A test showed the dead vole from the Riddle area — just north of the Duck Valley Indian Reservation — was probably infected with plague.
Five other voles and one wild mouse tested from the area of a rodent die-off did not test positive for plague, however, according to a Thursday notice from the state departments of Health and Welfare and Fish and Game, and Southwest District Health.
It’s the third report this spring of plague in Southwest Idaho wildlife. In May, plague was reported in ground squirrels in a large area stretching from Boise and Kuna southeast to near Mountain Home. Last week, voles just west of Caldwell were said to have possibly died from plague.
The agencies do not believe any of the three sites are connected, according to Thursday’s notice.
“Plague is endemic to our area. With heightened awareness in the public, Idaho officials are receiving a number of reports of die-offs of rodents in Southwest Idaho,” Dr. Leslie Tengelsen, state public health veterinarian, said in the notice. “Not all tested rodents are positive for plague, however, people need to be vigilant and take precautions for themselves and their pets.”
No humans have been infected this spring. One dog tentatively tested positive, was treated and recovered.
A bacterial disease, plague can be spread by the bites of fleas or by direct contact with infected animals. The plague is believed to have reached Idaho in about the 1930s and has likely been in rural rodent populations for decades. If you come across a group of dead rodents, do not touch them; report the location to Idaho Fish and Game through this tool.
Since 1940, only five human cases of plague have been reported in Idaho. The last two cases reported in Idaho occurred in 1991 and 1992, and both patients fully recovered, the Idaho Department of Health and Welfare reports.
Plague is generally transmitted through bites of infected fleas. It may also be transmitted by direct contact with infected animals, including rodents, rabbits and pets. Common rodents that can become infected include mice, rats, voles, chipmunks and ground squirrels, officials said. Tree squirrels in Idaho are not known to carry plague.
Plague activity can increase in the spring and summer months when rodents are more active. People can be exposed to plague when pets have contact with rodents or fleas outdoors, or bring infected rodents or fleas back into the home. People can also become infected by caring for a sick pet without proper precautions.
People can greatly reduce their risk of becoming infected with plague by taking simple precautions, including avoiding contact with wild rodents, their fleas and rodent carcasses. They should not feed rodents in parks, picnic or campground areas and never handle sick or dead rodents.
Health officials also suggest:
• See your doctor about any unexplained illness involving a sudden and severe fever.
• Keep your pets from roaming and hunting voles or other rodents. Sick pets should be examined promptly by a veterinarian, especially if they may have had contact with sick or dead rodents.
• Talk to your veterinarian about using an appropriate flea control product on pets. Not all products are safe for cats, dogs or children.
• Don’t leave pet food and water where rodents or other wild animals can access them.
• Clean up areas near your home where rodents can live, such as woodpiles and lots with tall grasses and weeds.
• Put hay, wood and compost piles as far as possible from your home.
Symptoms of plague in humans include sudden onset of fever, chills, headache, and weakness. In most cases there is a painful swelling of the lymph node in the groin, armpit or neck areas. Plague symptoms in cats and dogs are fever, lethargy and loss of appetite. There may be a swelling in the lymph node under the jaw. With prompt diagnosis and appropriate antibiotic treatment, the fatality rate in people and pets can be greatly reduced. Physicians who suspect plague are asked to promptly report it to their local public health district.