It is possible for a human to have a body temperature of 109 degrees Fahrenheit though this is potentially life threatening in some circumstances. U.S. Pharmacist reports that drug-induced fevers sometimes run as high as 109 F though temperatures between 102 F and 104 F are more typical.
A Fox News article reported on an August 2008 incident in which a high school football player died of heat stroke. The article cited a heat stroke expert who said the player likely had a 109 F temperature when he collapsed. Any extended period with a fever over 105 F can have serious consequences. U.S. Pharmacist notes that fevers of 100 F to 104 F are often beneficial in fighting off illnesses.