Listeria Infections

Listeria infections (known as listeriosis) are caused by the bacterium Listeria monocytogenes.
Infection is rare, but when it does occur it most frequently affects pregnant women in their last trimester, newborns, and kids and adults whose immunity is weakened by diseases such as cancer or HIV. People who have had various types of transplants are also more at risk for listeriosis.

Listeria bacteria can be transmitted through soil and water. A person can also ingest listeria by eating certain foods, such as deli meats and cold cuts, soft-ripened cheese, milk, undercooked chicken, uncooked hot dogs, shellfish, and coleslaw made from contaminated cabbage. Many cases of infection, however, have no identifiable source.

Listeria infections may create symptoms such as fever, vomiting, diarrhea, lethargy, difficulty breathing, and poor feeding. Pregnant women who develop listeriosis may experience only mild flu-like symptoms, although they are at risk for premature delivery, miscarriage, and stillbirth.
People who have weakened immune systems are at particular risk for developing other more serious illnesses from listeriosis, including pneumonia, meningitis, and sepsis.

Cases of listeriosis are relatively rare. In 2004, just 120 cases were reported in the United States. In all cases, the earlier listeriosis is detected and treated, the better. And particularly if you are pregnant or in one of the other high-risk groups, avoiding certain foods and beverages can reduce your risk of contracting this infection.

Treating Listeriosis

Listeriosis is usually treated with antibiotics administered in the hospital through an intravenous catheter (IV). Typically, treatment lasts for about 10 days but that can vary depending on the body's ability to fight off the infection.
Children whose immune systems are compromised by illness or infection, such as cancer or HIV, are more likely to develop severe listeriosis infections and may require additional treatment.

Preventing Listeriosis

Although there are no vaccines against the bacteria that cause listeriosis, you can help reduce the risk for your family by taking these food safety precautions:

• Always cook food (especially meat and eggs) thoroughly to the proper internal temperature.
• Wash fruits and vegetables thoroughly before eating.
• Only drink pasteurized milk, and make sure that milk is refrigerated at the appropriate temperature, which is less than 40° Fahrenheit (4° Celcius).
• Avoid foods made from unpasteurized milk.
• If you're in a high-risk group, avoid soft cheeses such as feta, Brie, Camembert, blue-veined and Mexican-style cheeses unless they have labels that clearly state they are made from pasteurized milk.
• Reheat precooked, prepackaged foods — such as deli meats or hot dogs — to steaming hot temperatures, especially if you're pregnant.

When to Call the Doctor

Call your doctor immediately if your child develops rapid or labored breathing, fever, poor feeding, vomiting, a high-pitched cry, excessive sleepiness (lethargy), or irritability. If your child has listeriosis, the doctor can rule out any other illnesses and start treatment.

FDA confirms Listeria monocytogenes on Jensen Farms’ Rocky Ford-brand cantaloupes

Today, the Food and Drug Administration announced that it found Listeria monocytogenes in samples of Jensen Farms’ Rocky Ford-brand cantaloupe taken from a Denver-area store and on samples taken from equipment and cantaloupe at the Jensen Farms’ packing facility. Tests confirmed that the Listeria monocytogenes found in the samples matches one of the three different strains of Listeria monocytogenes associated with the multi-state outbreak of listeriosis.

Jensen Farms recalled its Rocky Ford-brand cantaloupes on Sept. 14 in response to the multi-state outbreak of listeriosis. Cantaloupes from other farms in Colorado, including farms in the Rocky Ford growing area, have not been linked to this outbreak.

To date, the Centers for Diseases Control and Prevention reports that 35 people in 10 states, including four deaths, have been infected with the outbreak strains of Listeria monocytogenes.

FDA investigators collected cantaloupes and environmental samples from a Denver-area store and from the Jensen Farms packing facility in Granada, Colo., after Colorado state health officials identified Jensen Farms’ Rocky Ford-brand cantaloupes as the common food eaten by several listeriosis patients.

Jensen Farms, based in Holly, Colo., is cooperating with the FDA and state officials in Colorado. The company is working with federal and state authorities to ensure the recalled cantaloupes are promptly removed from the marketplace. Jensen Farms is also helping federal and state authorities determine the root cause of how the cantaloupes became contaminated.

The FDA’s root-cause investigation and environmental assessment includes the on-site expertise of FDA and state of Colorado microbiologists, environmental health specialists, veterinarians and investigative officers. The experts conducting the assessment will analyze the evidence, determine the most likely cause of contamination and identify potential controls to help prevent contamination in the future. The FDA will use the findings to help inform agency policy regarding Listeria and produce food safety best practices.

Jensen Farms shipped the recalled cantaloupes from July 29 through Sept. 10 to at least 17 states with possible further distribution.

The FDA advises consumers—especially persons at high risk for listeriosis, including older adults, persons with weakened immune systems and pregnant women—not to eat the recalled cantaloupes and to throw them away. Do not try to wash the harmful bacteria off the cantaloupe as contamination may be both on the inside and outside of the cantaloupe. Cutting, slicing and dicing may also transfer harmful bacteria from the fruit’s surface to the fruit’s flesh.

For additional information about the recalled products, including product labels: http://www.fda.gov/Safety/Recalls/ucm271879.htm¹.

For additional information about the outbreak:
• FDA warns consumers not to eat Rocky Ford Cantaloupes shipped by Jensen Farms²• CDC Investigation on multi-state listeriosis outbreak³• FoodSafety.gov on Listeria⁴

The FDA, an agency within the U.S. Department of Health and Human Services, protects the public health by assuring the safety, effectiveness, and security of human and veterinary drugs, vaccines and other biological products for human use, and medical devices. The agency also is responsible for the safety and security of our nation’s food supply, cosmetics, dietary supplements, products that give off electronic radiation, and for regulating tobacco products.

Listeriosis and its Symptons

What is Listeriosis?

Listeriosis, a serious infection usually caused by eating food contaminated with the bacterium Listeria monocytogenes, is an important public health problem in the United States. The disease primarily affects older adults, pregnant women, newborns, and adults with weakened immune systems. However, rarely, persons without these risk factors can also be affected. The risk may be reduced by following a few simple recommendations.

What are the Symptoms of Listeriosis?

A person with listeriosis usually has fever and muscle aches, sometimes preceded by diarrhea or other gastrointestinal symptoms. Almost everyone who is diagnosed with listeriosis has "invasive" infection, in which the bacteria spread beyond the gastrointestinal tract. The symptoms vary with the infected person:

• Pregnant women: Pregnant women typically experience only a mild, flu-like illness. However, infections during pregnancy can lead to miscarriage, stillbirth, premature delivery, or life-threatening infection of the newborn.
• Persons other than pregnant women: Symptoms, in addition to fever and muscle aches, can include headache, stiff neck, confusion, loss of balance, and convulsions.

Listeriosis can present in different ways depending on the type of infection. For a more detailed explanation, please read more on the Clinical Features of Listeriosis page.

Who is at Risk for Listeriosis

People at Risk

In the United States, an estimated 1,600 persons become seriously ill with listeriosis each year. Of these, 260 die.

Who Gets Listeriosis?

The following groups are at increased risk:

• Pregnant women: Pregnant women are about 20 times more likely than other healthy adults to get listeriosis. About one in six (17%) cases of listeriosis occurs during pregnancy.
• Newborn babies: Newborn babies suffer the most serious effects of infection in pregnancy.
• Persons with weakened immune systems from transplants or certain diseases, therapies, or medications.
• Persons with cancer, diabetes, alcoholism, liver or kidney disease.
• Persons with AIDS: They are almost 300 times more likely to get listeriosis than people with normal immune systems.
• Older adults
• Healthy children and adults occasionally get infected with Listeria, but they rarely become seriously ill.

Multistate Outbrak of Listeriosis - September 2011

The Centers for Disease Control and Prevention (CDC) and the Food and Drug Administration (FDA) are investigating a multistate outbreak of listeriosis in coordination with state and local health departments, including the Colorado Department of Public Health and Environment. The outbreak started in the late summer; Collaborative investigations by local, state, and federal public health and regulatory agencies indicate the source of the outbreak is whole cantaloupe grown at Jensen Farms’ production fields in Granada, Colorado.

As of 11am EDT on September 26, 2011, a total of 72 persons infected with the four outbreak-associated strains of Listeria monocytogenes have been reported to CDC from 18 states. All illnesses started on or after July 31, 2011. The number of infected persons identified in each state is as follows: California (1), Colorado (15), Florida (1), Illinois (1), Indiana (2), Kansas (5), Maryland (1), Missouri (1), Montana (1), Nebraska (6), New Mexico (10), North Dakota (1), Oklahoma (8), Texas (14), Virginia (1), West Virginia (1), Wisconsin (2), and Wyoming (1).

Thirteen deaths have been reported: 2 in Colorado, 1 in Kansas, 1 in Maryland, 1 in Missouri, 1 in Nebraska, 4 in New Mexico, 1 in Oklahoma, and 2 in Texas.

Collaborative investigations by local, state, and federal public health and regulatory agencies indicate the source of the outbreak is whole cantaloupe grown at Jensen Farms’ production fields in Granada, Colorado.

On September 14, 2011, FDA issued a press release to announce that Jensen Farms issued a voluntary recall of its Rocky Ford-brand cantaloupes after being linked to a multistate outbreak of listeriosis.

CDC recommends that persons at high risk for listeriosis, including older adults, persons with weakened immune systems, and pregnant women, do not eat Rocky Ford cantaloupes from Jensen Farms.

Other consumers who want to reduce their risk of Listeria infection should not eat Rocky Ford cantaloupes from Jensen Farms.

Even if some of the cantaloupe has been eaten without becoming ill, dispose of the rest of the cantaloupe immediately. Listeria bacteria can grow in the cantaloupe at room and refrigerator temperatures.

Cantaloupes that are known to NOT have come from Jensen Farms are safe to eat. If consumers are uncertain about the source of a cantaloupe for purchase, they should ask the grocery store. A cantaloupe purchased from an unknown source should be discarded: "when in doubt, throw it out."

Go to September 27, 2011 for a full report.

More information about listeriosis and recommendations to reduce the risk of getting listeriosis from food are available at CDC’s Listeriosis webpage.

For more information on food outbreaks, please visit CDC’s Multistate Foodborne Outbreaks page.