Division of Disease Control and Health Protection

Botulism

Botulism is a very rare disease in Florida. However, when a case does occur it is considered a public health emergency. Prompt diagnosis and treatment can prevent death, and the epidemiologic investigation of foodborne cases is important to keep other cases from occurring. Botulism is caused by toxin from the spore-forming anaerobic bacillus bacteria Clostridium botulinum. The hardy spore form of the bacteria can be found in soil and sediments worldwide. The bacteria germinate and produce toxin when the pH is low (acidic) and the oxygen concentration low. Seven strains of botulinum toxin (A-G) have been identified. These toxins are the most potent lethal toxins known¹. They all affect nerve function, resulting in symmetric progressive paralysis of the patient. There are four forms of the disease in humans: infant botulism, foodborne botulism, wound botulism, and cases with unknown origin.

Infants (usually < 1 yr old) become infected with spores through dust or food. In most cases the exact source is unknown, although honey has been implicated and should not be given to children younger than 12 months². The spores germinate in the intestine and the symptoms of the toxin-induced nerve damage often start with constipation and other feeding related problems that may spread progressively to eventually cause respiratory arrest and death. Infant botulism may be one of the causes of the sudden infant death syndrome³.

Foodborne botulism is usually caused by consumption of toxin produced in improperly prepared home-canned or cured foods that have been stored without refrigeration. The first symptoms, normally visible 12-36 hours after exposure, include visual problems and dysphagia (difficulty swallowing).

Botulinum toxin can also be formed by bacteria in wounds that are contaminated with soil or gravel, or from improperly treated compound fractures. The incubation period for wound botulism is from 4-14 days.

On average 110 cases of botulism are reported in the United States each year⁴. Thanks to modern intensive care practices, the mortality rate has decreased from 50% to 8% over the past 50 years⁵. Nationally, infant botulism (72%) and food-borne botulism (25%) are the most common forms of the disease. In Florida, infant botulism appears to be less common. Among the nine botulism cases reported in the state between 1995 and 2005, one case was infant botulism, three cases were of unknown origin, and five cases were foodborne. Of these five foodborne botulism cases, three cases (50%) were a result of a single 1999 foodborne botulism outbreak; the remaining cases were sporadic in occurrence.

Resources

1. Shapiro, Roger L., Hatheway, Charles and David L. Swerdlow. 1998. Botulism in the United States: A clinical and Epidemiological Review. Ann. Intern. Med. 129: 221-228.

2. Midura, Thaddeus F. 1996. Update: Infant Botulism. Clin. Microbiol. Rev. 9: 119-125.

3. Arnon, S. S, Damus, K. and J. Chin. 1981. Infant botulism: epidemiology and relation to sudden infant syndrome. Epidemiol. Rev. 3: 45-46.

4. MMWR Summary of Notifiable Diseases 1996. US Dept. of Health and Human Services, CDC. Vol. 45 no 53.

5.  Botulism (Clostridium botulinum), Frequently Asked Questions. 1998. The Division of Bacterial and Mycotic Diseases, CDC.

Every suspected case of botulism should be considered a public health emergency. Because botulism is such a serious life-threatening illness, every effort should be made to obtain a rapid diagnosis and institute prompt treatment, if required, to assure recovery. Since the foodborne form of the disease also has the potential to cause severe and sometimes widespread outbreaks, every confirmed case linked to food products must be promptly reported to the county health department so an epidemiologic investigation can be initiated.

The Florida Department of Health, Bureau of Epidemiology (850) 488-2905 provides 24-hour diagnostic consultation services, including support for access to laboratory diagnostic services and trivalent botulinum antitoxin if required.

Each form of the disease presents somewhat differently and has defined diagnostic criteria. All cases reported to the Florida Department of Health must meet a specified case classification and include a completed CDC case report form entitled Botulism Alert Summary.

Note! Specimens (food, feces, and sera) to be sent for laboratory diagnosis (toxin testing) from suspected cases of botulism must be cleared through the Bureau of Epidemiology (850) 488-2905

Clinical Description:

Ingestion of botulinum toxin results in an illness of variable severity. Common symptoms are diplopia, blurred vision, and bulbar weakness. Symmetric paralysis may progress rapidly.

Laboratory Criteria for Diagnosis:

· Detection of botulinum toxin in serum, stool, or patient’s food or

· Isolation of Clostridium botulinum from stool

Case Classification:

Confirmed : a clinically compatible case that is laboratory confirmed or that occurs among persons who ate the same food as persons with 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)

Clinical Description:

An illness of infants, characterized by constipation, poor feeding, and “failure to thrive” that may be followed by progressive weakness, impaired respiration, and death.

Laboratory Criteria for Diagnosis:

· Detection of botuninum toxin in stool or serum or

· Isolation of Clostridium botulinum from stool

Case Classification:

Confirmed : a clinically compatible case that is laboratory confirmed, occurring in a child <1 year

Clinical Description:

An illness resulting from toxin, produced by Clostridium botulinum that has infected a wound.

Common symptoms are diplopia, blurred vision, and bulbar weakness. Symmetric paralysis may progress rapidly.

Laboratory Criteria for Diagnosis:

· Detection of botuninum toxin in serum or

· Isolation of Clostridium botulinum from wound

Case Classification:

Confirmed : a clinically compatible case that is laboratory confirmed in a patient that has no suspected exposure to contaminated food and who has a history of a fresh, contaminated wound during the 2 weeks before onset of symptoms.

Clinical Description:

Ingestion of botulinum toxin results in an illness of variable severity. Common symptoms are diplopia, blurred vision, and bulbar weakness. Symmetric paralysis may progress rapidly.

Laboratory Criteria for Diagnosis:

· Detection of botuninum toxin in clinical specimen or

· Isolation of Clostridium botulinum from clinical specimen

Case Classification:

Confirmed : a clinically compatible case that is laboratory confirmed in a patient > 1 year who has no history of ingestion of suspect food and has no wounds.