Viral etiology of acute respiratory infections among children in Porto Alegre, RS, Brazil.

Selir M Straliotto,Gilberto B Fischer,Marilda M Siqueira,Rafael L Muller,Mara L.T Cunha,Sandra M Nestor

doi:10.1590/s0037-86822002000400002

Abstract

Although acute respiratory infections (ARIs) are a major cause of child morbidity and mortality in Southern Brazil, little information is available on their seasonality and viral etiology. This study was conducted on children under 5 years of age with ARI to assess viral etiology in the State of Rio Grande do Sul, from 1990 to 1992. A total of 862 nasopharyngeal secretion (NPS) samples were tested using indirect immunofluorescence. The results showed that 316 (36.6%) NPS samples were positive: 26.2% for RSV, 6% for adenovirus, 1.7% for influenza viruses, 1.5% for parainfluenza viruses, and 1.2% for mixed infection. The mean viral prevalence rates in out-patient services, emergency wards, and in-patient hospital wards were 26.7%, 53% and 42.3%, respectively. Respiratory syncytial virus (RSV) and adenovirus accounted for 91.4 % of the viral diagnoses. RSV was more frequent in children under one year of age at the three levels of health care and was prevalent in infants under six months. Adenovirus was the most prevalent pathogen in hospitalized children, in 1992. Influenza A virus showed an increased prevalence with age among out-patient children. This study shows the annual occurrence of viral respiratory infections in the coldest months, with a significant annual variation in the frequency of RSV infection.

Highlights

Acute respiratory infections (ARIs) are a major cause of child morbidity and mortality in Southern Brazil, little information is available on their seasonality and viral etiology
Over 200 viral serotypes are associated with human respiratory diseases[15], with the most frequently reported types in newborns and children under five years of age being respiratory syncytial virus (RSV), parainfluenza type 3 virus (PF3), adenovirus (Adeno), influenza virus (FLU), and enterovirus[11 23 27]
This study was conducted in two hospital from the city of Porto Alegre: Hospital da Criança Santo Antônio (HCSA) and Hospital de Clínicas de Porto Alegre (HCPA), in addition to an outlying urban public health clinic where out-patient nasopharyngeal secretion (NPS) samples were obtained

Summary

Introduction

Acute respiratory infections (ARIs) are a major cause of child morbidity and mortality in Southern Brazil, little information is available on their seasonality and viral etiology. Over 200 viral serotypes are associated with human respiratory diseases[15], with the most frequently reported types in newborns and children under five years of age being respiratory syncytial virus (RSV), parainfluenza type 3 virus (PF3), adenovirus (Adeno), influenza virus (FLU), and enterovirus[11 23 27]. Recommended by the World Health Organization[49], until 1993, epidemiological studies on acute respiratory infections (ARIs) of viral etiology in the Brazilian pediatric population had only been performed in a few medical research centers in the Southeast[17 40 42] and North[14], showing different seasonal patterns.

Methods

Results

Conclusion