Adenovirus type 7 associated with severe and fatal acute lower respiratory infections in Argentine children

BACKGROUND: Adenoviruses are the second most prevalent cause of acute lower respiratory infection of viral origin in children under four years of age in Buenos Aires, Argentina. The purpose of this study was to analyze the clinical features and outcome of acute lower respiratory infection associated with different adenovirus genotypes in children. METHODS: Twenty-four cases of acute lower respiratory infection and adenovirus diagnosis reported in a pediatric unit during a two-year period were retrospectively reviewed. Adenovirus was detected by antigen detection and isolation in HEp-2 cells. Adenovirus DNA from 17 isolates was studied by restriction enzyme analysis with Bam HI and Sma I. RESULTS: Subgenus b was found in 82.3% of the cases, and subgenus c in 17.7%. Within subgenus b, only genotype 7 was detected, with genomic variant 7h in 85.7% (12/14) and genomic variant 7i in 14.3% (2/14). Mean age was 8.8 ±; 6 months, and male to female ratio was 3.8: 1. At admission, pneumonia was observed in 71% of the cases and bronchiolitis in 29%. Malnutrition occurred in 37% of the cases; tachypnea in 79%; chest indrawing in 66%; wheezing in 58%; apneas in 16%; and conjunctivitis in 29%. Blood cultures for bacteria and antigen detection of other respiratory viruses were negative. During hospitalization, fatality rate was 16.7% (4 /24). Of the patients who died, three had Ad 7h and one Ad 7i. Thus, fatality rate for adenovirus type 7 reached 28.6% (4/14). CONCLUSIONS: These results show the predominance of adenovirus 7 and high lethality associated with the genomic variants 7h and 7i in children hospitalized with acute lower respiratory infection

Respiratory syncytial virus: Changes in prevalence of subgroups A and B among Argentinian children, 1990-1996

The frequency of respiratory syncytial virus (RSV) and the distribution of subgroups A and B strains during 7 consecutive years (1990-1996) were examined in two cities of Argentina. Nasopharyngeal aspirates from 1,304 children less than 2 years of age hospitalized with acute lower respiratory infection were studied by indirect immunofluorescence. RSV was detected in 352 cases (26.9%), and the peak activity was observed in midwinter. Subgroup characterization was performed with two monoclonal antibodies against the F protein on nasopharyngeal aspirate smears. Of 195 samples, 174 (89.2%) were identified as subgroup A strains and 21 (10.8%) as subgroup B. Both strains cocirculated during 5 of 7 years studied with subgroup A predominating. Subgroup A occurred at least 8 times as often in all years except for 1994-1995. Children infected by subgroup A were younger than those infected by subgroup B (P < 0.05). The association of subgroup A infection with bronchiolitis and subgroup B with pneumonia was statistically significant (P < 0.03).Fil: Carballal, Guadalupe. Centro de Educación Médica e Investigaciones Clínicas "Norberto Quirno"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Videla, Cristina Mónica. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Centro de Educación Médica e Investigaciones Clínicas "Norberto Quirno"; ArgentinaFil: Sequeira, María D.. Dirección Nacional del Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud "Dr.C.G.Malbran". Instituto Nacional de Epidemiologia; ArgentinaFil: Mistchenko, Alicia Susana. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez"; ArgentinaFil: Requeijo, Paula V.. Centro de Educación Médica e Investigaciones Clínicas "Norberto Quirno"; ArgentinaFil: Arbiza Rodonz, Juan Ramón. Universidad de la República. Facultad de Ciencias; Urugua