Shigella

Background

The Shigella bacteria causes Shigellosis resulting in a bloody diarrhea, fever, and stomach cramps starting a day or two after they are exposed to the bacterium. The infection usually resolves in 5 to 7 days but in some persons, especially young children and the elderly, the diarrhea can be so severe that the patient requires hospitalization. Some persons who are infected may have no symptoms at all, but may still pass the Shigella bacteria to others.

SYNONYMS Shigellosis
Dysentery

INCIDENCE
18,000 cases of shigellosis are reported in the United States. Actual number may be higher since many milder cases are not diagnosed or reported

AGE RANGE-MEDIAN Children, especially toddlers aged 2 to 4,

GEOGRAPHY

Poor hygiene communities

More common in summer than winter

Spread of illness in child-care settings

Developing countries

EPIDEMIOLOGIC ASSOCIATIONS CHARACTERIZATION

Fecal-oral contamination
Pass from one infected person to the next

Present in the diarrheal stools of infected persons while they are sick and for a week or two afterwards

May be acquired from eating contaminated food.

Be acquired by drinking or swimming in contaminated water

Prevention
Frequent and careful handwashing with soap

When possible, young children with a Shigella infection who are still in diapers should not be in contact with uninfected children

Drink only treated or boiled water, and eat only cooked hot foods or fruits you peel yourself, the same precautions for traveler's diarrhea

Reporting
Isolates of Shigella should be sent to the City, County or State Public Health Laboratory so the specific type can be determined

PATHOGENESIS CHARACTERIZATION

Gram negative rod Enterobacteriaciae

Group D
Shigella sonnei accounts for over two-thirds of the shigellosis in the United States

Group B
Shigella flexneri accounts for almost all of the rest

Shigella dysenteriae type 1
Developing world

GROSS APPEARANCE/CLINICAL VARIANTS CHARACTERIZATION

General

VARIANTS

Seizures A severe infection with high fever may be associated with seizures in children less than 2 years old

PROGNOSIS AND TREATMENT CHARACTERIZATION

Treatment
Ampicillin, trimethoprim/sulfamethoxazole, nalidixic acid, or ciprofloxacin.

Mild infections will usually recover quickly without antibiotic treatment

Antidiarrheal agents such as loperamide or diphenoxylate with atropine are to be avoided.

Henry JB. Clinical Diagnosis and Management by Laboratory Methods. Twentieth Edition. WB Saunders. 2001.

Commonly Used Terms

Bacteria

Last Updated 4/23/2001

SYNONYMS	Shigellosis Dysentery
INCIDENCE	18,000 cases of shigellosis are reported in the United States. Actual number may be higher since many milder cases are not diagnosed or reported
AGE RANGE-MEDIAN	Children, especially toddlers aged 2 to 4,
GEOGRAPHY	Poor hygiene communities More common in summer than winter Spread of illness in child-care settings Developing countries

EPIDEMIOLOGIC ASSOCIATIONS	CHARACTERIZATION
Fecal-oral contamination	Pass from one infected person to the next Present in the diarrheal stools of infected persons while they are sick and for a week or two afterwards May be acquired from eating contaminated food. Be acquired by drinking or swimming in contaminated water
Prevention	Frequent and careful handwashing with soap When possible, young children with a Shigella infection who are still in diapers should not be in contact with uninfected children Drink only treated or boiled water, and eat only cooked hot foods or fruits you peel yourself, the same precautions for traveler's diarrhea
Reporting	Isolates of Shigella should be sent to the City, County or State Public Health Laboratory so the specific type can be determined

PATHOGENESIS	CHARACTERIZATION
Gram negative rod	Enterobacteriaciae
Group D	Shigella sonnei accounts for over two-thirds of the shigellosis in the United States
Group B	Shigella flexneri accounts for almost all of the rest
Shigella dysenteriae type 1	Developing world

GROSS APPEARANCE/CLINICAL VARIANTS	CHARACTERIZATION
General
VARIANTS
Seizures	A severe infection with high fever may be associated with seizures in children less than 2 years old