Although far fewer Americans are infected with listeria than other foodborne illnesses each year, the bacteria has a much higher fatality rate.
Earlier this week, the Centers for Disease Control and Prevention (CDC) confirmed a link between listeria bacteria found in Blue Bell Creameries products and the recent listeria outbreak in mid and Southern United States. So far three people have died and another seven have been hospitalized in Arizona, Kansas, Oklahoma, and Texas.
Blue Bell, which sells ice cream, frozen yogurt, and other frozen snacks, voluntarily recalled all of its products from store shelves Monday. Listeria was found in products from several plants and the company said it still has no idea how the bacteria was introduced.
Between 2009 and 2011, there were 1,651 reported cases of listeria infection. Of them, 292 died, representing a case-fatality rate of 21 percent, according to the CDC. Most cases were in adults older than 65 years old (58 percent of cases). Pregnant women were also susceptible to the disease (14 percent of cases), which caused the death of the fetuses in some women.
The worst case was in 2011, when listeria contaminated Rocky Ford cantaloupes in Colorado affected 146 people in 28 states, leaving 36 dead.
By contrast, the CDC estimates that there are about 1 million salmonella infection cases each year, and 380 annual deaths resulting from it, giving it a fatality rate of roughly 0.04 percent.
Norovirus, the leading cause of foodborne illnesses in the United States—and the most common cause of the stomach flu—infects about 5.5 million people per year, but only kills about 150.
Like listeria, reported cases of illness due to dangerous strains of the e. coli bacteria, known as O157:H7, are relatively rare. Between 2003 and 2012, there were 4,930 cases, most of which resulted from people eating beef infected with the bacteria, according to the CDC. Of the infected individuals, 34 died, which amounts to less than 1 percent.
Listeria bacteria is most commonly found in processed meats, unpasteurized dairy products, and smoked seafood. Symptoms include fever, muscle aches, and diarrhea. Pregnant women, the elderly, and people with weakened immune systems are most at risk of getting sick.