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Anthrax

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Cattle

Anthrax is an acute disease caused by a germ known as Bacillus anthracis.

Symptoms

Among cattle and sheep, the period of illness is often short. The affected animals may be found dead without signs of illness having been noticed.  Nevertheless, anthrax is not always rapidly fatal in cattle and sheep. An affected animal may be ill for several days before death occurs.  Any of the following symptoms may be observed:

  • High temperature. 
  • Shivering and twitching. 
  • Harsh dry coat. 
  • Fits. 
  • Bright staring eyes.
  • Colicky pains. 
  • Dejection. 
  • Refusal of food. 
  • Marked decrease or complete loss of milk.  
  • Occasionally, blood from the nostrils is visible and there may also be blood in the dung.

In pigs and horses the disease is usually fatal, though less quickly than in cattle.  In both of these animals a hot, painful swelling in the region of the throat may be present. However, the absence of such a swelling does not rule out the possibility that death may have been due to anthrax.  In horses, symptoms of acute colic are frequently seen.  Pigs may simply refuse their food for a day or so, but variation in symptoms shown is very great indeed. Any sudden or unaccountable death in farm stock should always raise suspicion of anthrax.

When a fatal case of anthrax occurs in a herd of cattle, it frequently happens that some of the other animals have a latent infection and recover.  Such cases can be detected by taking the temperatures of all cattle, morning and evening for a week, following the outbreak.  It is not uncommon for pigs to be visibly sick for a few days and recover completely.  Following the attack, if animals are subjected to stress, for example farrowing, they may relapse and die.

Post-mortem appearances

The unopened carcases may be swollen and blood may ooze from the nostrils or other natural openings of the body. Absence of these conditions does not indicate that the case is not anthrax.

It is most important to remember that the carcase of a diseased or suspected animal must not be opened. In cases of sudden unexplained death, farmers should report the case to their veterinary surgeon and await veterinary opinion before disposing of the carcases. Veterinary tests for anthrax are free of charge when deaths are notified to the Regional Veterinary Lead for certain animals.

Precautions

The flesh, blood, offal and discharges from an anthrax infected carcase are full of anthrax germs. They are thus dangerous to animals and humans.

Consequently, an ailing animal to which the slightest suspicion of anthrax might be attached must not be killed and bled. It should be isolated and the Regional Veterinary Lead (or the police) informed. Similarly, an animal found dead under suspicious circumstances, should not be moved, skinned, or in any way cut or opened. Animals, vermin and poultry must be kept away from it and the Regional Veterinary Lead (or the police) informed. Any blood, which escapes from the body, should be immediately and thoroughly mixed with a large excess of Department for Environment, Food and Rural Affairs (DEFRA) approved disinfectant. This will destroy the anthrax organisms before they have time to form spores. This is most important as spores are very resistant to all destructive elements. Spores may survive for years, constituting a continuing danger to livestock.

Animals that have had contact with a suspected animal should be watched carefully and isolated at once if showing symptoms of illness. This is particularly necessary if cows in milk are affected. This milk may on rare occasions contain anthrax and thus could infect human beings.

Treatment

Treatment is seldom possible for infected animals because of the rapid, fatal course of the disease once symptoms become apparent. However, if time permits, antibiotic drugs prescribed by your veterinarian may be used with good effect. Animals continually exposed to infection, for example grazing infected pastures, may be considered for vaccination with the anthrax spore vaccine. You should apply through the local Regional Veterinary Lead.

This vaccine is safe to use and protects the animals for six months or more. Animals remain in a susceptible state for about ten days after vaccination. Animals should be isolated as far as possible from contact with possible sources of infection during this period.

Legislation

The Anthrax Order of 1991 as amended includes anthrax as a notifiable disease under the Animal Health Act. Any suspicion of the disease must be notified to the Regional Veterinary Lead. The Order provides for a veterinary inquiry as to the existence of disease. It explains the action to be taken in suspected and confirmed cases including the rules to be observed in an infected place.

Movement of animals is controlled  

The local authority has powers to dispose of carcasses. This can be on the infected place or by such other means as the Regional Veterinary Lead may approve.  Owners are not entitled to compensation, but the local authority pays for the destruction of the carcass(es).  

The Order also provides powers to require vaccination of animals and for cleansing and disinfection of infected premises.

Infection in man

There are three types of infection in man:

  • Anthrax may infect through cuts or damaged skin and cause a raised boil-like lesion developing a black centre, from which the word ‘anthrax’, meaning coal, derives. Normally, the skin infection responds to early treatment with appropriate antibiotics.
  • If inhaled as dust e.g. from handling contaminated wool it is often fatal.  
  • If infected meat and meat products are consumed, it may cause a bowel infection.