Plague was found in a dead tree squirrel near City Park after citizens noticed a die-off of squirrels in the neighborhood, state officials confirmed Thursday.Denver Animal Control investigated the squirrel deaths and tested the body of a dead squirrel. Officials said the tests were positive for plague.John Pape, an epidemiologist who specializes in animal-related diseases, said while plague is seen every year among rodent populations in rural areas of Colorado, including the Front Range, it's unusual to find plague in the center of an urban area. But, he said, it has happened before."Plague is a bacteria that is maintained in various species of rodents and rabbits and transmitted by fleas. When an infected rodent becomes sick and dies, its fleas can carry the infection to other warm-blooded animals, including humans," Pape said. "People also can be exposed through direct contact with infected rodents, rabbits and cats."Pape assured that the risk of Denver residents contracting plague is extremely low.Several groups, including the Colorado Department of Public Health and Environment and Denver Environmental Health, are working to figure out the extent of the die-off in the area.Pape explained that when the animals die, the fleas leave the carcass to find another host, thus spreading the disease. He warned residents to not handle any dead rodents and to keep all pets away from them. People should use gloves and a plastic bag if they do dispose of the carcasses.Residents can report dead rodents or rabbits to Colorado Health Education at 877-462-2911.Plague is treated with common antibiotics when recognized early. Symptoms include sudden fever, muscle pain, nausea and vomiting.For more information on plague, click here.