Infectious Doses

·         Shigella, enterohemorrhagic Escherichia coli, Giardia lamblia, or Entamoeba, as few as 10–100

·         Salmonella: 10³–10⁶

·         Vibrio cholera: 10⁵–10⁸

·         ETEC, EIEC, and EAggEC: 10⁶ to 10¹⁰

·         Cryptosporidium: 50% infectious dose: ~132 oocysts in nonimmune individuals

·         B. anthracis, While an LD50 of 10,000 spores is a generally accepted number it has also been suggested that as few as one to three spores may be adequate to cause disease in some settings.

·         F.turarensis: as few as 10 organisms causing infection