Botulism, a potentially fatal neuroparalytic illness, results from exposure to botulinum neurotoxin (BoNT), which is produced by the bacterium Clostridium botulinum and other Clostridium species. The earliest cases of botulism were described in Europe in 1735 and were attributed to improperly preserved German sausage; the name of the disease alludes to this association because botulus is the Latin word for sausage. Emile van Ermengem identified the causative organism in 1897 and named it Bacillus botulinum; it was later renamed Clostridium botulinum.25 These gram-positive, spore-forming bacteria produce eight serotypes of BoNT, denoted A through H.88,134
In adults, most cases result from ingestion of toxin in contaminated food, but in infants, most cases result from consumption of bacterial spores that proliferate and produce toxin in the gastrointestinal (GI) tract. Less common forms of botulism include wound botulism, in which spores are inoculated into a wound and locally produce toxin, and inhalational botulism caused by aerosolized BoNT, which potentially can be used as a weapon of bioterrorism.
Botulism outbreaks occur throughout the world149 and have been reported from such diverse areas as Uganda,179 Iran,137 Japan,128 Thailand,96 Pakistan,93 Australia,113 France,1 Portugal,103 Poland,58 Greenland,82 Chile,12 and Canada.123 In 2016, a total of 150 laboratory-confirmed cases and 10 probable cases of botulism were reported to the US Centers for Disease Control and Prevention (CDC).39 Foodborne botulism constituted 14% of cases, infant botulism 73% of cases, and wound botulism 12%. In this analysis, toxin type A accounted for 83% of cases of foodborne botulism, with the remainder split between type A and type B (27% each). Toxin type A was responsible in at least 88% of cases of wound botulism, and infant botulism was caused by toxin type A in 36% and to toxin type B in 59% of cases. Two deaths from foodborne botulism were reported in 2016.39 The case fatality rate has improved for all botulism toxin types, probably caused by increasing awareness of the condition and consequent earlier diagnosis, appropriate and early use of antitoxin, and better and more accessible life support techniques.
In the past 50 years, home-processed food has accounted for 65% of outbreaks, with commercial food processing constituting only 7% of reported cases; in the remaining outbreaks, the origin is unknown.45 Common home-canning errors responsible for botulism include failure to use a pressure cooker and allowing food to putrefy at room temperature. Minimally processed foods such as soft cheeses lack sufficient quantities of intrinsic barriers to BoNT production, such as salt and acidifying agents.143 These foods become high-risk sources of botulism when refrigeration standards are violated. The US Food and Drug Administration (FDA) continuously reviews recommendations for appropriate measures to process such foods.168,169
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