Difference between revisions of "Anthrax"

Revision as of 11:28, 29 July 2010

Description

Anthrax is a serious, often fatal zoonotic disease of wild and domestic mammals caused by the spore-forming bacterium Bacillus anthracis. The disease occurs worldwide and often in outbreaks. The infected host sheds bacteria into the environment which sporulate when exposed to air. These spores are highly resistant and can survive in the environment for many years. Grazing animals may become infected if ingestion of a large number of spores occurs. Additionally, biting flies appear to have a role in transmission of spores in areas of endemic disease. Inhalation of dust-borne spores may also be of importance.

Humans may be infected via contact with infected animal tissues, exposure to high concentrations of spores or contacted with infected animals. In herbivores, the disease commonly presents as a peracute onset septicaemia with a high mortality rate. In dogs, humans, horses and pigs the onset is less acute. There are three main forms of the disease; gastrointestinal, pulmonary or cutaneous.

Clinical signs

Ruminants and horses

In both cattle and horses, the disease course may range from peracute to chronic. Animals may be discovered dead in the field before any clinical signs have been observed.

Fatal peracute septicaemia
Sudden death
Acute onset severe pyrexia
Depression
Neurological signs such as staggering or trembling
Cessation of rumination
Subcutaneous oedematous swellings
Congested mucous membranes and petechiae

Pigs

Pigs are relatively resistant to anthrax and the disease often has a more chronic course affecting the oropharyngeal region. The disease often begins as an oedematous cellulitis of the the neck, head and regional lymph nodes. This may cause death by asphyxia.

Dogs

Dogs are rarely affected, but develop a similar disease to that found in pigs.

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 ===Description===
-Anthrax is a serious, often fatal zoonotic disease of wild and domestic mammals caused by the spore-forming bacterium [[Bacillus anthracis]]. The disease occurs worldwide and often in outbreaks. The infected host sheds bacteria into the environment which sporulate when exposed to air.''B. anthracis'' spores are highly resistant and can survive in the environment for many years.  These spores may be ingested by grazing animals but do not generally present a threat to humans. Animals may become infected if they ingested large quantities of spores. Additionally, biting flies seem to have a role in transmission of spores in areas of endemic disease.
+Anthrax is a serious, often fatal zoonotic disease of wild and domestic mammals caused by the spore-forming bacterium [[Bacillus anthracis]]. The disease occurs worldwide and often in outbreaks. The infected host sheds bacteria into the environment which sporulate when exposed to air. These spores are highly resistant and can survive in the environment for many years.  Grazing animals may become infected if ingestion of a large number of spores occurs. Additionally, biting flies appear to have a role in transmission of spores in areas of endemic disease. Inhalation of dust-borne spores may also be of importance.
 Humans may be infected via contact with infected animal tissues, exposure to high concentrations of spores or contacted with infected animals.
 In herbivores, the disease commonly presents as a peracute onset septicaemia with a high mortality rate. In dogs, humans, horses and pigs the onset is less acute.