Note for Pet Owners:

This information is provided by Provet for educational purposes only.

You should seek the advice of your veterinarian if your pet is ill as only he or she can correctly advise on the diagnosis and recommend the treatment that is most appropriate for your pet.

Anthrax is a serious, potentially fatal zoonosis and it is a notifiable disease in the UK. Extreme care is needed when handling infected animals or their by-products and protective clothing should be worn. Disposal of carcases must comply with local regulations eg incineration. 

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Anthrax is a disease characterised by causing sudden death . It occurs worldwide, although it is most common in Tropical and sub-tropical countries. The organism can survive for a long time in the environment, especially soil.. Anthrax is a notifiable disease in the UK and cases must be reported to the authorities.

e cause of anthrax is a gram-positive bacterium called Bacillus anthracis. These bacteria form spores when exposed to the air and the spores can survive for a long time in the environment - spores have been recorded to survive as long as 60 years . These spores are resistant to changes in environmental temperatures, common disinfectants and processing of meat and by-products such as curing hides or rendering to produce bone meal. Spores survive especially well in warm conditions, alkaline, poorly drained soil and in the presence of organic material.

Outbreaks of the disease occur when environmental temperatures exceed 150 C. 

The bacteria produce a deadly toxin which causes death by causing shock and acute renal failure.

If an infected animal is allowed to decompose the bacteria are destroyed, but opening the carcase exposes the bacteria to air, and results in spore formation and contamination of the soil, and an exposure risk for humans. For this reason post-mortem examination of suspect animals is not recommended.

Animals become infected from soil by spores entering:

  • Cuts - inside the mouth, or in the skin - common route of infection
  • By ingestion of contaminated soil/food or water. Common route of infection  - eg ingestion of contaminated bone meal.
  • By inhalation of spores -"Woolsorters disease" in humans is due to the inhalation of spores in wool workers.
  • Transmission from biting insects - possible source
  • Following vaccination against anthrax - if the spores have not been killed adequately

Anthrax can affect all vertebrates and is most common in :

  • Cattle
  • Sheep
  • Goats
  • Horses.

Humans are moderately susceptible and transmission is by :

  • Inhalation
  • Ingestion
  • Skin contact and inoculation of spores

Human infection is most often  contracted from :

  • Soil
  • Cattle
  • Sheep
  • Goats
  • Horses

Workers that are most at risk include :

The following species are quite resistant to anthrax :

  • Cats
  • Dogs
  • Pigs - except in Papua New Guinea where there is an unusual variant which kills pigs.

In general there are no breed susceptibilities, although it has been reported that Algerian sheep are resistant to it.


Signs usually occur 1-2 weeks after exposure to the spores. The disease is almost always fatal  in domestic animals except in pigs. . Signs that are seen include :

  • Cats
    • Anthrax is uncommon in cats.
    • Infection occurs following ingestion of infected meat or bone meal.
    • Swellings of the head and neck - can cause asphyxiation
    • Acute, fatal gastroenteritis
  • Cattle and Sheep
    • Sudden death
    • Fever (up to 420 C)
    • Muscle tremors
    • Difficulty breathing and increased breathing rate
    • Collapse
    • Exposed mucous membranes look dark in colour and congested
    • Increased heart rate
    • Anorexia
    • Depression
    • Abortion in pregnant cattle
    • Diarrhoea and dysentery
    • Swellings in the throat
    • Swelling (oedema) of the sternum flanks and perineal region may occur. 
    • Milk changes colour - yellow or blood-stained
    • After death blood does not clot may discharge out of the nose, mouth and other orifices.
  • Dogs
    • Anthrax is uncommon in dogs.
    • Infection occurs following ingestion of infected meat or bone meal.
    • Swellings of the head and neck - can cause asphyxiation
    • Acute, fatal gastroenteritis
  • Horses and Ponies
    • Abdominal pain (colic) following ingestion
    • Fever 
    • Depression
    • Swellings due to oedema - following insect bite - throat, and lower parts of the body including the  neck, underside of chest and abdomen.
    • Death in 2-8 days
  • Humans (Woolsorter's or Ragpicker's Disease)
  • Pigs
    • Swelling of the throat and face
    • Anorexia
    • Depression
    • Blotchy red-purple haemorrhages appear in the skin
    • Dysentery may occur
    • Pneumonia and pleurisy- in young pigs following inhalation of spores.
    • Death - up to 3 days after signs appear

The Bacillus anthracis spores can survive for very long periods in soil, which can present a problem of infected land.

In live animals anthrax can be diagnosed by :

  • Culturing from  swabs taken from the pharynx, or from ascitic fluid.
  • Examination of a blood sample

In animals that have died from anthrax :

  • Blood does not clot and so tarry blood leaks from body orifices after death
  • No rigor mortis sets in 
  • The spleen is very enlarged 


  • The antibiotics Procaine penicillin G, Tetracycline and Streptomycin are very effective against Bacillus anthracis and it should be administered intravenously to affected animals as early as possible following exposure .
  • Antiserum is available against anthrax for use in infected or in-contact animals

Prevention of transmission relies on rapid disposal of dead animals by incineration - or possibly deep burial (6 feet at least) with quick-lime.

Sterilisation of the environment can be difficult and once spores are present requires strong disinfectants :

Vaccines are available against anthrax for use in countries in which the disease is endemic and where vaccination is allowed. Vaccination is not allowed in the UK.

Good for patients with moderate susceptibility and superficial skin lesions, but guarded or poor for those with septicaemia. Poor for species that are highly susceptible (cattle and sheep).


Updated January 2016