An unidentified Oregon man is hospitalized in critical condition with what doctors believe is Oregon's fifth case of plague in the last 15 years, according to a report in The Oregonian.  The rural Crook County man was bitten on the hand on Saturday, June 2 as he tried to take a struggling mouse away from a neighborhood cat.  He fell ill several days later and was admitted to St. Charles Medical Center-Bend in Bend, OR.  It's not clear which of the animals bit the man or gave him the disease.

Plague is caused by the bacterium Yersinia pestis and manifests in the bodies of its victims in three ways (.pdf).  The Oregon man was admitted to the hospital with fever and classic signs of bubonic plague, so named for the painful, pus-filled black boils or "buboes" that swell and sometimes burst at the neck, groin and armpits.  These lesions form when the patient's lymph nodes expand out of control, filling with dead bacteria and spent white blood cells, the debris from a fierce battle being waged in the bloodstream.

As of Tuesday, however, the victim's illness was trending more toward septicemic plague, a manifestation of the disease wherein Yersinia attacks the circulatory system, causing severe abdominal pain, bleeding from the nose, mouth and rectum, high fever and tissue necrosis.  The deadliest but least common form of plague is pneumonic plague, which invades the lungs and drowns the patient in the fluids that result from their body's attempt to fight off the illness.

Plague is treatable with modern antibiotics, but is so virulent and damaging to the body's systems that it's important to diagnose and treat the disease early.  The so-called "Black Death" killed more than a third of the population of Europe in the Middle Ages.  It's rare today, although it has never been entirely eliminated.

Oregon has seen four plague deaths since 1934, all in rural areas.  The disease spreads through the bites of fleas that have fed on the blood of infected rodents.  Once entrenched in a victim's system, however, plague can be passed from human to human by way of contact with bodily fluids.

Crook County Health Department spokesperson Karen Yeargain told the Oregonian that tests to determine whether the man has contracted plague are still pending, but his symptoms are strongly indicative of the disease.  A plague vaccine exists, but it went off the market in the U.S. when cases dropped in the mid twentieth century.

(3-D image of Yersinia pestis via Shutterstock)