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Publisher’s Platform: What You Need to Know About Botulism



Publisher's Platform: What You Need to Know About Botulism

botulism: a rare but fatal disease

Botulism is a rare, life-threatening paralyzing disease caused by neurotoxins produced by an anaerobic, gram-positive, spore-forming bacterium. Clostridium botulinum.[1] unlike Clostridium perfringensrequiring the ingestion of large numbers of viable cells to produce symptoms, the symptoms of botulism are caused by the ingestion of highly toxic, soluble exotoxins produced by C. botulinum while growing in food.[2] These rod-shaped bacteria grow best under anaerobic (or low-oxygen), low-salt and low-acid conditions.[3] Bacterial growth is inhibited by cooling below 4°C, heating above 121°C and high water activity or acidity.[4] And although the toxin is destroyed by heating it at 85°C for at least five minutes, the spores formed by the bacteria are not inactivated until the food is heated to 121°C under high pressure for at least twenty minutes.[5] c. botulinum Bacteria and spores are widely distributed in nature because they are native to soils and waters.[6] They occur in both cultivated and forested soils, in the bottom sediment of streams, lakes and coastal waters, in the intestines of fish and mammals, and in the gills and intestines of crabs and other crustaceans.[7]

The incidence of foodborne botulism is extremely low.[8] Nevertheless, the extreme danger posed by the bacteria has necessitated “intensive surveillance of cases of botulism in the United States, and that each case be treated as a public health emergency.”[9] This danger includes a mortality rate of up to 65% when victims are not treated promptly and properly.[10] Most cases of botulism[11] reported annually in the United States are related to home-canned foods that have not been safely processed.[12] However, commercially processed foods have occasionally been implicated as the source of botulism events, including sausages, beef stew, canned vegetables and seafood.[13]

Symptoms of botulism

After ingestion, botulinum neurotoxins are primarily absorbed in the duodenum and jejunum, enter the bloodstream, and travel to synapses in the nervous system.[14] There, the neurotoxins cause flaccid paralysis by preventing the release of acetylcholine, a neurotransmitter, at neuromuscular junctions, thus preventing motor fiber stimulation.[15]The flaccid paralysis progresses symmetrically downward, usually starting at the eyes and face, before moving to the throat, chest and extremities.[16] When the diaphragm and chest muscles become fully involved, breathing is inhibited and, unless the patient is ventilated, death from asphyxiation results.[17]

Classic symptoms of botulism include nausea, vomiting, fatigue, dizziness, double vision, drooping eyelids, slurred speech, difficulty swallowing, dry skin, mouth and throat, lack of fever, muscle weakness and paralysis.[18] Babies with botulism appear lethargic, feed poorly, are constipated, cry weakly and have poor muscle tone.[19] During all these symptoms, the victims are fully alert and the results of the sensory examination are normal.[20]

In cases of foodborne botulism, symptoms usually begin anywhere between 12 and 72 hours after ingesting toxin-containing foods.[21] However, longer incubation periods – up to ten days – are not unknown. The duration of the disease is 1 to 10 (or more) days, depending on host resistance, amount of toxin ingested, and other factors.[22] Complete recovery often takes weeks to months.[23] And, as previously stated, the mortality rate can range from 30% to 65%, with mortality rates in European countries generally lower than in the United States.[24]

Detection and treatment of botulism

Although botulism can be diagnosed based on clinical symptoms, distinguishing it from other diseases is often difficult, especially if there are no other known individuals affected by the condition.[25] Once suspected, the most direct and effective way to confirm the diagnosis of botulism in the laboratory is to test for the presence of the botulinum toxin in the patient’s serum, feces, or gastric secretions.[26] The food consumed by the patient can also be tested for the presence of toxins.[27] Currently, the most sensitive and widely used method for detecting the toxins is the mouse neutralization test, which involves injecting serum into mice and looking for signs of botulism.[28] This test typically takes 48 hours, while direct sample culture takes 5-7 days.[29] Some cases of botulism may go undiagnosed because the symptoms are transient or mild, or be misdiagnosed as Guillain-Barre syndrome.[30]

If diagnosed early, foodborne botulism can be treated with an antitoxin that blocks the action of the toxin circulating in the blood.[31] This can prevent patients from getting worse, but recovery still takes many weeks.[32] The mainstay of therapy is supportive treatment in intensive care and mechanical ventilation in case of respiratory failure, which is common.[33]

Long-term and permanent injury

Although a minority of botulism patients eventually recover their pre-infection health, the majority do not. For those who make a full recovery, the greatest improvement in muscle strength occurs in the first three months after the acute phase of the disease.[34] However, the outer limit for such an improvement appears to be one year.[35] Consequently, physical limitations that still persist after a year are more likely than not to be permanent. Recovery from symptoms of acute botulism may also be followed by persistent psychological dysfunction that may require intervention.[36]

According to a recently published study that monitored the long-term outcomes of 217 cases of botulism, a large majority of patients reported “significant health, functional and psychosocial limitations that are likely consequences of the disease.”[37] These limitations include: fatigue, weakness, dizziness, dry mouth, and difficulty lifting things. The victims also reported difficulty breathing caused by moderate exertion, such as walking or lifting heavy objects. They were also more likely to have limitations in intensive activities, such as running or exercising, climbing three flights of stairs or carrying groceries. In summary, the study concluded the following:

Even several years after the acute illness, patients with botulism were more likely than controls to experience fatigue, general weakness, dizziness, dry mouth, difficulty lifting things, and difficulty breathing caused by moderate exertion… In addition, patients reported …generally worse. psychosocial status than controls, with patients significantly less likely to report feeling happy, calm and peaceful, or full of energy.[38]

There is no doubt that the harmful effects of botulism are lifelong.


[1] To see J. Sobel, et al., Foodborne botulism in the United States, 1990-2000, Emerging Infectious Diseases, Vol. 10, no. 9, in 1606 (September 2004).

[2] James M. Jay, MODERN FOOD MICROBIOLOGY, 466 (6e Ed. 2000)

[3] ID card. at 469-71; also see Sobel, up here note 2, in 1606.

[4] Sobel, up here note 2, in 1606.

[5] ID card.

[6] Jay, up here note 3, at 467-69. See also general H. Houschild, Clostridium botulinumin FOODBORNE BACTERIAL PATHOGENS, at 112-89 (M. Doyle Ed. 1989)

[7] Jay, up here note 3, at 467-69.

[8] Sobel, up here note 2, on 1607-1609; Jay, up here note 3, at 472-76.

[9] Sobel, up here note 2, at 1606-07 (also noting that CDC maintains a 24-hour clinical clinic and emergency antitoxin release service).

[10] Jay, up here note 3, at 474.

[11] In botulism, the broader term ‘event’ is used to include both outbreaks:i.e., two or more cases of botulism caused by a common source, as well as individual (or sporadic) cases.

[12] Sobel, up here note 2, in 1610; Jay, up here note 3, at 474.

[13] ID card.

[14] Thomas P. Bleck, Clostridium botulinum (Botulism), in MANDELL, DOUGLAS AND BENNETT’S PRINCIPLES AND PRACTICE OF INFECTIOUS DISEASES 2543, 2544 (5e ed. 2000).

[15] ID card.; Sobel, up here note 2, in 1606.

[16] Pale, up here note 15, at 2545; also see BOTULISM FACTSHEET, National Agricultural Bio-Security Center, Kansas State University, online at

[17] Pale, up here note 15, at 2545; Sobel, up here note 2, in 1606.

[18] Sobel, up here note 2, at 1606; Jay, up here note 3, at 474.

[19] Jay, up here note 3, at 476-77.

[20] Sobel, up here note 2, in 1606.

[21] Jay, up here note 3, at 474.

[22] ID card.

[23] R. Shapiro, et al., Botulism in the United States: A Clinical and Epidemiologic Review, Anna. Internal. Med. 1998; 129:221-28.

[24] Jay, up here note 3, at 474.

[25] Pale, up here note 15, at 2546 (noting that “botulism has a limited differential diagnosis”).

[26] Sobel, up here note 2, at 1607; also see FDA/CFSAN bad bug book, Clostridium botulinumAvailable at

[27] ID card.

[28] Pale, up here note 15, at 2546. See also e.g MMWWR, up here note 1, at 2 (“CDC detected botulinum toxin type A by mouse bioassay in man’s serum sample”).

[29] Bad insect book, up here note at 25.

[30] Sobel, up here note 2, at 1606; Shapiro, up here note 23, at 223.

[31] Jay, up here note 3, at 474; Sobel, up here note 2, in 1606.

[32] ID card.; Pale, up here note 15, at 2546-67.

[33] Sobel, up here note 2, in 1606.

[34] Pale, up here note 15, at 2547. Also see P.Wilcox, et al., Respiratory and upper airway muscle recovery and exercise performance after type A botulism, Chest, 98:620-26 (1990); J. Mann, et al., Patient recovery from type A botulism: assessment of morbidity after a major outbreak, Ben. J Public Health, 71 (3): 266-69 (March 1981).

[35] ID card.

[36] Pale, up here note 15, at 2547. Also see F. Cohen, et al., Physical and psychosocial health status three years after catastrophic illness – botulismMental health nurse expenditure, 9:387098 (1988)

[37] S. Gottlieb, et al., Long-term results of 217 cases of botulism in the Republic of Georgia, Klin. Infectious Disease, 45: 174-80, at 180 (220&).

[38] ID card. at 179.