The toxin is the protein botulinum toxin produced under anaerobic conditions (where there is no oxygen) by the bacterium Clostridium botulinum. Clostridium botulinum is a large anaerobic Gram-positive bacillus that forms subterminal endospores. There are eight serological varieties of the bacterium denoted by the letters A to H. The toxin from all of these acts in the same way and produces similar symptoms: the motor nerve endings are prevented from releasing acetylcholine, causing flaccid paralysis and symptoms of blurred vision, ptosis, nausea, vomiting, diarrhea or constipation, cramps, and respiratory difficulty. Botulinum toxin is broken into eight neurotoxins (labeled as types A, B, C C1, C2, D, E, F, and G), which are antigenically and serologically distinct but structurally similar. Human<unk>  is caused mainly by types A, B, E, and (rarely) F. Types C and D cause toxicity only in other animals. In October 2013, scientists released news of the discovery of type H, the first new<unk>  neurotoxin found in forty years. However, further studies showed type H to be a chimeric toxin composed of parts of types F and A (FA). Some types produce a characteristic putrefactive smell and digest meat (types A and some of B and F); these are said to be proteolytic; type E and some types of B, C, D and F are nonproteolytic and can go undetected because there is no strong odor associated with them. When the bacteria are under stress, they develop spores, which are inert. Their natural habitats are in the soil, in the silt that comprises the bottom sediment of streams, lakes, and coastal waters and ocean, while some types are natural inhabitants of the intestinal tracts of mammals (e.g., horses, cattle, humans), and are present in their excreta. The spores can survive in their inert form for many years. Toxin is produced by the bacteria when environmental conditions are favourable for the spores to replicate and grow, but the gene that encodes for the toxin protein is actually carried by a virus or phage that infects the bacteria. Unfortunately, little is known about the natural factors that control phage infection and replication within the bacteria. The spores require warm temperatures, a protein source, an anaerobic environment, and moisture in order to become active and produce toxin. In the wild, decomposing vegetation and invertebrates combined with warm temperatures can provide ideal conditions for the<unk>  bacteria to activate and produce toxin that may affect feeding birds and other animals. Spores are not killed by boiling, but<unk>  is uncommon because special, rarely obtained conditions are necessary for botulinum toxin production from C. botulinum spores, including an anaerobic, low-salt, low-acid, low-sugar environment at ambient temperatures. Botulinum inhibits the release within the nervous system of acetylcholine, a neurotransmitter, responsible for communication between motor neurons and muscle cells. All forms of<unk>  lead to paralysis that typically starts with the muscles of the face and then spreads towards the limbs. In severe forms,<unk>  leads to paralysis of the breathing muscles and causes respiratory failure. In light of this life-threatening complication, all suspected cases of<unk>  are treated as medical emergencies, and public health officials are usually involved to identify the source and take steps to prevent further cases from occurring. Botulinum toxin A, C, and E cleave the SNAP-25, ultimately leading to paralysis.
Botulism
Guillain–Barré syndrome
Tardive dyskinesia
Lambert–Eaton myasthenic syndrome
Quadrigia
Myasthenia gravis
Sadism
Amyotrophic lateral sclerosis