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| The Bad Bug Book |
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1. Name of the Organism:
Shigella spp. (Shigella sonnei, S. boydii, S. flexneri, and S. dysenteriae)
Shigella are Gram-negative, nonmotile, nonsporeforming rod-shaped
bacteria. The illness caused by Shigella (shigellosis) accounts for less
than 10% of the reported outbreaks of foodborne illness in this country.
Shigella rarely occurs in animals; principally a disease of humans
except other primates such as monkeys and chimpanzees. The
organism is frequently found in water polluted with human feces.
2. Nature of Acute Disease:
Shigellosis (bacillary dysentery).
3. Nature of Disease:
Symptoms -- Abdominal pain; cramps; diarrhea; fever; vomiting; blood,
pus, or mucus in stools; tenesmus.
Onset time -- 12 to 50 hours.
Infective dose -- As few as 10 cells depending on age and condition of
host. The Shigella spp. are highly infectious agents that are transmitted
by the fecal-oral route.
The disease is caused when virulent Shigella organisms attach to, and
penetrate, epithelial cells of the intestinal mucosa. After invasion, they
multiply intracellularly, and spread to contiguous epitheleal cells
resulting in tissue destruction. Some strains produce enterotoxin and
Shiga toxin (very much like the verotoxin of E. coli O157:H7).
Shigella spp. (Shigella sonnei, S. boydii, S. flexneri, and S. dysenteriae)
Shigella are Gram-negative, nonmotile, nonsporeforming rod-shaped
bacteria. The illness caused by Shigella (shigellosis) accounts for less
than 10% of the reported outbreaks of foodborne illness in this country.
Shigella rarely occurs in animals; principally a disease of humans
except other primates such as monkeys and chimpanzees. The
organism is frequently found in water polluted with human feces.
2. Nature of Acute Disease:
Shigellosis (bacillary dysentery).
3. Nature of Disease:
Symptoms -- Abdominal pain; cramps; diarrhea; fever; vomiting; blood,
pus, or mucus in stools; tenesmus.
Onset time -- 12 to 50 hours.
Infective dose -- As few as 10 cells depending on age and condition of
host. The Shigella spp. are highly infectious agents that are transmitted
by the fecal-oral route.
The disease is caused when virulent Shigella organisms attach to, and
penetrate, epithelial cells of the intestinal mucosa. After invasion, they
multiply intracellularly, and spread to contiguous epitheleal cells
resulting in tissue destruction. Some strains produce enterotoxin and
Shiga toxin (very much like the verotoxin of E. coli O157:H7).
| The United States Food and Drug Administration's Bad Bug Book: Shigella spp. |