In response to World Health Organization´s warning that some regions of China may be involved in extensive influenza outbreak this year, the Shenzhen CDC issues an influenza alert to warn that the municipality is under the threat of flu outbreak and must be prevented Due to unusual climate this autumn with greater diurnal temperature difference and low flu activity during late spring and early summer period, it is expected that the flu virus could cause outbreak in the coming autumn. If the scale is large, Guangdong, Hong Kong and Macao may also be affected