Colonies of prairie dogs potentially infected with the plague have shut down parks across Colorado.
Unaffected areas of the Rocky Mountain Arsenal National Wildlife Refuge reopened over the weekend after nearly a month-long closure.
"The prairie dog colonies are being monitored and burrows are being treated with insecticide, but there is still evidence of fleas in the hiking and camping areas, which could put people and pets at risk, so those areas will remain closed," John M. Douglas, Jr., executive director of Tri-County Health Department, told CNN.
The areas that are still off-limits to the public are clearly marked, the park said in a statement.
The 15,000-acre park near Denver issued a temporary close in late July. During the closure, park employees did a “strategic insecticide application to kill the fleas that spread plague to black-tailed prairie dogs.” The wildlife refuge has one of the country’s largest populations of black-footed ferrets, an endangered species, which rely on the health of the prairie dog colonies.
No human infections have been reported but the U.S. Fish & Wildlife Service says it is still possible the disease could spread to humans. Select closures will remain in place at least through Labor Day.
Small mammals and insects can carry the disease, which is often transmitted through a bite. The Fish & Wildlife Service suggests avoiding contact with prairie dogs and other rodents, avoiding touching sick or dead animals and wearing insect repellant when in the wild.
Although the plague carries some very sinister connotations, it is now considered a curable disease in the U.S. through a round of antibiotics. There is an average of seven human cases of plague in the U.S. each year, according to the Center for Disease Control and Prevention.