(AP) - Authorities say the search for the body of a Canadian man who disappeared in northeastern Nevada is over.      Elko County Sheriff's Lt. Marvin Morton told The Times-News that 10 people searched again for 59-year-old Albert Chretien of Penticton, B.C. and failed to find any sign of him.    Morton believes Chretien is dead, his remains scattered.    Chretien and his wife, Rita, were on their way to Las Vegas when they detoured to visit Jackpot, Nev. and their van became stuck on a muddy road in Bruneau Canyon. Rita was found alive nearly 50 days later, but Albert - who had left the van earlier in search of help - was never found.      Morton said that he still holds hope that a hunter will find Chretien's remains this fall.