In the U.S., most cases of botulism happen in infants. Infant botulism occurs when a baby eats spores of the bacteria. The spores then grow in the intestines and release toxin. As an adult, 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. The bacteria that cause botulism are anaerobic. This means they grow in places where little oxygen is present. Like many bacteria, the botulism bacteria reproduce by forming spores. These can lie dormant until conditions are right for growth.

Foods with a low acid content are especially likely to have the botulism bacteria. These foods include asparagus and home-canned foods such as potatoes, green beans, beets, and corn that have not been canned correctly. Other sources have been:

• Chopped garlic in oil
• Chile peppers
• Tomatoes
• Potatoes baked in foil
• Frozen, fully cooked foods
• 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 botulism bacteria toxin.

A baby's digestive tract is an inviting place for the botulism 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 the botulism bacteria when they gather pollen. The spores then become part of the honey made by those bees. Honey is considered safe for adults and children older than 1 year. But it should not be given to infants. Babies with botulism appear sluggish. They 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 down through the body. Over time it affects the muscles that regulate breathing. Other symptoms include blurred vision, trouble swallowing, and dry mouth. The first symptoms usually are double vision and blurred vision. Symptoms often 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.

The botulism bacteria are common. But to get botulism you must eat food that has the toxin in it that the bacteria make. This is food that has not been correctly cooked. Or food that has been reheated after the toxin is in it. For infant botulism, the baby must eat the spores. The spores then make the toxin in the baby's digestive tract. Wound botulism is another way to get botulism. The bacteria enter a wound and make toxin.

A person with severe botulism may need to be connected to a respirator for weeks during recovery. They may need to stay in intensive care. The paralysis caused by the botulism toxin gradually eases. Adults can get an antitoxin if the diagnosis is made early enough. It stops the condition from getting worse. The healthcare provider may induce vomiting or give an enema early on. This is 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°F (100°C) for 10 minutes. The botulism toxin can only be destroyed by boiling foods for 10 minutes. Commercially prepared foods also have been included in botulism outbreaks. Some outbreaks have been caused by incorrectly 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, trained healthcare providers inject botulinum toxin into the skin. This is a purified form of the bacteria. The toxin paralyzes the facial muscles that were injected. This temporarily smoothes out fine lines or wrinkles. Ophthalmologists use the toxin to treat the blurred vision caused by some eye diseases. The injected toxin also seems to help ease the pain of migraine headaches. Injections often have to be repeated, because the effects often last only 3 to 4 months. In rare cases they can last for more than a year. Because of this, over time some people develop antibodies to the toxin. This is more likely in people who get higher doses more often. For this reason, the manufacturers advise that the dosage be kept as low as possible.