An Oregon man suffering from the Black Death is in critical condition. The rural Crook County resident, in his 50s, fell ill after he was bitten in the hand as he tried to grab a mouse from a stray cat. It's the fifth plague case in Oregon since 1995. The other four victims recovered. It's usually treatable and preventable, but it is also a "serious illness" that can be deadly, a health expert tells the Oregonian. The plague wiped out at least a third of the European population in the Middle Ages. The disease is rare today, but the bacterium that causes it still exists. The current victim seems to be suffering from septic plague, one of three forms of the plague caused by the bacterium Yersinia pestis. Symptoms include abdominal pain, bleeding, and gangrene.