Shigella Infection – Symptoms and Causes

Overview

Shigellosis is an intestinal illness caused by shigella bacteria. This infection spreads easily through contaminated stool, surfaces, food, or water. Once ingested, these bacteria can cause various digestive symptoms.

Children younger than 5 years face the highest risk of infection, though it can affect people of any age. The bacteria spreads when tiny amounts of stool get on hands, objects, or into consumable items.

Common symptoms include:

• Diarrhea (possibly bloody)
• Persistent loose stools
• Fever
• Abdominal pain

Most infections resolve without treatment within a week. However, severe cases might require antibiotics to eliminate the bacteria.

Prevention methods:

1. Wash hands thoroughly, especially after bathroom use or diaper changes
2. Avoid swallowing water while swimming in pools, lakes, or ponds
3. Practice good food handling hygiene
4. Properly dispose of soiled diapers
5. Clean contaminated surfaces

The bacteria’s high contagiousness makes prevention particularly important in settings with young children or in crowded living conditions.

Signs and Symptoms

Shigella infection typically shows symptoms 1-2 days after exposure to the bacteria, though it may take up to a week in some cases.

Common symptoms include:

• Bloody or mucus-filled diarrhea that may continue for more than 3 days
• Stomach pain or cramping
• Tenesmus (feeling like you need to use the bathroom when your bowels are empty)
• Fever
• Nausea or vomiting

Most people experience symptoms for about a week, though they can last longer in some cases. Some infected people show no symptoms at all but can still spread the bacteria through their stool for several weeks.

When Medical Help Is Needed

Contact your doctor or seek urgent care if you or your child experiences:

• Diarrhea containing blood
• Weight loss or dehydration from diarrhea
• Fever above 102°F (39°C) with diarrhea
• Severe abdominal pain or tenderness
• Continuous vomiting that prevents drinking fluids
• Signs of dehydration including:
  • Little or no urination
  • Very dry mouth and throat
  • Dizziness when standing up

People with weakened immune systems should contact their doctor as soon as symptoms appear, as they’re more likely to develop a longer, more serious illness.

Causes

Shigella infection happens when bacteria enter the body through the mouth. This most often occurs through hand-to-mouth contact. People may touch contaminated surfaces or objects and then touch their mouths without washing their hands first.

Changing diapers of infected children creates a high risk of transmission. The bacteria can easily spread to caregivers’ hands during this process. Sexual contact with an infected person can also transfer the bacteria.

Food contamination is another common cause. When food handlers have a Shigella infection and don’t practice proper hygiene, they can spread the bacteria to food. Foods grown in fields irrigated with contaminated water may also carry the bacteria.

Contaminated water sources pose a significant risk. This includes:

• Drinking untreated water
• Swimming in polluted water
• Consuming beverages made with contaminated water

Sewage contamination of water supplies can introduce Shigella bacteria into drinking or recreational water. When infected individuals swim in pools or lakes, they may release bacteria that others can accidentally swallow.

Risk Factors

Several factors can increase your chance of getting a shigella infection:

• Age: Children under 5 years old face the highest risk, though people of any age can become infected.

• Group Environments: Living or participating in crowded settings increases transmission risk. Outbreaks commonly occur in:
  • Child care centers
  • Schools
  • Swimming pools and water parks
  • Nursing homes

• Travel or Residence in Developing Regions: Areas with poor water sanitation and inadequate sewage systems present higher infection risks.

• Certain Sexual Activities: Sexual contact involving the anus can spread shigella bacteria from one person to another.

• Homelessness: People experiencing homelessness may face higher risks due to:
  • Crowded living conditions
  • Limited access to clean water
  • Reduced toilet access
  • Exposure when bacteria spreads through a community
• Weakened Immune System: People with compromised immunity face a greater risk of serious infection. This includes those with:
  • HIV
  • Cancer undergoing chemotherapy
  • Other conditions affecting immune function

Health Complications

Water Loss

When you have shigella, ongoing loose stools can lead to water loss in your body. Signs include feeling dizzy, children not crying tears, sunken eyes, and babies having dry diapers.

If severe water loss happens, it can cause the body to go into shock and may even lead to death if not treated quickly.

Convulsions

Children with shigella infections sometimes have convulsions. These involve sudden changes in behavior, jerking movements, and passing out. They happen more often in children with high fevers but can occur even without fever.

Doctors aren’t sure if these convulsions happen because of the fever or from the infection itself. Call a doctor right away if your child shows signs of a convulsion.

Intestinal Protrusion

This problem happens when part of the lower intestine pushes out through the anus. Children with shigella who aren’t getting enough nutrients may be more likely to develop this condition.

Blood Vessel Disorder

This rare but serious problem affects blood and blood vessels. It can damage the kidneys so badly that they stop working properly.

Enlarged Bowel

In this rare case, the large intestine can’t pass waste or gas, causing it to swell. People with this problem have belly pain, swelling, fever, and weakness.

Without treatment, the bowel might burst, causing a dangerous infection that needs emergency surgery.

Joint Inflammation

This condition can start weeks after recovering from shigella. It causes pain and swelling in joints, especially ankles, knees, feet, and hips. Other signs include painful urination and eye problems like redness, itching, and discharge.

Blood Infection

Shigella bacteria can damage the lining of the intestines. In rare cases, these germs enter the bloodstream through this damaged lining. This type of infection happens more often in adults with weak immune systems and in children.

Prevention

Shigella infection can be avoided with proper hygiene and careful practices. Here are important steps to protect yourself and others:

Daily Hygiene Practices:

• Wash hands thoroughly with soap and water for at least 20 seconds. Clean hands before cooking, eating, and sexual activity.
• Always wash after using the bathroom or changing diapers. Place soiled diapers in covered trash cans with liners.

Environmental Safety:

• Disinfect diaper-changing areas immediately after use. Avoid swallowing water from untreated sources like ponds or lakes.
• Stay away from sexual contact with anyone who has or recently had diarrhea. You should wait at least two weeks.

If You or Your Child Has Diarrhea:

1. Continue frequent handwashing. Also, supervise young children during handwashing.
2. Avoid preparing food for others. Stay home from work if you work in healthcare, food service, or childcare.
3. Keep sick children home from school and group activities.
4. Don’t go swimming until completely recovered.