What is the most lethal route of exposure for botulism?

The most lethal route of exposure for botulism is ingestion. Botulism is primarily caused by the ingestion of preformed toxins produced by the bacterium Clostridium botulinum, most commonly found in improperly preserved or canned foods. When these toxins are ingested, they can rapidly enter the bloodstream and affect the nervous system, leading to paralysis and potentially fatal outcomes.

Ingestion poses a high risk because the toxins can be present in food without any visual signs of contamination, making it difficult for individuals to identify hazardous foods. In contrast, inhalation, skin absorption, and intravenous administration are less common routes for exposure to botulinum toxin and are not the primary concern in typical botulism cases. Although inhalation of the toxin can be very dangerous, it is not a usual or prevalent route of transmission compared to ingestion, which is why ingestion is considered the most lethal.