A teenager in Oregon, USA, has been diagnosed with bubonic plague, the illness that killed tens of millions of people in the 14th century but is treatable today.

Oregon health officials said the Crook County girl is believed to have acquired the disease from a flea bite during a hunting trip near Heppner in Morrow County. The trip started on October 16, she fell ill five days later, and was hospitalised three days after that.

The unnamed girl is recovering but is still in intensive care, officials said.

During the 14th century, the plague, also known as the Black Death because of the symptom of oozing, blackened sores, killed tens of millions of people in Europe, Asia and Africa. An estimated 25 per cent to 60 per cent of the population of Europe - some 50 million people - died and some histories put the toll as high as 200 million throughout the world over the century.

The plague is treatable with antibiotics if caught early. Symptoms of the bubonic plague, the most common form of the bacterial infection, include high fever, lethargy and swollen lymph nodes.

An average of seven human plague cases are reported each year in the United States