An Oregon resident has been diagnosed with the plague. It is the first human case in the US state in more than eight years, according to health officials.
The most common exposure in humans comes from the bites of fleas carrying the bacteria – Yersinia pestis – that causes the disease.
Deschutes County Health Services said the person may have been infected by their cat, which could have been bitten by an infected flea, NBC News reported – but it could have happened in other ways .
The infection is “very easily treated with simple antibiotics,” the experts said.
Dr. Richard Fawcett, Deschutes County health officer, said there is no significant risk to the community and he would be “very surprised” if more cases emerge.
He said the cat suspected of being involved in the Oregon case was “very ill” – but it was not entirely clear whether the infection had been transmitted to its owner from his cat.
Dr Fawcett said some doctors had reported that the patient may have developed a cough while being treated at the hospital, indicating a pneumonic version of the plague that is transmitted between humans.
The owner responded “very well” to antibiotic treatment for the infection, which most likely started in the lymph node, Dr Fawcett added.
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Swollen, painful lymph nodes can be an early symptom of infection, along with fever and muscle pain.
On average, there are seven cases of human plague each year in the United States, according to the Centers for Disease Control And Prevention (CDC).
Cases can also involve other pets, such as dogs: in 2014, there were four cases of plague involving people who had contact with an infected pit bull terrier in Colorado.
The last case in Oregon in 2015 involved a teenager who was reportedly bitten by a flea during a hunting trip.
The CDC said plague infection is primarily found in semi-arid forests and grasslands that are home to rodents. The latest case in Deschutes involved a person living in a rural area with “open land not far away.”
A previous study reported how humans were most likely responsible for the spread of the plague during the Black Death, which killed a estimated between 75 and 200 million people in medieval Europe between 1346 and 1353.
The researchers said there was “little historical and archaeological evidence” that rats spread the plague.