Iinfluenza and ARI intensity in Bulgaria was low during week No 31 (29.07.2013 - 04.08.2013) and the total incidence per 10,000 population was 20.47(during week No 30 the incidence was 21.99). From a total of 381 562 persons under surveillance, belonging to all age groups, a total of 781 ARI cases have been reported (during week No 30 the cases were 839). The incidence was highest in the age group 0-4 yrs (107.94 per 10,000 population), followed by age group of 5-14 yrs (51.14 per 10,000).