Skip to content


Reportable Disease Toolkit Badge

Reporting Obligations

Confirmed and suspected cases shall be reported immediately by phone to the local Health Unit.

Reporting Form Button


Aetiologic Agent

Botulinum toxin is produced by Clostridium botulinum (C. botulinum), which is a gram-positive, spore-forming obligate anaerobic bacillus.

Clinical Presentation

There are three main forms of botulism depending on the mode of transmission: foodborne, wound, and intestinal (infant and adult) botulism. All forms cause flaccid paralysis as a result from the botulinum neurotoxin.

Foodborne botulism is a severe intoxication resulting from ingestion of preformed toxin present in contaminated food. Most individuals develop the following symptoms: nausea, vomiting, diarrhea, constipation, fatigue, weakness, dizziness, blurred or double vision, dysphasia, and dry mouth may occur. Acute bilateral cranial nerve impairment and descending weakness or paralysis characterize the illness. Most people recover if diagnosed and treated quickly, but recovery may take months and some have residual weakness.

Wound botulism occurs when spores penetrate an open wound and produce the toxin in an anaerobic environment. Symptoms are similar to food borne botulism but may take up to two weeks to appear.

Intestinal (infant and adult colonization) botulism occurs following spore ingestion, subsequent outgrowth and in-vivo toxin production in the intestine; it affects children under one year but can also affect adults who have altered intestinal microflora because of antimicrobial use or because of bowel abnormalities. Clinical symptoms in infants include constipation, loss of appetite, poor suck, weakness, lethargy, altered cry, and a striking loss of head control known as “floppy head”.

Modes of Transmission

Foodborne botulism is transmitted by the ingestion of improperly prepared, stored or cooked food containing the toxin. The foods most often implicated are lightly preserved foods (such as smoked and salted fish) and in inadequately processed, home-preserved foods (including fruits, vegetables, and herbs in oil) that are low in sugar, salt, and acid.

Wound botulism results from contamination of traumatized tissue by C. botulinum found in soil that grows in the wound and produces toxin.

Intestinal (infant and adult) botulism is typically associated with the ingestion of spores that germinate and produce toxin in the colon that may be present in items such as foods, soil, dust, unpasteurized honey and peanut butter.

Incubation Period

In food borne botulism neurological symptoms usually appear within 12–36 hours after ingestion of contaminated food, or up to several days after eating contaminated food. The shorter the incubation period, the more severe the disease and the higher the case-fatality rate. For wound botulism, the incubation period is generally 4 to 14 days. The incubation period of intestinal botulism in infants is estimated to be up to 30 days, but for adults in unknown since the precise time of spore ingestion often cannot be determined.

Period of Communicability

No instance of secondary person to person transmission has been documented despite excretion of C. botulinum toxin and organisms in the feces of intestinal (infant) and foodborne botulism cases.

Risk Factors/Susceptibility

Susceptibility is general. Adults with anatomical or functional bowel abnormalities leading to altered intestinal flora (unintentionally altered by antibiotic treatment for other purposes) may be predisposed to intestinal botulism. Injection drug users are more susceptible to wound botulism.

Diagnosis and Laboratory Testing

Diagnosis of foodborne botulism is made by demonstration of botulinum toxin in serum, stool, gastric aspirate or incriminated food or isolation of C. botulinum from stool or gastric aspirate. Refer to Botulism Guide for Health Care Professionals.

Treatment and Case Management

Immediate medical treatment is required; do not await laboratory confirmation. Botulinum Antitoxin (BAT) can be accessed through the Population and Public Health Division – Ministry of Health and Long-Term Care during business hours by calling 416-327-7392. After-hours and on weekends and holidays please call the ministry’s Health Care Provider Hotline at 1-866-212-2272 and request to speak to the Population and Public Health Division staff on call.

Treatment of infant botulism requires Botulism Immune Globulin, Intravenous (BIG-IV) or BabyBIG®. This can only be obtained through Health Canada’s Special Access Program (SAP).

For more information on placing a request for BAT or BabyBIG® refer to the Ministry of Health and Long-Term Care document Botulism Guide for Health Care Professionals.

Given the severity and rarity of botulism, one case of botulism should be treated as if it was an outbreak and should be managed with great urgency. Public Health staff will be involved for managing contacts of foodborne botulism.

Patient Information

Patient Fact Sheet Button

Additional Resources

Ministry of Health and Long-Term Care. “Botulism Guide for Health Care Professionals.”

Heymann, D.L. Control of Communicable Disease Manual (Twentieth Edition). Washington, American Public Health Association, 2015.


Ministry of Health and Long-Term Care, Infectious Diseases Protocol, 2022.