WASHINGTON (AP) — As many as 14 people have died from possible listeria illnesses traced to Colorado cantaloupes, health officials say — a death toll that would make the food outbreak the deadliest in more than a decade.

The Centers for Disease Control said last week that 55 illnesses and eight deaths were linked to the outbreak. Since then, state and local health departments in Kansas, Nebraska, Texas and Wyoming have reported six additional deaths that may be linked to the tainted fruit.

Nine people died in an outbreak linked to salmonella-tainted peanuts almost three years ago. Deaths linked to the cantaloupes are expected to easily surpass that number.

Listeria is more deadly than more well-known pathogens like salmonella and E. coli, though those outbreaks generally cause many more illnesses. Twenty-one people died in an outbreak of listeria poisoning in 1998 traced to contaminated hot dogs and possibly deli meats made by Bil Mar Foods, a subsidiary of Sara Lee Corp. Another large listeria outbreak in 1985 killed 52 people and was linked to Mexican-style soft cheese.

Listeria generally only sickens the elderly, pregnant women and others with compromised immune systems. The CDC said last week that the median age of those sickened was 78.

Dr. Robert Tauxe of the CDC says the number of illnesses and deaths will probably grow in coming weeks because the symptoms of listeria don't always show up right away. It can take four weeks or more for a person to fall ill after eating food contaminated with listeria.

"That long incubation period is a real