrax vaccine and a range of antimicrobials (e.g. Ciprofloxacin, Doxycycline, Amoxycillin Paediatrics etc.). Access to these countermeasures is through the National Incident Room.

Antitoxins (Raxibacumab and Anthrax immunoglobulin) are currently not USFDA approved, but only approved in the US as Investigational New Drugs for Emergency Use or USFDA approved as Post Exposure Prophylactic (PEP) drugs for use under the Animal Rule program in the US. Given these antitoxins are still under investigation and not USFDA approved for license and market authorisation, the NMS currently does not stockpile them for use in Australia.


The case should be advised of the nature of the infection and its mode of transmission.


Contact Tracing

Yes - person exposed to an identified source of infection.

InvestigationSearch for other cases


Exposure to suspected deliberate aerosol release

Antibiotic prophylaxis may be indicated, depending on the level of threat (see guidance on management of suspected bioterrorist incidents below).

Exposure to patients who have inhalational anthrax

Generally, there is no need to provide antibiotic prophylaxis to contacts of these patients, unless there has been a deliberate release of anthrax bacillus and the contact:

· may have also been exposed to the initial release


· is a member of the same household, and may have come into contact with the patient’s contaminated clothing or other personal effects immediately after the release.

Exposure to patients who have cutaneous anthrax

Generally, there is no need to provide antibiotic prophylaxis to contacts of these patients. Cutaneous anthrax has very rarely been passed from one person to another although discharges from skin lesions may contain anthrax bacteria. Lesions usually become sterile within 24-48 hours after antibiotics with efficacy against B. anthracis. If there are exceptional circumstances (eg. exposure to material from cutaneous lesions when the contact has cuts or abrasions on their skin and is not wearing gloves), prophylaxis should be considered, but this should be on a case by case basis, after consultation with an expert panel.

Exposure to infected animals or animal products

Generally, there is no need to provide antibiotic prophylaxis to these contacts. If there are exceptional circumstances (eg. significant exposure to body fluids / tissues from an infectious animal, carcass or animal product when the contact has cuts or abrasions on their skin and is not wearing personal protective equipment), prophylaxis should be considered, but this should be on a case by case basis, after consultation with an expert panel.

If a decision is made to offer post-exposure prophylaxis refer to the current edition of the Therapeutic Guidelines: Antibiotic.


Contacts should be advised of the nature of the infection and its mode of transmission.

Guidance on management of suspected bioterrorist incidents

  • If it is determined that the incident:
    • may involve a biological agent (ie. bacteria/spores) 
    • a credible threat has been made
    • there is intelligence from security agencies that clearly confirms the threat
    • persons have been exposed to the substance,
    • notify the police
    • arrange urgent laboratory assessment if material available
    • commence post exposure prophylaxis with ciprofloxacin or doxycycline for 60 days
  • Responders should use an approved, pressure–demand self-contained breathing apparatus (SCBA) in conjunction with a level A protective suit in responding to a suspected biological incident where any of the following information is unknown or the event uncontrolled: the type of airborne agents; the dissemination agent; if aerosol dissemination is still occurring or it has stopped but there is no information on the duration of the dissemination; or what the exposure concentration might be.
  • Responders may use a level B protective suit with an exposed or enclosed, approved pressure demand SCBA in a situation in which the suspected biological aerosol is no longer being generated, or in which other conditions may present a splash hazard.
  • Responders may use a full face piece respirator with a P100 filter or powered air-purifying respirator with efficiency particular air filters when it can be demonstrated that: an aerosol generating device was not used to create high airborne concentration; or dissemination was by a letter or package that can be easily bagged.
  • Persons who may have been exposed and may be contaminated should be decontaminated with soap and copious amounts of water in a shower. Bleach solutions are usually not required; a 1:10 dilution of household bleach – final hypochlorite concentration 0.5%) should be used only if there is gross contamination with the agent and it is impossible to remove the materials through soap and water decontamination. The bleach solution to be used only after soap and water decontamination and must be rinsed off after 10 to 15 minutes.
  • All persons who are to be decontaminated should remove clothing and personal effects and place all items in plastic bags which should be clearly labelled with the owner’s name, contact telephone number and inventory of contents.
  • The release zone should be regarded as a crime scene and advice sought from the police. Environmental samples and clinical specimens should be regarded as potential forensic material and appropriate chain of custody procedures put in place.

For further guidance see Queensland Government Interagency Guidelines for determining the level of response for incidents suspected of involving a terrorist-related biological agent (Appendix) and Anthrax: Guidelines for preparedness, response and management following deliberate release of Bacillus anthracis. 2012. Commonwealth of Australia.

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Preventive Measures

  • Educate employees who handle potentially contaminated items about modes of anthrax transmission, care of skin abrasions and personal cleanliness.
  • Control dust and properly ventilate work areas in hazardous industries, especially those handling raw animal material.
  • Maintain continuing medical supervision of employees and provide prompt medical care of all suspicious skin lesions.
  • Workers must wear protective clothing with adequate facilities for washing and changing clothes after work.
  • Thoroughly wash, disinfect or sterilise hair, wool and bone meal or other feed of animal origin prior to processing.
  • Do not sell the hides of animals exposed to anthrax or use their carcases as food or feed supplements (bone or blood meal).
  • If an animal dies of suspected anthrax, do not necropsy the animal but aseptically collect a blood sample for culture. Avoid contamination of the area.
  • Because anthrax spores may survive for years if carcases are buried, it is important to refer to Biosecurity Queensland for advice on the management of infected animal carcases.
  • Control effluents and wastes from rendering plants that handle potentially infected animals and from factories that manufacture products from hair, wool bones or hides likely to be contaminated.
  • Promptly immunise and annually reimmunise all domestic animals at risk.  Treat symptomatic animals with penicillin or tetracyclines and immunise them after cessation of treatment.
  • No human vaccine is currently registered for general marketing or available for civilian use in Australia.
  • Subject to the availability of a vaccine in the future, it will only be provided under the Special Access Scheme administered by the Therapeutic Goods Administration (TGA) for those groups at highest risk of infection with B. anthracis, that is, laboratory staff working with cultures of the organism. Vaccination will be offered to these staff only when the threat assessment is sufficiently high.


Prepare a summary report of the investigation for the Communicable Diseases Unit, Queensland Health, on request.

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Anthrax:  Guidelines for preparedness, response and management following the deliberate release of Bacillus anthracis. 2012. Commonwealth of Australia$File/anthrax-edition-2-oct-12.pdf (accessed 21 May 2014).

Hendricks KA, Wright ME, Shadomy SV, Bradley JS, Morrow MG, Pavia AT, et al. Centers for Disease Control and Prevention expert panel meetings on prevention and treatment of anthrax in adults. Emerg Infect Dis [Internet]. 2014 Feb [accessed 23 May 2014].

Heymann D. (Ed). Control of Communicable Diseases Manual, 19th edition. American Public Health Association: Washington, 2008.

Jernigan D et al.  Investigation of Bioterrorism-Related Anthrax, United States: Epidemiologic Findings. Emerging Infectious Diseases 2002;8(10):1019-1028. 

National Notifiable Diseases Surveillance System Annual Report Writing Group, Australia’s Notifiable Disease Status, 2010: Annual report of the National Notifiable Diseases Surveillance System. CDI 2012; 36 (1): 1-69

World Health Organisation. Anthrax in Humans and Animals, 4th edition World Health Organisation, 2008

Zakowska D, Bartoszcae M, Niemcewica M, Bielawska-Drozd A, Kocik J. New aspects of the infection mechanisms of Bacillus anthracis. Annals of Agricultural and Environmental Medicine 2012; 19(4): 613-8.

Appendix 1: ANTHRAX CASE ASSESSMENT - Data Gathering Guidelines

Standard demographic information:Age, gender, ATSI, address, occupation, workplace, contact details, NOK, attendance at institutions, child care, school, university

Clinical features - inhalation anthrax:

  • Rapid onset of severe, un-explained febrile illness (fever, chills, fatigue, non-productive cough)
  • Rapid onset of severe sepsis not due to a predisposing illness
  • Abrupt onset respiratory failure and the presence of widened mediastinum or pleural effusions on chest x-ray
  • Nausea
  • Sweats (often drenching)
  • Confusion or altered mental status
  • Vomiting
  • Pallor or cyanosis
  • Raised red cell count
  • Dyspnoea
  • Tachycardia
  • Abdominal pain
  • Pleuritic chest pain
  • Sore throat


  • Chest X-ray: mediastinal widening, pleural effusion, pulmonary infiltrate
  • FBC: to look for raised haematocrit, raised WCC, especially neutrophilia
  • LFT: to look for high transaminases
  • CT Chest if high suspicion and normal Chest X-ray
  • Blood culture

Clinical features – cutaneous anthrax: Major features

  • Surrounded by extensive oedema
  • Painless and non-tender (although may be pruritic or accompanied by a tingling sensation)

Minor features

  • Development of black eschar.
  • Progresses over 2-6 days through papular, vesicular and ulcerated stages before eschar appears
  • Most commonly affects hands, forearms, face and neck
  • Discharge of serous fluid
  • Local erythema and induration
  • Local lymphadenopathy
  • Associated with systemic malaise including headache, chills and sore throat; but afebrile


  • Blood culture
  • Skin swab

Treatment Used
Ciprofloxacin, rifampicin, vancomycin, gentamicin, chloramphenicol, penicillin, amoxicillin, imipenem, meropenem and clindamycin

Risk Factors

  • All movements of the case in the two weeks prior to illness (travel, attendance at work, gatherings).
    • Use table format to record Date, Location, Activity
  • Contact with animals, animal products, fertiliser (eg blood and bone)
  • Making, owning or playing animal hide drums
  • Injecting drug use
  • Working in postal sorting offices or handling large volumes of mail
  • Received threatening letter or package containing white powder

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Appendix 2: Guidelines for determining the level of response required for incidents suspected of involving a terrorist-related biological agent

The following guidelines should be followed when determining the level of response required to an incident suspected of involving a terrorist-related biological agent.

  1. In the first instance, all incidents to be managed in accordance with existing HAZMAT procedures.
  2. If a credible threat has been made (verbal or written threat made in relation to the incident) and the threat mentions a biological agent:

ACTION: Queensland Health (QHealth) should be contacted and QHealth officers will attend the incident site.

When at the incident site, officers from QHealth through Forward Command will determine the level of response required having regard to the following assessment guidelines:

  1. If it has been assessed that the incident may potentially involve a biological agent
    ANDthere is intelligence from security agencies that clearly confirms the threat:

    ACTION: a full biological response will be necessary.

  2. If it has been assessed that the incident may potentially involve a biological agent
    ANDit involves a high profile person (eg. prominent politician), BUT there is no intelligence from security agencies that confirms the threat:

    ACTION: Sample to be sent for biological testing. Details of exposed persons will be obtained. Decontamination will not be required unless Emergency Services personnel determine that a chemical agent is involved. Results on the biological sample will normally be available in 12 to 18 hours, but on some occasions up to 48 hours. QHealth will follow up with exposed persons.

  3. If it has been assessed that the incident may potentially involve a biological agent
    ANDit does not involve a high profile person nor is there intelligence from security agencies that confirms the threat:

    ACTION:  Incident to be managed in accordance with existing HAZMAT procedures for chemical/radiological incidents.

  4. If it has been assessed that the incident does not potentially involve a biological agent:

    ACTION: Incident to be managed in accordance with existing HAZMAT procedures for chemical/radiological incidents.






    It will be assumed that for incidents involving ‘white powders’, a biological agent is not involved.



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Last updated: 10 August 2017