China has reported its third death from a mysterious new virus and nearly 140 fresh cases as the disease spread to other parts of the country, including Beijing, raising concerns about more infections as millions begin trips for the Lunar New Year.Medical experts are still struggling to understand the new strain of coronavirus but its connection with Severe Acute Respiratory Syndrome has caused alarm. SARS originated in southern China in 2002 before spreading to Hong Kong and elsewhere in the world, infecting thousands and leaving more than 800 people dead.