Foodborne Diseases: Botulism

Overview

Botulism is a rare but serious illness. Each year, U.S. health care providers report an average of 110 cases of botulism to the Centers for Disease Control and Prevention (CDC). This fact sheet will focus on botulism caused by eating contaminated food. About 10 to 30 outbreaks of foodborne botulism are reported annually. Although this illness does not occur frequently, it can be fatal if not treated quickly and properly.

Cause

Botulism is caused by toxin (poison) produced by Clostridium botulinum bacteria. This toxin affects your nerves and, if untreated, can cause paralysis and respiratory failure. C. botulinum toxin is one of the most powerful naturally occuring toxins. Exposure to the toxin, particularly in an aerosolized (spray) form, can be fatal.

C. botulinum has been made into bioweapons by rogue states and is one focus of current efforts to counter bioterrorism.

Transmission

Cases of foodborne botulism often originate with home-canned foods with low acid content, such as asparagus, green beans, beets, and corn. C. botulinum thrives in sealed containers because it is anaerobic, meaning it can survive and grow with little or no oxygen. Outbreaks of botulism, however, are often from more unusual sources such as baked potatoes wrapped in aluminum foil but not kept hot, and tomatoes.

Symptoms

Symptoms of foodborne botulism include
 Double vision and drooping eyelids
 Slurred speech
 Dry mouth and difficulty swallowing
 Weak muscles

Symptoms usually begin within 18 to 36 hours after you eat contaminated food, but can occur in as few as 6 hours or as long as 10 days afterward.

Diagnosis

A health care provider can use laboratory tests to identify C. botulinum toxin in your blood or stool if you are infected.

Treatment

If you are diagnosed with botulism early, your health care provider can treat you successfully with an antitoxin that blocks the action of the bacterial toxin circulating in your blood. Although antitoxin keeps the disease from becoming worse, it will still take many weeks before you recover. Your health care provider may try to remove any contaminated food still in your gut by making you vomit or by giving you an enema.

Prevention

To prevent getting foodborne botulism you should
 Follow strict hygienic steps when canning foods at home.
 Refrigerate oils containing garlic or herbs.
 Keep baked potatoes wrapped in aluminum foil should either be kept hot until served or refrigerated.
 Consider boiling home-canned food before eating it to kill any bacteria lurking in the food.
Complications

If left untreated, botulism can temporarily paralyze your arms, legs, trunk, and the muscles that help you breathe. The paralysis usually improves slowly over several weeks. People who develop severe botulism experience breathing failure and paralysis and need to be put on ventilators (breathing machines).



Topic Courtesy of the National Institute of Allergy and Infectious Diseases. February 27, 2012