Deaths continue to rise in the nation's deadliest foodborne listeria outbreak in years. Federal health officials report three new deaths in Colorado, Kansas, and Missouri.

Whole or cut cantaloupes from Colorado-based Jensen Farms have been identified as the cause of the outbreak that began in July. Since then, 133 people in 26 different states have been sickened, and 28 are now dead. One woman who was pregnant when she became ill has had a miscarriage, according to the Centers for Disease Control and Prevention.

Because of listeria's two-month incubation period, people may continue to fall ill for up to 60 days after eating the tainted fruit. Contaminated cantaloupes were recalled in mid-September. Federal officials say they will monitor the outbreak until November at least.

The elderly, pregnant women and those with weakened immune systems are most at risk of becoming ill after exposure to listeria. Symptoms include fever, muscle aches and diarrhea.