Listeriosis Symptoms, Signs, and Diagnosis

  • Medical Author:
    John P. Cunha, DO, FACOEP

    John P. Cunha, DO, is a U.S. board-certified Emergency Medicine Physician. Dr. Cunha's educational background includes a BS in Biology from Rutgers, the State University of New Jersey, and a DO from the Kansas City University of Medicine and Biosciences in Kansas City, MO. He completed residency training in Emergency Medicine at Newark Beth Israel Medical Center in Newark, New Jersey.

  • Medical Editor: Charles Patrick Davis, MD, PhD
    Charles Patrick Davis, MD, PhD

    Charles Patrick Davis, MD, PhD

    Dr. Charles "Pat" Davis, MD, PhD, is a board certified Emergency Medicine doctor who currently practices as a consultant and staff member for hospitals. He has a PhD in Microbiology (UT at Austin), and the MD (Univ. Texas Medical Branch, Galveston). He is a Clinical Professor (retired) in the Division of Emergency Medicine, UT Health Science Center at San Antonio, and has been the Chief of Emergency Medicine at UT Medical Branch and at UTHSCSA with over 250 publications.

What are Listeria infection symptoms and signs?

In most people, Listeria infection symptoms and signs mainly include the common symptoms of food poisoning such as

If Listeria causes more severe illness, patients may also experience

At-risk patients (such as immune-compromised individuals) may become very ill or even die from a Listeria infection.

How is listeriosis diagnosed?

Listeriosis is diagnosed based on the results of medical tests. These tests may include the following:

  • Stool culture: A stool sample is tested in the lab for the presence of the Listeria bacterium. Results from this test may take several days to return.
  • Blood tests: These tests may indicate the presence of infection or tell the doctor how sick someone is, but they are not able to pinpoint Listeria as the cause unless blood cultures are done. Blood cultures are used to isolate the specific bacteria that are causing the infection and may show Listeria.
  • A "spinal tap” (lumbar puncture): Cerebrospinal fluid (CSF) is taken from a needle placed in the lower back. Microscopic testing and cultures are done on this fluid and may show the presence of Listeria.
  • Cultures of amniotic fluid may be used in at-risk pregnant patients who develop symptoms of listeriosis.

Medically reviewed by Robert Cox, MD; American Board of Internal Medicine with subspecialty in Infectious Disease


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Gelfand, Michael S. "Treatment, Prognosis, and Prevention of Listeria monocytogenes Infection." Nov. 2014. <>.

United States. Centers for Disease Control and Prevention. "Listeria (Listeriosis)." July 31, 2014. <>.

United States. Centers for Disease Control and Prevention. "Multistate Outbreak of Listeriosis Linked to Whole Cantaloupes from Jensen Farms, Colorado." Aug. 27, 2012. <>.

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