Anthrax

Alert

Anthrax is detected occasionally in southern Queensland. There have been cases in cattle in the St George-Dirranbandi area early 2018, early 2017, and 10 years previously. This region appears to be part of the ‘anthrax belt’ that extends the length of NSW and into Victoria. Properties in the anthrax belt have a higher risk of anthrax in cattle, sheep or other animals than in other areas. Given the repeated cases of anthrax in this region, graziers in southern Queensland especially should consider and manage their exposure to anthrax risk.

Anthrax is category 1 restricted matter.

Under Queensland legislation, if you suspect the presence of this disease in any species of animal, you must report it to Biosecurity Queensland on 13 25 23 or contact the Emergency Disease Watch Hotline on 1800 675 888.

Anthrax can be rapidly fatal to large numbers of livestock, particularly cattle. The bacteria may form spores that survive in the environment for more than 50 years. Anthrax is a zoonotic disease which means it can affect humans.

Cause

Bacillus anthracis

Distribution

Anthrax occurs in Australia, most commonly in New South Wales, in what is known as the 'anthrax belt' (extending the length of New South Wales, into Victoria, and into southern Queensland).

Repeated incidents have occurred in Queensland near St George-Dirranbandi. Isolated incidents have also occurred on the Marlborough peninsula, and near Wandoan.

Anthrax occurs throughout the world. Incidents can vary from occasional cases to widespread outbreaks, depending on soil, climate and degree of contamination.

Affected animals

  • cattle
  • sheep
  • horses
  • goats
  • pigs
  • dogs
  • humans

Symptoms

In animals

The signs of anthrax are:

  • sudden death in grazing animals
  • weakness, staggering and laboured breathing
  • blood-stained discharges after death, usually seen at all external orifices, and rapidly decaying carcass.

In humans

Various symptoms may occur in people due to the varied nature of the disease.

Impacts

Depending on the severity of the outbreak, impacts to businesses include:

  • animal deaths
  • increased labour due to intense animal observation
  • treatment and vaccination costs
  • decontamination and disposal costs of carcasses
  • marketing restrictions
  • abattoir rejection
  • consumer rejection of animal product
  • human health risks.

These impacts can be very costly for livestock producers. If your property is at risk of anthrax due to being  in southern Queensland, or having received livestock from a high-risk area, you should consider preventative measures (see below).

How it is spread

Environment

When exposed to air, spores form rapidly and are resistant to most external influences. They rarely persist beyond 4 years where soil moisture and microbial activity are high, but can remain viable in dry soil for much longer (upwards of 50 years).

The organism can be spread by pigs, dogs, wild birds, in flowing water, and through contamination by infected animals.

Effluent from tanneries, run-off from infected soil, and carcasses can contaminate water.

Animals

Animals become infected with anthrax from eating contaminated feedstuffs or grazing on contaminated land. Infected animals often die suddenly, with only a brief illness preceding death.

The incubation period (time from exposure to bacteria until clinical signs) is 2-14 days.

Pigs may become infected after eating contaminated blood and meat from carcasses. Cattle have been infected after chewing on old bones containing spores. Large outbreaks have resulted from contaminated feed additives such as bone flour and peanut meal. Inhalation is of minor importance in animals, but contaminated dust can be a source. Wound contamination occasionally occurs.

Humans

People are most likely to become infected when handling infected animals or breathing in anthrax spores from infected animal products (e.g. hides and wool). There are 3 forms of anthrax disease in people:

  • lung (inhalation)
  • skin (cutaneous)
  • intestinal.

Read about Anthrax infections in people on the Queensland Health website.

Risk period

Outbreaks from contaminated soil typically occur after a major climate change (i.e. rain following drought), and in warm weather when the temperature is over 15°C. Earthworks may increase risk.

In an uncontrolled outbreak, an initial case may be followed by secondary cases becoming infected from contamination by the initial case.

Monitoring and action

Call Biosecurity Queensland immediately if you suspect anthrax.

Do not open the carcass. This prevents people, other animals and the land from becoming contaminated.

If you suspect that a person has been exposed to anthrax, seek medical advice and contact a Queensland public health unit.

Control

Control of anthrax in domestic livestock is important for preventing its spread to people, animals and land. Control measures are to restrict movements of animals and animal products, and to vaccinate all animals at risk of exposure to infection. Biosecurity Queensland will provide advice on measures, that are consistent with the national guidelines, that can be taken to control the disease. Carcasses will be disposed of by deep burial or burning to minimise long-term soil contamination.

In rare cases, valuable individual animals can be treated with large doses of antibiotic. Treatment must be started quickly. It is more effective in pigs, dogs, and humans than in ruminants. Treatment with antibiotics will render vaccination ineffective, as the vaccine is live and will be killed by antibiotics. Early treatment with antibiotics for people infected with anthrax can prevent severe disease.

Rendering plants and factories processing wool and hides must adhere to workplace health and safety regulations.

Restrictions

If anthrax is confirmed or suspected, movements of animals and animal products from the property will be restricted. All cattle retained on the infected property, and possibly those on neighbouring properties, will be vaccinated to prevent further cases occurring.

Prevention

Livestock should be excluded from areas that have previously been contaminated by anthrax.

Livestock may be protected from the impacts of anthrax by vaccination. Supply and use of anthrax vaccine requires authorisation by the Chief Veterinary Officer. Refer to your veterinarian for further information on vaccination.

Keep livestock away from soil disturbances caused by earthworks or flooding. 

Monitor stock health, and investigate incidents of ill-health, especially rapid deaths.  

Maintain secure boundary fences to prevent stock straying. Control feral animals to reduce soil disturbance, the risk of animals becoming infected and the risk of spreading infection to new areas.

Livestock producers, especially in southern Queensland, should consider anthrax in their farm biosecurity plans. Consult your local veterinary practitioner to decide what preventative measures to take to protect your property and health.