How Much Do You Know About Botulism?

You can get botulism in 3 ways: by eating foods that contain the botulism toxin, by eating foods that contain spores of the bacteria, or through a wound infected with the bacteria. C. botulinum is an anaerobic bacterium, meaning it grows in places where little oxygen is present. Like many bacteria, C. botulinum reproduces by forming spores. These can lie in a dormant state until conditions are right for growth. Infant botulism occurs when a baby consumes spores of the bacteria, which then grow in the intestines and release toxin. In the U.S., about 145 cases of botulism are reported each year. Of these, about 15% are foodborne, 65% are infant botulism, and the rest are wound botulism.

Foods with a low acid content such as asparagus, green beans, beets, and corn seem especially likely to be contaminated by the botulinum bacteria. Other sources have been chopped garlic in oil; chile peppers; tomatoes; potatoes baked in foil; frozen, fully cooked foods; and home-canned or fermented fish. Spores are often found on the skin or rind of fruits and vegetables and in seafood. The bacteria and spores themselves are harmless. The dangerous substance is the toxin made by the bacteria when they grow. The other foods listed as answers (raw tuna, raw eggs, and mayonnaise on a hot day) may also cause foodborne illness, but the culprits are not the botulinum bacteria toxin.

A baby's intestinal tract is an inviting environment for the C. botulinum toxin. This is because the tract doesn't yet have all of good bacteria found in the intestines of older children and adults. Bees can pick up spores of C. botulinum when they gather pollen. The spores then become part of the honey made by those bees. Although honey is considered safe for adults and children older than a year, it should not be given to infants. Because the spores are nearly everywhere in the environment, children and adults regularly eat them, yet very rarely get sick. Infants with botulism appear lethargic, don't eat well, are constipated, and have a weak cry and poor muscle tone.

Once in the body, the botulism toxin binds to nerve endings at the point where the nerves join muscles. This keeps the nerves from signaling the muscles to contract. The result is weakness and paralysis that starts at the head and works downward through the body. It eventually affects the muscles that regulate breathing. Other symptoms include blurred vision, difficulty swallowing, and dry mouth. The first symptoms usually are double vision and blurred vision. Symptoms usually appear 18 to 36 hours after eating a contaminated food, but they can show up as early as 6 hours or as late as 10 days.

C. botulinum is a common bacterium, but to get botulism a person must eat food containing the toxin the bacterium makes. This is food that has not been properly cooked or has been reheated after the toxin is present. For infant botulism, the baby must eat the spores, which then make the toxin in the baby's intestinal tract. (Wound botulism is another way to get botulism. The bacteria enter a wound and make toxin.)

To rule out these other diseases, a health care provider will use tests, including a brain scan, spinal fluid check, electromyography, and a tensilon test. Botulism is confirmed by finding the botulinum toxin in the food a person ate, in the person's blood or feces, or cultured from a wound. It's important to make the diagnosis, particularly for foodborne botulism, to help others avoid the contaminated food.

A person with severe botulism may need to be connected to a respirator for weeks during recovery and remain in intensive care. The paralysis caused by the botulism toxin gradually eases. An antitoxin can be given to adults if the diagnosis is made early enough. It stops the person's condition from getting worse. The health care provider may induce vomiting or give an enema early on to remove any contaminated food still in the digestive tract.

You can get a copy of home-canning guidelines from your county agricultural extension office. The botulism spores in home-canned foods can only be killed by the high heat of a pressure canner. This means keeping the foods at over 212 degrees F (100 degrees C) for 10 minutes. The botulism toxin can only be destroyed by boiling foods for 10 minutes. Commercially prepared foods also have been involved in botulism outbreaks. Some outbreaks have been caused by improperly handled restaurant foods such as potato salad. Many outbreaks involving commercially prepared foods have been caused by consumers' mishandling the foods. For instance, foods that need to be refrigerated can become contaminated if they are not kept cold. Protect yourself against botulism by reading food labels and following storage instructions. Don’t open a home-canned container that is bulging. Throw out packages that look damaged. Also throw out commercially canned products that have bulging or rusty lids.

To treat facial wrinkles, dermatologists inject very low doses of the toxin into the skin. The toxin paralyzes the facial muscles, smoothing out wrinkles. Ophthalmologists use the toxin to treat the blurred vision caused by some eye diseases. The injected toxin also appears to help ease the pain of migraine headaches. Injections usually have to be repeated, because the effects usually last only 3 to 4 months. Sometimes they can last for more than a year. Because of this, some people eventually develop antibodies to the toxin. This is more likely in people who get higher doses more often. Therefore, the manufacturers recommend that its dosage be kept as low as possible.