Iinfluenza and ARI intensity in Bulgaria was increased during week No 49 (02.12.2013 - 08.12.2013) and the total incidence per 10,000 population was 107.26 (during week No 48 the incidence was 105.55). From a total of 380 586 persons under surveillance, belonging to all age groups, a total of 4 082 ARI cases have been reported (during week No 48 the cases were 4 017). The incidence was highest in the age group 0-4 yrs (489.64 per 10,000 population), followed by age group of 5-14 yrs (322.01 per 10,000).