Botulism
At a glance
- Reporting time frame: Immediately (by phone within 4 hours of suspected diagnosis)
- Individual cases need follow-up? Yes
- Timeline for patient interview: 24 hours
- Responsibility for investigation: Local public health agency + CDPHE
- CDPHE program: Foodborne, Enteric, Waterborne, and Wastewater Diseases
- Mode(s) of transmission: ingestion of contaminated food (foodborne botulism); ingestion of spores (infant botulism, adult intestinal colonization); exposure of wound to soil or gravel, drug use (wound botulism); or injection of high doses of unapproved botulinum toxin product for cosmetic or clinical purposes (iatrogenic botulism).
- Incubation period: Foodborne: 12-36 hours (range: 6 hours-10 days); Infant: 3 -30 days; Wound: approximately 10 days (range: 4-14 days); Iatrogenic: unknown
- Infectious period: Not known to spread from person to person.
- Treatment: Heptavalent botulinum antitoxin (HBAT) is used to treat foodborne, wound, adult toxemia, and iatrogenic botulism. Botulism immune globulin (BabyBIG) is used to treat infant botulism. Both treatments must be released to clinical providers by public health. Prompt diagnosis and early treatment are essential to minimize the risk of death.
- Prophylaxis: None
- Exclusion criteria: None
- Additional: Suspect botulism cases of any form must be reported to CDPHE immediately. Antitoxin can only be released by public health. Testing for botulism in Colorado can only be done through CDC and requires CDPHE approval prior to sending specimens. Testing will only be performed if antitoxin is released.
Contents
What and how to report to the Colorado Department of Public Health and Environment (CDPHE) or local public health agency
- Health care providers, laboratories, and local public health agencies should report any suspicion of foodborne, infant, intestinal, or wound botulism to CDPHE immediately by telephone. If a case is suspected after regular business hours, the after-hours telephone number should be used.
- CDPHE will conduct a clinical consultation by telephone, and, if indicated, release of botulinum antitoxin for adult cases.
- For infant cases, the California Department of Public Health’s Infant Botulism Treatment and Prevention Program must be contacted by either the provider or CDPHE for release of BabyBIG. Providers can contact California Department of Public Health’s Infant Botulism Treatment and Prevention Program first and then notify CDPHE. See telephone numbers at the end of this document.
- All potential foodborne, waterborne, and enteric disease outbreaks should be reported immediately to CDPHE or local health departments and entered into EpiTrax, even if the causative agent is not yet known.
- In general, an “outbreak” is defined as an increase in the number of illnesses above what is normally expected among a specific population, within a given area, over a certain period of time.
- Specifically, a foodborne disease outbreak occurs when two or more people get the same illness from the same contaminated food or drink.
Purpose of surveillance and reporting
- To ensure the patient receives antitoxin treatment in a timely manner if indicated
- To coordinate testing
- To identify cases for investigation and potential outbreaks
- To monitor trends in disease incidence
Etiologic agent
Botulism is caused by a potent neurotoxin produced by Clostridium botulinum, an anaerobic (reproduces in low oxygen conditions), rod-shaped, gram-positive bacterium that is ubiquitous in soil. The bacteria form heat-resistant spores that survive in a dormant state until exposed to favorable conditions that support growth; such as high-moisture, low-salt, low sugar, and low-acid (pH > 4) environments where there is little or no oxygen and moisture content and temperatures are suitable. There are seven types of botulinum toxin (types A-G). Types A, B, E, and F may cause botulism in humans.
Clinical description
Botulism is a rare but serious intoxication that causes a neuroparalytic illness. Five main forms of botulism can occur: foodborne, infant, wound, adult intestinal toxemia, and iatrogenic botulism. The site of botulinum toxin production differs for each form; however, all five forms result in flaccid paralysis. Clinically, other diagnoses may appear similar to botulism, such as Guillain-Barré syndrome, myasthenia gravis, chemical intoxication (such as carbon monoxide poisoning), mushroom poisoning, drug reactions, tick paralysis, or stroke. Consultation with CDPHE and the Centers for Disease Control and Prevention (CDC) is available to help distinguish between botulism and other diagnoses. Prompt diagnosis and early treatment are essential to minimize the risk of death.
Foodborne
Foodborne botulism is caused by ingesting foods that contain botulinum toxin. The toxin is absorbed through the gastrointestinal tract into the bloodstream and is carried to nerve endings where it blocks the release of neurotransmitters that allow for muscle response. Neurological symptoms always progress in a descending symmetric pattern causing flaccid paralysis: the head and neck are the first affected, then the shoulders, upper arms, lower arms, thighs, calves, etc. Paralysis of breathing muscles can result in death unless mechanical ventilation is provided. Early signs and symptoms of botulism are typically: blurred vision, diplopia (double vision), drooping eyelids, dry mouth, dysphagia (difficulty in swallowing), and dysarthria (difficulty speaking). These symptoms may also present as dizziness (vertigo) or change in voice (dysarthria). Vomiting, diarrhea, constipation, and abdominal swelling may occur but should not be determining factors for including botulism in a patient’s differential diagnosis. Reports of fever, loss of consciousness, numbness or tingling, and abnormal cerebrospinal fluid (CSF) findings are extremely rare. The case fatality rate is 5% to 10%, although recovery may take months.
Wound
Wound botulism occurs when Clostridium botulinum spores contaminate a wound through soil or gravel and germinate. The bacteria multiply in the wound and produce toxin. Symptoms are similar to foodborne botulism but may take up to two weeks to appear. It occurs more frequently among people who inject drugs (particularly subcutaneous injection of black tar heroin, also called “skin popping”), but can also occur in cases of traumatic injury (motorbike accidents).
Infant
Infant botulism is the most commonly reported form of botulism and affects children less than one year of age. Infants less than six months of age are more commonly affected. Infant botulism occurs when ingested Clostridium botulinum spores germinate in the intestine, the bacteria multiply, and produce toxin. Illness in infants ranges from mild with gradual onset to rapidly progressive resulting in sudden death. Symptoms seen in infants include constipation, loss of appetite, weak suck, decreased movement, loss of facial expression, weakness, an altered cry, and a loss of neck control. Affected infants are often described as being “floppy.” Honey, honey-containing homeopathic teething products, and soil exposure (nearby construction) are risk factors for infant botulism.
Intestinal
Adult intestinal toxemia (also known as adult intestinal colonization) botulism is rare and occurs when spores of the bacteria get into an adult’s intestines, grow, and produce the toxin (similar to infant botulism). Cases of intestinal botulism occur in individuals with severe gut illnesses or previous intestinal surgery.
Iatrogenic
Rarely, iatrogenic botulism can happen if too much botulinum toxin or unapproved botulinum toxin product is injected for cosmetic reasons or medical reasons. The dose of commercial botulinum toxin necessary to cause systemic botulism is very high.
Reservoirs
Clostridium botulinum spores are ubiquitous in the soil. While the spores are generally harmless, the danger can occur once the spores begin to grow out into active bacteria and produce neurotoxins. Spores are also found in marine sediments, agricultural products, including honey and vegetables, and in the intestinal tract of animals, including birds and fish.
Modes of transmission
The mode of transmission for botulism varies depending on the form. For some forms of botulism (foodborne, iatrogenic), the individual must be exposed to or ingest preformed botulinum toxin. Other forms, including wound, infant, and adult intestinal botulism, occur after exposure to or ingestion of Clostridium botulinum spores and its subsequent germination of botulinum toxin. Regardless of form, botulism is not known to spread person to person.
Foodborne
When a food item contaminated with Clostridium botulinum spores is preserved improperly and stored under anaerobic conditions (such as canned or vacuum packaged items), the spores can germinate and the bacteria can multiply, resulting in botulinum toxin production. If the food is eaten without extreme heating to inactivate the toxin, foodborne botulism can occur. Implicated foods include fermented, salted, or smoked fish and meat products, and home-canned vegetables and fruits such as potatoes, asparagus, green beans, beets, chile peppers, corn, tomatoes, figs, apricots, pears, peaches, applesauce, persimmons, and mangoes. Other implicated foods include aluminum foil-wrapped and stored baked potatoes, commercial pot pies, homemade salsa, sautéed onions, potato salad, cheese sauce, chile peppers, and minced garlic in oil.
Occasionally, commercially prepared foods are implicated, although this is rare due to the safe canning and manufacturing practices used today. Cases associated with commercially prepared foods have most likely been caused by improper handling, such as neglecting to refrigerate the product. Therefore, it is important to discuss food handling practices during the public health investigation. Every case of foodborne botulism represents a public health emergency as the implicated food, whether homemade or commercial, may still be available for consumption and would have the potential to cause additional illness.
Illicitly produced alcohol (called pruno or hooch) in correctional settings have caused large foodborne botulism outbreaks.
Infant/Adult Intestinal toxemia
Infant botulism and adult intestinal toxemia occurs when Clostridium botulinum spores are ingested, rather than through ingestion of toxin. Possible sources of spores include foods (such as honey), soil, and dust; however, in most cases the source is not identified. Botulism has been associated with use of honey-filled pacifiers, often purchased in other countries. It is common for cases of infant botulism to live near construction sites that increase exposure to soil.
Wound
Wounds with ground-in soil or gravel can become contaminated with Clostridium botulinum spores. Wound botulism has been reported among people who use illicit drugs (particularly subcutaneous injection of black tar heroin, also called “skin popping”).
Iatrogenic
This has occurred after injection of high doses of botulinum toxin product for cosmetic indications, such as treating wrinkles or lines. Theoretically, it could also occur after a high-dose injection for medical purposes, such as treating migraine headaches or hyperhidrosis. Unapproved or counterfeit botulinum toxin (e.g., Botox) may contain more botulinum toxin than labeled.
Incubation period
Foodborne
Symptoms of foodborne botulism usually appear within 12 to 36 hours (range: 6 hours to 10 days) after eating contaminated food.
Infant /Intestinal toxemia
The symptoms of infant/intestinal toxemia botulism are estimated to appear 3 to 30 days after exposure to the spore-containing material.
Wound
Symptoms of wound botulism usually appear about 10 days after the time of injury, with a range of 4 to 14 days.
Iatrogenic
There is no known incubation period.
Infectious period
Botulism is not known to spread from person to person.
Epidemiology
According to the National Botulism Surveillance Summary for 2019, 215 cases of botulism were reported to the CDC. Of those cases, 71% were infant, 19% were wound, 10% were foodborne, and < 1% was adult intestinal colonization. Iatrogenic botulism is rarely reported. Per CDC, 2% of cases died, and there were three botulism outbreaks in 2019.
Infant
During 2024, four infant botulism cases were reported in Colorado, with a five-year average of 2-3 cases per year (2020﹘2024). Nationwide, 152 infant botulism cases were reported to CDC in 2019.
Foodborne
Foodborne botulism cases occur sporadically and in outbreaks worldwide. During 2024, four foodborne botulism cases were reported in Colorado, with a five-year average of 2-3 cases per year (2020﹘2024). Implicated food items included home-canned jalapenos and various commercial products that were accidentally mishandled in the home. Nationwide, 21 foodborne botulism cases were reported to CDC in 2019.
Wound
The number of cases of wound botulism in the United States has increased in recent years because of the use of black-tar heroin. Forty-one cases of wound botulism were reported to CDC during 2019. In Colorado, from 2019 through 2023, three cases of wound botulism were reported, each of which were associated with injection drug use.
Colorado did not have any cases of adult intestinal or iatrogenic botulism reported in the last five years.
For more data, see Colorado reportable disease data (Colorado data) and CDC’s annual botulism surveillance reports (national data).
Foodborne
- Clinical description
- An illness of variable severity, characterized by diplopia (double vision), blurred vision, and bulbar weakness (e.g., difficulty with speaking, swallowing). Symmetric paralysis may progress rapidly, typically beginning with facial muscles and descending to neck, arms, chest, and legs.
- Laboratory criteria for diagnosis
- Confirmed
- Detection of botulinum toxin in serum, stool, or patient’s food, OR
- Isolation (i.e., culture) of Clostridium botulinum from stool
- Confirmed
- Case classification
- Confirmed
- A clinically compatible case that is laboratory-confirmed or that occurs among persons who ate the same food as persons who have laboratory-confirmed botulism.
- Probable
- A clinically compatible case with an epidemiologic link (e.g., ingestion of a home-canned food within the previous 48 hours).
- Confirmed
Infant
- Clinical description
- An illness of infants, characterized by constipation, poor feeding, and “failure to thrive” that may be followed by progressive muscle weakness (i.e., a “floppy” appearance), impaired respiration, a “weak cry,” drooling, droopy eyelids, and death.
- Laboratory criteria for diagnosis
- Confirmed
- Detection of botulinum toxin in stool or serum*, OR
- Isolation of Clostridium botulinum from stool
- Confirmed
*Stool is the preferred specimen for infant botulism testing.
- Case classification
- Confirmed
- A clinically compatible case that is laboratory-confirmed, occurring in a child aged less than one year.
- Confirmed
Wound
- Clinical description
- An illness resulting from toxin produced by Clostridium botulinum that has infected a wound. Common symptoms are diplopia (double vision), blurred vision, and bulbar weakness (e.g., difficulty with speaking, swallowing). Symmetric paralysis may progress rapidly, typically beginning with facial muscles and descending to neck, arms, chest, and legs.
- Laboratory criteria for diagnosis
- Confirmed
- Detection of botulinum toxin in serum OR
- Isolation (i.e., culture) of Clostridium botulinum from wound
- Confirmed
- Case classification
- Confirmed
- A clinically compatible case that is laboratory-confirmed in a patient who has no suspected exposure to contaminated food and who has a history of a fresh, contaminated wound during the two weeks before onset of symptoms, or a history of injection drug use within the 2 weeks before onset of symptoms.
- Probable
- A clinically compatible case in a patient who has no suspected exposure to contaminated food and who has either a history of a fresh, contaminated wound during the 2 weeks before onset of symptoms, or a history of injection drug use within the 2 weeks before onset of symptoms.
- Confirmed
Intestinal (reported as “Botulism, other” in EpiTrax)
- Clinical description
- An illness of variable severity, characterized by diplopia (double vision), blurred vision, and bulbar weakness (e.g., difficulty with speaking, swallowing). Symmetric paralysis may progress rapidly, typically beginning with facial muscles and descending to neck, arms, chest, and legs.
- Laboratory criteria for diagnosis
- Confirmed
- Detection of botulinum toxin in clinical specimen OR
- Isolation (i.e., culture) of Clostridium botulinum from clinical specimen
- Confirmed
- Case classification
- Confirmed
- A clinically compatible case that is laboratory-confirmed in a patient aged greater than or equal to 1 year who has no history of ingestion of suspect food and has no wounds
- Confirmed
Iatrogenic
There is currently no standardized surveillance case definition for iatrogenic botulism. CDPHE will provide consultation and guidance if a case is suspected.
- Currently, botulism testing (clinical and food specimens) is done by the CDC. Specimens should be sent to the State Lab after approval from CDPHE’s Communicable Disease Branch, which will then send the specimens to the CDC laboratory.
- Approval for botulism testing MUST be obtained from CDPHE prior to submission (phone numbers below). No testing can occur without treatment with antitoxin.
- Each clinical specimen must have a lab requisition form with patient identifiers and time of collection.
- Food specimens should include a Sample Collection Form. If your agency does not have one, contact CDPHE.
- Stool must be received by CDC within 72 hours of collection and cannot be accepted on weekends or federal holidays.
- CDPHE will provide additional guidance on specimen collection and submission during consultation.
Table 1: Specimen collection and transportation guidance by botulism and specimen type
- Due to the nature of botulism laboratory testing, results may not be reported until several days or weeks after specimens are received. Do not delay patient treatment while laboratory results are pending.
- For more information on botulism testing, contact CDPHE.
Foodborne
The investigation of a case of suspected foodborne botulism is done jointly by the health care provider, local public health agency, CDPHE, and the CDC. All cases must be rapidly investigated to determine the potential source of infection, and to implement control measures as appropriate. Prompt epidemiological investigation is critical to prevent further cases from occurring if a hazardous food is still available for consumption. Individuals who have consumed an implicated product should undergo close medical observation. While home-canned foods are the prime suspect until ruled out, recent outbreaks have implicated unusual food items, so these should also be considered.
Interview the suspected case or a surrogate (someone familiar with what the case likely ate) as soon as possible.The interview should capture the following information:
- Demographics (including address, date of birth, gender, ethnicity and race)
- Detailed description of symptoms and onset date and time (obtain medical record if possible)
- Food history (during the seven days prior to onset)
- Ask specifically about any home-canned foods; any foods eaten that were received as a gift that were prepared in someone else’s home; potato products; chiles; or fermented, salted, or smoked fish or meat products.
- See Appendix A for additional food history considerations.
- Restaurant history (include food items and date consumed)
- Recent group activities where food was consumed
Depending on food history and food availability, a home visit may be warranted to collect the suspected food items for testing. Consult with CDPHE to assess the need of sending food items to CDC for testing based on food preparation methods. If antitoxin is released, CDC will also request that the treating physician complete a form documenting the patient’s response to antitoxin (the form will be sent with the antitoxin). Completed forms should be forwarded to CDC when the patient is discharged.
Infant
CDPHE can assist health care providers in obtaining laboratory testing (through CDC) and treatment (through the California Department of Health). LPHAs or CDPHE should interview the parents/guardians of infant botulism cases with the California Department of Health questionnaire, available through CDPHE.
Wound
The investigation of a case of wound botulism is done jointly by the health care provider, local public health agency, CDPHE, and the CDC to determine the potential source of infection and rule out foodborne transmission (see above).
Adult intestinal toxemia
Suspected cases of intestinal botulism in individuals greater than 12 months of age should be investigated to determine that the source is not foodborne (see above), after which no further investigation is usually performed.
Forms
Upload any botulism questionnaires into EpiTrax in the “Notes” tab.
Identify and evaluate contacts
Botulism is not known to spread person to person. However, it’s important to assess if other individuals known to the case are experiencing similar symptoms, particularly if they reside in the same household, share meals, or use drugs together.
Treatment
Supportive medical care, particularly respiratory and nutritional support, is an important component of treatment for all forms of botulism.
Foodborne
Foodborne botulism cases must receive heptavalent botulinum antitoxin (HBAT) as soon as possible. The antitoxin is administered intravenously and blocks the action of the toxin circulating in the blood unbound to nerve endings. The antitoxin is most effective if given early in the course of the illness, and can prevent the illness from worsening. Notify CDPHE immediately of a suspected case of botulism so the process of obtaining antitoxin can be initiated as quickly as possible. The antitoxin must be requested by CDPHE. Serum and stool specimens must be collected before the antitoxin is administered. Antitoxin should not be withheld pending test results, as results may not be available for several days or weeks. Even with antitoxin treatment, recovery still takes many weeks or months.
Infant
Human botulism immune globulin (BabyBIG) is available from the California Department of Health Services to treat infant botulism. This should be initiated as early in the illness as possible, before lab results are known. Contact CDPHE or the California Department of Health Services to obtain it. Antitoxin is used to treat type F infant botulism, which is very rare, but has occurred in Colorado.
Wound
Wound botulism is treated similarly to foodborne botulism. In addition to the HBAT, appropriate wound care is required.
Iatrogenic
Treatment for iatrogenic botulism is only warranted if the case has systemic symptoms. Iatrogenic botulism is treated similarly to foodborne botulism. HBAT is administered.
Adult intestinal toxemia
Adult intestinal toxemia is treated similarly to foodborne botulism. HBAT is administered.
Prophylaxis
No prophylactic treatment of close contacts is recommended, even if they are known to have ingested a food known to contain botulinum toxin.
Education
- Persons who practice home canning should be educated regarding safe canning practices. Because of the high altitude in Colorado, safe canning procedures are different than at sea level. Instructions on safe home canning can be obtained from extension services or from the United States Department of Agriculture.
- Commercially canned or home-canned products showing signs of spoilage (such as mold growth or a bad odor) should not be consumed and should be disposed of properly. Bulging, leaking, or badly dented cans should be discarded.
- Oils infused with garlic or herbs should be refrigerated.
- Honey or honey products (including teething products or toys) should not be given to children younger than 12 months of age.
- Wound botulism can be prevented by promptly seeking medical care for infected wounds and by not injecting drugs.
Environmental measures
- Food samples associated with suspect or confirmed cases must be obtained immediately for laboratory analysis. Please consult with CDPHE.
- Implicated or recalled food items must be removed from the environment. Consult with CDPHE about proper disposal.
- If a commercial product is suspected, CDPHE Communicable Disease Branch will coordinate follow-up with the CDPHE Division of Environmental Health and Sustainability and relevant outside agencies.
- Testing of suspected heroin is not feasible. The Drug Enforcement Administration is only able to test heroin purchased by DEA agents (not by cases of wound botulism).
American Academy of Pediatrics. Red Book: 2024-2027 Report of the Committee on Infectious Diseases, 33rd Edition. Illinois, Academy of Pediatrics, 2024.
Botulism (Clostridium botulinum) 2011 Case Definition | CDC. (n.d.). https://ndc.services.cdc.gov/case-definitions/botulism-2011/
Heymann DL, ed. Control of Communicable Diseases Manual, 21st Edition. Washington, DC, American Public Health Association, 2022.
Colorado State University Cooperative Extension Botulism Fact Sheet
CDC. Botulism in the United States 1899-1996. Handbook for Epidemiologists, Clinicians, and Laboratory Workers
CDPHE Communicable Disease Branch
- Phone: 303-692-2700 or 800-866-2759
- Fax: 303-782-0338
- After hours: 303-370-9395
CDPHE Lab Coordinators:
- Email (preferred): cdphe_labcoordinators@state.co.us
- Phone: 303-692-3480