The deadliest foodborne outbreak in the U.S. in a decade has killed 13 people, infected 72 and is spreading through the country, with the Centers for Disease Control and Prevention reporting cases from 18 states.

Deaths have been reported in Colorado, Kansas, Maryland, Missouri, Nebraska, New Mexico, Oklahoma and Texas, according to latest updates from the CDC. The experts have traced the origin of the outbreak to whole cantaloupe grown at Jensen Farms' production fields in Granada, Colo.

The New York Times reported that though Jensen Farms said it shipped cantaloupes to 25 states, illnesses have been discovered in several states that were not on the shipping list. The CDC has warned that consumers who buy cantaloupes should verify if the produce is from Jensen Farms.

If it's not Jensen Farms, it's okay to eat ... But if you can't confirm it's not Jensen Farms, then it's best to throw it out, said CDC Director Thomas Frieden.

What is Listeriosis?
According to a document published by the Illinois Department of Public Health, listeriosis is caused by eating food contaminated by the bacterium listeria monocytogenes.

The document says an estimated 1,850 Americans become seriously ill with listeriosis every year and there are 425 reported deaths.

The Route of the Infection
One can be infected with listeriosis by eating food contaminated by the bacterium. Although healthy adults and children may consume contaminated food without becoming ill, those who are at increased risk are more likely to contract the disease after consuming even a small portion of infected food. According to the CDC, older adults, persons with weakened immune systems and pregnant women are more vulnerable to the listeria outbreak.

The bacterium, Listeria monocytogenes, is found in both soil and water and can contaminate vegetables by traveling through the soil and manure. Animals can also carry the bacterium, without appearing ill, and meat or dairy products from these animals could be contaminated.

According to the health department, the bacterium is also found in a variety of raw foods like uncooked meats and vegetables.

What are the Symptoms?

An infected person has symptoms such as fever, muscle aches and sometimes gastrointestinal symptoms such as nausea and diarrhea. If the infection spreads to the nervous system, symptoms such as headaches, a stiff neck, confusion, loss of balance or convulsions can occur.
Infected pregnant women may experience only a mild, flu-like illness. However, infection during pregnancy can lead to premature delivery, infection to the newborn or even stillbirth.

How to Limit Risk of Listeriosis
Listeriosis is essentially a foodborne illness and several measures can be taken to limit exposure and damage.

Some precautions are:

-Thoroughly cook any raw food from animal sources, such as beef, pork or poultry.
-Wash raw vegetables thoroughly before eating.
-Keep uncooked meats separate from vegetables and cooked and ready-to-eat foods.
-Avoid raw (unpasteurized) milk or foods made from raw milk.
-Wash hands, knives and other utensils and cutting surfaces after handling uncooked foods.

The Treatment
According to the Illinois Health Department, even with prompt treatment, some infections could result in death. This is particularly likely in the elderly and in persons with other serious medical problems.

When infection occurs during pregnancy, antibiotics administered promptly to the pregnant woman can often prevent infection of the fetus or the newborn. Babies with listeriosis receive the same antibiotics as adults.

According to medicinenet.com, in most cases, the infections clear away spontaneously in about seven days. However, the prognosis is different for people in the increased risk category, like pregnant patients. For such people, immediate IV antibiotic treatment is required to prevent, halt, or slow the development of the more severe disease.