What Is Salmonella?

Salmonella infection (salmonellosis), sometimes called salmonella poisoning, is an infection caused by a group of bacteria called Salmonella. Each year, there are about 1.35 million salmonella infection cases in the United States, leading to about 26,000 hospitalizations and about 420 deaths.

Salmonella bacteria are spread through contact with infected human or animal feces, usually via contaminated foods such as beef, seafood, poultry, eggs, or milk. A less common type of Salmonella (Salmonella typhi), which lives only in humans, causes a serious condition called typhoid fever.

This article will discuss the symptoms of salmonella infections, how they are contracted and treated, and ways to prevent getting sick from Salmonella bacteria.

<p>VLG / Getty Images</p>

VLG / Getty Images

How Do You Get Salmonella Poisoning?

Salmonella infection is typically spread to humans through:

  • Food that has been contaminated by Salmonella-infected feces (human or animal)

  • Contact with contaminated feces, person to person

  • Handling animals, particularly reptiles and birds

  • Contaminated water supplies

Foods can be contaminated with Salmonella bacteria at many stages of production and preparation, including:

  • Food being handled by someone carrying Salmonella bacteria who has not properly washed their hands after using the washroom

  • Cross-contamination from foods that are carrying Salmonella, including improperly cleaned surfaces or not washing hands thoroughly before and after handling foods

  • Animals and animal environments

  • During the butchering of raw meat

  • During the growing or harvesting of fruits and vegetables (usually through contact with contaminated manure or water)

Animal products, such as beef, seafood, poultry, eggs, or milk, are the most common sources of salmonella infection.

Homemade products that contain raw eggs or unpasteurized dairy can also increase the risk of salmonella poisoning. These foods may include:

  • Mayonnaise

  • Cookie dough

  • Unpasteurized dairy products such as raw milk or cream, or cheeses made with raw milk

  • Hollandaise sauce (a sauce made with raw egg yolk)

  • Some salad dressings using raw ingredients

  • Some desserts, such as ice cream, frostings, tiramisu, and cream-filled desserts and toppings

  • Raw fruits and vegetables, particularly sprouts (uncommon)

The bacterium that causes typhoid fever only spreads through contact with a person infected with the bacterium or contact with an item contaminated by a person carrying the bacterium. Typhoid fever can be fatal in up to 30% of cases. It is very rare in the United States, but infection may occur through travel to areas such as:

  • India

  • Latin America

  • Africa

  • Parts of Asia

A vaccine to prevent typhoid fever is available. Talk to your healthcare provider about how you can protect yourself if you plan to travel.

Salmonella Symptoms

Symptoms can vary, but common symptoms of salmonella infection include:

  • Nausea and/or vomiting

  • Diarrhea (sometimes bloody)

  • Fever

  • Chills

  • Abdominal cramps

  • Headache

Symptoms of typhoid fever typically develop slowly and may include:

  • Fever

  • Headache

  • Loss of appetite

  • Lethargy (lack of energy and interest)

  • Abdominal pain

  • Changes in mental status

  • Enlarged spleen

  • Constipation or diarrhea

Is Salmonella Contagious?

Humans and animals can carry and spread Salmonella bacteria to other humans and animals, even if they are asymptomatic (not sick or showing symptoms).

Even after being treated, people can continue to carry and shed Salmonella bacteria in their feces for up to a year after their infection. People who carry Salmonella bacteria can spread the infection by preparing food for others.

How Long Does Salmonella Last?

Symptoms from salmonella infection typically last four to seven days. Some people who experience salmonella poisoning develop Reiter's syndrome (reactive arthritis) weeks to months later. Symptoms of Reiter's syndrome include joint pain, eye irritation, and painful urination.

Seek urgent medical care if you experience:

  • Diarrhea and a fever higher than 102 degrees F

  • Diarrhea that does not improve within three days

  • Bloody stools (poop)

  • Vomiting that makes you unable to keep liquids down (prolonged)

You should also seek urgent care if you have signs of dehydration, including:

  • Minimal urine production

  • Dry mouth and throat

  • Dizziness when standing up

Which Conditions Increase Your Risk of Salmonella Poisoning?

Factors that may increase your risk of more serious illness from salmonella infection include:

  • Young age, particularly babies and children under 4 years old

  • Conditions that cause problems with the immune system, such as human immunodeficiency virus (HIV)

  • Taking medications that affect the immune system, including cancer-fighting drugs

  • Sickle cell disease

  • Not having a spleen or having a spleen that does not function well

  • Taking chronic stomach acid suppression medication

How Do I Know If I Have Salmonella?

Symptoms of salmonella infection can be similar to those of many other illnesses. To diagnose salmonella poisoning, your healthcare provider may send a stool sample to a lab to look for Salmonella bacteria.

If the infection is severe, more testing may be done to determine which specific bacterium is present and which antibiotics to use to treat the infection.

While salmonella poisoning is not usually fatal, about 450 people die yearly from acute salmonellosis in the United States.

Though much less common, Salmonella bacteria can also cause serious disorders such as:

  • Bacteremia (bacteria in the blood)

  • Meningitis (inflammation of the membranes of the brain or spinal cord)

  • Osteomyelitis (inflammation of the bone)

Salmonella Treatment

Salmonella infection typically runs its course within a few days without medical treatment.

If the infection is severe, the person is at risk for complications, or the infection has spread to the bloodstream or other parts of the body, antibiotics may be necessary. Antibiotics are not recommended for otherwise healthy people who don't have a severe salmonella infection as they don't tend to be helpful and may extend the amount of time the person will carry the bacteria.

Tylenol (acetaminophen) may help lower fever and relieve cramping.

If vomiting, diarrhea, and/or fever are present, preventing dehydration is essential, especially in children. To help keep children hydrated, you can:

  • Try giving 1 ounce (2 tablespoons) of fluid every 30 to 60 minutes (more can be added if this is well tolerated).

  • Continue to breastfeed infants and children who are still nursing.

  • Give watered-down fruit juice or broth.

  • Restore fluids by giving drinks such as Pedialyte or Enfalyte, or Pedialyte freezer pops. (First, check with your healthcare provider before giving to an infant, and follow the instructions. Do not water these down.)

If you or your child has severe diarrhea and/or can't keep fluids down, intravenous (IV) fluids may need to be administered at the hospital to prevent dehydration.

How to Prevent Salmonella Contamination

Taking proper precautions can help prevent the spread of Salmonella bacteria.

Kitchen

Ways to help prevent salmonella infections from food preparation include:

  • Cook foods containing meats, poultry, seafood, and eggs to a minimum internal temperature of 165 degrees F. (Note that microwaving is not a reliable way to kill Salmonella bacteria.)

  • Be especially careful with undercooked foods, including eggs, if you are pregnant.

  • Don't consume raw or unpasteurized dairy products or eggs (such as poached, sunny-side-up, or runny yolks).

  • Avoid foods that may contain raw meat, dairy, or eggs, such as some sauces, desserts, and salad dressings.

  • Throw away cracked eggs.

  • Keep foods properly refrigerated at under 40 degrees F.

  • Store foods promptly, and don't allow cooked food to stay out of the fridge for more than two hours after serving (or one hour on a hot day).

  • Wash fruits and vegetables thoroughly before eating them.

  • Keep uncooked meats (and items that have touched them) separate from foods they could contaminate, such as produce, cooked foods, and ready-to-eat foods.

  • Thoroughly wash your hands before handling foods and between handling different food items.

  • Thoroughly wash anything that has come into contact with uncooked foods, such as utensils, cutting boards, knives, dishes, and counters.

  • Clean kitchen surfaces regularly.

  • Don't cook food for others if you are sick.

  • Make sure everyone washes their hands before eating.

To help prevent the spread of infection from public places, contact your local public health authority if you see:

  • Restaurants, grocery stores, or other food establishments that are unclean or not following proper health and safety practices

  • If you suspect you or someone you know contracted food poisoning at a restaurant or other food vendor

Bathroom

Wash your hands thoroughly with soap and water after:

  • Using the washroom

  • Changing a diaper

  • Helping a child or someone else use the washroom

  • Cleaning the washroom

  • Coming into contact with feces, even if not visible

Wash your child's hands frequently, and teach them how to properly wash their hands, especially after using the washroom and before touching food.

From Pets

Handling animals, including pets, can spread Salmonella bacteria, particularly birds and reptiles.

Thoroughly wash your hands after:

  • Playing with or handling pets or animals

  • Handing pet food, treats, and toys

  • Handling animal waste, such as cleaning cat litter boxes or picking up after your dog

  • Cleaning animal habitats, like tanks, bowls, and cages

  • Handling reptiles and amphibians, which can have Salmonella bacteria on their bodies, even if they look clean and appear healthy

Also, make sure to:

  • Dispose of water used for animal habitats in a place away from sinks used for drinking water or food. preparation.

  • Keep pets away from areas where food is stored and prepared.

Watch for food recalls and outbreaks to avoid consuming contaminated items.

You can also contact the Food and Drug Administration (FDA) to submit a report, complaint, illness, or serious allergic reaction related to a food product.

Healing Timeline for Salmonella Poisoning

Symptoms can start from six to 72 hours after ingesting Salmonella bacteria. Once symptoms start, the illness typically lasts for four to seven days.

For people who experience long-term symptoms, such as Reiter's syndrome, additional symptoms typically appear three to four weeks after the first symptoms of salmonella poisoning appear.

For typhoid fever, symptoms can begin between three and 60 days after exposure and tend to appear gradually.

When to See a Healthcare Provider for Salmonella Symptoms

It's a good idea to see your healthcare provider if you have symptoms that may indicate a salmonella infection, both to confirm or rule out a diagnosis, and because there is a range of severity for the infection.

See your healthcare provider if you have:

  • Blood or pus in your stool

  • Diarrhea and cannot keep fluids down because of nausea or vomiting

  • Diarrhea and a fever above 101 degrees F

  • Diarrhea that does not stop within five days or gets worse

  • Signs of dehydration

  • Severe abdominal pain

  • Recently traveled outside of the United States and developed diarrhea

Contact your healthcare provider if your child has:

  • Diarrhea and a fever above 100.4 degrees F

  • Diarrhea that does not go away in two days or gets worse

  • Been vomiting for more than 12 hours (call as soon as vomiting or diarrhea begins for babies under 3 months)

  • Has signs of dehydration, such as reduced urine, sunken eyes, a sticky or dry mouth, and/or no tears while crying