Botulinum toxin
In 1895 (seventy-five years later), Émile van Ermengem, professor of bacteriology and a student of Robert Koch, correctly described "Clostridium botulinum" as the bacterial source of the toxin. Thirty-four attendees at a funeral were poisoned by eating partially salted ham, an extract of which was found to cause botulism-like paralysis in laboratory animals. Van Ermengem isolated and grew the bacterium, and described its toxin, which was later purified by P Tessmer Snipe and Hermann Sommer.
Botulinum toxin
The seven toxin types (A-G) have different tertiary structures and sequence differences. While the different toxin types all target members of the SNARE family, different toxin types target different SNARE family members. The A, B, and E serotypes cause human botulism, with the activities of types A and B enduring longest "in vivo" (from several weeks to months).