Evaluation of dengue NS1 antigen detection for diagnosis in public health laboratories, São Paulo State, 2009

The present work evaluated the diagnostic accuracy of detection of Dengue NS1 antigen employing two NS1 assays, an immunochromatographic assay and ELISA, in the diagnostic routine of Public Health laboratories. The results obtained with NS1 assay were compared with virus isolation and, in a subpopulation of cases, they were compared with the IgM-ELISA results obtained with convalescent samples. A total of 2,321 sera samples were analyzed by one of two NS1 techniques from March to October 2009. The samples were divided into five groups: groups I, II and III included samples tested by NS1 and virus isolation, and groups IV and V included patients with a first sample tested by NS1 and a second sample tested by IgM-ELISA. Sensitivity, specificity, positive and negative predictive values, Kappa Index and Kappa Concordance were calculated. The results showed that NS1 testing in groups I, II and III had high sensitivity (98.0%, 99.5% and 99.3%), and predictive values and Kappa index between 0.9 - 1.0. Groups IV and V only had Kappa Concordance calculated, since the samples were analyzed according to the presence of NS1 antigen or IgM antibody. Concordance of 92.1% was observed when comparing the results of NS1-negative samples with IgM-ELISA. Based on the findings, it is possible to suggest that the tests for NS1 detection may be important tools for monitoring the introduction and spread of Dengue serotypes.

Scientific authorships and collaboration network analysis on Chagas disease: papers indexed in PubMed (1940-2009)

Chagas disease is a chronic, tropical, parasitic disease, endemic throughout Latin America. The large-scale migration of populations has increased the geographic distribution of the disease and cases have been observed in many other countries around the world. To strengthen the critical mass of knowledge generated in different countries, it is essential to promote cooperative and translational research initiatives. We analyzed authorship of scientific documents on Chagas disease indexed in the Medline database from 1940 to 2009. Bibliometrics was used to analyze the evolution of collaboration patterns. A Social Network Analysis was carried out to identify the main research groups in the area by applying clustering methods. We then analyzed 13,989 papers produced by 21,350 authors. Collaboration among authors dramatically increased over the study period, reaching an average of 6.2 authors per paper in the last five-year period. Applying a threshold of collaboration of five or more papers signed in co-authorship, we identified 148 consolidated research groups made up of 1,750 authors. The Chagas disease network identified constitutes a "small world," characterized by a high degree of clustering and a notably high number of Brazilian researchers.

Evaluation of seroepidemiological toxoplasmosis in HIV/AIDS patients in the south of Brazil

Toxoplasmosis is considered one of the opportunistic infections for individuals with the Acquired Immunodeficiency Syndrome (AIDS), and is also a major cause of morbidity and mortality. The aim of this study was to evaluate the prevalence of neurotoxoplasmosis, ocular toxoplasmosis and antibodies for Toxoplasma gondii in HIV-positive patients attending the SAE (Specialized Assistance Service for HIV/AIDS), as well as to associate their serological profile with epidemiological and clinical data. A total of 250 patients participated in the study from December, 2009 to November, 2010. Serological analysis was performed using the indirect immunofluorescent technique; epidemiological data were gathered by a questionnaire, and clinical history was based on the analysis of medical charts. Prevalence of seropositivity was 80%, with history of neurotoxoplasmosis in 4.8% and of ocular toxoplasmosis in 1.6% of the patients. The Highly Active Antiretroviral Treatment (HAART) was not used by 32% of the patients, 18.4% of the patients had CD4+ T- lymphocyte count less than 200 cells/mm³ and 96.8% of them were not aware of the modes of disease transmission. These findings led us to conclude that the study population is at high risk of clinical toxoplasmosis, because of both reactivation of infection in the seropositive patients who do not make a regular use of HAART, and primo-infection in seronegative patients worsened by an unawareness of the modes of infection reported in this study.

Yellow fever epizootics in non-human primates, São Paulo state, Brazil, 2008-2009

Since 2000, the expansion of Sylvatic Yellow Fever (YF) has been observed in the southeast of Brazil, being detected in areas considered silent for decades. Epizootics in non-human primates (NHPs) are considered sentinel events for the detection of human cases. It is important to report epizootic events that could have impact on the conservation status of susceptible species. We describe the epizootics in NHPs, notified in state of São Paulo, Brazil, between September 2008 to August 2009. Ninety-one epizootic events, involving 147 animals, were reported in 36 counties. Samples were obtained from 65 animals (44.2%). Most of the epizootics (46.6%) were reported between March and April, the same period during which human cases of YF occurred in the state. Biological samples were collected from animals found dead and were sent to Instituto Adolfo Lutz, in São Paulo. Two samples, collected in two counties without an indication for YF vaccination, were positive for the virus. Another 48 animals were associated with YF by clinical-epidemiological linkage with laboratory confirmed cases. Because the disease in human and NHPs occurred in the same period, the detection of the virus in NHPs did not work as sentinel, but aided in the delineation of new areas of risk.

SPATIOTEMPORAL TRENDS OF CASES OF PANDEMIC INFLUENZA A(H1N1)PDM09 IN ARGENTINA, 2009-2012

The aim of this paper was to analyze the spatiotemporal variations of cases of influenza A(H1N1)pdm09 in Argentina. A space-time permutation scan statistic was performed to test the non-randomness in the interaction between space and time in reported influenza A(H1N1)pdm09 cases. In 2009, two clusters were recorded in the east of Buenos Aires Province (May and June) and in the central and northern part of Argentina (July and August). Between 2011 and 2012, clusters near areas bordering other countries were registered. Within the clusters, in 2009, the high notification rates were first observed in the school-age population and then extended to the older population (15-59 years). From 2011 onwards, higher rates of reported cases of influenza A(H1N1)pdm09 occurred in children under five years in center of the country. Two stages of transmission of influenza A(H1N1)pdm09 can be characterized. The first stage had high rates of notification and a possible interaction with individuals from other countries in the major cities of Argentina (pattern of hierarchy), and the second stage had an increased interaction in some border areas without a clear pattern of hierarchy. These results suggest the need for greater coordination in the Southern Cone countries, in order to implement joint prevention and vaccination policies.

Efeitos da implantação da Usina Hidrelétrica de Rosal, Rio Itabapoana, Estados do Espírito Santo e Rio de Janeiro, sobre anofelinos, planorbídeos e flebotomíneos

A construção de represas geralmente causa modificações na composição da fauna em sua área de influência. Na área de implantação da Usina Hidrelétrica de Rosal, Estados do Espírito Santo e Rio de Janeiro, foram avaliadas modificações na abundância de anofelinos, planorbídeos e flebotomíneos antes (1998-2000) e após (2000-2005) o represamento. Foram definidos nove pontos de coleta, cada qual representado por uma moradia e seus anexos, abrigos de animais domésticos e coleções hídricas num raio de 150m. Coletaram-se 103 anofelinos adultos antes do represamento e 313 depois, 200 imaturos antes e 708 depois, 868 planorbídeos antes e 486 depois, e 2.979 flebotomíneos antes e 912 depois. O registro de vetores dentre anofelinos, planorbídeos e flebotomíneos revela o potencial da área para transmissão de malária, esquistossomose e leishmaniose tegumentar. As transformações ambientais ocorridas, no entanto, não aumentaram o risco para ocorrência dessas doenças.

Aedes aegypti e fauna associada em área rural de Manaus, na Amazônia brasileira

Após detectar larvas de Aedes aegypti em área rural de Manaus, realizou-se durante dois anos consecutivos um trabalho de notificação da ocorrência dessa espécie naquela área, através da vigilância entomológica, ferramenta que representa um importante papel entre as medidas preventivas contra doenças de transmissão por insetos em particular as arboviroses.

Hepatitis C virus and human T-lymphotropic virus coinfection: epidemiological, clinical, laboratory and histopathological features

Twenty-four hepatitis C virus patients coinfected with human T-lymphotropic virus type 1 were compared with six coinfected with HTLV-2 and 55 with HCV alone, regarding clinical, epidemiological, laboratory and histopathological data. Fischer's discriminant analysis was applied to define functions capable of differentiating between the study groups (HCV, HCV/HTLV-1 and HCV/HTLV-2). The discriminant accuracy was evaluated by cross-validation. Alcohol consumption, use of intravenous drugs or inhaled cocaine and sexual partnership with intravenous drug users were more frequent in the HCV/HTLV-2 group, whereas patients in the HCV group more often reported abdominal pain or a sexual partner with hepatitis. Coinfected patients presented higher platelet counts, but aminotransferase and gamma-glutamyl transpeptidase levels were higher among HCV-infected subjects. No significant difference between the groups was seen regarding liver histopathological findings. Through discriminant analysis, classification functions were defined, including sex, age group, intravenous drug use and sexual partner with hepatitis. Cross-validation revealed high discriminant accuracy for the HCV group.

Ocorrência de triatomíneos em ambientes silvestres e domiciliares do município de Manaus, Estado do Amazonas

A análise da distribuição de triatomíneos é essencial para a formulação de estratégias de controle da doença de Chagas na Região Amazônica. Neste trabalho, apresentam-se os resultados de capturas realizadas em ambientes silvestres e artificiais, em localidades rurais e urbanas de Manaus, Amazonas. Dos 115 triatomíneos coletados, 85 (73,9%) são da espécie Rhodnius pictipes, 25 (21,7%) de Rhodnius robustus e cinco (4,4%) de Panstrongylus geniculatus. A taxa de infecção natural por flagelados foi de 5,9% para Rhodnius pictipes e 8% para Rhodnius robustus. Nenhum exemplar de Panstrongylus geniculatus estava infectado. Todos os exemplares infectados eram oriundos de fragmentos de matas da zona urbana. Verificou-se que 106 (92,2%) triatomíneos foram coletados no ambiente silvestre e nove (7,8%) nas unidades domiciliares pela busca ativa. O gênero Rhodnius predominou nitidamente no ambiente silvestre. Os exemplares de Panstrongylus geniculatus, todos adultos, foram coletados no intradomicílio. Não foram encontrados indícios de colonização domiciliar por triatomíneos.