The child, who has not been identified, is now home after a course of antibiotics in a local hospital, Christine Myron, spokesperson for the Central District Health Department, said on Wednesday.
While it may sound like something out of the Middle Ages, the plague infects around seven Americans a year, and is generally treatable with antibiotics.
However, it is most common in southern Colorado, and northern Arizona and New Mexico - hundreds of miles from Idaho and half a country away from Oregon.
That said, researchers last year found traces of Yersinia pestis, the bacterium which causes the plague, among squirrels in Elmore County. This, though, has been the first human case contracted nearby.
The plague is generally transmitted to humans through the bites of infected fleas but can be transmitted by direct contact with infected animals including rodents and pets.
It is infamous for killing millions of people in Europe centuries ago.
Antibiotics are now effective in treating the disease, but officials say without prompt treatment, it can cause serious illness or death.
To lower your risk of contracting the disease, the CDC urges people to respond quickly to any rat or mouse infestations in your home, wear gloves when dealing with animals that could carry it, and keep fleas off your pets.
TYPES AND SYMPTOMS OF HUMAN PLAGUE
• BUBONIC: High fever, headache, chills, and weakness.
One or more swollen, tender and painful lymph nodes, or buboes, usually from the bite of an infected flea.
• SEPTICEMIC: Fever, chills, extreme weakness, abdominal pain, shock
Possible bleeding into the skin and other organs.
Skin and other tissue, normally on fingers, toes and the nose, can turn black and die. Can develop from untreated bubonic plague.
• PNEUMONIC: Fever, headache, weakness.
Rapidly developing pneumonia with shortness of breath, chest pain, cough, bloody or watery mucous.
This is the only type that can be spread from person to person.
