Since early August 1998, 40 illnesses caused by a single strain of Listeria monocytogenes (LM) have been identified in 10 states: Ohio (13 cases); New York (12); Tennessee, Massachusetts, and West Virginia (three each); Michigan (two); and Connecticut, Oregon, Vermont, and Georgia (one each). Dates of illness onset or LM isolation ranged from August 2 through December 2. All LM isolates from these cases are serotype 4b and share an unusual pattern when subtyped either by pulsed-field gel electrophoresis or by ribotyping methods. Historically, this pattern is rare among LM isolates from humans.
Among 38 patients for whom demographic data are available, six were newborns and 32 were adults (median age: 69 years; range: 18-88 years); 55% of patients were female. Four deaths occurred, including one fetus and three elderly persons.
In collaboration with CDC, health departments in Connecticut, New York, Ohio, and Tennessee conducted a multistate case-control study comparing 4-week food histories of 20 patients infected with the outbreak strain with those of 20 control patients infected with other LM strains. Sixteen (89%) of 18 cases but only six (32%) of 19 controls consumed cooked hot dogs during the month before illness onset (odds ratio=17.3; 95% confidence interval=2.4-160.0; pless than 0.01). On December 19, the outbreak strain of LM was isolated from an open package of hot dogs. These hot dogs had been eaten by a patient 4 weeks before onset of listeriosis caused by the outbreak strain.
On December 22, the manufacturer, Bil Mar Foods, voluntarily recalled specific production lots of hot dogs and other meat products that might be contaminated. The affected products bear the establishment numbers EST P261 or EST 6911 and include the Ball Park, Bil Mar, Bryan Bunsize and Bryan 3-lb Club Pack, Grillmaster, Hygrade, Mr. Turkey, Sara Lee Deli Meat, and Sara Lee Home Roast brands. The establishment number appears on the outer edge of all packages. Packages for the above brand names that carry any other establishment numbers are not affected by the recall.
An investigation by CDC is ongoing with local and state health departments. Recent cases of listeriosis should be reported to CDC through state and local health departments. Consumers should return recalled product to the point of purchase.
Reported by: Local and state health depts. Foodborne and Diarrheal Diseases Br, Div of Bacterial and Mycotic Diseases, National Center for Infectious Diseases, CDC.
Editorial Note: The general guidelines for preventing listeriosis are similar to those for preventing other foodborne illnesses, such as salmonellosis. The general recommendations are
? Cook thoroughly raw food from animal sources (e.g., beef, pork, or poultry).
? Wash raw vegetables thoroughly before eating.
? Keep uncooked meats separate from vegetables and from cooked foods and ready-to-eat foods.
? Avoid raw (unpasteurized) milk or foods made from raw milk.
? Wash hands, knives, and cutting boards after each handling of uncooked foods.
In addition, persons at high risk for complications from listeriosis
(i.e., pregnant women and immunocompromised persons) should
? Avoid soft cheeses (i.e., feta, Brie, Camembert, blue-veined, and Mexican-style cheese). Hard cheeses, processed cheeses, cream cheese, cottage cheese, or yogurt need not be avoided.
? Cook leftover foods or ready-to-eat foods (e.g., hot dogs) until steaming hot.
? Although the risk for listeriosis associated with foods from deli counters is low, pregnant women and immunocompromised persons may choose to avoid these foods or thoroughly reheat cold cuts before eating