Common Name: Shiga bacillus, Bacillary dysenteriae
- Short rods, 0.5 to 0.7 u in width and 2 to 3 u in length
- Non encapsulated, non spore forming, non-motile
- Stain well with aniline dyes; gram negative
- Aerobic but facultatively anaerobic
- On EMB agar plate, colonies are smooth, convex, colorless, smooth and round
- On lactose medium; do not ferment lactose but do ferment sucrose with acid and no gas production
- Lipopolysaccharide as endotoxin contribute to the irritation of the bowel wall
- Heat-labile endotoxin affects both the gut and the central nervous system to paralyze the host
- Destroyed easily by pasteurization and boiling
- Inhabit intestinal tract of man
- Causes shigellosis
- An acute bacterial disease of the intestine characterized by diarrhea, accompanied by fever and vomiting, cramps and tenesmus.
- In severe cases, the stools may contain blood, mucus and pus after a short incubation period of 1-3 days. Watery diarrhea is due to an exotoxin acting in the small intestine.
- Always limited to the gastrointestinal tract; bloodstream invasion is quite rare.
- Highly communicable; infective dose is less than 10 organisms
Mode of Transmission
- Via personal contact with sick persons and carriers
- Via fingers, feces, food, fomites and flies
- Rectal swabbing under direct vision through a sigmoidoscope
Prevention and Control
- Isolation of sick persons.
- Detection and control of carriers.
- Examination of flies by use of baits, traps or insecticides.
- Sanitation and safeguarding of food supplies either by refrigeration or by covering foods on the table to avoid contamination.
- Effective disposal of sewage,
- Restoring water and chemical salts lost from the patient due to dehydration. Rehydration is accomplished by intravenous injections, administered preferably in a hospital.
- Overcoming the infection by use of drugs. Drugs are available to combat this disease and minimize its complications.
- The provision of adequate nourishment. The problem of nutrition is serious in the case of an infant. For older children, a high protein with low residue supplemented by vitamins is indicated.
- Immunization with vaccine is effective.
- Opiates should be avoided