Shigella infection, also called shigellosis, is a bacterial infection of the intestines. It often causes diarrhea, stomach cramps, fever, and a strong urge to use the bathroom. Because only a tiny number of bacteria can make you sick, it spreads fast in homes, daycares, shared living spaces, and through contaminated food or water.
In the United States, Shigella sonnei is the most common species. Other types include Shigella flexneri, Shigella dysenteriae, and Shigella boydii. Some strains cause more severe illness, and antibiotic resistance is becoming a bigger concern.
What Is Shigella Infection? An Overview
Shigella bacteria infect the gut, mainly the colon, and irritate the lining of the intestines. That irritation leads to diarrhea, pain, and sometimes mucus or blood in the stool. Symptoms usually start 1 to 3 days after exposure.
The four main species are Shigella sonnei, Shigella flexneri, Shigella dysenteriae, and Shigella boydii. In the US, S. sonnei causes most cases, while some S. flexneri and S. dysenteriae strains can be more serious.
How Shigella infection is different from a common stomach bug
A common stomach bug is often viral and clears up quickly. Shigella is a bacterial infection, so it can cause bloody diarrhea and may need stool testing or antibiotics in severe cases. That matters even more for young children, older adults, and people with weakened immune systems.
Common Symptoms of Shigella Infection
Symptoms can range from mild to severe, and they often last 5 to 7 days. Some bowel changes, like loose stools or cramps, can hang around longer.
Common signs include:
- watery diarrhea
- bloody diarrhea
- stomach cramps
- fever
- an urgent need to defecate
- mucus in the stool
- nausea
- sometimes vomiting
For a public health summary of the usual symptoms, see the CDC signs and symptoms page.
Warning signs that mean you should call a doctor
Call a doctor if there is blood in the stool, a high fever, severe belly pain, or signs of dehydration such as dry mouth, dizziness, or very low urine output. Confusion, symptoms that last longer than expected, or illness in infants, older adults, pregnant people, or anyone at high risk also require prompt medical care.
How Shigella Is Transmitted: Know the Causes
Shigella spreads by the fecal-oral route. In plain terms, germs from an infected person’s stool reach another person’s mouth, often through unwashed hands, diaper changes, contaminated food, unsafe water, or close contact. It can also spread through recreational water and some forms of sexual contact.
It takes only a very small amount of Shigella to cause illness, so prevention matters a lot.
Risk factors for contracting Shigella
Young children get sick more often, especially in daycare settings. Risk also rises for staff and family members, travelers, people in crowded housing, people with poor access to sanitation, men who have sex with men, and anyone with a weakened immune system.
Shigella in children and immunocompromised people
Children under 5 are at higher risk because they touch shared surfaces often and can dehydrate faster. People with weakened immune systems may have more severe illness, longer symptoms, and a higher chance of needing close medical follow-up.
How doctors diagnose Shigella and how long it usually lasts
Doctors usually diagnose Shigella infection with a stool sample. Labs may use culture or PCR testing, and those tests can also help show whether the bacteria are resistant to common antibiotics.
Many healthy people improve in 5 to 7 days. Still, recovery can take longer in severe cases or in people at higher risk.
Complications to know about, even though most people recover
Dehydration is the most common problem. Less often, Shigella can lead to seizures in children, bloodstream infection, reactive arthritis, or hemolytic uremic syndrome, especially with toxin-producing strains such as some Shigella dysenteriae. These problems are uncommon, but they are why severe symptoms should not be ignored.
Treatment options for Shigella infection
Treatment depends on how sick you are. Many mild cases improve with fluids, rest, and oral rehydration solutions. More severe illness, or infection in someone who is high risk, may need prescription antibiotics.
Doctors may choose drugs such as ciprofloxacin, azithromycin, or ceftriaxone, but resistance patterns matter. Recent CDC findings, covered in this report on rising US shigella infections, show that drug-resistant strains are becoming more common.
Over-the-counter vs. prescription medications for Shigella
Over-the-counter products can help with hydration and comfort, but they do not kill Shigella bacteria. Don’t start antibiotics on your own, and don’t use anti-diarrheal drugs unless a clinician says they are safe, because they can worsen some infections.
Natural remedies, do they help with Shigella?
There is no strong evidence that herbs, supplements, or home remedies cure Shigella infection. Bland foods and, in some cases, probiotics may help you feel better, but they should never replace medical care when symptoms are severe.
Preventing shigella infection and staying safe at home or while traveling
Prevention starts with soap and water. Wash your hands for at least 20 seconds after using the bathroom, changing diapers, and before eating or preparing food. Alcohol hand sanitizer may not work as well against Shigella.
Also, clean shared bathrooms, avoid swimming when you have diarrhea, and use safer food and water habits while traveling. The CDC prevention guidance is especially useful for homes, caregiving, and travel. There is no widely available vaccine yet.
The role of hand hygiene in Shigella prevention
Handwashing is the strongest takeaway because it protects both the sick person and everyone around them. A quick rinse is not enough. In daycare, households, travel, and caregiving, soap and running water can break the chain of spread.
Shigella and antibiotic resistance: what you need to know
Some Shigella sonnei and Shigella flexneri strains no longer respond to drugs that used to work well. In April 2026, CDC data showed extensively drug-resistant Shigella made up 8.5% of tested US isolates in 2023. That means treatment should be guided by a healthcare professional, and sometimes by lab results.
Why Shigella still matters worldwide
Shigella remains a global problem, especially where clean water and sanitation are limited. In the United States, it causes about 450,000 infections each year, and outbreaks still appear in childcare settings, crowded environments, and among travelers.
Shigella infection is common, easy to spread, and sometimes more serious than it first appears. The key steps are simple: watch symptoms closely, stay hydrated, get medical care for severe signs, and use careful handwashing and safer food and water habits to stop it from moving through a household or community.
FAQs
How does a person get Shigella?
Shigella infection spreads through contact with contaminated food, water, or an infected person. Poor hand hygiene, especially after using the bathroom or before handling food, is a common cause. It can also spread in crowded settings like daycare centers.
How serious is a Shigella infection?
Most cases are mild, but some can become severe. Serious infections may cause dehydration, high fever, or complications like intestinal damage. Young children and people with weakened immune systems are at higher risk.
How long is Shigella contagious?
A person can be contagious for about 1 to 4 weeks after symptoms start. Even after symptoms improve, the bacteria can still spread through poor hygiene practices.
What foods are Shigella found in?
Shigella is often found in contaminated foods like raw vegetables, salads, unwashed fruits, and improperly handled food. It can also spread through contaminated drinking water.
What are the first signs of Shigella?
The first signs usually include diarrhea, stomach cramps, and fever. Some people may also experience nausea or vomiting within 1 to 3 days after exposure.
Does Shigella clear up on its own?
Yes, many mild cases go away on their own within a week. However, proper hydration and rest are important, and severe cases may require medical treatment.
How long does Shigella take to go away?
Shigella infection typically lasts about 5 to 7 days. Recovery may take longer in severe cases or in people with weaker immune systems.
Is shigellosis an STD?
Shigellosis is not considered a traditional sexually transmitted disease. However, it can spread through certain types of sexual contact, especially involving poor hygiene.
What kills Shigella naturally?
The body’s immune system can clear mild infections naturally. Drinking plenty of fluids and maintaining good hygiene can support recovery, but there is no proven natural cure that directly kills Shigella bacteria.
What happens if Shigella goes untreated?
Untreated Shigella can lead to dehydration, severe diarrhea, or complications like intestinal inflammation. In rare cases, it may cause conditions such as reactive arthritis or kidney problems.
