Seroprevalence of Kaposi Sarcoma–associated Herpesvirus and Other Serologic Markers in the Brazilian Amazon

To determine the presence of Kaposi sarcoma–associated herpesvirus (KSHV) and other serologic markers, we tested serum specimens of 339 Amerindians, 181 rural non-Amerindians, and 1,133 urban blood donors (13 Amerindians) in the Brazilian Amazon. High KSHV seroprevalence in children and inverse association with herpes simplex virus type 2 indicates predominant nonsexual transmission among Amerindians

Predictors related to the occurrence of a measles epidemic in the city of São Paulo in 1997

A matched case-control study was performed to identify risk factors for measles during an epidemic that occurred in 1997 in the city of São Paulo, in the Brazilian state of the same name. Measles cases from the city of São Paulo from 1 January 1997 to 15 August 1997 were included in the study. The criteria for case definition were age below 30 years, having received no measles vaccine 5-21 days before the onset of rash, and laboratory confirmation by IgM antibodies detection. From a bank of confirmed measles cases, 130 cases for each of five age ranges (under 1 year, 1-5 years, 6-20 years, 21-24 years, and 25-29 years) were picked at random according to a systematic criterion proportional to the number of cases in seven areas of the city. Data were collected through a home survey, and for each measles case studied two controls matched by age and place of residence were selected. The matched conditional logistic regression analysis for the potential risk factors from the univariate analysis showed that the best predictors for acquiring measles during the epidemic were: lack of measles vaccination, previous contact with a measles-like disease at home or on the job, having been born either outside the state of São Paulo or in a rural area, being employed, and spending time in a semiclosed institution, such as a nursery, day care center, or school. The risk factors were not homogeneous for the different age groups. The data in the present survey suggest that, in addition to lack of vaccination, other risk factors should be considered when planning a measles vaccination strategy for a developing country

Identification of Primary and Secondary Measles Vaccine Failures by Measurement of Immunoglobulin G Avidity in Measles Cases during the 1997 São Paulo Epidemic

Despite almost universal use of measles vaccines in recent decades, epidemics of the disease continue to occur. Understanding the role of primary vaccine failure (failure to seroconvert after vaccination) and secondary vaccine failures (waning immunity after seroconversion) in measles epidemics is important for the evaluation of measles control programs in developing countries. After a measles epidemic in São Paulo, Brazil, 159 cases previously confirmed by detection of specific immunoglobulin M (IgM) antibodies were tested for IgG avidity, and a secondary immune response, defined by an IgG avidity index of at least 30%, was established in 30 of 159 (18.9%) patients. Among the 159 patients, 107 (67.3%) had not been vaccinated and 52 (32.7%) had received one or more doses of measles vaccine. Of the 107 unvaccinated patients, 104 (97.2%) showed a primary immune response, defined as an IgG avidity index of less than 30%. Among the 52 patients with documented vaccination, 25 (48.1%) showed a primary immune response and 27 (51.9%) showed a secondary immune response, thereby constituting a secondary vaccine failure. Primary vaccine failure was observed in 13 of 13 patients vaccinated prior to 1 year of age and in 43.5 and 12.5%, respectively, of patients receiving one or two doses after their first birthdays. These results provide evidence that measurement of IgG avidity can be used to distinguish between primary and secondary vaccine failures in vaccinated patients with measles; the method can also be a useful tool for the evaluation of measles control programs

Diagnóstico sorológico do sarampo: padronização e avaliação do teste Dot-ELISA

A Dot-ELISA using a measles virus (MV) antigen obtained by sodium deoxycholate treatment was standardized and evaluated for IgM and IgG antibody detection in measles patients and measles-vaccinated subjects. A total of 192 serum samples were studied, comprising 47 from patients with acute and convalescent measles, 55 from 9-month old children prior to measles vaccination and 41 from children of the same age after vaccination, and 49 from patients with unrelated diseases. The diagnostic performances of the IgG Dot-ELISA and IgG immuno fluorescence test (IFT) were found to be close, varying from 0.97 to 1.00 in sensitivity and the specificities were maximum (1.00). Nevertheless, the sensitivity of the IgM Dot-ELISA (0.85) was higher than that (0.63) of the IgM IFT, although both assays had comparably high (1.00) specificities. The IgM Dot-ELISA in particular proved to be more sensitive in relation to other assays studied by revealing antibodies in 80.0% (12/15) of vaccinated children on the 15th day after immunization. In contrast the IgM IFT, failed to detect antibodies in the same group of vaccinated children. The stability of the MV antigen was longer than that of the IFT antigen, and the reproducibility of the Dot-Elisa was satisfactory.A técnica de Dot-ELISA (DE) para detecção de anticorpos IgM e IgG anti vírus do sarampo foi padronizada e avaliada utilizando-se antígeno viral obtido por tratamento com desoxicolato de sódio (DOC). Foram estudadas 192 amostras de soros, compreendendo 47 amostras de 22 pacientes com sarampo nas fases aguda e convalescente, 55 amostras de soros de crianças antes da vacinação, tendo 9 meses de idade, 41 amostras de soros de crianças da mesma idade colhidas após vacinação e 49 amostras de soros de pacientes com outras patologias. O desempenho diagnóstico da técnica de Dot-ELISA-IgG foi semelhante ao de Imunofluorescência indireta (IFI) IgG cujos índices de sensibilidade variaram de 0,97 a 1,00 e os de especificidade sendo de valor máximo, 1,00. Contudo, a sensibilidade da técnica de Dot-ELISA IgM (0,85) foi mais alta que a de IFT IgM (0,63), embora ambos os ensaios apresentassem especificidades máximas (1,00). A técnica de Dot-ELISA IgM em particular mostrou-se mais sensível em relação a IFT, revelando anticorpos em 80% das crianças vacinadas (12/15), 15 dias após a imunização. Ao contrário, IFT IgM falhou em detectar anticorpos no mesmo grupo de crianças vacinadas. A estabilidade do antígeno viral obtido com detergente (DOC) foi maior que a do antígeno de IFT, e a reprodutibilidade da técnica de Dot-ELISA foi satisfatória

Avaliação sorológica de imunização contra o sarampo com duas doses administradas aos 6 e 11 meses de idade: estudo prospectivo

A prospective study was designed to evaluate the serologic efficacy of a two dose meas les vaccination schedule, at 6 months and 11 months of age. Infants were given a further attenuated measles virus vaccine (BIKEN CAM 70, Fundação Oswaldo Cruz) and serum samples were tested for measles antibodies using the indirect immunofluorescence technique (IFA) and ELISA. Seroconversion rates 6 to 12 months (mean of 8.0 ±1.7 months) following the second dose of measles vaccine were 88.5% (85/96) by IFA and 96.8% (93/96) by ELISA. No measles cases were reported during the study period. In regions where a significant proportion of measles cases occurs before nine months of age, vaccination with a two doses schedule, at 6 and 11 months of age, may represent an alternative for measles control.A eficácia sorológica de um esquema de vacinação contra o sarampo empregando duas doses da vacina BIKEN CAM 70, sendo a primeira dose administrada aos 6 meses de idade e a segunda aos 11 meses de idade foi avaliada através de um estudo prospectivo. A amostra de sangue foi colhida entre 6 e 12 meses (média de 8,0 ± 1,7 meses) após a segunda dose da vacina, tendo-se empregado para pesquisa de anticorpos específicos a reação de imunofluorescência indireta (RIFI) e a técnica imunoenzimática ELISA. Anticorpos para o sarampo na amostra de sangue pós-vacinal foram detectados em 88,5% (85/96) das crianças quando foi empregada a RIFI e em 96,8% (93/96) quando se empregou a técnica imunoenzimática ELISA. Nenhuma das crianças apresentou, durante o período do estudo, quadro clínico compatível com sarampo. Em regiões em que uma proporção significativa de casos ocorrem antes dos 9 meses de idade, o esquema de vacinação de 2 doses, a primeira aos 6 e a segunda aos 11 meses de idade, pode representar alternativa válida para o controle do sarampo

Dengue and dengue hemorrhagic fever among adults: Clinical outcomes related to viremia, serotypes, and antibody response

Background. Clinical manifestations of dengue vary in different areas of endemicity and between specific age groups, whereas predictors of outcome have remained controversial. In Brazil, the disease burden predominantly affects adults, with an increasing trend toward progression to dengue hemorrhagic fever (DHF) noted. Methods. A cohort of adults with confirmed cases of dengue was recruited in central Brazil in 2005. Patients were classified according to the severity of their disease. Associations of antibody responses, viremia levels (as determined by real-time polymerase chain reaction [PCR]), and serotypes (as determined by multiplex PCR) with disease severity were evaluated. Results. Of the 185 symptomatic patients > 14 years of age who had a confirmed case of dengue, 26.5% and 23.2% were classified as having intermediate dengue fever (DF)/ DHF (defined as internal hemorrhage, plasma leakage, manifested signs of shock, and/ or thrombocytopenia [platelet count, <= 50,000 platelets/mm(3)]) and DHF, respectively. The onset of intermediate DF/ DHF and DHF occurred at a late stage of disease, around the period of defervescence. Patients with DHF had abnormal liver enzyme levels, with a > 3-fold increase in aspartate aminotransferase level, compared with the range of values considered to be normal. Overall, 65% of patients presented with secondary infections with dengue virus, with such infection occurring in similar proportions of patients in each of the 3 disease category groups. Dengue virus serotype 3 (DV3) was the predominant serotype, and viremia was detected during and after defervescence among patients with DHF or intermediate DF/ DHF. Conclusions. Viremia was detected after defervescence in adult patients classified as having DHF or intermediate DF/ DHF. Secondary infection was not a predictor of severe clinical manifestation in adults with infected with the DV3 serotype

Dengue and dengue hemorrhagic fever among adults: Clinical outcomes related to viremia, serotypes, and antibody response

Background. Clinical manifestations of dengue vary in different areas of endemicity and between specific age groups, whereas predictors of outcome have remained controversial. In Brazil, the disease burden predominantly affects adults, with an increasing trend toward progression to dengue hemorrhagic fever (DHF) noted. Methods. A cohort of adults with confirmed cases of dengue was recruited in central Brazil in 2005. Patients were classified according to the severity of their disease. Associations of antibody responses, viremia levels (as determined by real-time polymerase chain reaction [PCR]), and serotypes (as determined by multiplex PCR) with disease severity were evaluated. Results. Of the 185 symptomatic patients > 14 years of age who had a confirmed case of dengue, 26.5% and 23.2% were classified as having intermediate dengue fever (DF)/ DHF (defined as internal hemorrhage, plasma leakage, manifested signs of shock, and/ or thrombocytopenia [platelet count, <= 50,000 platelets/mm(3)]) and DHF, respectively. The onset of intermediate DF/ DHF and DHF occurred at a late stage of disease, around the period of defervescence. Patients with DHF had abnormal liver enzyme levels, with a > 3-fold increase in aspartate aminotransferase level, compared with the range of values considered to be normal. Overall, 65% of patients presented with secondary infections with dengue virus, with such infection occurring in similar proportions of patients in each of the 3 disease category groups. Dengue virus serotype 3 (DV3) was the predominant serotype, and viremia was detected during and after defervescence among patients with DHF or intermediate DF/ DHF. Conclusions. Viremia was detected after defervescence in adult patients classified as having DHF or intermediate DF/ DHF. Secondary infection was not a predictor of severe clinical manifestation in adults with infected with the DV3 serotype

Recent immunization against measles does not interfere with the sero-response to yellow fever vaccine

Secretaria de Estado de Saúde de São Paulo. Centro de Vigilância Epidemiológica Prof. Alexandre Vranjac. São Paulo, SP, Brasil.Secretaria de Estado de Saúde de São Paulo. Centro de Vigilância Epidemiológica Prof. Alexandre Vranjac. São Paulo, SP, Brasil.Universidade de São Paulo. Faculdade de Medicina. Instituto de Medicina Tropical de São Paulo. Departamento de Doenças Infecciosas e Parasitárias. São Paulo, SP, Brasil.Secretaria de Estado de Saúde de São Paulo. Centro de Vigilância Epidemiológica Prof. Alexandre Vranjac. São Paulo, SP, Brasil.Fundação Oswaldo Cruz. Instituto de Tecnologia em Imunobiológicos. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto de Tecnologia em Imunobiológicos. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto de Tecnologia em Imunobiológicos. Rio de Janeiro, RJ, Brasil.Ministério da Saúde. Fundação Nacional de Saúde. Instituto Evandro Chagas. Belém, PA, Brasil.Secretaria de Estado de Saúde de São Paulo. Centro de Vigilância Epidemiológica Prof. Alexandre Vranjac. São Paulo, SP, Brasil.Secretaria de Estado de Saúde de São Paulo. Centro de Vigilância Epidemiológica Prof. Alexandre Vranjac. São Paulo, SP, Brasil.Secretaria de Estado de Saúde de São Paulo. Centro de Vigilância Epidemiológica Prof. Alexandre Vranjac. São Paulo, SP, Brasil.Secretaria de Estado de Saúde de São Paulo. Centro de Vigilância Epidemiológica Prof. Alexandre Vranjac. São Paulo, SP, Brasil.Universidade de São Paulo. Faculdade de Medicina. Instituto de Medicina Tropical de São Paulo. Departamento de Doenças Infecciosas e Parasitárias. São Paulo, SP, Brasil.In order to determine whether previous measles vaccination interferes with the sero-response to yellow fever vaccine, 294 children at nine months of age were randomly assigned to immunization with yellow fever vaccine at di erent time intervals after measles vaccination. The seroconversion rate (SCR) and the log10 geometric mean titer (GMT) for 17 DD yellow fever vaccine at di erent intervals after Schwarz measles vaccination were: 1±6 days: SCR= 44/57= 77%; GMT= 4.57; 7±13 days: SCR= 36/53= 68%; GMT= 4.46; 14±21 days: SCR= 55/65= 85%; GMT= 4.46; 22±27 days: SCR= 41/54= 76%; GMT= 4.41 and >28 days: SCR= 52/65= 80%; GMT= 4.24 ( p> 0.05). We conclude that recent immunization against measles does not interfere with the sero-response to yellow fever vaccine