US Listeria outbreak infects 84, kills 15

Added by Erik West on October 1, 2011

The US Centers for Disease Control (CDC) reported 84 people are infected with any of the four strains of Listeria that originated from a batch of cantaloupes from a farm about 375km (232mi) southwest of Denver, Colorado.

The outbreak covers 19 US states and is expected to continue since people can develop listeriosis up to two months after eating contaminated foods.

Listeria, caused by a pathogen called Listeria monocytogenes, is a food-borne bacteria that can be found in soil, yet animals carry the bacteria too. Listeria can cause fever, muscle aches, headache, stiff neck, loss of balance, confusion, and diarrhea. Listeria is an opportunistic bacteria that generally affects people with weakened immune systems, older adults, and pregnant women, with about 800 cases, and 3-4 outbreaks reported each year in the United States. Listeria can be found on food processing equipment as well, as was the case in the 2008 Canadian Listeria outbreak.

In an update on its website, the CDC says the illness actually started around July 31. Affected people range in age between 35 to 96 years old with a median age of 78. Of 79 people with information about whether they were hospitalized, 78 of them were hospitalized, with two of them being pregnant women.

The farm cantaloupes originated from has recalled all cantaloupes, yet the CDC says more infections could occur because up to 2 months can elapse between eating contaminated food and developing listeriosis.

The CDC reports that most of the previous US outbreaks were caused by meats and cheeses made with unpasteurized milk with produce being an infrequent source, except in 2009 where sprouts caused an outbreak followed by celery in 2010.

The CDC advises consumers to ask about the origin of cantaloupes they may have, and advises people dispose cantaloupes from the affected farm, even if someone has eaten one without becoming sick.

Listeria can grow at room and refrigerator temperatures and may remain on refrigerator surfaces even after cantaloupes have been removed and discarded.

The last major outbreak of Listeriosis in North America occurred in Canada in 2008, where 23 people died out of a total of 57 confirmed cases.