Story highlights CDC: 11 cases of plague in six states reported since April

Doctors should consider plague in patients with fever or swollen lymph nodes who have traveled to areas where plague is found

Individuals should protect themselves in rural areas of Western United States from rodents and fleas

(CNN) Since April 1, there have been 11 cases of human plague in the United States, the Centers for Disease Control and Prevention said Thursday. Three of those patients have died. This is according to a new report from the CDC putting doctors on alert that the number of cases this year seems to be higher than usual.

The average number of cases between 2001 and 2012 was seven, with less than one death each year.

"We don't want people to panic but we do want people to be aware of the heightened risk," said Dr. Natalie Kwit, a veterinarian with the division of vector borne diseases at the CDC.

The cases, which are required to be reported to the CDC, have been reported in six states. There have been two cases in Arizona, one in California, four in Colorado , one in Georgia, two in New Mexico and one in Oregon. The cases in California and Georgia have been linked to areas in or near Yosemite National Park in the southern Sierra Nevada, the report says.

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