Anthrax

Dairy cow with antrax

What to look for

  • Animals are usually found dead
  • Bloody discharge from the mouth, nostrils and anus after death
  • In the very early stages animals have a high temperature, muscle tremors, difficulty in breathing and/or convulsions.

Cause – a bacteria (Bacillus anthracis)

Bacillus anthracis forms spores that allow it to persist in soil for decades. Animals become infected by eating or inhaling the anthrax bacteria from contaminated soil or water. Cases of anthrax sometimes occur after heavy rain following hot dry weather.

Animals likely to be affected

Ruminants (cattle, sheep and goats) and horses. Anthrax is a rare disease in dairy cattle in Australia. The disease usually causes only 1 or 2 cases on a farm (or in a district). Occasionally, larger numbers of animals will die on a farm or cases may occur on other farms in the district.

Other diseases with similar signs

Other causes of Sudden Death.

Confirming the diagnosis

  • If you find an animal that has died suddenly and has blood coming from the nostrils, mouth or elsewhere, call your vet or the nearest office of the state Department of Primary Industries. It is important NOT to touch the carcase and to remove any stock from the paddock.
  • The diagnosis is confirmed by laboratory examination of a blood sample that has been carefully collected from the dead animal.

Spread of the disease

Contamination of food and water. Carcases of infected animals contain huge numbers of the anthrax bacteria and can be a source of future infection. Anthrax is a notifiable disease so the affected property is placed in quarantine and animal movements are restricted until deaths cease and all animals are protected by vaccination. Government animal health staff will organise carcase disposal.

When a case occurs, the remainder of the herd will be vaccinated. Full immunity occurs 14 days after vaccination and lasts about a year. Vaccination may be extended to neighbouring herds when a number of farms are affected. Because the vaccine is alive, vaccination is carried out by veterinarians or other trained staff. Milk production may drop for a short time after vaccination.

Anthrax in people

People can become infected via cuts and abrasions when handling infectious material such as an animal that has died from anthrax. Carcases of dead animals should always be handled with care, using protective clothing and good personal hygiene.

The infection usually stays localised as a pustule or “malignant carbuncle”. Seek immediate medical attention if you suspect that you have an infection. In people treatment with antibiotics is generally successful although the rarity of anthrax means that medical authorities may not make the link between “malignant carbuncles” and anthrax.

More rarely, infection may occur from inhaling the anthrax bacteria and this can result in very severe pneumonia which can be fatal. This form of the disease was once called “wool sorter’s disease” because it occurred in people that handled wool from dead sheep.

Prevention

Sites where animals have died should be thoroughly cleaned up and disinfected.

Do you want animal health info delivered?

Subscribe to Dairy Australia publications