Anthrax

Description

Anthrax is a zoonotic disease caused by the spore forming bacterium Bacillus anthracis. Although anthrax is common in herbivores (e.g. cattle, sheep, and goats) and wild animals, humans can be exposed to tissue from infected animals, or directly to B anthracis spores under certain conditions.  Most cases of anthrax in NSW occur in sheep and cattle within the geographical area known as the “anthrax belt”.

When anthrax is suspected, a post mortem should not be undertaken as it will cause the vegetative forms of Bacillus anthracis to sporulate. These spores will remain a source of infection for long periods.

Anthrax can have different clinical presentations depending on the route of infection, host factors, and strain-specific factors. Herbivores affected by anthrax commonly present with acute septicaemia with a high fatality rate, often accompanied by haemorrhagic lymphadenitis.

Signs of acute septicaemia include fever and hyperexcitability followed by depression, respiratory or cardiac distress, staggering, convulsions, and death. Animals can be found dead without signs of disease. There may be bloody discharges from the natural body orifices.

Diagnosis and tests available

Diagnosis

Diagnosis is strongly supported by history, clinical signs and the use of an Immunochromatographic test (ICT) in the field. Confirmation is by smear examination and PCR in the laboratory. If the ICT test is used, samples must still be submitted to the laboratory for confirmation.

ICT test kits can be ordered from the laboratory by contacting Customer Service.

Tests available

Test

Sample(s) required

Days of the week test is conducted

Turnaround time1

Anthrax PCR

Clotted blood (red top tube), lithium heparin blood (green top tube), EDTA blood (purple top tube) or fresh tissue

Monday – Saturday2

Same day

Smear examination

Blood smear or fresh tissue

Monday – Saturday2

Same day

1 Turnaround times are provided as a guide only. For specific information about your submission please contact Customer Service.
2 Prior approval of delivery and testing on Saturday is required. Please contact Customer Service on 1800 675 623 to seek approval.

Specimen requirements

Blood smear

  • Blood smears from peripheral blood vessels (e.g. those in the ear)
    • Smears should be sent from more than one animal
    • Blood smears should be thin and air-dried, for Polychrome methylene blue (PMB) stain
    • Do not fix smears by heat or other agents
    • One end of the slide must be left clean

Blood (with anti-coagulant)

  • 10ml of blood collected into a lithium heparin tube
    • Submit chilled
  • 10ml of blood collected into an EDTA tube
    • Submit chilled

Blood (without anti-coagulant)

  • 10ml of blood collected into a  plain red top tube
    • Submit chilled

Fresh tissue

  • A 2cm square portion of the ear
    • Bacillus anthracis DNA can be extracted from the tissue for PCR when no blood or fluid can be collected.
    • Submit chilled

Further information

Note

  • The preferred sample for anthrax testing is a peripheral blood smear. When an ICT test has been performed, please submit the used ICT kit in addition to any other samples. Where possible, please submit duplicate samples in case confirmatory testing is required.
  • Fees for tests undertaken to confirm or exclude a diagnosis of Anthrax  are paid by NSW Department of Primary Industries
  • Contact Customer Service to provide advance notice of your submission. This will allow specific biosecurity precautions to be undertaken at the laboratory.
  • Clearly label specimens as Suspect Anthrax. A Suspect Anthrax warning should also be placed under the lid of the outer package. This will ensure specific biosecurity precautions are undertaken at the laboratory.
  • Pack specimens securely (i.e. double bag and send in a rigid container) and forward to the laboratory separate from any other specimens.