Public-health officials in two northern Arizona counties are warning residents about plague found in two counties, Navajo and Coconino, that are separated by 120 miles of desert.
Health officials said fleas carrying yersinia pestis, the bacteria that causes plague, were discovered this month in both counties and pose a potentially grave threat to people and their pets, especially cats.
The U.S. Centers for Disease Control and Prevention said that plague can be transmitted by fleas to pets and people: Fleas can bite rabbits, prairie dogs and other rodents — and anything that may eat them — and transfer the disease to pets, who in turn can infect humans. Cats that get plague transmit it through coughing. Dogs typically carry the fleas on their fur.
Health officials cautioned county residents and visitors to keep their pets leashed and to avoid touching dead animals. Evidence of a large die-off could indicate plague is present, they said.
Scientists have been testing a plague vaccine for prairie dogs, enticing them to eat it by baiting them with peanut butter-flavored treats. The approach has proved effective at lowering death rates and reducing outbreaks in the animal colonies, according to a U.S. Geological Survey study published in June.
Plague is treatable with antibiotics if detected early, but the symptoms very quickly can grow deadly. While bubonic plague is perhaps the best known form, septicemic plague and pneumonic plague are equally serious. Bubonic plague can cause skin and limbs to turn black and die. Pneumonic afflicts the lungs and can lead to respiratory failure.
Fatal human cases are rare, averaging just seven a year in the United States dating to the mid-1920s, when the disease swept through Los Angeles, the last significant outbreak in a major American city. Arizona, California, Colorado and New Mexico experience the highest concentration of cases, though since the 1970s, plague has appeared in Nevada, Oregon, Idaho, Wyoming and parts of western Texas.
Globally, about 1,000 to 2,000 cases of plague are reported annually, with most occurring in Africa.