A resident in Oregon has been diagnosed with the plague in the US state’s first human case in more than eight years, according to health officials.
The most common exposure to humans is from the bites of fleas carrying the bacterium – Yersinia pestis – which causes the disease.
Deschutes County Health Services said the person may have been infected by their cat, who could have been bitten by an infected flea, NBC News reported – but it may have happened through other means.
The infection is “very easily treated with simple antibiotics,” said experts.
Dr Richard Fawcett, a health officer for Deschutes County, said there was no significant risk to the community and he would be “very surprised” were any other cases to emerge.
He said the cat believed to have been involved in the Oregon case had been “very sick” – but it was not entirely clear if the infection had been passed to its owner from their cat.
Dr Fawcett said it had been reported by some doctors that the patient may have been developing a cough when being treated in hospital – indicating a pneumonic version of the plague, which is transmitted among humans.
The owner had “responded very well” to antibiotic treatment for the infection, which most likely started in the lymph node, Dr Fawcett added.
Read more on Sky News:
Swollen and painful lymph nodes can be an early symptom of the infection, along with fever and muscle aches.
On average, there are seven human plague cases every year in the US, 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 the plague involving people who had been in contact with an infected pit bull terrier in Colorado.
Oregon’s last case in 2015 involved a teenager thought to have been bitten by a flea during a hunting trip.
The CDC said the plague infection is mostly found in semi-arid forests and grasslands with 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 an estimated 75 to 200 million people in medieval Europe between 1346 and 1353.
Researchers said there was “little historical and archaeological support” that rats spread the plague.