The number of infectious diseases reported in South Korea dropped 83 percent on-year in 2010 mainly because fewer people were sickened by the Influenza A virus, a government report showed Thursday. The Korea Centers for Disease Control and Prevention (KCDC) said 133,559 people were diagnosed with contagious diseases last year, down sharply from the 782,754 tallied nationwide in 2009. \"The main reason for the decrease can be found in the number of Influenza A cases that plunged from over 706,000 in 2009 to 56,000 last year,\" the KCDC said. It also said that number of typhoid fever, tetanus and scarlet fever cases fell compared to the year before, although instances of measles and Japanese encephalitis increased. Despite the drop in Influenza A cases last year, it still accounted for 42.6 percent of all infectious diseases reported by clinics and hospitals throughout the country, followed by tuberculosis and chicken pox, the agency said.