Botulism

Botulism (BOH-chu-lih-zum) is an uncommon, nerve-paralyzing illness caused by toxins * produced by Clostridium botulinum (klo-STRIH-dee-um boh-chu-LIE-num) bacteria.

There are seven types of botulinum toxin, each designated by a letter from A through G. Only four types (A, B, E, and F) make people sick. There are three forms of naturally occurring human botulism: infant botulism, food-borne botulism, and wound botulism. Inhalation (in-huh-LAY-shun) botulism is an additional form of the illness that could possibly be purposely spread through the air by someone intent on harming others. Clostridium botulinum is commonly found in soil and grows best in lowoxygen environments. The bacteria form spores that remain dormant, or inactive, waiting for conditions that allow them to grow. The spores can exist anywhere, and people might eat food containing these spores without becoming sick. In certain conditions, however, the spores can activate and produce toxin.

Food contaminated with the toxin is the culprit in cases of foodborne botulism. Most outbreaks stem from food that is improperly cooked or incorrectly canned or preserved. In food-borne botulism, the toxin itself is swallowed, but in cases of infant botulism, an infant swallows the spores, which then activate in the intestine and produce toxin. It is believed that the infant intestine lacks enough protective intestinal bacteria, stomach acid, and immune globulin * to prevent the spores from activating. Wound botulism is rare and develops when bacteria infect a wound and multiply, producing the toxin. Bioterrorists have attempted without success to aerosolize * botulinum toxin, but the threat of inhalation botulism as a biological weapon has raised concerns.

More than 100 cases of botulism are reported in the United States each year. Infant botulism accounts for about 72 percent of reported cases and food-borne botulism for about 25 percent. Wound botulism is the rarest form, but health officials have noted an increase in this type in California, a rise they attribute to the intravenous * use of illegal drugs from Mexico.

Botulism is not contagious. Outbreaks of food-borne botulism usually can be traced to improperly home-canned foods, especially those with low amounts of acid, such as asparagus, green beans, beets, and corn, which allow the Clostridium botulinum bacteria to grow. Various frozen foods have also been implicated in outbreaks of the disease. Many infants contract botulism by inhaling or swallowing spores; honey is one source of these spores. Wound botulism sometimes is linked to crush injuries.

Two or more of the following symptoms may indicate botulism: sudden blood in the urine * , difficulty swallowing, blurred or double vision * , droopy eyelids, slurred speech, dry mouth, and muscle weakness. These symptoms appear when the toxin interrupts nerve impulses to the muscles, which paralyzes the muscles. If untreated, paralysis may progress to involve the arms, legs, trunk, and muscles of the respiratory tract * .

In food-borne botulism, symptoms generally begin 18 to 36 hours after eating the contaminated food, but they can occur after as little as 6 hours or as long as 10 days. Infants with botulism may appear drowsy or sluggish, not eat well, be constipated, and have a weak cry and muscle weakness. In infants, it can take 3 to 30 days for the symptoms to appear and progress.

Laboratory tests can detect the toxin in blood, stool (feces), or wound samples. Because the symptoms of botulism are similar to those of stroke * * , or other nerve- and muscle-function tests to rule out other possible causes. The doctor may ask whether the patient has eaten any home-canned foods and, if so, order tests on the suspect food.

The Centers for Disease Control and Prevention (CDC) has a supply of antitoxin * against botulism. The antitoxin can slow or halt the damage caused by botulinum toxin. The sooner it is given, the more effective it is in easing the symptoms. To help rid the body of the toxin, doctors sometimes cause vomiting or prescribe enemas * . In severe cases, patients who are unable to breathe well enough on their own might need a ventilator (VEN-tuh-lay-ter), a machine that can help a person breathe for several weeks. Wound botulism might require surgery to remove the source of the toxin-producing bacteria.

Most people with botulism require hospitalization, but they typically recover after weeks or perhaps months of care. Paralysis of the respiratory muscles can lead to pneumonia * . Even after recovery, some patients may be tired and feel short of breath.

Although botulinum toxin is extremely potent, it can be destroyed easily. Heating foods and drinks to an internal temperature of 185°F (85°C) for at least five minutes will detoxify them. Boiling home-canned foods before eating them also lessens risk. Health officials advise that people who can or preserve foods at home use a pressure cooker and high temperatures—about 250°F (121°C)—to kill the spores. It is also best to avoid eating commercially prepared foods from cans that are swollen, punctured, or leaking. Because honey can contain spores of Clostridium botulinum, doctors advise that infants younger than one year not be given this sweetener. Breastfeeding can help protect against infant botulism. Receiving prompt medical care for infected wounds and not injecting street drugs can help prevent wound botulism.

See also Food Poisoning • Intestinal Infections

* immune globulin (ih-MYOON GLAH-byoo-lin), also called gamma globulin, is the protein material that contains antibodies.

* aerosolize (AIR-o-suh-lize) is to put something, such as a medication, in the form of small particles or droplets that can be sprayed or released into the air.

* intravenous (in-tra-VEE-nus), or IV, means within or through a vein. For example, medications, fluid, or other substances can be given through a needle or soft tube inserted through the skin's surface directly into a vein.

* urine is the liquid waste material secreted by the kidneys and removed from the body through the urinary tract.

* double vision is a vision problem in which a person sees two images of a single object.

* respiratory tract includes the nose, mouth, throat, and lungs. It is the pathway through which air and gases are transported down into the lungs and back out of the body.

* stroke is a brain-damaging event usually caused by interference with blood flow to the brain. A stroke may occur when a blood vessel supplying the brain becomes clogged or bursts, depriving brain tissue of oxygen. As a result, nerve cells in the affected area of the brain, and the specific body parts they control, do not properly function.

* spinal tap also called a lumbar puncture, is a medical procedure in which a needle is used to withdraw a sample of the fluid surrounding the spinal cord and brain. The fluid is then tested, usually to detect signs of infection, such as meningitis, or other diseases.

* antitoxin (an-tih-TOK-sin) counteracts the effects of toxins, or poisons, on the body. It is produced to act against specific toxins, such as those made by the bacteria that cause botulism or diphtheria.

* enemas (EH-nuh-muhz) are procedures in which liquid is injected through the anus into the intestine, usually to flush out the intestines.

* pneumonia (nu-MO-nyah) is inflammation of the lungs.