Perfil epidemiológico das infecções respiratórias agudas causadas pelo vírus influenza em crianças atendidas no Hospital Infantil Albert Sabin, Fortaleza-Ce (2001 - 2004)

Abstract

The influenza virus is unique with it is ability to cause recurring annual epidemics in a short time interval, affecting all ages, with larger gravity in children and elderly people. The aim of this study is to describe demographic features and the pattern of the seasonality of acute respiratory infections caused by influenza virus in children attended at Albert Sabin Children Hospital, in Fortaleza – Ceará, over the period of January period 2001 at July 2004. A total of 1950 samples of nasopharyngeal aspirates were collected from chidren with symptoms of acute respiratory infection. All samples were analyzed by indirect imunofluorescense assay (IFA). Forty seven Influenza A or B positive samples by IFA, in 2003 and 2004, were submitted to polimerase chain reaction with reverse transcription (RTPCR) for analysis of viral variant H1 and H3 and influenza b. A total of 156 samples were influenza A or influenza B positive, representing a prevalence rate of 8%. Among the viral infections, those caused by influenza viruses represented 24,1%. The influenza virus showed a pattern of regular annual occurrence, observed during the first semester of each year, correlated to the rainy periods. The peak of the epidemic periods of influenza preceded or occurred concomitantly to the national campaigns of vaccination. Influenza virus A and B cocirculated in all years of the study, with a significant predominance of the virus influenza A (91%) over influenza B (9%). Regarding to the medical care setting, the majority of the children with influenza infection were attended in ambulatories (48,7%) and emergency (39.7%). Eighteen children with influenza were attended in wards (11,5%). Regarding to the age of the children with influenza these infections predominated in children until two years of age. About 65,4% of the influenza infections were diagnosed as upper respiratory tract infections. Lower respiratory tract infection predominated in children until two years of age. In 2003 and 2004 were identified the variants A/H3 and B, with predominance of the first (78,7%)