Preventing and dealing with infant botulism
By Jennifer Vines, CareOregon Quality Improvement team
A mother of a newborn member had inquired about conflicting advice provided by a couple of health care professionals. In an effort to raise awareness about infant botulism, we have compiled some information about the condition and ways to avoid it. Visit the USDA website for information on safe home canning. More information on botulism can be found at the CDC website. |
As families enjoy produce from their local farmers’ markets and gardens this summer, health care providers should be aware of the rare but serious illness called infant botulism caused by the bacteria Clostridium botulinum. This bacterium is commonly found in soil and prefers low-oxygen environments. C. botulinum produces seven neurotoxins, named A through G, although only types A, B, E, and F cause illness in humans. The toxins are presynaptic cholinergic neurotoxins that affect skeletal and smooth muscle as well as autonomic function.
Individuals can get foodborne botulism by consuming food contaminated with toxin, as sometimes happens with canned food that has been improperly handled. Another mode of infection is ingestion of clostridial spores that multiply in the intestines and release the toxin. Infants between 2 and 12 months are particularly susceptible to infection with spores because of their young age and lack of competitive bowel flora. In some cases of infant botulism these spores have been directly linked to wild honey which has led to the current recommendation that infants under one year of age not be fed honey. Corn syrup has also been implicated in cases of infant botulism, but a direct link has never been shown.
Every year in United States there are approximately 100 cases of botulism, and about 75 percent of these cases are infant botulism. Clinical features ranging from mild to severe are consistent with progressive neuromuscular blockade, typically with muscles innervated by the cranial nerves affected first and followed by those of the trunk, extremities, and diaphragm. Presentation of botulism in infants includes constipation, weak cry, poor feeding, and poor muscle tone. Cranial nerve manifestations include decreased gag and suck, ptosis, and pupillary paralysis. Signs of autonomic effects include decreased tearing and salivation, fluctuating pulse and blood pressure, and flushed skin. Onset of symptoms is typically 18 to 36 hours after eating a contaminated food, but can occur anywhere from 6 hours to 10 days after ingestion.
Botulism is diagnosed by history and physical exam with confirmation by nerve stimulation testing, EMG and isolation of C. botulinum spores from stool specimens. Botulism immune globulin prevents worsening in some individuals and has been shown in studies to shorten length of hospitalization in cases of infant botulism. Care is supportive, consisting primarily of assisted ventilation. Antibiotics are used only for secondary infections due to the risk of bacterial lysis and increased release of toxin. With intensive medical care the vast majority of affected individuals recover over a period of one to two months. Infant botulism carries a mortality rate of approximately 8 percent and some individuals who survive an episode of botulism will suffer fatigue and shortness of breath for several years requiring ongoing supportive care.
Preventive measures include advising parents to avoid giving honey to children less than 1 year of age. They may consider avoiding corn syrup although there is no hard evidence to suggest it as a source of infection. Individuals should also follow strict hygienic procedures during home canning to avoid contamination. Because the botulinum toxin is destroyed at high temperatures, boiling canned food for 10 minutes before eating will help ensure its safety. Health care providers should immediately contact their state public health agency for suspected cases of botulism so that public health officials can immediately investigate the source and facilitate acquisition of the antitoxin from the CDC if necessary.
