Since the beginning of 2009, eight cases of highly pathogenic human avian influenza have been reported in China. Three of the cases have been confirmed to be from central China’s Hunan province. However, individual cases have also been reported from nearby Shanxi, Shandong, and Guizhou provinces among others. It is suspected that China’s winter weather is aiding in the spread of the virus. While exposure to sick or deceased poultry continues to be the main route that humans become infected, experts warn that H5N1 may evolve into a form that can be easily transmitted from person-to-person. Since the beginning of a pandemic cannot be predicted, all contacts of avian influenza cases are closely monitored to ensure that the disease does not spread. In addition, epidemiologic investigations are carried out in each case to determine the most likely source of infection so that the appropriate actions can be taken such as the culling of poultry.
Why such concern about the spread of one type of influenza? Of the 37 cases to date in China, 25 of them have been fatal. With a case fatality rate over 65% a pandemic of H5N1 would surely have a devastating impact around the globe.