BOTULISM

BOTULISM


Among its more common names, botulism is also known as limberneck in birds and shaker foal syndrome in horses. Botulism is caused by the toxins (byproducts of bacterial growth) of Clostridium botulinum. The disease is characterized by progressive muscle paralysis, in which the muscles go flaccid or floppy. The paralysis can eventually affect cardiac and respiratory muscles, resulting in death. While the disease is relatively rare, the outcome can be devastating. The C. botulinum toxins are some of the most deadly poisons known. They could be used in a bioterrorist attack by aerosol dispersal or food and/or water contamination. One gram of crystallized C. botulinum toxin is enough to kill a million people.



MORBIDITY: +




MORTALITY: + TO ++++




ETIOLOGY: BACTERIAL NEUROTOXIN


Botulism is caused by toxins that attach themselves to the ends of nerves and interfere with the ability of the nerve to send impulses to muscles. The muscles become flaccid (muscle tone is absent), resulting in paralysis. The toxins are produced by the bacterium C. botulinum, an anaerobic, gram-positive, spore-forming, rod-shaped organism. It grows in an environment that is low in oxygen. If this condition is not available it produces spores, a dormant form of the organism that can survive in soil for a long time. When conditions are right, the spores will germinate and start growing, producing toxins. There are seven distinct toxins produced by C. botulinum that are designated by the first seven letters of the alphabet.



HOSTS


Many species of mammals, fish, and birds may be hosts.


• Types A, B, E, and F cause diseases in humans. Type A is found mostly west of the Mississippi River, type B is found in eastern states, and type E is found in Alaska and in the Great Lakes area.

• Type A is used to manufacture Botox for cosmetic and therapeutic purposes.

• Type B can cause disease in horses and cattle.

• Type C is the most common toxin to cause disease in animals. It is found most often in the western United States.

• Type D can cause disease in cattle and dogs. It is seen most often in South Africa, South America, and Australia.

• Types A and E are found in birds and mink.

• Type G rarely causes disease, but it has been associated with disease in humans.


TRANSMISSION


C. botulinum and C. botulinum spores are found in soil worldwide, in the intestinal tracts of mammals and fish, and in the gills and internal organs of shellfish. Transmission occurs when animals (including humans) ingest the toxins preformed by the bacteria or ingest the bacteria, which then start to produce toxins. Preformed toxins are found in decaying carcasses; decaying vegetable matter; and improperly home-canned foods (especially vegetables with low acid content, such as asparagus, green beans, beets, and corn) and fruits. They can also be found in improperly cooked beef, pork, poultry, and milk products. Transmission can also occur through a wound infection. Botulism is not spread directly between animals by casual contact, but an infected dead animal can be toxic if ingested by another animal. Maggots feeding on an infected carcass can also be a source of infection, if eaten by another animal.



BOTULISM IN ANIMALS


Botulism is seen most commonly in wild birds, domestic poultry, cattle, sheep, horses, and some species of fish. Pigs and dogs are relatively resistant to botulism. There have been no reported cases of botulism in cats.


Botulism in animals is generally associated with ingestion of preformed toxins that cause a progressive paralysis, resulting in a lack of muscle tone. The symptoms appear anywhere from 2 hours to 2 weeks after infection, but most often within 24 hours. Clinical signs include difficulty chewing and swallowing, visual impairment, and generalized weakness. The paralysis eventually may affect the muscles of the heart and lungs, resulting in death. A form of botulism called toxicoinfectious botulism results from eating the C. botulinum organism that then produces toxins in the gastrointestinal tract.



CATTLE


Botulism in cattle is usually associated with eating preformed toxins in contaminated feed. If small animals (mice, snakes, etc.) or animal carcasses are baled into hay or packed into silage, they could be a source of C. botulinum toxins at a later time, when the cattle are fed the hay or silage. Botulism is sometimes seen when cattle that are lacking phosphorus or protein in their diets eat carcass bones, with attached bits of meat, or soil to supply the lacking nutrients. Both the bones and the soil could be contaminated with C. botulinum toxins. Clinical signs of botulism include drooling and tongue paralysis, resulting in the tongue hanging out of the mouth; incoordination; difficulty eating; drooping eyelids; and lying down in a sternal position (lying on the chest). Weakness starts in the back legs and moves toward the head. If the animal goes into lateral recumbency (lying on its side), it is near death.

Related posts:

  1. ABOUT THE DISEASES
  2. BRUCELLOSIS
  3. EASTERN EQUINE ENCEPHALITIS
  4. LEPTOSPIROSIS

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Oct 1, 2016 | Posted by in EXOTIC, WILD, ZOO | Comments Off on BOTULISM

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