ABSTRACT
Respiratory syncytial virus (RSV) is well recognized as the most important pathogen causing acute respiratory disease in infants and young children, mainly in the form of bronchiolitis and pneumonia. Two major antigenic groups, A and B, have been identified; however, there is disagreement about the severity of the diseases caused by these two types. This study investigated a possible association between RSV groups and severity of disease. Reverse transcription-polymerase chain reaction was used to characterize 128 RSV nasopharyngeal specimens from children less than five years old experiencing acute respiratory disease. A total of 82 of 128 samples (64.1 percent) could be typed, and, of these, 78 percent were group A, and 22 percent were group B. Severity was measured by clinical evaluation associated with demographic factors: for RSV A-infected patients, 53.1 percent were hospitalized, whereas for RSV B patients, 27.8 percent were hospitalized (p = 0.07). Around 35.0 percent of the patients presented risk factors for severity (e.g., prematurity). For those without risk factors, the hospitalization occurred in 47.6 percent of patients infected with RSV A and in 18.2 percent infected with RSV B. There was a trend for RSV B infections to be milder than those of RSV A. Even though RSV A-infected patients, including cases without underlying condition and prematurity, were more likely to require hospitalization than those infected by RSV B, the disease severity could not to be attributed to the RSV groups.
Subject(s)
Child , Child, Preschool , Female , Humans , Infant , Male , Respiratory Syncytial Virus Infections , Respiratory Tract Infections , Respiratory Syncytial Virus, Human/classification , Acute Disease , Brazil/epidemiology , Fluorescent Antibody Technique, Indirect , Nasopharynx/virology , Prevalence , Reverse Transcriptase Polymerase Chain Reaction , RNA, Viral/genetics , Respiratory Syncytial Virus Infections/epidemiology , Respiratory Syncytial Virus Infections/virology , Respiratory Syncytial Virus, Human/genetics , Respiratory Tract Infections/epidemiology , Respiratory Tract Infections/virology , Seasons , Severity of Illness IndexABSTRACT
We have evaluated the cellular and humoral immune response to primary respiratory syncytial virus (RSV) infection in young infants. Serum specimens from 65 patients <=12 months of age (39 males and 26 females, 28 cases <3 months and 37 cases > or = 3 months; median 3 ± 3.9 months) were tested for anti-RSV IgG and IgG subclass antibodies by EIA. Flow cytometry was used to characterize cell surface markers expressed on peripheral blood mononuclear cells (PBMC) from 29 RSV-infected children. There was a low rate of seroconversion in children <3 months of age, whose acute-phase PBMC were mostly T lymphocytes (63.0 ± 9.0 percent). In contrast, a higher rate of seroconversion was observed in children >3 months of age, with predominance of B lymphocytes (71.0 ± 17.7 percent). Stimulation of PBMC with RSV (2 x 10(5) TCID50) for 48 h did not induce a detectable increase in intracellular cytokines and only a few showed a detectable increase in RSV-specific secreted cytokines. These data suggest that age is an important factor affecting the infants' ability to develop an immune response to RSV
Subject(s)
Humans , Male , Female , Infant , Infant, Newborn , B-Lymphocytes , Cytokines , Respiratory Syncytial Virus Infections , Respiratory Syncytial Virus, Human , T-Lymphocytes , Age Factors , Antibodies, Viral , Antigens, Surface , Biomarkers , Brazil , Flow Cytometry , Immunoenzyme TechniquesABSTRACT
Um estudo seroepidemiologico para o virus da hepatite A (VHA), investigando os marcadores de infeccao passada (anti-VHA total anti-IgG e IgM) e infeccao recente (anti-VHA IgM), foi realizado entre 1991 e 1992, em criancas de creche de Goiania-Brasil central. Das 310 criancas com idade entre 03 meses e 09 anos, 69,7 por cento mostraram soropositividade ao anti-VHA total, sendo 60 por cento, na faixa etaria entre 1 e 3 anos. A prevalencia do marcador anti-VHA IgM foi de 3,2 por cento visto em idade de 1-4 anos e com distribuicao uniforme nas 10 creches estudadas. Entre as variaveis sociodemograficas estudadas, apenas o tempo de frequencia das criancas nas creches, igual ou superior a um ano, mostrou, em analise multivariada ajustada para idade, um risco de 4,7 vezes maior quando comparado com o periodo de um mes (LC 95 por cento 2,3-9,9)...
Subject(s)
Humans , Male , Female , Infant , Child, Preschool , Child , Child Day Care Centers , Hepatitis A/epidemiology , Risk Factors , Brazil , Hepatitis A/immunology , Serologic TestsABSTRACT
Um estudo soro epidemiológico, para anticorpos contra o virus da hepatite A (anti-VHA total-IgM e IgG), foi realizado no período de 1991-1992, em 397 "meninos de/na rua" em Goiânia. Destes, 313 apresentavam vínculo familiar e desenvolviam, em sua maioria, atividades de trabalho informal, enquanto que 84 nao possuiam vínculo familiar e se encontravam na rua ou em Instituiçoes do Governo Estadual. A taxa média de prevalência foi de 90,4 por cento, variando de 80,0 por cento a 92,9 por cento, sem contudo apresentar diferença estatística significante relativa à idade (7-21). Também nao se evidenciou qualquer diferença quando este grupo foi estratificado para presença ou ausência de vínculo familiar ou mesmo quando analisado em relaçao a outras variáveis sócio-demográficas. Estes dados sugerem que a hepatite A é endêmica na populaçao de baixa condiçao sócio-econômica da regiao e que nesta faixa etária a maioria dos indivíduos já adquiriu a infecçao. Outras investigaçoes em grupos e camadas sociais diferentes sao necessárias a fim de parametrar estratégias vacinais em países subdesenvolvidos.