Everything You Need To Know About Listeria Infection | Symptoms, Causes, Treatment & Prevention


Listeria infection, also known as Listeriosis is a serious food-borne infection and the result of this infection is severely fatal.¬† Center for Disease Control and Prevention reports an estimated 260 Americans die of listeriosis yearly, hence, it’s of prime importance to know all the facts about this life-threatening disease.

Listeriosis ranks third in a total number of death among foodborne pathogens. It can happen anywhere, anytime if you consume contaminated food and by that we mean, food that contains the causative agent, bacteria Listeria monocytogenes.


What is Listeria Monocytogenes?

Listeria monocytogenes is the causative agent of Listeriosis, a pathogenic bacteria which is facultatively anaerobic (can survive both in the presence and absence of oxygen). It grows and reproduces inside the host’s cell and has been considered as one of the most virulent foodborne pathogens. The bacteria is present in the environment, particularly in the soil containing decaying vegetation or water, also in the feces of mammals, including healthy human adults.

The bacteria is commonly found in contaminated foods like raw vegetables, melons, deli meats, unpasteurized dairy products like soft cheese and so on.


Know more about Listeria:

Symptoms of Listeriosis

Although the disease is fatal and can take lives, the symptoms of it can, however, go unnoticed. For many people, the symptoms might be mild and hence the infection might also be undiagnosed. The incubation period of the disease is one to three days post the consumption of contaminated food.

At first, you might get a flu-like sickness with fever and diarrhea but the effects of the infection can even reach to severe form affecting the heart, nervous system and even the circular system. The most common symptoms of Listeriosis include:


If the bacteria reach the nervous system then it might trigger some serious complications like:

  • headache
  • stiff neck
  • Loss of Balance
  • Convulsions and seizures

Also, the bacteria can even infect the bloodstream leading to a serious blood infection (septicemia) and even cause meningitis. Once the infection spreads to the brain it can cause several other diseases including:

  • Encephalitis
  • Meningoencephalitis
  • Cerebral abscesses
  • Cranial nerve palsies
  • Meningitis

Pregnant women are 10 times more at risk of this infection and others that are susceptible include elderly people and immunosuppressed people.


The infection is caused by the Listeria bacteria which are highly resistant to freezing temperatures but these bacteria get destroyed by high heat. Hence it’s advised to eat any frozen food only after it’s been heated to a proper temperature.

Who are at risk of Listeria?

Listeria affects all age group but people who are:

  • old (over 65 years of age)
  • Immuno-suppressed
  • pregnant
  • on medications to prevent organ transplant rejection
  • infected with HIV
  • diagnosed with diabetes
  • undergoing treatments of chemotherapy
  • taking dialysis
  • alcoholic and have liver diseases

are at greater risks of severe and advanced listeriosis infections and complications. During pregnancy the infected mother can also transmit the bacteria into the growing fetus via umbilicus into the baby’s bloodstream, infecting the baby as well.



Preliminary diagnosis is usually based on the patient’s clinical history and physical exam, especially after the patient gives a history of likely exposure to a contaminated food source. The disease is diagnosed by a blood test. Urine or spinal fluid might also be conducted to detect the presence of Listeria bacteria.


Doctors and experts state that Listeriosis is “usually a self-limited disease” as it might get cured without the need of medical care but for those who have been suffering from severe symptoms, antibiotic treatment is required. The antibiotic Ampicillin is considered as the best drug for treatment of the infections. In addition, for the patients who have the invasive infection, treatment needs to be more specific and quick. giving intravenous antibiotics and up to 6 weeks of hospitalization and proper treatment.

The disease is not contagious (i.e. the bacteria doesn’t get transmitted from person to person) as it’s source of transmission is usually fecal-oral route. The one major exception is for pregnant mothers who can transmit the bacteria to the fetus from either breast milk or through the umbilicus.

Any Home Remedies For Listeriosis?

Unfortunately, there is no home-based treatment for Listeriosis hence, it’s always best to prefer medical treatment as soon as you’ve been diagnosed with the infection. Despite this, there can be certain home remedies to soothe the symptoms like taking in activated charcoal, garlic, ipecac syrup and alcohol-free goldenseal to treat food poisoning.

How to Prevent Listeriosis?

As the saying goes, “Prevention is Better than Cure” and yes Listeriosis is preventable. Good hygiene, sanitation and consuming properly cooked food will certainly prevent the fatal infection. CDC has recommended some of the safety measures including:

  1. Always avoid raw fruits and vegetables and wash them properly with filtered water if possible before eating.
  2. Cook the raw meat (pork, beef, poultry and other sources of animal meat) thoroughly. High heat kills the Listeria bacteria.
  3. Unpasteurized milk, cheese, and other dairy products should be avoided.
  4. Avoid old Canned foods and ready-to-eat foods.
  5. Don’t consume hot dogs, deli meat unless they have been heated properly to steaming hot.
  6. Stop eating refrigerated meat spreads, and pates.
  7. Always use cheese and milk that have labels of pasteurization.
  8. After cutting meats and other uncooked foods, wash hands, knives and cutting boards properly with hot water or detergent.

Though serious and fatal, Listeria is a treatable and preventable disease. Due to improved and better treatment facilities, the prevalence of the disease is on the decreasing trend, although various small outbreaks of the infection have still been reported in different countries. All in all,¬† it’s always better to adopt healthy habits and safety measures to avoid getting infected from the Listeria bacteria.



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