Botulism Topics

• infant botulism
• wound botulism
• intestinal toxemia
• botulinum toxin
• artificial ventilation
• exact source
• eventual outcome
• bacterium
• western countries
• digestive tract
• spores
• colonization
• foodstuffs
• shortness of breath
• bloodstream
• intestine
• sweetener
• spore
• ingestion

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Botulism, Botulism

The toxin enters the body in one of four ways: by colonization of the digestive tract by the bacterium in children ( infant botulism ) or adults ( adult intestinal toxemia ), by ingestion of toxin from foodstuffs ( foodborne botulism ) or by contamination of a wound by the bacterium ( wound botulism ).

The most common form in Western countries is infant botulism . This occurs in small children who are colonized with the bacterium during the early stages of their life. The bacterium then releases the toxin into the intestine, which is absorbed into the bloodstream. While the consumption of honey during the first year of life has been identified as a risk factor for infant botulism, it is only a factor in a fifth of all cases.

It affects about 100 infants per year in the United States. Infants less than 12 months of age are susceptible, with almost 90% of cases occurring between the ages of 3 weeks and 6 months of age at presentation. The mode of action of this form is through colonization by germinating spore in the gut of an infant. The first symptom is usually constipation, followed by generalized weakness, loss of head control and difficulty feeding. Like the other forms of botulism, the symptoms are caused by the absorption of botulinum toxin, and typically progress to a symmetric descending flaccid paralysis. Death is often the eventual outcome unless the infant receives artificial ventilation.

For this reason, it is advised that no sweetener be given to children until after 12 months. Nevertheless, the majority of infants with botulism have no dietary history, and the exact source of the offending spores is unclear about 85% of the time. Spores present in the soil are a leading candidate for most cases, and often a history of construction near the home of an affected infant may be obtained.

Patients who survive an episode of botulism poisoning may have fatigue and shortness of breath for years and long-term therapy may be needed to aid their recovery.

However, these clues are often not enough to allow a diagnosis. Other diseases such as Guillain-Barr syndrome, stroke, and myasthenia gravis can appear similar to botulism, and special tests may be needed to exclude these other conditions. These tests may include a brain scan, cerebrospinal fluid examination, nerve conduction test (electromyography, or EMG), and an Edrophonium Chloride (Tensilon) test for myasthenia gravis. A definite diagnosis can be made if botulinum toxin is identified in the feed, stomach or intestinal contents, vomit or feces. The toxin is occasionally found in the blood in peracute cases. Botulinum toxin can be detected by a variety of techniques, including enzyme-linked immunosorbent assays (ELISAs), electrochemiluminescent (ECL) tests and mouse inoculation or feeding trials. The toxins can be typed with neutralization tests in mice. In toxicoinfectious botulism, the organism can be cultured from tissues. On egg yolk medium, toxin-producing colonies usually display surface iridescence that extends beyond the colony. Weber,J.T. "Botulism" In Infectious Diseases, 5th ed. Edited by P.D. Hpeprich, J.B. Lippincott Company, 1994, pp. 1185-1194.

Reported symptoms include anorexia, refusal to drink, vomiting, pupillary dilation, and muscle paralysis. "Botulism." In the Merck Veterinary Manual, 8th ed. Edited by S.E. Aiello and A. Mays. Whitehouse Station, NJ: Merck and CO., 1988, pp.442-444.

After several weeks, the paralysis slowly improves. If diagnosed early, foodborne and wound botulism can be treated by inducing passive immunity with a horse-derived antitoxin, which blocks the action of toxin circulating in the blood.

Wounds should be treated, usually surgically, to remove the source of the toxin-producing bacteria. Good supportive care in a hospital is the mainstay of therapy for all forms of botulism.

Other sources report that, in the U.S., the overall mortality rate is about 7.5%, but the mortality rate among adults over 60 is 30%. The mortality rate for wound botulism is about 10%. The infant botulism mortality rate is about 1.3%.

In some large outbreaks, a million or more birds may die. Ducks appear to be affected most often. Botulism also affects commercially raised poultry. In chickens, the mortality rate varies from a few birds to 40% of the flock. Some affected birds may recover without treatment.

The prognosis is poor in large animals that are recumbent. Most dogs with botulism recover within 2 weeks.

Of these, approximately, 72% are infant botulism, and 3% are wound botulism. Outbreaks of foodborne botulism involving two or more persons occur most years and are usually caused by the consumption of home-canned foods.

Source: Wikipedia > Botulism