Anthrax

Anthrax is caused by the bacterium Bacillus anthracis, which produces toxins that:

• destroy blood cells and blood vessels, causing haemorrhage, shock and death
• affect the central nervous system and other tissues.

Anthrax is a serious bacterial disease that can cause sudden death in livestock. When exposed to air, the bacterium forms spores that are extremely resilient and can survive in the environment for decades.

Anthrax is zoonotic, meaning it can spread between animals and humans. Cases of anthrax in humans are notifiable to Queensland Health.

Worldwide

Anthrax occurs all over the world, with outbreaks that can infect many animals simultaneously.

The extent of an outbreak depends on:

• environmental contamination
• soil type
• disturbance of soil
• weather conditions.

Australia

Anthrax is most common in the ‘anthrax belt’.

The 'anthrax belt' is a high-risk region. It stretches from northern Victoria through western New South Wales and into southern Queensland.

Western Australia has also experienced outbreaks.

Queensland

Anthrax occurs occasionally in Queensland.

The St George–Dirranbandi region lies within the ‘anthrax belt’.

Isolated cases have occurred near Wandoan and Marlborough.

Livestock owners in high-risk areas like St George–Dirranbandi and Wandoan should actively manage anthrax risks.

In animals:

• Infection usually occurs when animals ingest spores from contaminated pasture, feed, water, or (for pigs, dogs and cats) infected prey carcases.
• Once inside, spores germinate and multiply rapidly in blood and tissues.
• Toxins produced by the bacteria cause septicaemia, shock and rapid death.
• Incubation typically lasts 2–10 days but can extend up to 20 days.

In the environment:

• Disturbing or opening anthrax-infected carcases releases bacteria that quickly form spores when exposed to air.
• Spores are extremely resilient, surviving heat, dryness and most disinfectants.
• Spores can persist for decades in buried carcases and deep soil.
• On the soil surface, spores are usually destroyed within several years by moisture, microbes and sunlight.
• Soil disturbance can bring spores to the surface, increasing the risk of infection.

The first sign of anthrax is often sudden death in grazing animals.

If animals survive long enough, symptoms may include:

• weakness
• staggering
• laboured breathing.

After death, these signs may be observed in some cases:

• blood-stained discharge from body openings (not always present)
• rapid decomposition
• unclotted blood.

View the full list of clinical signs across different animal species.

Delays in responding to anthrax can result in:

• significant animal suffering and death
• increased costs for livestock owners.

Business impacts include:

• livestock deaths
• movement restrictions
• increased labour from monitoring animals
• treatment, vaccination and disposal expenses
• decontamination costs for yards, equipment and soil
• loss of export markets
• consumer rejection of animal products.

Human health

Anthrax poses serious risks to humans exposed to infected animals, carcases or contaminated sites.

Potential health impacts include:

• lung anthrax (from inhaling spores)
• skin anthrax (‘cutaneous anthrax’ or ‘malignant pustule’)
• intestinal anthrax (from consuming contaminated food)
• death in severe cases.

Environmental

Anthrax spores enter the environment when infected carcases are disturbed or opened.

Spores can:

• persist for decades in buried carcases and soil
• contaminate water through run-off or tannery effluent
• spread locally through scavengers, flooding or soil disturbance.

Animal

Animals are infected by:

• grazing contaminated pasture
• eating infected feed (for example, hay, bone meal or animal-based additives)
• chewing old bones or carcase material
• drinking contaminated water.

Inhalation of spores or infection through wounds is rare but possible.

Moving infected animals can introduce anthrax to new properties.

There is risk of infection throughout the year.

Anthrax outbreaks are more likely:

• after major climate changes (for example, rain after drought)
• during warm weather (above 15°C)
• when soil is disturbed (for example, by earthworks, flooding or erosion).

Properties at higher risk include those:

• in or near the ‘anthrax belt’
• receiving animals or feed from high-risk areas.

If you suspect anthrax:

1. Do not open or move carcases.
2. Contact your veterinarian immediately.
3. Stay away from the carcase and any fluids.
4. Follow guidelines for responding to a suspected anthrax outbreak.

If you have been exposed to anthrax:

• Seek urgent medical attention.
• Notify your general practitioner (GP) or the local public health unit.

Veterinarians can refer to clinical guidelines for anthrax.

Legal obligations

If you suspect or become aware of anthrax, you must report it immediately to:

• Biosecurity Queensland on 13 25 23
  or
• the Emergency Animal Disease Hotline on 1800 675 888.

If you own, treat or manage livestock, you have a general biosecurity obligation to take all reasonable and practical measures to prevent or minimise the effects of biosecurity risks such as anthrax. This means you are legally required to reduce the risk of anthrax and limit its spread when dealing with possible carriers.

Refer to detailed guidelines for:

• responding to a suspected anthrax outbreak
• decontaminating and disposing of anthrax carcases
• managing anthrax risk
• anthrax clinical guidelines for veterinarians.

Vaccination

Vaccinating animals against anthrax is crucial for controlling the disease and minimising its spread and impacts.

Antibiotic treatment for animals is rare and is determined on a case-by-case basis by the veterinarian and livestock owner. Prevention through vaccination remains the best approach to protect animals.