Transmission of human herpesvirus type 8 infection within families in american indigenous populations from the Brazilian Amazon.

BACKGROUND: The intrafamilial dynamics of endemic infection with human herpesvirus type 8 (HHV-8) in Amerindian populations is unknown. METHODS: Serum samples were obtained from 517 Amerindians and tested for HHV-8 anti-latent nuclear antigen (anti-LANA) and antilytic antibodies by immunofluorescence assays. Logistic regression and mixed logistic models were used to estimate the odds of being HHV-8 seropositive among intrafamilial pairs. RESULTS: HHV-8 seroprevalence by either assay was 75.4% (95% confidence interval [CI]: 71.5%-79.1%), and it was age-dependent (P(trend) < .001). Familial dependence in HHV-8 seroprevalence by either assay was found between mother-offspring (odds ratio [OR], 5.44; 95% CI: 1.62-18.28) and siblings aged ≥10 years (OR 4.42, 95% CI: 1.70-11.45) or siblings in close age range (<5 years difference) (OR 3.37, 95% CI: 1.21-9.40), or in families with large (>4) number of siblings (OR, 3.20, 95% CI: 1.33-7.67). In separate analyses by serological assay, there was strong dependence in mother-offspring (OR 8.94, 95% CI: 2.94-27.23) and sibling pairs aged ≥10 years (OR, 11.91, 95% CI: 2.23-63.64) measured by LANA but not lytic antibodies. CONCLUSIONS: This pattern of familial dependence suggests that, in this endemic population, HHV-8 transmission mainly occurs from mother to offspring and between close siblings during early childhood, probably via saliva. The mother to offspring dependence was derived chiefly from anti-LANA antibodies.

Variations in human herpesvirus type 8 seroprevalence in Native Americans, South America.

To determine the epidemiology of human herpesvirus type 8 (HHV-8) among non-Amazonian native populations, we conducted a cross-sectional study in Brazil, Bolivia, and Paraguay. Our data show striking ethnic and geographic variations in the distribution of HHV-8 seroprevalences in Amazonian (77%) and non-Amazonian native populations (range 0%-83%).

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, < or =50,000 platelets/mm3]) 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.

Human herpesvirus-8 infection and oral shedding in Amerindian and non-Amerindian populations in the Brazilian Amazon region.

BACKGROUND: Human herpesvirus type 8 (HHV-8) is hyperendemic in Amerindian populations, but its modes of transmission are unknown. METHODS: Antibodies against either HHV-8 lytic antigen or HHV-8 latency-associated nuclear antigen (LANA) were detected, by immunofluorescence assays, in 339 Amerindians and 181 non-Amerindians from the Brazilian Amazon. Serological markers of oro-fecal (hepatitis A), parenteral (hepatitis B and C), and sexual (herpes simplex virus type 2 and syphilis) transmission were measured by specific ELISAs. Salivary HHV-8 DNA was detected by use of a nested polymerase chain reaction assay and was sequenced. RESULTS: Antibodies against either lytic antigen or LANA were detected in 79.1% of Amerindians and in 6.1% of non-Amerindians (adjusted seroprevalence ratio [SR], 12.63 [95% confidence interval {CI}, 7.1-22.4]; P<.0001). HHV-8 seroprevalence increased with age among Amerindians (P(Trend) < .001) and already had high prevalence in childhood but was not sex specific in either population. The 2 populations did not differ in seroprevalence of oro-fecal or parenteral markers, but seroprevalence of markers of sexual transmission was lower among Amerindians. HHV-8 DNA in saliva was detected in 47 (23.7%) of 198 HHV-8 seropositive Amerindians. Detection of HHV-8 DNA decreased with age (P(Trend) < .04) and was more common in men (SR, 2.14 [95% CI, 1.3-3.5]; P=.003). A total of 36 (76.6%) of the 47 saliva HHV-8 DNA samples were sequenced, and all clustered as subtype E. CONCLUSION: The data support the hypothesis of early acquisition and horizontal transmission, via saliva, of HHV-8 subtype E in Amerindian populations.

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.

Measles in bone marrow transplant recipients during an outbreak in São Paulo, Brazil.

In 1997, a measles outbreak was identified in São Paulo. Between February and December, 20 185 cases were confirmed. From April to July 1997, a seroepidemiologic survey was conducted to identify the recipients of bone marrow (BM) transplants who were susceptible to measles and the occurrence of measles in this population. A total of 156 patients were screened by enzyme immunoassay (EIA). Patients with IgG titers more than 100 mIU/mL were considered immune. Measles reimmunization records were also reviewed. Thirty-two vaccinated patients underwent serologic evaluation. Six of 22 patients (27.3%) within 3 years after vaccination lost measles immunity, in contrast to 7 of 10 patients (70%) vaccinated longer than 3 years previously (P =.049). Among the 122 nonvaccinated patients, 41 (33.6%) were susceptible to measles: 4 of 47 patients (8.5%) within the first year after BM transplantation (BMT), and 37 of the 75 patients (49.3%) after the first year after BMT (P <.001). Eight recipients acquired measles, confirmed by serology (EIA). High-avidity IgG antibodies were observed in the acute phase of measles, suggesting a secondary immune response. Measles interstitial pneumonia was observed in one patient. Seven patients had mild symptoms. Exanthema was present in all patients. All but one patient had fever and nonproductive cough. Koplik spots could be observed in 5 patients. Measles can be mild in BM transplant recipients. Exanthema is frequently present but not often typical. Immunity to measles decreases after day +365 after BMT. Additional studies are needed to evaluate the safety of measles vaccine after the first year of BMT, mostly during outbreaks.

Predictors related to the occurrence of a measles epidemic in the city of Sao Paulo in 1997 / Factores predictivos de la ocurrencia de una epidemia de sarampión en la ciudad de São Paulo en 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 Sao Paulo, in the Brazilian state of the same name. Measles cases from the city of Sao 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 Sao 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

Se realizó un estudio de casos y controles apareados para identificar los factores de riesgo de sarampión durante una epidemia que tuvo lugar en 1997 en la ciudad de São Paulo, en el estado brasileño del mismo nombre. Se incluyeron los casos de sarampión ocurridos en esa ciudad entre el 1 de enero y el 15 de agosto de 1997. Los criterios para definir los casos fueron: edad inferior a 30 años, no haber sido vacunado contra el sarampión en los 5­21 días anteriores al inicio del exantema y confirmación mediante la detección de anticuerpos IgM. A partir de un banco de datos de casos confirmados de sarampión, se seleccionaron aleatoriamente 130 casos de cada uno de los siguientes grupos de edad: menores de 1 año, 1 a 5 años, 6 a 20 años, 21 a 24 años y 25 a 29 años; la selección se hizo de acuerdo con un criterio sistemático proporcional al número de casos en siete zonas de la ciudad. Los datos fueron recolectados mediante una encuesta domiciliaria y por cada caso de sarampión se estudiaron dos controles emparejados según la edad y el lugar de residencia. El análisis de regresión logística condicional de los posibles factores de riesgo identificados en el análisis univariado reveló que los factores que mejor predecían la adquisición de la enfermedad durante la epidemia eran: 1) la ausencia de vacunación contra el sarampión; 2) el contacto previo, en casa o en el trabajo, con un caso de enfermedad similar al sarampión; 3) el haber nacido fuera de São Paulo o en una zona rural; 4) el estar empleado, y 5) el pasar parte del día en una institución semicerrada, como una guardería, un centro infantil o una escuela. Los factores de riesgo no fueron homogéneos para los diferentes grupos de edad. Los datos de este estudio indican que, además de la falta de vacunación, habría que considerar otros factores de riesgo a la hora de planificar una estrategia de vacunación contra el sarampión en países en desarrollo

Soroprevalência de sarampo entre pediatras de um hospital-escola / Prevalence of antibodies against measles among pediatricians in a teaching hospital

Introduçäo: Em 1996-1997, ocorreu no Estado de Säo Paulo uma epidemia de sarampo. Uma das estratégias de controle da Secretaria do Estado da Saúde foi a vacinaçäo dos profissionais da saúde. Nesse sentido, objetivou-se avaliar a soroprevalência de sarampo entre os pediatras. Métodos: Foram colhidas 150 amostras de sangue de médicos pediatras voluntários, as quais foram submetidas ao teste de ELISA. Um questionário sobre história de sarampo e situaçäo vacinal foi respondido pelos pediatras estudados. Resultados: A maioria dos pediatras 147/150 tinha títulos protetores: sendo 80,3 por cento sem e 19,7 por cento com história pregressa de sarampo. Em 2 por cento dos pediatras as sorologias foram negativas. Nos sem história de doença, 67 por cento afirmavam terem sido vacinados e 33 por cento apesar de apresentarem títulos protetores ignoravam sua situaçäo vacinal. Dos 79 médicos vacinados, 81 por cento tinham recebido a vacina há pelo menos 25 anos e mantido títulos protetores. Dos 3 com sorologias negativas, um referia vacinaçäo anterior. Conclusöes: Apesar da elevada soroprevalência para sarampo, 2 por cento de pessoas susceptíveis podem constituir grupo de risco para aquisiçäo e disseminaçäo da doença em situaçäo epidêmica

Estudo dos preditores relacionados a ocorrência da epidemia de sarampo no município de Säo Paulo, em 1997

Relatório contendo os resultados da pesquisa "Estudo dos Preditores relacionados a Ocorrência de Sarampo no Município de Säo Paulo em 1997" cuja divulgaçäo na íntegra pretende disponibilizar os resultados desta pesquisa e ampliar a discussäo sobre as estratégias de controle do sarampo (CAC)

Avaliaçäo sorológica de imunizaçäo contra o sarampo com duas doses administradas aos 6 e 11 meses de idade: estudo prospectivo / Serological evaluation of the immunization against meales with 2 doses administered at 6 and 11 months of age: a prospective study

A eficácia sorológica de um esquema de vacinaçäo 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 ñ 1,7 meses) após a segunda dose da vacina, tendo-se empregado para pesquisa de anticorpos específicos a reaçäo 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 perído do estudo, quadro clínico compatível com sarampo. Em regiöes em que uma proporçäo significativa de casos ocorrem antes s 9 meses de idade, o esquema de vacinaçäo de 2 doses, a primeira aos 6 e a segunda aos 11 meses de idade, pode representar alternativa válida para o controle do sarampo