The bacterium Clostridium botulinum produces a nerve cell poison, botulinum toxin, which causes botulism. Three botulism diseases can occur, depending on the route and type of exposure to the botulism bacteria and toxin. The disease courses vary for food-borne, infant and wound botulism. The Centers for Disease Control and Prevention indicates that approximately 110 children and adults in the United States contract botulism annually.
Food-Borne Botulism
Ingestion of stored food products contaminated with Clostridium botulinum bacteria and botulinum toxin causes food-borne botulism. The bacteria multiply in the food, producing botulinum toxin. Upon ingestion, the toxin passes from the small intestine into the bloodstream, which carries the toxin to nerve cells throughout the body. The medical reference text, "Principles and Practice of Infectious Diseases," explains that botulinum toxin binds to nerve cells at the synapse, the location where nerves intersect with one another. The presence of the toxin prevents nerve cell communication and destroys the synapse. Destruction of nerve cell synapses leads to widespread muscular weakness or paralysis.
Nausea, vomiting, cramps and diarrhea mark the onset of food-borne botulism. Muscle weakness follows, typically beginning in the muscles of the head and face and progressing downward through the body. The University of Maryland Medical Center reports that symptoms of food-borne botulism typically begin within 18 to 36 hours of ingestion of the botulinum toxin. Common neurological signs and symptoms include drooping eyes, blurred or double vision, dry mouth, drooping of the corners of the mouth, slurred speech and difficulty swallowing. Chest muscle involvement causes difficulty breathing, and respiratory failure commonly follows. Patients with food-borne botulism often require several months of ventilator support until the nerve cell synapses destroyed by the toxin regenerate.
Infant Botulism
Ingestion of Clostridium botulinum spores--an inactive form of the bacteria--causes infant botulism. Once in the intestine, the bacteria resume an active form. The microbes multiply and produce botulinum toxin, which readily enters the bloodstream. The onset of infant botulism proves more gradual than that of food-borne botulism because toxin production evolves as the bacteria multiply. In a review article on infant botulism published in "American Family Physician," Drs. Nadine Cox and Randy Hinkle report that the illness typically occur in infants 6 weeks to 9 months old. Weakness, poor muscle tone, decreased activity level, constipation, a weak cry and difficulty breathing gradually develop. Respiratory support often proves necessary.
Wound Botulism
Contamination of a skin wound with Clostridium botulinum spores from the environment provides the route of entry for wound botulism. Infection develops in the wound with replication of the bacteria and production of botulinum toxin. According to the Centers for Disease Control and Prevention, symptoms of wound botulism mirror those of the food-borne illness, with the exception of gastrointestinal symptoms, which do not occur with wound botulism.
References
- Centers for Disease Control and Prevention: Botulism, Epidemiological Overview for Clinicians
- Centers for Disease Control and Prevention: Botulism Handbook
- American Medical Association: Diagnosis and Management of Foodborne Illnesses--Botulism Poisoning
- "American Family Physician"; Infant Botulism; Nadine Cox, M.D., Randy Hinkle, D.O.; April 2002
- University of Maryland Medical Center: Botulism
