Anthrax Information for Producers

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Anthrax - the disease

Anthrax is an environmental disease caused by the spore-forming, rod-shaped bacterium- Bacillus anthracis. Animals on pasture acquire the disease by ingesting soil contaminated with anthrax spores. There is no direct animal to animal transmission of the disease.

Bacillus anthracis bacteria exists in two forms, a “vegetative” form that only survives inside a living animal and a “spore” form that can exist in the environment for prolonged periods of time. When an animal dies from an anthrax infection, the vegetative form of the bacteria in blood and body fluids escapes from the body and will form spores when exposed to oxygen (the ambient temperatures must be over 20° for this process to be completed). The vegetative form of the bacteria is fragile and easily inactivated by disinfectants or temperatures less than 4° or greater than 58°C. The spore form of the bacteria is markedly resistant to temperature and disinfectant and can survive for prolonged periods of time in the environment. Control measures for anthrax are aimed at interrupting the infection cycle by reducing or eliminating the environmental contamination with spores.

There are three components to Canada’s anthrax control program

  1. Quarantine
  2. Vaccination
  3. Disposal 

Quarantine

Vaccination

Note: In some situations deaths can occur up to 14 days post vaccination. Animals should be monitored twice daily for a minimum of 14 days post vaccination. Deaths occurring more than 14 days after vaccination should be investigated for other causes.

Disposal

This is an extremely important component of the anthrax program. Prompt disposal will limit or prevent further contamination of the environment with anthrax spores and thereby reduce the risk to animals grazing on these sites in the future.

Carcass Management/Control

When anthrax is suspected carcass management should begin immediately and continue until a negative laboratory diagnosis is received or the carcass is disposed of in accordance with CFIA guidelines.

Methods of Disposal

Incineration/Burning:

This is the preferred method of disposal - especially when a carcass has been opened for post mortem examination or scavenged. The goal of burning is to destroy as many spores as possible and thereby decrease environmental contamination. General considerations include:

Burn permits may be required by municipal or provincial governing authorities - it is the responsibility of the owner to ensure all requirements are met.

Pyre System:

Wood

Note: Approximately one cord of wood (4'x4'x8' or 128 cubic feet; 1.2x1.2 x 2.4 or 3.4m3 ) is required per 1000 lb (~500 kg) of carcass to be incinerated.

Straw

Note: Flax bales burn at a very high temperature and are well suited to burning carcasses, however, when used as the sole fuel they may burn too fast for effective incineration of the carcass. Use of flax bales in the centre of the pyre surrounded by other straw bales will burn hot enough for complete carcass incineration. When other types of straw bales are used as the sole fuel source more accelerant will be required.

Note: After an effective burn primarily ash and bits of bone should remain and with minimal fly attraction to the site.

Burn pits/trenches

Note: it will be necessary to decontaminate the ground where the carcass laid as well as the equipment, tools, etc. used in handling the carcass and any contaminated materials. Decontamination is done by burning the area using a propane torch and/or formaldehyde, or bleach.

In all cases, CFIA must be able to assess the burn site to ensure there was adequate incineration of the carcass. CFIA will also document the identification of carcass(es) involved.

Burial

In the event that incineration is not feasible or cannot take place immediately, deep burial may be permitted.

General Considerations

Special Circumstances

In certain situations, due to environmental conditions such as prolonged rain, carcass inaccessibility (i.e. standing water, heavy bush) or logistical problems such as lack of proper equipment, manpower etc., the prompt disposal of infected carcasses may not be possible. In these circumstances, to prevent or minimize anthrax environmental contamination, the CFIA will assess the situation with the owner and decide on an appropriate course of action. The carcass and the surrounding area must be covered with disinfectants such as 10% formalin or 5% solution of lye (sodium hydroxide) and repeated as needed.

Cleaning and Disinfection (Decontamination)

For animals that die on pasture decontamination is only required for the place where the animal died.

Equipment

Other disinfectants with activity against spores include chlorine, a Javex 6% solution diluted at a one part Javex to two parts water, and peracetic acid at a 3% solution. Autoclaving is also an effective means to sterilize equipment.

Clothing and Boots