Dengue fever: a post-epidemic sero-epidemiological survey in an urban setting at a northwestern county of S. Paulo State - Brazil

Objective The objective of this study was to evaluate the real size of the epidemics registered in thr urban area of the county of Santa Barbara D'Oeste, SP Brazil, from April to June, 1995. The measurement of the epidemiological validity of the official surveillance system criteria and its positive predicted value It were adopted as specific goals. Methods A sero-epidemiological sun,ey was carried out over a sample of 1,113 sera from citizens of Santa Barbara D'Oeste, through a systematic random sampling of houses, five months after the end of the epidemics. Infection rates were compared with the infestation indexes by Aedes aegipty and the notified cases amongst the county sections. The importance of submitting patients with clinical suspicion of dengue to laboratory rests was discussed. Results and Discussion it was found that infection rates by dengue virus varied in the same direction and proportion as the presence of Aedes aegipty larvae reported by the 'Breteau Index', as well as the number of cases,reported by the official notifiable diseases surveillance system during the epidemics. A prevalence of 630 by 100 thousand inhabitants was found, a 15-fold rate when compared to rite laboratory positive sera from cases detected by the surveillance system during the epidemics. A retrospective comparison with the surveillance reports, using serological results as a gold standard, also showed that the majority of dengue specific serum-positive individuals were not detected during the epidemics. otherwise cases that did not present serological reaction were notified exhibiting a low positive predictive value of clinical diagnosis (15,6).33656657

Estimating Dengue Transmission Intensity from Case-Notification Data from Multiple Countries

Despite being the most widely distributed mosquito-borne viral infection, estimates of dengue transmission intensity and associated burden remain ambiguous. With advances in the development of novel control measures, obtaining robust estimates of average dengue transmission intensity is key for assessing the burden of disease and the likely impact of interventions.We estimated the force of infection (λ) and corresponding basic reproduction numbers (R0) by fitting catalytic models to age-stratified incidence data identified from the literature. We compared estimates derived from incidence and seroprevalence data and assessed the level of under-reporting of dengue disease. In addition, we estimated the relative contribution of primary to quaternary infections to the observed burden of dengue disease incidence. The majority of R0 estimates ranged from one to five and the force of infection estimates from incidence data were consistent with those previously estimated from seroprevalence data. The baseline reporting rate (or the probability of detecting a secondary infection) was generally low (<25%) and varied within and between countries.As expected, estimates varied widely across and within countries, highlighting the spatio-temporally heterogeneous nature of dengue transmission. Although seroprevalence data provide the maximum information, the incidence models presented in this paper provide a method for estimating dengue transmission intensity from age-stratified incidence data, which will be an important consideration in areas where seroprevalence data are not available

Serological identification of Rickettsia spp from the spotted fever group in capybaras in the region of Campinas-SP-Brazil

Diseases transmitted by ticks have been an important health problem all over the world. Brazilian Spotted Fever (BSF) stands for a serious epidemiological concern due to the high mortality rates pointed out. Capybaras are commonly incriminated as possible reservoirs in the BSF transmission cycle. In the last decades the numbers of these animals raised sharply and they have invaded human areas. They intensify the contact between ticks and humans beings. This study aim is to contribute to the possible role performed for this rodent in the BSF epidemiology in some areas located in Campinas region. Sao paulo. Cabybaras infected by rickettsiae of BSF group were studied through the analysis of the frequencies of BSF-group rickettsiae antibodies titer = 64 buy indirect immunofluorescence test (IFA), and data from human cases epidemiological surveillance. The serum frequency positiveness varied greatly according to areas where animals were captured. However it was found serum positiveness only in the areas where human cases of BSF were reported. These findings suggest the capybara may be seen as sentinel animal. Due to presence of serological cross reactivity between microorganisms belonging to SF group, the results must be interpreted carefully and additional methods to distinguish pathogenic rickettsiae are required in our country.3861694169

Padronização e uso de um método imunoenzimático que utiliza células infectadas como antígeno no diagnóstico rotineiro do dengue Standardization and use of an immunoenzymatic method using infected cells as antigens in routine diagnosing of dengue

INTRODUÇÃO: Este trabalho mostra a padronização e o uso do método imunoenzimático utilizando células infectadas como antígeno (EIA-ICC) no diagnóstico sorológico rotineiro do dengue. MÉTODOS: Na otimização do teste, com a dose de 1.000 TCID50 de vírus do dengue tipo 3 (DENV-3), foram utilizadas 100.000 células C636 infectadas 1000 TCID50 (DENV-3). RESULTADOS: Os resultados obtidos com EIA-ICC foram comparados com o kit comercial de dengue HUMAN. Os resultados foram altamente coincidentes; o EIA-ICC mostrou-se moderadamente sensível e com alta especificidade. O teste foi usado no diagnóstico sorológico de 1.797 amostras sorológicas de casos suspeitos de dengue durante a epidemia de Ribeirão Preto, em 2006. Na avaliação sorológica, 228 amostras foram positivas para IgM contra DENV-3, e 235 amostras foram positivas para IgG contra DEV-3, e em 35 amostras detectou-se positividade para IgM e IgG. CONCLUSÕES: O EIA-ICC mostrou-se confiável e simples sendo adequado ao diagnóstico sorológico do dengue.<br>INTRODUCTION: This paper show the standardization and use of the immunoenzymatic method using infected cells as antigens (EIA-ICC) for routine serological diagnosing of dengue. METHODS: In optimizing the test, a dose of 1,000 TCID50 of dengue type 3 virus (DENV-3) was used, and 100,000 C636 cells infected with 1,000 TCID50 (DENV-3) were used. RESULTS: The results obtained with EIA-ICC were compared with the HUMAN commercial dengue kit. The results were highly concordant. The EIA-ICC showed moderate sensitivity and high specificity. The test was used for serologically diagnosing 1,797 blood samples from suspected dengue cases during the 2006 epidemic in Ribeirao Preto. From the serological evaluation, 228 samples were positive for IgM against DENV-3; 235 samples were positive for IgG against DENV-3; and 35 samples were positive for both IgG and IgM. CONCLUSIONS: EIA-ICC was shown to be reliable and simple, and suitable for serologically diagnosing dengue

Dengue: inquérito populacional para pesquisa de anticorpos e vigilância virológica no Município de Campinas, São Paulo, Brasil Dengue: sero-epidemiological survey and virological surveillance in Campinas, São Paulo, Brazil

Estudou-se a epidemiologia do dengue no Município de Campinas, São Paulo, Brasil, por meio de um inquérito populacional aleatório realizado em 1998, visando à detecção dos níveis de anticorpos para dengue, e de dados de vigilância epidemiológica do período de 1996 a 2003, com ênfase na vigilância virológica. Foram coletadas 1.260 amostras, por meio de punção digital, utilizando-se papel de filtro, sendo as amostras testadas pelo teste imunoenzimático em culturas celulares infectadas (EIA-ICC). Observou-se que a prevalência de soro reagentes (14,79%) é mais baixa que as encontradas em outros inquéritos realizados no país e superior às encontradas em dois inquéritos realizados em cidades do Estado de São Paulo. Detectou-se uma prevalência de soro reagentes muito superior à incidência de casos notificados e confirmados laboratorialmente durante as epidemias de 1996, 1997 e 1998. Não se encontrou proporcionalidade entre a prevalência de anticorpos para dengue e a incidência de casos durante a epidemia nos diferentes Distritos de Saúde da cidade. Sugerem-se um estudo aprofundado do significado dos indicadores de transmissão utilizados em epidemias e uma vigilância virológica mais intensa, principalmente em anos com níveis de transmissão baixos.<br>The epidemiology of dengue in the municipality of Campinas, São Paulo, Brazil, was studied in 1998 using a randomized sero-epidemiological survey. Epidemiological surveillance data from 1996-2003 were also analyzed, with an emphasis on virological surveillance. 1,260 individuals participated in the survey and had blood samples drawn by finger stick on filter paper. Blood samples were tested by EIA-ICC, an enzyme immunoassay using infected cells as antigen. Dengue antibody prevalence (14.79%) was lower than in other surveys in other States of Brazil, but higher than in two other serological surveys in São Paulo State. Dengue antibody prevalence was far higher than the reported case incidence during the 1996, 1997, and 1998 epidemics. Antibody prevalence and reported case incidence in different health districts were disproportional. The article concludes by recommending further research on the significance of transmission rates during epidemics and more intensive virological surveillance, especially in years with few reported cases

Triatoma infestans em área sob vigilância entomológica para doença de Chagas, Estado de São Paulo, Brasil Triatoma infestans in area under entomological surveillance for Chagas' disease in São Paulo State, Brazil

Atendendo a notificação de encontro, por habitantes da Fazenda Paraíso, área rural do Município de Paulínia, Estado de São Paulo, de um exemplar alado de triatomíneo, procedeu-se a uma investigação epidemiológica em que capturaram-se 109 exemplares de Triatoma infestans em focos situados em construções peridomiciliares. As condições locais favoreciam a colonização por triatomíneos: grande número de construções peridomiciliares abandonadas, habitadas por pombos e pardais, fornecedores de farto alimento para os hemípteros. Eliminaram-se os focos por meio de controle mecânico dos ninhos dos pássaros. Borrifaram-se, com inseticida de ação residual, todas as unidades domiciliares da região. Desde que persistam as condições para a instalação de focos de triatomíneos nessa localidade, é obrigatória a implementação de ações de vigilância. Entretanto, os indicadores entomológicos e sorológicos sugerem não ser preocupante a situação atual. Destaca-se aqui a importância da notificação triatomínica para a detecção de focos de triatomíneos, particularmente os de Triatoma infestans.<br>In response to notification of the capture of a winged triatomine bug by local inhabitants, an epidemiological investigation was investigated in the rural area of the Municipality of Paulínia, São Paulo State (Brazil). This led to the collection of 109 specimens of Triatoma infestans from peridomiciliary breeding sites. Local conditions favored colonization by triatomine bugs: many abandoned outbuildings were inhabited by pigeons and sparrows, which meant abundant feed for these bugs. Thus, surveillance is mandatory as long as conditions for triatomine breeding persist. Nevertheless, entomological and serological indicators ruled out immediate concern over vectorial transmission of Chagas' disease in this municipality. All domiciliary units of the region were sprayed with residual-effect insecticides and the triatomine breeding sites were destroyed by the use of mechanical control of bird nests. The importance of reporting the occurrence of triatomine bugs, particularly Triatoma infestans, in this region, is emphasized