Listeriosis: Causes, Symptoms, and Treatment
Medically reviewed by Harsha Moole, MD, Internal Medicine. Last reviewed: October 23, 2026.
What kind of doctor treats Listeriosis?
An infectious disease doctor, a doctor who treats germ infections, usually treats listeriosis. A primary care doctor can often start the evaluation. A direct primary care or concierge doctor can be a first stop for an evaluation and can refer you to a specialist when needed.
What is listeriosis?
Listeriosis is an infection. It can happen when you eat food that has Listeria germs in it. Listeria infection is rare, but serious.
It is most likely to harm pregnant women and newborns. It is also more harmful to adults aged 65 or older and people with weakened immune systems. Other people can be infected with Listeria, but they rarely become seriously ill.
Listeria can cause an intestinal illness, which affects the gut. It can also cause an invasive illness. Invasive means the germs have spread beyond the intestines.
Symptoms
Intestinal illness usually causes:
- Diarrhea.
- Vomiting.
These symptoms usually start within 24 hours after eating the food. They are usually mild. Some people with intestinal illness go on to develop invasive illness.
Invasive illness usually starts within 2 weeks after eating the food. In people who are not pregnant, symptoms typically include:
- Fever.
- Flu-like symptoms, such as muscle aches and fatigue.
- Headache.
- Stiff neck.
- Confusion.
- Loss of balance.
- Seizures.
Symptoms in people who are not pregnant can be severe. In pregnant women, symptoms typically include fever and flu-like symptoms. They are usually mild, and some pregnant women never have symptoms.
In newborns, symptoms may show up in the first few days of life. They can include loss of appetite, lethargy (very low energy), and jaundice (yellow skin). Other signs are breathing trouble, shock, skin rash, and vomiting.
Causes and who gets it
Listeria germs live in wild animals, farm animals, soil, and water. Vegetables, meats, and other foods can pick up the germs from soil or manure (animal waste). Raw milk and foods made from raw milk may also carry the germs.
Higher risk groups are pregnant women, newborns, adults aged 65 or older, and people with weakened immune systems. In a pregnant woman, the germs may cross the placenta and infect the baby.
MedlinePlus advises you to cook food thoroughly.
How doctors diagnose it
Listeria infection is usually found when a lab test grows the germ from a sample of body fluid or tissue. Lab tests may look for the bacteria in blood, stool, urine, or the fluid around a baby in the womb. If a spinal tap is done, the spinal fluid is tested too.
Intestinal illness from Listeria is rarely found. Labs do not regularly test for it.
Treatment
Treatment depends on the kind of illness and how severe it is. People with invasive illness are treated with antibiotics. These are medicines that kill bacteria.
Most people get better from an intestinal illness without antibiotics. Only people who are very ill, or at risk of getting very ill, need them. People with diarrhea should drink plenty of fluids. This helps prevent dehydration, which means not having enough water in the body.
In invasive listeriosis not linked to pregnancy, almost 1 in 6 people die. In a fetus or infant, the illness is often fatal. Infants who survive may have long-term brain and nervous system damage and delayed development.
When to see a doctor
Contact a healthcare provider if both of these are true. You ate food that was recalled or linked to an outbreak. You also have a fever and other symptoms, such as fatigue and muscle aches. If you are pregnant and have a fever or flu-like symptoms, contact your provider too, even if you do not know of a food link. Tell the provider about any food that may have had Listeria. This is especially important if you are pregnant, are 65 or older, or have a weakened immune system.
Call 911 or go to the emergency room if you have severe trouble breathing, fainting, a seizure, confusion, or a fever with a stiff neck.
If you ate food that may have Listeria and do not feel sick, most experts believe you do not need tests or treatment.
How a direct primary care or concierge doctor fits in
A direct primary care doctor charges a flat monthly fee instead of billing insurance, while a concierge doctor usually charges more and often works alongside insurance. Such a doctor can review your symptoms and what you ate. They can arrange tests and refer you to a specialist or a hospital when needed.
Common questions
Is listeriosis serious?
It can be. Listeria infection is rare, but serious. It is most likely to harm pregnant women, newborns, older adults, and people with weakened immune systems. Other people rarely become seriously ill.
Do I need treatment if I ate recalled food but feel fine?
Usually not. Most experts believe you do not need tests or treatment if you ate food that may have Listeria and feel fine. Talk with a healthcare provider if you have questions.
How long after eating bad food do symptoms start?
It depends on the kind of illness. Intestinal symptoms usually start within 24 hours. Invasive symptoms usually start within 2 weeks.
Can listeriosis harm an unborn baby?
Yes. In pregnancy, the infection usually leads to miscarriage, stillbirth, early delivery, or a life-threatening infection in the newborn. Symptoms in pregnant women are usually mild. Some never have symptoms.
Sources
- Centers for Disease Control and Prevention - Symptoms of Listeria Infection
- Centers for Disease Control and Prevention - About Listeria Infection
- MedlinePlus - Listeriosis
Medical Disclaimer
This content is for general educational and informational purposes only and is not medical advice. It is not a substitute for professional medical advice, diagnosis, or treatment, and reading it does not create a doctor-patient relationship. Always seek the advice of your physician or another qualified health provider with any questions about a medical condition, and never disregard or delay seeking professional advice because of something you read here. If you think you may have a medical emergency, call 911 (or your local emergency number) immediately.
