The significance of breast-feeding as a risk factor is controversial. It is clear that many infants who are diagnosed with infantile botulism are primarily breast-fed. However, it it not clear whether it confers some protection, slowing the process of the disease and allowing the infant to reach the hospital alive. Preexisting host factors such as frequency of bowel movement may be other risk factors for the disease. The clinical spectrum ranges from asymptomatic carriage of infant botulism to a fulminant forms of the disease that may mimic sudden infant death syndrome.
Most infants suffer from the moderate to severe form of the disease and require hospitalization.
Constipation is a characteristically early sign, reflecting formation of toxin within the GI tract, although this is frequently overlooked. The child is usually afebrile. Infants then become listless and progressively weak over a period of days to weeks with decreased suck, weak cry, and hypotonia. Symmetric descending paralysis is the rule, and the cranial nerves are the first to be affected. The typical patient manifests hypoactive tendon reflexes, decreased suck and gag, poorly reactive pupils, bilateral ptosis, oculomotor palsies, and facial diplegia.