Task: Question Answering
Input (English): Passage: In July 1873 the U.S. Navy dispatched USS Juniata to Greenland, to search for survivors from the Polaris expedition which had disintegrated after the death of its leader, Charles Francis Hall. Juniata's second-in-command was George W. De Long, a 28-year-old graduate of the United States Naval Academy, making his first visit to the Arctic. Ice conditions prevented Juniata from advancing beyond Upernavik; De Long volunteered to take the ship's tender, a small steamer named the Little Juniata, in the hope of finding survivors at Cape York, a further 400 nautical miles (740 km) north.The attempt failed; Little Juniata faced extreme weather conditions, and was forced to retreat a few miles from Cape York. De Long returned to Juniata in mid-August, having found no trace of the Polaris crew—who had meanwhile been rescued by the Scottish whaler SS Ravenscraig—but the experience had profoundly affected his outlook. Having earlier described the Greenland coast in a letter to his wife Emma as "a dreary land of desolation ... I hope I may never find myself cast away in such a perfectly God-forsaken place", he returned home captivated by the Arctic. Emma wrote: "The polar virus was in his blood and would not let him rest".The abortive Little Juniata mission brought De Long to public notice, and he saw himself as a possible leader of the next U.S. Arctic expedition. He approached Henry Grinnell, the philanthropic shipping magnate who had funded several previous expeditions. Grinnell was not prepared to offer financial support, instead advising De Long to approach James Gordon Bennett Jr., owner and publisher of the New York Herald and a known sponsor of bold schemes. De Long met Bennett in New York early in 1874; the newspaperman was impressed by De Long, and assured him that his Arctic ambitions would have the enthusiastic support of the Herald. In the meantime De Long had applied to the Navy Department for an Arctic command, a request that he was informed would "receive due attention". 
Question: What is the last name of the person who is described as having the polar virus in his blood?
Output (English): De Long.