Botulism is a rare but potentially life-threatening bacterial illness. Clostridium Botulinum bacteria grows on food and produces toxins that, when ingested, cause paralysis. Botulism poisoning is extremely rare, but so dangerous that each case is considered a public health emergency.
A virus is a small infectious agent that can only replicate inside cells of another organisms. Unlike other pathogens, viruses require a host cell to replicate and spread to other adjacent cells as they do not possess the ability to reproduce on their own.
Plague is caused by Yersinia pestis bacteria. It can be a life threatening infection if not treated promptly. Plague has caused several major epidemics in Europe and Asia over the last 2,000 years. Plague has most famously been called "the Black Death" because it can cause skin sores that form black scabs.