MEANING & STATISTICS

Shigella infection, also known as “Shigellosis,” is an intestinal infection caused by a family of rod-shaped
bacteria known as shigella. Shigellosis can spread easily from one person to another—and it only takes a
small amount of it to cause illness. It is endemic to temperate and tropical climates. Shigella has been
classified into four species and subgroups comprising of 43 serotypes

The four species of Shigella are:

1. Shigella dysenteriae
- 15 serotypes
- common in sub-Saharan Africa and South Asia.
- causes most severe dysentery, often associated with more severe cases of shigellosis.
- high mortality rate if untreated

2. Shigella flexneri
- 8 serotypes
- most common in developing countries (Cambodia)
- elicits less severe dysentery than S. dysenteriae
- highly invasive, especially in the colonic mucosa

3. Shigella boydii
- 19 serotypes
- mostly restricted to the Indian subcontinent
- biochemically identical to S. flexneri, but distinguished by serology (i.e antigenic properties)
- least common Shigella specie, less well-studied compared to other species of Shigella.

4. Shigella sonnei
- only 1 serotype
- common in developed countries (Thailand, United States, United Kingdom)
- produces mildest form of shigellosis, the most common specie of shigellosis worldwide
- primarily affects the colon's surface.

Worldwide, Shigellosis is estimated to cause 80–165 million cases of disease and 600,000 deaths
annually, and most cases and deaths are among children.

About 450,000 infections occur in the United States each year and an estimated $93 million in direct
medical costs.

INFECTION

Shigella is found in the stool (feces) of infected people, in food or water contaminated by an infected
person, and on surfaces that have been touched by infected people. The bacteria are spread when
someone comes into contact with the stool of an infected person or comes into contact with an item that’s
been contaminated with the stool or the bacteria. Certain serotypes tend to be responsible for the majority
of cases worldwide, including S. flexneri serotypes 2a, 1b, 3a, 4a, and 6; S. sonnei, which has a single
serotype; and S. dysenteriae type 1.

People get shigellosis by eating food or drinking water that has been contaminated, or through sexual
contact with an infected person. Many different foods can be contaminated, but Shigella is found typically
in uncooked vegetables or shellfish.
Shigellosis often occurs in toddlers who are not fully toilet-trained. Family members and playmates of
children infected with Shigella are at high risk of becoming infected. Shigella can spread easily in
environments such as day care facilities.

People become infected with Shigella by:

● Eating food or drinking liquids contaminated by an infected person.

SIGNS and SYMPTOMS

Symptoms usually last about 5 to 7 days. Treatment for shigellosis may be available from your healthcare
provider. People with mild symptoms usually recover on their own without treatment.

EFFECTS

This manifests primarily through gastrointestinal symptoms including severe diarrhea, often bloody,
accompanied by abdominal cramps, fever, and occasionally nausea and vomiting. The infection may lead
to dehydration, particularly risky for vulnerable populations like children and the elderly. Fatigue and
malaise commonly accompany the illness, persisting beyond the resolution of other symptoms.

In severe cases, complications such as rectal prolapse, seizures (especially in children), reactive arthritis,
and hemolytic-uremic syndrome (HUS) may arise. Prompt medical attention is essential, typically
involving antibiotics to combat the infection and supportive measures to manage symptoms and prevent
dehydration, especially in high-risk individuals.

PREVENTION

You can lessen your risk of getting or spreading shigellosis in the following ways:

1. Wash your hands with soap and water thoroughly and often, especially before and after eating, after
using the bathroom and changing diapers, before preparing food, and after coming into contact with an
infected person.
2. Wash foods well and cook them well.
3. Avoid swallowing water in pools, lakes or ponds.
4. Throw away soiled diapers in a lined garbage can with a lid.
5. Follow safe food and water instructions when traveling in other countries.
6. Wait for a week after your partner has recovered from diarrhea before engaging in sexual activities.

Avoid close personal contact with someone who has shigellosis until at least several days after the
diarrhea has ended. People who have shigellosis shouldn’t prepare food for others until they feel better
and stop having diarrhea.

Your doctor may test your stool again after your symptoms end to be sure Shigella is no longer present.

CURE
Treatment for Shigella depends on how severe it is. Contact your healthcare provider if you or one of your
family members has bloody or prolonged diarrhea (diarrhea lasting more than 3 days) or severe stomach
cramping or tenderness, especially if you also have a fever or feel very sick. Tell your healthcare provider
if you have other medical conditions or a weakened immune system—for example, because of an HIV
infection or chemotherapy treatment. If you have a weakened immune system, you may be more likely to
become severely ill.

1. Self-care at home
- If your symptoms are mild, you can treat it with rest and by drinking fluids to prevent dehydration
(a dangerous loss of water in your body).
- You can also take bismuth subsalicylate (Pepto-Bismol®) for the diarrhea. Don’t take loperamide
(Imodium®) or diphenoxylate with atropine (Lomotil®) because these drugs slow bowel function
and keep the bacteria in your system.

2. Medical treatment
- In more severe cases of shigellosis, and for people with weak immune systems, doctors may
prescribe an antibiotic to treat the infection. Antibiotics can shorten the time you have fever and
diarrhea by about 2 days. Your provider may prescribe ciprofloxacin or azithromycin.
- People with bloody diarrhea should not use anti-diarrheal medicines, such as loperamide
(Imodium) or diphenoxylate with atropine (Lomotil). These medicines may make symptoms
worse.
- Make sure you follow directions and take all of the antibiotics even if you start feeling better
before they’re gone.

Shigella infection usually runs its course in five to seven days. Replacing lost fluids from diarrhea may be
all the treatment you need, particularly if your general health is good and your shigella infection is mild.

https://www.mayoclinic.org/diseases-conditions/shigella/diagnosis-treatment/drc-20377533