Victoria agricultural officials are responding to a confirmed incident of anthrax in sheep on a single property near Swan Hill.

Public domain image/Titus Tscharntke
Public domain image/Titus Tscharntke

Victorian Acting Chief Veterinary Officer Dr Cameron Bell said quarantine notices had been put in place until the necessary biosecurity requirements, including carcass disposal and site disinfection, were completed. He said the case was on a farm which has had a history of anthrax and at-risk stock on the property are vaccinated.

“Anthrax detections in livestock occur in Victoria from time to time. They commonly occur during the warmer months when it is drier and cattle and sheep forage deeper into the soil when grazing. Quarantine controls will not affect the movement of local people or vehicles, including school bus routes.”

Local farmers, veterinarians and Agriculture Victoria are well prepared to handle these incidents. This isolated case was detected as part of ongoing surveillance for anthrax and other livestock diseases.

“We are taking the necessary steps to reduce the chance of more livestock being affected,” Dr Bell said.

Anthrax is a bacterial pathogen in livestock and wild animals. Some of the more common herbivores are cattle, sheep,goats, horses, camels and deer. Anthrax is a very serious disease of livestock because it can potentially cause the rapid lossof a large number of animals in a very short time. Affected animals are often found dead with no illness detected.

It infects humans primarily through occupational or incidental exposure with infected animals of their skins.

Bacillus anthracis bacteria Image/CDC
Bacillus anthracis bacteria

When conditions become favorable, the spores germinate into colonies of bacteria. An example would be a grazing cow ingests spores that in the cow, germinate, grow spread and eventually kill the animal. Anthrax is caused by the bacteriumBacillus anthracis. This spore forming bacteria can survive in the environment for years because of its ability to resist heat, cold, drying, etc.  This is usually the infectious stage of anthrax.

The bacteria will form spores in the carcass and then return to the soil to infect other animals. The vegetative form is rarely implicated in transmission.  Strict enforcement of quarantines and proper burning and burying of carcasses from livestock suspected to have died from anthrax is important to prevent further soil contamination with the bacterial spores.

There are no reports of person-to-person transmission of anthrax. People get anthrax by handling contaminated animal or animal products, consuming undercooked meat of infected animals and more recently, intentional release of spores.

There are three types of human anthrax with differing degrees of seriousness: cutaneousgastrointestinal and inhalation.