Umatilla County health officials confirmed Friday that a local man was hospitalized with septicemic plague.
The man is believed to have been infected while hunting in Lake County, Ore. He is receiving treatment for the disease.
"Plague is spread to humans through a bite from an infected flea," said Genni Lehnert-Beers, Umatilla County public health administrator. "Plague is serious but it is treatable with antibiotics if caught early."
Plague is caused by the bacterium Yersinia pestis, which can be found on rodents and their fleas. It can be passed from fleas feeding on infected rodents, and then transmitted to humans.
Only three human cases of plague have been diagnosed since 1995, including two in Lake County in 2010. All three people recovered.
Lehnert-Beers recommends that people stay away from flea-infested areas and learn to recognize plague symptoms.
Symptoms typically develop within one to four days, and up to seven days, after exposure and include fever, chills, headache, weakness and bloody or watery cough from infection of the lungs.
Other symptoms can include enlarged, tender lymph nodes, abdominal pain and bleeding into the skin or other organs.
Anyone who suspects they have plague should contact a doctor, or a veterinarian if they think their pet has symptoms of plague.
Plague can be cured with antibiotics, but early treatment is essential. Untreated plague can be fatal.
Lehnert-Beers also recommends taking precautions against fleas and flea bites, including using flea treatment on pets, wearing insect repellent, tucking pant cuffs into socks when in areas heavily occupied by rodents and avoiding contact with wildlife.