Botulism (cont.)

A neurotoxin actually paralyzes the nerves so that the muscles cannot contract. This happens when the neurotoxin enters nerve cells and eventually interferes with the release of acetylcholine so the nerve cannot stimulate the muscle to contract. Unless the nerve can regenerate a new axon that has no exposure to the neurotoxin, the interference at the neuromuscular junction is permanent. This is why it takes so long to recover from botulism and also why cosmetic and therapeutic uses of diluted neurotoxin can be effective for relatively lengthy time periods.

Clostridium botulinum is the name of bacteria commonly found in soil all over the world. The bacteria are considered to be anaerobic, which means these organisms grow best in low or absent oxygen levels. Clostridium bacteria are gram-positive rod-shaped bacteria that form spores that allow the bacteria to survive in a dormant state until exposed to conditions that can support growth. There are seven types of botulism neurotoxin designated by the letters A through G. Only types A, B, E, and F cause illness in humans.

Because of better canning processes, especially with home canning or home processing of food, the number of yearly cases has dropped to about 1,000 worldwide. In the United States, on average, 110 cases of botulism are reported each year. Of these, nearly 25% of cases are food-borne, approximately 72% are infant botulism, and the remainder (about 3%) are wound botulism, which until recently was rare. Outbreaks of food-borne botulism involving two or more people are usually caused by eating contaminated home-canned foods. The number of cases of food-borne and infant botulism has changed little in recent years. However, the incidence of wound botulism has increased, especially in California, from the use of black-tar heroin, which causes infected wounds at heroin injection sites.

Source: MedicineNet.com
http://www.medicinenet.com/botulism/article.htm