Influenza and ARI intensity in Bulgaria is medium during week No 51  (2012.2010 - 26.12.2010). The total incidence per 10, 000 population  was 94,67 (during the week 50 the incidence was 94,67). From a total of 380,729 persons under surveillance, belonging to all age groups, a total of 2 803 ARI cases have been reported (during the week 50 were 3 606). The incidence is highest in the age group 0-4 ys (322.99 per 10,000 population), followed by age group of 5-14 ys old (202.62  per 10,000).  The highest incidence has been reported in: Vratsa (150.44) and Sofia- region (159.79).