BEIJING, Dec 11 (Reuters) - The health authority in the southern Chinese province of Guangdong said on Saturday that one case of a human being infected with the H5N6 strain of bird flu has been reported in the city of Huizhou. The Health Commission of Guangdong Province said in a statement that experts considered the risk of transmission to be low at this stage. Still, it said experts advised citizens to remain on alert and take preventive measures such as avoiding visiting marketplaces with live poultry, as infections of H5N6 and H9N2 viruses are likely to happen during winter and spring. The infected 68-year-old man was being treated at a hospital, according to the statement. The number of people in China infected with H5N6 bird flu this year has jumped, raising concern among some experts, who say a previously circulating strain appears to have changed and may be more infectious to people. read more Several H5N6 infections in China had died this year, according to local government statements and WHO reports. read more Reporting by Roxanne Liu and Dominique Patton; Editing by William Mallard