Anthrax Fact Sheet

Cause:

Bacillus anthracis, a spore-forming bacteria. Anthrax spores are found in soil samples throughout the world. Plant/grass eating animals acquire the disease by ingesting spores from the soil. Prior to development of animal vaccines and antibiotics, the disease was one of the main causes of uncontrolled death in cattle, sheep, goats, horses and pigs worldwide.

Occurrence in Animals:

More commonly in seen in ruminants (cattle, sheep, and goats), occurs in horses and pigs, but rarely in dogs and cats.

Source of Infection in Animals:

The bacteria and/or spores are found in animal blood and other tissues; the spores are also found on wool, animal hide or hair.

Transmission:

Humans can become infected with anthrax by contact with anthrax-infected animals or contaminated animal products. Anthrax spores can enter a human directly (through cuts/abrasions), or by breathing in anthrax spores from infected animal products (wool, animal hides, etc). People also can also become infected with gastrointestinal anthrax by eating undercooked meat from infected animals.

Observable Signs of Infection:

Animals:

• Sudden death in ruminants where carcasses are frequently bloated, have little rigor mortis, and may have blood discharges that do not clot.
• Pigs and horses have less severe disease, and signs may include edema (watery swelling) of the throat regions (pigs), fever, colic, and bloody diarrhea (horses)

Humans (three forms):

• Cutaneous: most common form; localized, painless ulceration with central, black scab.
• Pulmonary: initially may have flu-like symptoms, with subsequent development of respiratory distress and failure.
  
• Intestinal/GI: this form is rare; fever, anorexia, vomiting, bloody diarrhea.

Precautions:

• A human vaccine is available for high risk individuals (people working)
  
• If anthrax is a suspected as cause of death of an animal, a necropsy should not be performed, and appropriate public health authorities should be informed immediately
  
• Source of animal (e.g. herd/region) could be quarantined as part of control measures.
  
• Due to concerns with bioterrorism ? any potential cases of anthrax must be immediately reported to authorities.

Reference:

Handbook of Zoonoses: Identification and Prevention; Colville JL and Berryhill DL eds. Mosby. St Lois. 2007.

Additional Information:

CDC- Anthrax: Emergency Preparedness and Response
CDC- Anthrax: What You Need to Know