For the second year in a row, Idaho health officials say preliminary tests on dead ground squirrels south of Boise have come back positive for plague.
The Idaho Department of Health and Welfare is still confirming the diagnosis, but officials are asking the public to be cautious.
A map of the infected area is a circle shape extending about 45 miles south from Boise to the Snake River. The boundary also extends over Interstate 84 but doesn't reach Mountain Home.
The bacterial disease can be spread by flea bites or by direct contact with infected animals. The last human cases to have the plague occurred in 1991 and 1992, where both patients fully recovered.
Officials say symptoms of plague in humans include fever, chills, headache and weakness, and that prompt diagnosis and treatment greatly reduces the fatality rate.
“Just like last year, our investigation began in May after hearing reports from people finding dead ground squirrels in the desert southeast of Boise,” State Wildlife Veterinarian Dr. Mark Drew said. “We hope to have confirmation of these results soon and will keep the public up to date as we learn more.”
According to experts, 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.
Health officials recommend:
• Do not feed rodents in picnic or campground areas and never handle sick or dead rodents.
• Keep your pets from roaming and hunting ground squirrels or other rodents in affected desert areas.
• Talk to your veterinarian about using an appropriate flea control product on pets as not all products are safe for cats, dogs or children.
• Clean up areas near your home where rodents can live, such as woodpiles.
• Sick pets should be examined promptly by a veterinarian, especially if they may have had contact with sick or dead rodents in the desert areas south and east of Boise.
• See your doctor if you have any unexplained illness involving a sudden and severe fever after being in a plague-impacted area.
Officials also recommend you put hay, wood, and compost piles as far as possible from your home.
They also say Don’t leave pet food and water where rodents or other wild animals can access them.
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, with possible 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 should promptly report it to their local public health district.
Idaho Fish and Game is interested in reports of multiple (greater than five) dead ground squirrels, yellow-bellied marmots (aka “rock-chucks”), voles, cottontail rabbits or jackrabbits. Please do not report single mortalities; observations of multiple mortalities are a greater indicator of possible plague activity.
If people find groups of five or more such dead animals, they should not touch them, but should report the location to the Idaho Department of Fish and Game at https://idfg.idaho.gov/plague.
All reports are reviewed and appropriately handled, however, not all people submitting reports will be contacted for follow-up.
(The Associated Press contributed to this story.)