Anthrax

What is anthrax?

Anthrax is a serious, usually fatal disease caused by the bacterium Bacillus anthracis. It occurs world-wide and can infect a wide range of domestic and wild animal species as well as humans.

In grazing livestock, anthrax usually presents as the sudden death of one, or a group of animals in a mob. Anthrax can kill stock of any age or class with no warning and can result in significant losses.

Anthrax is listed as prohibited matter under the Biosecurity Act because of the potential danger it poses to people, other livestock and the possible impact on Australia’s export markets. It is a notifiable disease in NSW, and anyone who suspects anthrax must report it immediately.

Preventing the risk of anthrax in dry conditions

Hot and dry conditions favour the development of anthrax. With drought now covering much of NSW, the conditions for infection are ideal and may result in more anthrax incidents than would normally occur. Anthrax can be prevented by annual vaccination of cattle and sheep.

Producers are encouraged to consider vaccinating animals if they are grazing in high risk locations (Figure 1).

What are the risk factors for anthrax?

  • Ingestion of soil by cattle, sheep and other ruminants. This is why in prolonged dry conditions such as the current drought, the risk of anthrax infection increases. Other factors include:
    • grazing of stubbles or very short pastures
    • low ground cover
    • deep cultivation of paddocks
    • earthworks in paddocks
    • heavy rain causing movement of soil or exposure of old anthrax grave sites
    • contact with infected carcases.
  • Moderate rainfall following prolonged dry periods.
  • The presence of alkaline soils which favour spore survival.
  • A history of anthrax on the property.

How can anthrax be prevented?

Anthrax vaccine is used to protect livestock from infection in NSW. Annual vaccination of cattle and sheep on properties with a history of anthrax is strongly recommended. Vaccination provides effective protection against anthrax when the manufacturer’s directions are followed.

You must apply to use the vaccine by submitting a form to your Local Land Services district veterinarian. Once authorised, you can then place an order for the vaccine with your local rural supplier or private veterinarian.

For more information, contact Local Land Services on 1300 795 299.

How can I spot the signs of anthrax?

Be suspicious of anthrax if animals die suddenly and one or more of the following occur:

  • there is a history of anthrax at any time on the property
  • the property is located within the central part of NSW where most cases of anthrax occur
  • blood may be present around the nose, mouth and anus of carcasses. However, in many cases you may not see this sign, so it should not be relied upon to diagnose anthrax
  • blood from the carcase does not clot.

What should I do if I suspect anthrax?

Immediately contact Local Land Services on 1300 795 299 or call the Emergency Animal Disease Hotline on 1800 675 888.

The carcase of an animal that has died of anthrax poses an extreme infection risk to people and other animals. If you suspect an animal has died of anthrax:

  • report it immediately
  • do not handle, open or skin the carcase
  • do not move the carcase
  • keep all other animals away from the carcase
  • do not move any other animals off the property
  • keep the affected mob separate to all other animals on the farm.

A veterinarian or an authorised officer under the Biosecurity Act will investigate suspect cases of anthrax. If suitable samples can be collected, they can be tested on-farm. If samples are not available, smears of blood and a piece of the animal’s ear will be collected for examination at the laboratory.

If you have any concerns for your own health or those on your property, please see your GP or call 1300 066 055 to be directed to your local Public Health Unit.

Does anthrax occur in NSW?

Cases of anthrax in NSW tend to occur in an area which runs through the centre of the state and into Victoria. The area lies approximately between Bourke and Moree in the north, to Albury and Deniliquin in the south.

Although anthrax does not occur frequently in NSW, its re-appearance is unpredictable. Anthrax can survive for long periods in the environment by forming tough spores which can lie dormant in the soil for decades.

You need to remain alert to the disease and report any suspicious livestock deaths immediately by calling the Emergency Animal Disease Hotline on 1800 675 888.

Figure 1. For the last 50 years almost all cases of anthrax in NSW have occurred within the highlighted region

Case studies

The following scenarios highlight the fact that anthrax is unpredictable, can survive for long periods in the environment without manifestation and kill stock of any age or class without warning. While most incidents involve low numbers of animals, in some instances, hundreds may die. All three scenarios occurred in the central part of the state (as shown in Figure 1) where most anthrax cases occur. Annual vaccination of cattle and sheep can prevent anthrax.

Scenario one

In November 2009, several deaths occured in a mob of 1100 second-cross lambs grazing a wheat stubble paddock in the Riverina. The owner assumed pulpy kidney and yarded the remaining stock to vaccinate. The deaths however continued, increasing rapidly with over 355 reported dead. Anthrax was subsequently confirmed.

Following an investigation, it was established that:

  • there was no previous history of anthrax on the property
  • earthworks (contour banks to reduce soil erosion) had been conducted in the paddock where deaths commenced in the previous 12 months
  • storms on the property were reported as having occurred two to three days before the deaths commenced.

Scenario two

An anthrax infection was recently confirmed as the cause of death of 12 cows in a mob of 160 on a property in the Central West region of NSW. Initially, nine animals had died suddenly while the calving cows were grazing stubble and silage. The herd was vaccinated with 5 in 1 and moved to an oat paddock where a further three animals died. Samples were collected by the district vet several days later. Anthrax was confirmed.

Following an investigation, it was established that:

  • the affected mob had moved on to the property nine months prior to the deaths
  • in 1997, anthrax was confirmed on a nearby holding that is part of the same Property Identification Code (PIC)
  • an increased frequency of anthrax infections is not unusual when stock are in paddocks with poor pasture cover.

Scenario three

In November 2016, a farm manager in the Central West region of NSW contacted their district veterinarian to report three sudden, unusual deaths in a mob of cows and calves on the property he was managing.

Upon examination of samples taken from the animal carcases, anthrax was confirmed.

An order was issued to the landowner to vaccinate immediately and burn the affected carcases to ash. Given the total fire ban in place at the time, the carcases were unable to be burnt immediately.  The owner was instead ordered to secure the carcases to ensure predation by foxes, wild pigs and dogs did not occur. Burning occured when the fire risk could be managed.

Following an investigation, it was established that:

  • the infected animals had been moved into the paddock in which they were found, 10 days prior to the discovery
  • there was no known history of anthrax on the property
  • the property had been in the family since the mid 1950s
  • a neighbouring property had reported cases of anthrax in the past
  • the source of the anthrax spores was not identified. It is possible that soil disturbance related to cleaning out dams in this paddock brought long buried spores to the surface
  • the absentee landowner had never vaccinated any livestock on the property in the past, nor had he instructed the farm manager to do so.

More information

For more information, contact Local Land Services on 1300 795 299, visit NSW DPI or call the Emergency Animal Disease Hotline on 1800 675 888.