Botulism firstly results in visual problems, dry mouth and difficulty swallowing. More serious symptoms then develop, starting with fatigue and then progressive paralysis of all of the muscles of the body.
There are seven types of botulism although only four of these (types A, B, E and rarely F) are pathogenic to human beings. The others (C, D and E) are pathogenic to Mammals, Birds and Fish.
Spores of the bacteria are commonly found in the ground, sea beds and in fish. The spores are resistant to heat and germinate under anaerobic conditions. The bacteria can then grow and produce the toxin.
The danger, comes from eating the toxin which may be present in poorly prepared food and may be fatal. Above all, it is a form of food poisoning although botulism is occasionally transmitted from wounds or colonisation of the bowel in children. It is not spread between human beings.
There is a botulism vaccine which may have harmful side effects and is therefore only reserved for at risk people.
The best measures is to protect against the source of contamination by observing food hygiene measures.
Botulism may be caused by eating poorly preserved foods. © Cpt Obvious, Flickr, CC by-nc-nd 2.0