Health authorities are investigating a listeria outbreak in four states -- Michigan, Pennsylvania, New York, and New Jersey -- related to sliced deli meats and cheeses.

A total of eight people have been infected with the outbreak strain of Listeria monocytogenes according to the Centers for Disease Control. All eight people have been hospitalized and one person from Michigan has died.

Listeria infection can cause fever, muscle aches, headache, stiff neck, confusion, loss of balance, and convulsions. Pregnant women may face additional complications and the symptoms can be more severe for the elderly, young children, and anyone with a weakened immune system.

No common supplier of the tainted deli products has been identified.

The CDC is not telling consumers to avoid eating food prepared at delis but is urging deli personnel to be vigilant about cleaning food slicers and areas where food is stored, prepared, or served.