Salmonellosis

Overview

Salmonellosis is an infection of the intestines caused by Salmonella bacteria. It is one of the most common causes of foodborne illness worldwide. People usually become infected by eating food or drinking water contaminated with the bacteria, often from raw or undercooked poultry, eggs, meat, or unpasteurized dairy, as well as contaminated fruits and vegetables.

Most healthy people recover within a week without specific treatment, and the main risk is dehydration from fluid loss. However, the infection can be more serious in infants, older adults, pregnant people, and those with weakened immune systems, sometimes spreading beyond the intestines.

Symptoms

Symptoms usually begin 6 hours to 6 days after exposure and last about 4 to 7 days. They commonly include:

• Diarrhea, sometimes containing blood
• Fever and chills
• Abdominal cramps and pain
• Nausea and sometimes vomiting
• Headache and muscle aches

Signs of dehydration, such as very dark urine, dizziness, dry mouth, and reduced urination, are a concern, especially in young children and older adults. High fever, bloody diarrhea, or symptoms that do not improve need medical attention.

Causes

Salmonellosis is caused by Salmonella bacteria entering the body, most often through the mouth. Common sources include:

• Undercooked poultry, eggs, and meat
• Unpasteurized milk and dairy products
• Contaminated raw fruits, vegetables, and sprouts
• Food prepared by someone who did not wash their hands properly
• Contact with reptiles, amphibians, baby chicks, or their environments

The bacteria can also spread from person to person through poor hand hygiene after using the bathroom.

Risk Factors

• Infants and young children
• Adults over 65
• Pregnancy
• Weakened immune system from illness or medication
• Contact with reptiles, amphibians, or poultry
• Travel to areas with poor sanitation
• Use of medications that reduce stomach acid

Diagnosis

Diagnosis is based on symptoms and laboratory testing:

• Stool test: A sample is tested to detect Salmonella bacteria and confirm the diagnosis.
• Blood tests: Used if the infection may have spread beyond the intestines.
• Antibiotic sensitivity testing: Helps guide treatment if antibiotics are needed, since some strains are resistant.

Treatment

Most cases are mild and improve on their own. The main goals are replacing lost fluids and preventing dehydration.

• Fluids: Drink plenty of water and use oral rehydration solutions to replace water and salts lost through diarrhea and vomiting.
• Rest: Allow the body to recover.
• Antibiotics: Not needed for most healthy people and may even prolong carriage of the bacteria. They are reserved for severe illness, infection that has spread, or people at high risk.
• Hospital care: Severe dehydration may require intravenous fluids.

Anti-diarrheal medicines are generally used with caution because slowing the gut can sometimes prolong the illness.

Prevention

• Cook poultry, eggs, and meat thoroughly
• Wash hands with soap before and after handling food and after using the bathroom
• Keep raw meat separate from ready-to-eat foods to avoid cross-contamination
• Refrigerate perishable foods promptly
• Avoid unpasteurized milk and juices
• Wash hands after contact with reptiles, amphibians, or poultry

When to See a Doctor

See a doctor if you have a high fever, blood in your stool, persistent vomiting that prevents keeping fluids down, diarrhea lasting more than a few days, or signs of dehydration such as dizziness, very dark urine, or little urination. Infants, older adults, pregnant people, and those with weakened immune systems should seek care earlier, as the infection can become more serious in these groups.

Related Topics

Frequently Asked Questions

References

1. Centers for Disease Control and Prevention (CDC). Salmonella.
2. MedlinePlus, U.S. National Library of Medicine. Salmonella infections.
3. Mayo Clinic. Salmonella infection — Symptoms and causes.
4. World Health Organization (WHO). Salmonella (non-typhoidal).