Cholera is an acute diarrhoeal infection caused by the bacterium Vibrio cholera of serogroups O1 or O139. Humans are the only relevant reservoir, even though Vibrios can survive for a long time in coastal waters contaminated by human excreta.
Botulism is a serious paralytic illness caused by a nerve toxin produced by the bacterium Clostridium botulinum. The disease may occur after eating foods containing the toxin or due to development of the spores within the intestine of young children or within wounds.
Severe acute respiratory syndrome (SARS) is a life-threatening respiratory disease caused by a recently identified coronavirus; the SARS-associated coronavirus (SARS-CoV). This is believed to be an animal virus that recently crossed the species barrier to infect humans.