Earlier this month, the Texas Department of State Health Services issued a health alert after four infants were diagnosed with botulism since August. The cases were believed to be linked to the use of infant pacifiers containing raw honey. Botulism, which I’ll discuss in more detail shortly, is a potentially life-threatening condition and a bad way to go. Thankfully there were no deaths among the Texas cases thought to be related to the tainted pacifiers, which are widely available in Mexico and for purchase online.
Honey pacifiers are not a new phenomenon. Their use is fairly common in Mexico, as is simply giving infants raw honey. During my three years as a newborn hospitalist in Houston, where I primarily worked at a county hospital almost exclusively caring for babies born to mothers from Mexico, I frequently confiscated pacifiers filled with honey, and sometimes corn syrup. They often were sticky because of seepage or because they were additionally dipped in honey. This 2013 study of families seen at a county clinic in Houston is consistent with my experience, finding that about 10% of families offered honey pacifiers to their infants.
Offering honey, or honey pacifiers, to infants is a traditional intervention felt by many Mexican parents to be preferred by infants. Belief in medical benefits also appears to be common, such as reduced crying and less constipation. The Houston survey also revealed that roughly 80% of responding caregivers were not aware of the risk of botulism associated with raw honey exposure in babies.
The Texas cases and subsequent alert were heavily featured by news media, which actually did a decent job for a change. They didn’t, as far as I could find, feature any proponents of infant honey consumption for “balance”. These people do exist and they are as awful as you would expect. The FDA has also weighed in, as has the American Academy of Pediatrics.
Concerns regarding infant exposure to raw honey are not new. In fact, pediatric healthcare professionals have been warning caregivers ever since the first cases of infant botulism were reported in 1976. Unfortunately, widespread educational campaigns have not been very successful in reducing the incidence of this condition. This is because the actual risk from honey is probably low compared to exposure from other environmental sources, such as from ingestion of soil or dust containing the causative bacterial spores. Still, it isn’t a risk worth taking.
What is infant botulism anyway?
Botulism is a toxin-mediated neuroparalytic syndrome caused by infection with the bacterium Clostridium botulinum. And though the condition has been known for almost 200 years, being first identified in southern Germany during a cluster of “sausage poisoning” cases in the 1820s, the causative organism wasn’t isolated until many years later. That discovery occurred during a cluster of cases in Belgium that were linked to some bad ham.
The name “botulinum” was based on the Latin word for sausage, which shouldn’t come as a surprise given the historical association with digging on swine. But the bacteria’s hardy spore form is fairly ubiquitous in soil and marine sediment worldwide. Because of this they are often found on the surface of fruits, vegetables, and various foods of the sea. They are also found in raw honey, although I’m pretty sure you’ve put that together by now. Spores are also frequently dispersed into the air by digging and construction work.
When exposed to the right environment, such as the infant gut or a deep wound, the combination of low oxygen, low acidity, and an ideal temperature range allows these spores to germinate. The resulting bacteria can then begin to multiply and, as the numbers increase, produce the deadly toxin. And I do mean deadly. Botulinum toxin, the same stuff that Jenny McCarthy believes is safer than vaccines, is the most potent poison known, with a lethal dose in experimental mice of 0.003 micrograms per kilogram. That works out to roughly a gram of toxin being capable of killing over a million non-experimental humans.
How does botulinum toxin affect the body?
Botulinum toxin prevents the neurotransmitter acetylcholine from being released by axons which terminate at the junction between the nerve and the muscle it innervates, resulting in paralysis. The more neurons that are involved, the more severe the weakness. This process can also inhibit release of other important neurotransmitters like dopamine, serotonin, and GABA, and the clinical presentation of botulism can vary considerably.
The classic form initially starts with abnormal function of one or more cranial nerves, often resulting in blurred or double vision, difficulty speaking or swallowing, or facial weakness. This is soon followed by a symmetric weakness that descends from the head and neck down to the lower extremities, often causing difficulty urinating and constipation. Though the severity of the muscle weakness is variable, many patients become too weak to generate enough force to breathe and require mechanical ventilation to survive. The toxin does not alter a patient’s mental status, so they are awake and fully aware of their dire situation.
The bacteria that causes botulism can enter the body in different ways, and this can alter a patient’s symptoms somewhat. For example, consuming contaminated home-canned foods tend to result in more substantial gastrointestinal symptoms such as vomiting and abdominal pain prior to the onset of the classic features described above. Infant botulism has some of its own unique signs and symptoms.
What is infant botulism?
Infant botulism is by far the most common form of botulism diagnosed in the United States every year, with about 3 out of every 4 cases being diagnosed in babies under the age of 12 months. This comes out to roughly 150 cases per year. Infant botulism has been diagnosed on every continent, but the distribution is very uneven. This is likely because of a lack of resources and of mandated reporting.
Although the risk exists throughout the first year of life, most cases occur during the first few months. Young infants are at increased risk because the so-called “good bacteria” and other organisms that make up the intestinal microbiome have yet to fully coat the lining of the gut. This gives certain pathogenic bacteria a better chance of establishing a foothold. An infant’s smaller size also likely plays a role.
Because of differences in prevalence of toxin producing strains of Clostridium species, most cases occur in Western states, particularly California, but Utah and Pennsylvania (higher prevalence of a different strain associated with botulism) also see more than their fair share. Finally, most cases in the United States result from the ingestion of spores found in soil and dust rather than honey.
As with classic botulism, the infant form also typically involves cranial neuropathy followed by a descending weakness/paralysis. Unlike in adult cases, caregivers are most likely to bring their baby in with concerns of constipation and poor feeding prior to the development of floppy muscles. Infants are also more likely than adults to progress quickly to respiratory failure and about 50% of cases ultimately involve a need for mechanical ventilation. Some infants have only a brief period of poor feeding before suffering severe and rapid deterioration.
Infant botulism, as with other forms, used to have a very high mortality rate but is generally a self-limited condition. The nerves will eventually regenerate working connections to the muscle if enough time is allowed by not dying. With supportive modern medical interventions, infant botulism survival did improve significantly, but prior to the development of a safe and effective therapy it often meant months of hospitalization and several weeks on a ventilator. With appropriate dosing of botulinum antitoxin, however, the average total time in the hospital is down to less than 3 weeks.
Conclusion: Put down the honey pacifier
Infant botulism is a rare condition, and most cases are not caused by the ingestion of honey. But honey is not risk free and there is no benefit to potentially leaky honey pacifiers compared to the safer versions. So a rational assessment of risk versus benefit yields a clear answer: put down the honey pacifier.
Again, infant botulism is a rare condition. So excessive parental worry is definitely not my desired outcome. I don’t want parents of constipated infants demanding testing for the presence of botulinum toxin or Clostridium spores in their child’s stool. But pediatric healthcare providers do need be aware of the classic signs and symptoms so that testing and treatment can be initiated in a timely fashion. Studies have shown that more than half of infants ultimately found to have botulism were initially misdiagnosed and their treatment delayed.