ShigellosisBacterial dysentery

Microbial Agent

• Four species of Shigella:– boydii– dysenteriae (causes deadly

epidemics)– flexneri (1/3 of U.S.)– sonnei (about 2/3 of U.S.)

• 448,240 cases in U.S. last year for sonnei and flexneri.

• dysenteriae occurs mostly in Africa and Central America

• Case fatality rates of 5-15%.

Signs and Symptoms

• Infectious disease causing diarrhea (bloody), fever, and stomach cramps

• Usually resolves in 5-7 days.• Children and elderly may

have diarrhea so severe they need to be hospitalized.

• A severe infection in a child less than 2 may have seizures.

• Some show no signs at all, but still pass the Shigella bacteria to others.

Diagnosis

• Many diseases cause the same symptoms

• Determining that Shigella is the cause of the illness depends on laboratory

• Tests identify if it is Shigella, and what type

• Stools of an infected person are tested

Diarrhea with blood and mucus is a typical symptom of Shigella.

Treatment and Prevention

• Can usually be treated with antibiotics

• There is no vaccine to prevent shigellosis

• Frequent hand washing can help

• Food safety and regular drinking water treatment is best prevention

Vegetables could be contaminated by crops harvested from a field with sewage, flies bred in infected feces, and food handlers that are not properly washing their hands