Monitoramento das Produções

by Kay M. Tomashek, Bridget Wills, Lucy Chai See Lum, Laurent Thomas, Anna Durbin, Yee-Sin Leo, Norma de Bosch, Elsa Rojas, Kim Hendrickx, Martin Erpicum, Liane Agulto, Thomas Jaenisch, Hasitha Tissera, Piyarat Suntarattiwong, Beth Ann Collers, Derek Wallace, Alexander C. Schmidt, Alexander Precioso, Federico Narvaez, Stephen J. Thomas, Robert Edelman, João Bosco Siqueira, M. Cristina Cassetti, Walla Dempsey, Duane J. Gubler

Dengue is a major public health problem worldwide. Although several drug candidates have been evaluated in randomized controlled trials, none has been effective and at present, early recognition of severe dengue and timely supportive care are used to reduce mortality. While the first dengue vaccine was recently licensed, and several other candidates are in late stage clinical trials, future decisions regarding widespread deployment of vaccines and/or therapeutics will require evidence of product safety, efficacy and effectiveness. Standard, quantifiable clinical endpoints are needed to ensure reproducibility and comparability of research findings. To address this need, we established a working group of dengue researchers and public health specialists to develop standardized endpoints and work towards consensus opinion on those endpoints. After discussion at two working group meetings and presentations at international conferences, a Delphi methodology-based query was used to finalize and operationalize the clinical endpoints. Participants were asked to select the best endpoints from proposed definitions or offer revised/new definitions, and to indicate whether contributing items should be designated as optional or required. After the third round of inquiry, 70% or greater agreement was reached on moderate and severe plasma leakage, moderate and severe bleeding, acute hepatitis and acute liver failure, and moderate and severe neurologic disease. There was less agreement regarding moderate and severe thrombocytopenia and moderate and severe myocarditis. Notably, 68% of participants agreed that a 50,000 to 20,000 mm3 platelet range be used to define moderate thrombocytopenia; however, they remained divided on whether a rapid decreasing trend or one platelet count should be case defining. While at least 70% agreement was reached on most endpoints, the process identified areas for further evaluation and standardization within the context of ongoing clinical studies. These endpoints can be used to harmonize data collection and improve comparability between dengue clinical trials.

by Sangshin Park, Anon Srikiatkhachorn, Siripen Kalayanarooj, Louis Macareo, Sharone Green, Jennifer F. Friedman, Alan L. Rothman
Background Early recognition of dengue, particularly patients at risk for plasma leakage, is important to clinical management. The objective of this study was to build predictive models for dengue, dengue hemorrhagic fever (DHF), and dengue shock syndrome (DSS) using structural equation modelling (SEM), a statistical method that evaluates mechanistic pathways. Methods/Findings We performed SEM using data from 257 Thai children enrolled within 72 h of febrile illness onset, 156 with dengue and 101 with non-dengue febrile illnesses. Models for dengue, DHF, and DSS were developed based on data obtained three and one day(s) prior to fever resolution (fever days -3 and -1, respectively). Models were validated using data from 897 subjects who were not used for model development. Predictors for dengue and DSS included age, tourniquet test, aspartate aminotransferase, and white blood cell, % lymphocytes, and platelet counts. Predictors for DHF included age, aspartate aminotransferase, hematocrit, tourniquet test, and white blood cell and platelet counts. The models showed good predictive performances in the validation set, with area under the receiver operating characteristic curves (AUC) at fever day -3 of 0.84, 0.67, and 0.70 for prediction of dengue, DHF, and DSS, respectively. Predictive performance was comparable using data based on the timing relative to enrollment or illness onset, and improved closer to the critical phase (AUC 0.73 to 0.94, 0.61 to 0.93, and 0.70 to 0.96 for dengue, DHF, and DSS, respectively). Conclusions Predictive models developed using SEM have potential use in guiding clinical management of suspected dengue prior to the critical phase of illness.

by Dulharie T. Wijeratne, Samitha Fernando, Laksiri Gomes, Chandima Jeewandara, Anushka Ginneliya, Supun Samarasekara, Ananda Wijewickrama, Clare S. Hardman, Graham S. Ogg, Gathsaurie Neelika Malavige
Background In order to understand the role of dengue virus (DENV) specific T cell responses that associate with protection, we studied their frequency and phenotype in relation to clinical disease severity and resolution of viraemia in a large cohort of patients with varying severity of acute dengue infection. Methodology/Principal findings Using ex vivo IFNγ ELISpot assays we determined the frequency of dengue viral peptide (DENV)-NS3, NS1 and NS5 responsive T cells in 74 adult patients with acute dengue infection and examined the association of responsive T cell frequency with the extent of viraemia and clinical disease severity. We found that total DENV-specific and DENV-NS3-specific T cell responses, were higher in patients with dengue fever (DF), when compared to those with dengue haemorrhagic fever (DHF). In addition, those with DF had significantly higher (p = 0.02) DENV-specific T cell responses on day 4 of infection compared to those who subsequently developed DHF. DENV peptide specific T cell responses inversely correlated with the degree of viraemia, which was most significant for DENV-NS3 specific T cell responses (Spearman’s r = -0.47, p = 0.0003). The frequency of T cell responses to NS1, NS5 and pooled DENV peptides, correlated with the degree of thrombocytopenia but had no association with levels of liver transaminases. In contrast, total DENV-IgG inversely correlated with the degree of thrombocytopenia and levels of liver transaminases. Conclusions/Significance Early appearance of DENV-specific T cell IFNγ responses before the onset of plasma leakage, appears to associate with milder clinical disease and resolution of viraemia, suggesting a protective role in acute dengue infection.

by Pei-Shi Yen, Fadila Amraoui, Anubis Vega Rúa, Anna-Bella Failloux

The recent yellow fever epidemic in Brazil has raised the concern of outbreaks in neighboring countries, particularly in the Caribbean region where the vector Aedes aegypti is predominant. This threat comes from the past when in the Americas, this disease caused devastating urban epidemics. We report the vector competence of Ae. aegypti from Guadeloupe for yellow fever virus by determining different parameters describing virus infection, dissemination, and transmission. The results indicate that Ae. aegypti Guadeloupe are susceptible to yellow fever virus with viral particles detected in mosquito saliva at 14 and 21 days post-infection. Local authorities and more broadly, international organizations should maintain the active surveillance of Aedes mosquitoes and the spreading of human cases from South America.

by Mathieu Bangert, Aishath Thimna Latheef, Shushil Dev Pant, Ibrahim Nishan Ahmed, Sana Saleem, Fathimath Nazla Rafeeq, Moomina Abdulla, Fathimath Shamah, Ahmed Jamsheed Mohamed, Christopher Fitzpatrick, Raman Velayudhan, Donald S. Shepard

As tourism is the mainstay of the Maldives’ economy, this country recognizes the importance of controlling mosquito-borne diseases in an environmentally responsible manner. This study sought to estimate the economic costs of dengue in this Small Island Developing State of 417,492 residents. The authors reviewed relevant available documents on dengue epidemiology and conducted site visits and interviews with public health offices, health centers, referral hospitals, health insurers, and drug distribution organizations. An average of 1,543 symptomatic dengue cases was reported annually from 2011 through 2016. Intensive waste and water management on a resort island cost $1.60 per occupied room night. Local vector control programs on inhabited islands cost $35.93 for waste collection and $7.89 for household visits by community health workers per person per year. Ambulatory care for a dengue episode cost $49.87 at a health center, while inpatient episodes averaged $127.74 at a health center, $1,164.78 at a regional hospital, and $1,655.50 at a tertiary referral hospital. Overall, the cost of dengue illness in the Maldives in 2015 was $2,495,747 (0.06% of gross national income, GNI, or $6.10 per resident) plus $1,338,141 (0.03% of GNI or $3.27 per resident) for dengue surveillance. With tourism generating annual income of $898 and tax revenues of $119 per resident, results of an international analysis suggest that the risk of dengue lowers the country’s gross annual income by $110 per resident (95% confidence interval $50 to $160) and its annual tax receipts by $14 per resident (95% confidence interval $7 to $22). Many innovative vector control efforts are affordable and could decrease future costs of dengue illness in the Maldives.

by Stefan W. Metz, Ashlie Thomas, Alex Brackbill, Yi Xianwen, Michele Stone, Katie Horvath, Michael J. Miley, Chris Luft, Joseph M. DeSimone, Shaomin Tian, Aravinda M. de Silva

Dengue virus (DENV) is the causative agent of dengue fever and dengue hemorrhagic shock syndrome. Dengue vaccine development is challenging because of the need to induce protection against four antigenically distinct DENV serotypes. Recent studies indicate that tetravalent DENV vaccines must induce balanced, serotype-specific neutralizing antibodies to achieve durable protective immunity against all 4 serotypes. With the leading live attenuated tetravalent DENV vaccines, it has been difficult to achieve balanced and type-specific responses to each serotype, most likely because of unbalanced replication of vaccine viral strains. Here we evaluate a tetravalent DENV protein subunit vaccine, based on recombinant envelope protein (rE) adsorbed to the surface of poly (lactic-co-glycolic acid) (PLGA) nanoparticles for immunogenicity in mice. In monovalent and tetravalent formulations, we show that particulate rE induced higher neutralizing antibody titers compared to the soluble rE antigen alone. Importantly, we show the trend that tetravalent rE adsorbed to nanoparticles stimulated a more balanced serotype specific antibody response to each DENV serotype compared to soluble antigens. Our results demonstrate that tetravalent DENV subunit vaccines displayed on nanoparticles have the potential to overcome unbalanced immunity observed for leading live-attenuated vaccine candidates.

Title: Dengue virus capsid protein usurps lipid droplets for viral particle formation
Authors: Samsa, Marcelo M.; Mondotte, Juan A.; Iglesias, Nestor G.; Assunção-Miranda, Iranaia; Lima, Giselle Barbosa; Da Poian, Andrea T.; Bozza, Patricia T.; Gamarnik, Andrea V.

Title: Multiplex cytokine profile from dengue patients: MIP-1beta and IFN-gamma as predictive factors for severity
Authors: Bozza, Fernando A.; Cruz, Oswaldo G.; Zagne, Sonia M. O.; Azeredo, Elzinandes L.; Nogueira, Rita M. R.; Assis, Edson F.; Bozza, Patricia T.; Kubelka, Claire F.

Title: Dengue-2 infection and the induction of apoptosis in human primary monocytes
Authors: Torrentes-Carvalho, Amanda; Azeredo, Elzinandes L.; Reis, Sonia R. I.; Miranda, Alessandro S.; Gandini, Mariana; Barbosa, Luciana S.; Kubelka, Claire F.

by Cheng-Fen Yang, Shu-Fen Chang, Tung-Chien Hsu, Chien-Ling Su, Tzy-Chen Wang, Shih-Hung Lin, Su-Lin Yang, Chien-Chou Lin, Pei-Yun Shu

A total of 1,596 laboratory-confirmed imported dengue cases were identified in Taiwan during 2011–2016. Most of the imported cases arrived from Southeast Asia as well as the Indian subcontinent, the Pacific region, Latin America, Australia and Africa. Phylogenetic analyses of the complete envelope protein gene sequences from 784 imported dengue virus (DENV) isolates were conducted, and the results suggest that the DENV-1 genotype I and DENV-2 Cosmopolitan genotype comprise the predominant serotype/genotype of DENV strains circulating in Southeast Asia. The DENV-1 genotype III, DENV-3 genotype III and DENV-4 genotype I and II strains were found to be newly emerging in several Southeast Asian countries. Our results also showed that geographical restrictions of DENV-1 genotype I, DENV-1 genotype III and DENV-2 Cosmopolitan genotype are becoming blurred, indicating the extensive introductions and continuous expansions of DENV strains between nations in Southeast Asia. In this study, we present the geographic distribution and dynamic transmission of DENV strains circulating in Southeast Asian countries. In addition, we demonstrated local dengue epidemics caused by several imported DENV strains in Taiwan during 2011–2016.

by Naoki Yanagisawa, Koji Wada, John D. Spengler, Ramon Sanchez-Pina
Background Participants in mass gathering events are at risk of acquiring imported and locally endemic infectious diseases. The 2014 dengue outbreak in Tokyo gathered attention since it was the first time in 70 years for Japan to experience an autochthonous transmission. Preparation for emerging infectious threats is essential even in places where these outbreaks have been largely unknown. The aim of this study is to identify strategies for early detection and prevention of dengue infection during the 2020 summer Olympics and Paralympics in Tokyo. Methodology/Principal findings We modified and adapted the failure mode and effect analysis (FMEA) methodology, generally used in industrial manufacturing, to examine the current controls for dengue detection and assessment. Information on existing controls were obtained from publicly available resources. Our analysis revealed that the national infectious disease control system to detect dengue in Japan is robust. However, in the case of large assemblies of international visitors for special events when the spread of communicable and vector-borne diseases increases, there are three main gaps that could be reinforced. First, cyclical training or a certification program on tropical disease management is warranted for physicians, especially those working in non-infectious disease-designated hospitals or clinics. Second, multi-language communication methods need to be strengthened especially in the health and hospitality sector. Third, owners of accommodations should consider incorporating a formal tropical disease-training program for their staff members and have a contingency plan for infectious disease-suspected travelers. Conclusions/Significance Our findings may facilitate physicians and public health officials where new controls would be beneficial for the 2020 summer Olympics and Paralympics. The FMEA framework has the potential to be applied to other infectious diseases, not just dengue.

by Jeyanthi Suppiah, Siew-Mooi Ching, Syafinaz Amin-Nordin, Lailatul-Akmar Mat-Nor, Naematul-Ain Ahmad-Najimudin, Gary Kim-Kuan Low, Manisya-Zauri Abdul-Wahid, Ravindran Thayan, Hui-Yee Chee
Background Malaysia experienced an unprecedented dengue outbreak from the year 2014 to 2016 that resulted in an enormous increase in the number of cases and mortality as compared to previous years. The causes that attribute to a dengue outbreak can be multifactorial. Viral factors, such as dengue serotype and genotype, are the components of interest in this study. Although only a small number of studies investigated the association between the serotype of dengue virus and clinical manifestations, none of these studies included analyses on dengue genotypes. The present study aims to investigate dengue serotype and genotype-specific clinical characteristics among dengue fever and severe dengue cases from two Malaysian tertiary hospitals between 2014 and mid-2017. Methodology and principal findings A total of 120 retrospective dengue serum specimens were subjected to serotyping and genotyping by Taqman Real-Time RT-PCR, sequencing and phylogenetic analysis. Subsequently, the dengue serotype and genotype data were statistically analyzed for 101 of 120 corresponding patients’ clinical manifestations to generate a descriptive relation between the genetic components and clinical outcomes of dengue infected patients. During the study period, predominant dengue serotype and genotype were found to be DENV 1 genotype I. Additionally, non-severe clinical manifestations were commonly observed in patients infected with DENV 1 and DENV 3. Meanwhile, patients with DENV 2 infection showed significant warning signs and developed severe dengue (p = 0.007). Cases infected with DENV 2 were also commonly presented with persistent vomiting (p = 0.010), epigastric pain (p = 0.018), plasma leakage (p = 0.004) and shock (p = 0.038). Moreover, myalgia and arthralgia were highly prevalent among DENV 3 infection (p = 0.015; p = 0.014). The comparison of genotype-specific clinical manifestations showed that DENV 2 Cosmopolitan was significantly common among severe dengue patients. An association was also found between genotype I of DENV 3 and myalgia. In a similar vein, genotype III of DENV 3 was significantly common among patients with arthralgia. Conclusion The current data contended that different dengue serotype and genotype had caused distinct clinical characteristics in infected patients.

by Jehangir Khan, Abdul Ghaffar, Shujaat Ali Khan

Title: Análise da imunogenicidade e grau de proteção de uma vacina inativada para febre amarela em modelo murino
Authors: Pereira, Renata Carvalho; Rangel, Andréa Nazaré M.; Souza, Marta Cristina de O.; Simôes, Marisol; Gaspar, Luciane P.; Caride, Elena; Galler, Ricardo

by Ana Paula Abílio, Gastão Abudasse, Ayubo Kampango, Baltazar Candrinho, Salomão Sitoi, Jacinta Luciano, Dário Tembisse, Samira Sibindy, António Paulo Gouveia de Almeida, Gabriela Azambuja Garcia, Mariana Rocha David, Rafael Maciel-de-Freitas, Eduardo Samo Gudo
Background Aedes-borne arboviruses have emerged as an important public health problem worldwide and, in Mozambique, the number of cases and its geographical spread have been growing. However, information on the occurrence, distribution and ecology of Aedes aegypti and Ae. albopictus mosquitoes remain poorly known in the country. Methods Between March and April 2016, a cross-sectional study was conducted in 32 districts in Mozambique to determine the distribution and breeding sites of Ae. aegypti and Ae. albopictus. Larvae and pupae were collected from a total of 2,807 water-holding containers using pipette, dipper, funnel and sweeping procedures, depending on the container type and location. Both outdoor and indoor water-holding containers were inspected. The immature forms were reared to adults and the identifications of the mosquito species was carried out with a stereomicroscope using a taxonomic key. Results Aedes aegypti was found in every district sampled, while Ae. albopictus was only found in Moatize district, situated in Tete Province in the central part of the country. Six hundred and twenty-eight of 2,807 (22.4%) containers were positive for Ae. aegypti but only one (0.03%) was positive for Ae. albopictus. The Container Index (CI) of Aedes was highest in densely populated suburban areas of the central region (260/604; 43.0%), followed by suburban areas in northern areas (228/617; 36.9%) whilst the lowest proportion was found in urbanized southern areas (140/1586; 8.8%). The highest CI of Aedes was found in used tires (448/1268; 35.3%), cement tanks (20/62; 32.3%) and drums (21/95; 22.1%). Conclusion Data from our study showed that Ae. aegypti is present nation-wide, since it occurred in every sampled district, whilst Ae. albopictus had a limited distribution. Therefore, the risk of transmission of dengue and chikungunya is likely to have been underestimated in Mozambique. This study highlights the need for the establishment of a national entomological surveillance program for Aedes spp. in Mozambique in order to gain a better understanding about vector bionomics and to support the development of informed effective vector control strategies.

by Minu Bharati, Dhiraj Saha
Background Mosquitoes belonging to genus Aedes are the prime vectors of several arboviral diseases such as Dengue, Zika and Chikungunya worldwide. Every year numerous cases of dengue infections occur throughout the world, proper control of which depends on efficient vector control. However the onset of insecticide resistance has resulted in failure of vector control approaches. Principal findings This study was carried out to unveil the degree of prevailing insecticide resistance along with its underlying mechanisms among the primary dengue vector in dengue endemic districts of West Bengal, India through standard WHO protocol. It was observed that, the majority of the tested populations were found to possess resistance to more than one insecticide. In adult bioassay, the toxicity levels of the six tested insecticides was found to decrease in the following order: deltamethrin > lambdacyhalothrin > malathion > propoxur > permethrin > DDT. In larval bioassay, one of the tested populations was found to possess moderate resistance against temephos, mortality percentage 92.5% and 79.8% for WHO (0.0200 ppm) and National Vector Borne disease Programme, India recommended dose (0.0125 ppm) respectively. Carboxylesterases were found to be involved in conferring resistance as revealed in synergistic and quantitative assay against temephos in North Dinajpur (NDP) population and malathion in Alipurduar (APD) and Darjeeling (DAR) populations. Similar correlations were also observed in the majority of the tested populations between reduced susceptibilities against pyrethroid insecticides and Cytochrome P450s activity. Conclusion Efficient disease management in this region can only be achieved through proper integrated vector management along with tools to minimize insecticide resistance. This study may help the concerned authorities in the formulation of an effective vector control strategy throughout this region incorporating the knowledge gained through this study.

by Chen Chen, Dong Jiang, Ming Ni, Jing Li, Zhihai Chen, Jingyuan Liu, Hanhui Ye, Gary Wong, Wei Li, Yuanyuan Zhang, Beibei Wang, Yuhai Bi, Danying Chen, Ping Zhang, Xuesen Zhao, Yaxian Kong, Weifeng Shi, Pengcheng Du, Gengfu Xiao, Juncai Ma, George F. Gao, Jie Cui, Fujie Zhang, Wenjun Liu, Xiaochen Bo, Ang Li, Hui Zeng, Di Liu

The yellow fever virus (YFV) recently reemerged in the large outbreaks in Africa and Brazil, and the first imported patients into Asia have recalled the concerns of YFV evolution. Here we show phylogenomics of YFV with serial clinical samples of the 2016 YFV infections. Phylogenetics exhibited that the 2016 strains were close to Angola 1971 strains and only three amino acid changes presented new to other lineages. Deep sequencing of viral genomes discovered 101 intrahost single nucleotide variations (iSNVs) and 234 single nucleotide polymorphisms (SNPs). Analysis of iSNV distribution and mutated allele frequency revealed that the coding regions were under purifying selection. Comparison of the evolutionary rates estimated by iSNV and SNP showed that the intrahost rate was ~2.25 times higher than the epidemic rate, and both rates were higher than the long-term YFV substitution rate, as expected. In addition, the result also hinted that short viremia duration of YFV might further hinder the evolution of YFV.

Title: Contribuição ao estudo da infecção pelos vírus da dengue tipo 1, 2 e 3, no Estado do Rio de Janeiro
Authors: Souza, Rogerio Valls de
Abstract: Essa tese é composta de uma revisão da literatura que aborda aspectos históricos, da circulação desses arbovírus no mundo e no Brasil, informações sobre a epidemiologia e biologia molecular dos vírus Dengue e procura situar o estado atual do conhecimento relativo à imunopatogenia e às manifestações clínicas das diferentes formas de apresentação da doença. Quatro artigos descritos seguir são a principal contribuição: 1) Dengue virus surveillance: the co-circulation of DENV-1, DENV-2 and DENV-3 in the State of Rio de Janeiro, Brazil. Esse artigo resulta da atividade de vigilância epidemiológica realizada em colaboração com Laboratório de Flavivírus do Instituto Oswaldo Cruz na área metropolitana do Rio de Janeiro, onde são caracterizadas 5.324 amostras de casos suspeitos de infecção por vírus dengue nos anos 2000-2001. Detectamos a circulação de DENV-1, DENV-2 e DENV-3. A técnica da reação em cadeia da polimerase após restrição sítio-específico demonstrou que os vírus DENV-1 e DENV-2 pertenciam aos mesmos genótipos das epidemias de 1986-1987 e 1990-1991, respectivamente. Em relação à DENV-3, confirma a circulação de cepa proveniente do subcontinente indiano. São também descritos sinais de maior gravidade associados à circulação de DENV-3, quando comparados à DENV-1 e DENV-2. 2) Inducible nitric oxide synthetase (iNOS) expression in monocytes during acute Dengue Fever in patients and during in vitro infection Esse artigo é uma contribuição original ao estudo do papel do óxido nítrico (NO) na resposta imune ao DENV-1. Observa-se a expressão de óxido nítrico sintetase induzível (iNOS) em monócitos de pacientes com febre da dengue, através da citometria de fluxo. A mesma metodologia detectou antígeno de vírus Dengue em monócitos humanos até 3 dias após infecção in vitro. Os monócitos apresentaram aumento da produção de iNOS, de maneira inversamente proporcional à redução do antígeno viral. Demonstramos que doadores de NO como o Nitroprussiato de Sódio, reduzem a detecção de antígeno viral pós-infecção, enquanto inibidores da produção de NO como a NG-metil L arginina aumentam a proporção de células C6/36 infectadas. Esses dados demonstram o papel dos monócitos na produção de NO, assim como a sua importância no controle da replicação viral. 3) Correlation of serum neopterin levels with disease severity in dengue patients. Esse artigo compara as dosagens séricas de neopterina em três momentos: fase aguda, defervescência da febre e convalescença, em três grupos de pacientes, i.e., pacientes com dengue grave, pacientes com febre da dengue e controles sadios, estabelece a cinética de neopterina nesses três grupos Demonstra que na fase aguda pacientes com dengue grave ou não apresentam níveis elevados de neopterina em relação aos controles, enquanto na convalescência os pacientes com dengue grave permanecem com níveis elevados. Na fase de defervescência definida como o intervalo entre 6-10 dias de doença observamos que, em especial nesse período, os pacientes graves podem ser discriminados dos casos de febre da dengue e dos controles sadios. Esses resultados demonstram pela primeira vez a cinética da neopterina em pacientes com diferentes níveis de gravidade de doença. 4) Aspectos clínicos e laboratoriais relacionados à introdução de Dengue 1, 2 e 3, no Estado do Rio de Janeiro. Esse estudo descreve as manifestações clínicas e laboratoriais observadas em três períodos epidêmicos, relacionados à introdução dos vii sorotipos endêmicos no Brasil. Demonstramos que com a introdução de DENV-2 e DENV-3, houve uma maior freqüência de manifestações clínicas associadas à gravidade como vômitos, dor abdominal e hemorragias, acompanhadas de alterações laboratoriais sugestivas de um comprometimento sistêmico maior, traduzido pela maior intensidade das alterações das provas de função hepática e trombocitopenia. O estudo da resposta imunológica demonstrou uma associação da resposta secundária com esse perfil de agravamento nas infecções por DENV-2, porém, no período de circulação de DENV-3, observamos uma maior freqüência de vômitos, dor abdominal, elevação de transaminases, leucopenia, trombocitopenia em pacientes com resposta imune primária. Esses dados confirmam o agravamento do perfil clínico e laboratorial da doença associada à introdução de DENV-2 e DENV-3 e demonstra o potencial patogênico de DENV-3, mesmo em infecções primárias por flavivírus.

Title: Contribuição ao estudo da infecção pelos vírus da dengue tipo 1, 2 e 3, no Estado do Rio de Janeiro /
Authors: Souza, Rogerio Valls de
Abstract: Essa tese é composta de uma revisão da literatura que aborda aspectos históricos, da circulação desses arbovírus no mundo e no Brasil, informações sobre a epidemiologia e biologia molecular dos vírus Dengue e procura situar o estado atual do conhecimento relativo à imunopatogenia e às manifestações clínicas das diferentes formas de apresentação da doença. Quatro artigos descritos seguir são a principal contribuição: 1) Dengue virus surveillance: the co-circulation of DENV-1, DENV-2 and DENV-3 in the State of Rio de Janeiro, Brazil. Esse artigo resulta da atividade de vigilância epidemiológica realizada em colaboração com Laboratório de Flavivírus do Instituto Oswaldo Cruz na área metropolitana do Rio de Janeiro, onde são caracterizadas 5.324 amostras de casos suspeitos de infecção por vírus dengue nos anos 2000-2001. Detectamos a circulação de DENV-1, DENV-2 e DENV-3. A técnica da reação em cadeia da polimerase após restrição sítio-específico demonstrou que os vírus DENV-1 e DENV-2 pertenciam aos mesmos genótipos das epidemias de 1986-1987 e 1990-1991, respectivamente. Em relação à DENV-3, confirma a circulação de cepa proveniente do subcontinente indiano. São também descritos sinais de maior gravidade associados à circulação de DENV-3, quando comparados à DENV-1 e DENV-2. 2) Inducible nitric oxide synthetase (iNOS) expression in monocytes during acute Dengue Fever in patients and during in vitro infection Esse artigo é uma contribuição original ao estudo do papel do óxido nítrico (NO) na resposta imune ao DENV-1. Observa-se a expressão de óxido nítrico sintetase induzível (iNOS) em monócitos de pacientes com febre da dengue, através da citometria de fluxo. A mesma metodologia detectou antígeno de vírus Dengue em monócitos humanos até 3 dias após infecção in vitro. Os monócitos apresentaram aumento da produção de iNOS, de maneira inversamente proporcional à redução do antígeno viral. Demonstramos que doadores de NO como o Nitroprussiato de Sódio, reduzem a detecção de antígeno viral pós-infecção, enquanto inibidores da produção de NO como a NG-metil L arginina aumentam a proporção de células C6/36 infectadas. Esses dados demonstram o papel dos monócitos na produção de NO, assim como a sua importância no controle da replicação viral. 3) Correlation of serum neopterin levels with disease severity in dengue patients. Esse artigo compara as dosagens séricas de neopterina em três momentos: fase aguda, defervescência da febre e convalescença, em três grupos de pacientes, i.e., pacientes com dengue grave, pacientes com febre da dengue e controles sadios, estabelece a cinética de neopterina nesses três grupos Demonstra que na fase aguda pacientes com dengue grave ou não apresentam níveis elevados de neopterina em relação aos controles, enquanto na convalescência os pacientes com dengue grave permanecem com níveis elevados. Na fase de defervescência definida como o intervalo entre 6-10 dias de doença observamos que, em especial nesse período, os pacientes graves podem ser discriminados dos casos de febre da dengue e dos controles sadios. Esses resultados demonstram pela primeira vez a cinética da neopterina em pacientes com diferentes níveis de gravidade de doença. 4) Aspectos clínicos e laboratoriais relacionados à introdução de Dengue 1, 2 e 3, no Estado do Rio de Janeiro. Esse estudo descreve as manifestações clínicas e laboratoriais observadas em três períodos epidêmicos, relacionados à introdução dos vii sorotipos endêmicos no Brasil. Demonstramos que com a introdução de DENV-2 e DENV-3, houve uma maior freqüência de manifestações clínicas associadas à gravidade como vômitos, dor abdominal e hemorragias, acompanhadas de alterações laboratoriais sugestivas de um comprometimento sistêmico maior, traduzido pela maior intensidade das alterações das provas de função hepática e trombocitopenia. O estudo da resposta imunológica demonstrou uma associação da resposta secundária com esse perfil de agravamento nas infecções por DENV-2, porém, no período de circulação de DENV-3, observamos uma maior freqüência de vômitos, dor abdominal, elevação de transaminases, leucopenia, trombocitopenia em pacientes com resposta imune primária. Esses dados confirmam o agravamento do perfil clínico e laboratorial da doença associada à introdução de DENV-2 e DENV-3 e demonstra o potencial patogênico de DENV-3, mesmo em infecções primárias por flavivírus

by Irma Sánchez-Vargas, Laura C. Harrington, Jeffrey B. Doty, William C. Black 4th, Ken E. Olson

Aedes aegypti is the primary mosquito vector of dengue viruses (DENV; serotypes 1–4). Human-mosquito transmission cycles maintain DENV during epidemics but questions remain regarding how these viruses survive when human infections and vector abundance are minimal. Aedes mosquitoes can transmit DENV within the vector population through two alternate routes: vertical and venereal transmission (VT and VNT, respectively). We tested the efficiency of VT and VNT in a genetically diverse laboratory (GDLS) strain of Ae. aegypti orally infected with DENV2 (Jamaica 1409). We examined F1 larvae from infected females generated during the first and second gonotrophic cycles (E1 and E2) for viral envelope (E) antigen by amplifying virus in C6/36 cells and then performing an indirect immunofluorescence assay (IFA). RT-PCR/nested PCR analyses confirmed DENV2 RNA in samples positive by IFA. We observed VT of virus to larvae and adult male progeny and VNT of virus to uninfected virgin females after mating with males that had acquired virus by the VT route. We detected no DENV2 in 30 pools (20 larvae/pool) of F1 larvae following the first gonotrophic cycle, suggesting limited virus dissemination at 7 days post-infection. DENV2 was detected by IFA in 27 of 49 (55%) and 35 of 51 (68.6%) F1 larval pools (20 larvae/pool) from infected E2 females that received a second blood meal without virus at 10 or 21 days post-infection (E2-10d-F1 and E2-21-F1), respectively. The minimum filial infection rates by IFA for E2-10d-F1 and E2-21d-F1 mosquitoes were 1:36 and 1:29, respectively. The VNT rate from E2-10d-F1 males to virgin (uninfected) GDLS females was 31.6% (118 of 374) at 8 days post mating. Twenty one percent of VNT-infected females receiving a blood meal prior to mating had disseminated virus in their heads, suggesting a potential pathway for virus to re-enter the human-mosquito transmission cycle. This is the first report of VNT of DENV by male Ae. aegypti and the first demonstration of sexual transmission in Aedes by naturally infected males. Our results demonstrate the potential for VT and VNT of DENV in nature as mechanisms for virus maintenance during inter-epidemic periods.

by Caroline T. Weldon, Amy R. Riley-Powell, Ines M. Aguerre, Rosa A. Celis Nacimento, Amy C. Morrison, Richard A. Oberhelman, Valerie A. Paz-Soldan

Zika virus was reported in the rainforest city of Iquitos, Peru in 2016. The potential associations between Zika and fetal neurological disorders were reported extensively in the media regarding neighboring Brazil, and led to great concern about the impact Zika could have on people’s health in Iquitos when it arrived. The aim of this study was to explore the knowledge, attitudes, and preventative practices related to Zika virus and its transmission among women of childbearing age in Iquitos, Peru. Six focus group discussions with 46 women of ages 20–35 from an Iquitos district with confirmed Zika cases were conducted to explore: 1) knowledge of Zika transmission, its symptoms, and treatment, 2) attitudes regarding Zika, including perceptions of risk for and severity of Zika, and 3) preventative practices, including awareness of health promotion activities. Participants were knowledgeable about Zika symptoms and knew it was transmitted by mosquitoes, and about half had heard about the association between Zika and microcephaly, but most lacked knowledge about the associated neurological disorders in adults, its sexual transmission, and ways to prevent infection. They expressed concern for pregnant women exposed to the virus and the impact on the fetus. Participants felt at risk of contracting the Zika virus, yet had not changed preventive practices, possibly in part because their perception of the severity of this disease was low. This study reveals knowledge gaps that could be addressed via health promotion messages that might improve prevention practices to help community members protect themselves from Zika virus during this outbreak.

by Cinthy L. Jiménez-Silva, María Fernanda Carreño, Ayda Susana Ortiz-Baez, Luz Aida Rey, Christian Julián Villabona-Arenas, Raquel E. Ocazionez

Dengue is a prevalent disease in Colombia and all dengue virus serotypes (DENV-1 to -4) co-circulate in the country since 2001. However, the relative impact of gene flow and local diversification on epidemic dynamics is unknown due to heterogeneous sampling and lack of sufficient genetic data. The region of Santander is one of the areas with the highest incidence of dengue in Colombia. To provide a better understanding of the epidemiology of dengue, we inferred DENV population dynamics using samples collected between 1998 and 2015. We used Bayesian phylogenetic analysis and included 143 new envelope gene sequences from Colombia, mainly from the region of Santander, and 235 published sequences from representative countries in the Americas. We documented one single genotype for each serotype but multiple introductions. Whereas the majority of DENV-1, DENV-2, and DENV-4 strains fell into one single lineage, DENV-3 strains fell into two distinct lineages that co-circulated. The inferred times to the most recent common ancestors for the most recent clades of DENV-1, DENV-2, and DENV-4 fell between 1977 and 1987, and for DENV-3 was around 1995. Demographic reconstructions suggested a gradual increase in viral diversity over time. A phylogeographical analysis underscored that Colombia mainly receives viral lineages and a significant diffusion route between Colombia and Venezuela. Our findings contribute to a better understanding of the viral diversity and dengue epidemiology in Colombia.

by Freek Cox, Leslie van der Fits, Peter Abbink, Rafael A. Larocca, Ella van Huizen, Eirikur Saeland, Janneke Verhagen, Rebecca Peterson, Jeroen Tolboom, Baerbel Kaufmann, Hanneke Schuitemaker, Dan H. Barouch, Roland Zahn

In 2015, there was a large outbreak of Zika virus (ZIKV) in Brazil. Despite its relatively mild impact on healthy adults, ZIKV infection during pregnancy has been associated with severe birth defects. Currently, there is no ZIKV vaccine available, but several vaccine candidates based on the ZIKV membrane (M) and envelope (Env) structural proteins showed promising results in preclinical and clinical studies. Here, the immunogenicity and protective efficacy of a non-replicating adenoviral vector type 26 (Ad26) that encodes the ZIKV M-Env antigens (Ad26.ZIKV.M-Env) was evaluated in mice and non-human primates (NHP). Ad26.ZIKV.M-Env induced strong and durable cellular and humoral immune responses in preclinical models. Humoral responses were characterized by Env-binding and ZIKV neutralizing antibody responses while cellular responses were characterized by ZIKV reactive CD4+ and CD8+ T cells. Importantly, a single immunization with a very low dose of 4x107 vp of Ad26.ZIKV.M-Env protected mice from ZIKV challenge. In NHP, a single immunization with a typical human dose of 1x1011 vp of Ad26.ZIKV.M-Env also induced Env-binding and ZIKV neutralizing antibodies and Env and M specific cellular immune responses that associated with complete protection against viremia from ZIKV challenge as measured in plasma and other body fluids. Together these data provide the rationale to progress the Ad26.ZIKV.M-Env candidate vaccine to clinical testing.

by Blanka Tesla, Leah R. Demakovsky, Hannah S. Packiam, Erin A. Mordecai, Américo D. Rodríguez, Matthew H. Bonds, Melinda A. Brindley, Courtney C. Murdock

Zika virus (ZIKV) is an arbovirus primarily transmitted by Aedes mosquitoes. Like most viral infections, ZIKV viremia varies over several orders of magnitude, with unknown consequences for transmission. To determine the effect of viral concentration on ZIKV transmission risk, we exposed field-derived Ae. aegypti mosquitoes to four doses (103, 104, 105, 106 PFU/mL) representative of potential variation in the field. We demonstrate that increasing ZIKV dose in the blood-meal significantly increases the probability of mosquitoes becoming infected, and consequently disseminating virus and becoming infectious. Additionally, we observed significant interactions between dose and days post-infection on dissemination and overall transmission efficiency, suggesting that variation in ZIKV dose affects the rates of midgut escape and salivary gland invasion. We did not find significant effects of dose on mosquito mortality. We also demonstrate that detecting virus using RT-qPCR approaches rather than plaque assays potentially over-estimates key transmission parameters, including the time at which mosquitoes become infectious and viral burden. Finally, using these data to parameterize an R0 model, we showed that increasing viremia from 104 to 106 PFU/mL increased relative R0 3.8-fold, demonstrating that variation in viremia substantially affects transmission risk.

by Priscila Fernandes Viana Medeiros, Diogo Fernandes Bellinato, Denise Valle
Background Resistance to pyrethroids and to the organophosphate temephos is widespread in Brazilian populations of the dengue vector, Aedes aegypti. Thereof, since 2009 Insect Growth Regulators are employed as larvicides, and malathion is used against adults. Methodology/Principal findings We performed laboratory selection with malathion of two A. aegypti field populations initially susceptible to this organophosphate but resistant to temephos and deltamethrin. A fixed malathion dose inducing at least 80% mortality in the first generation, was used throughout the selection process, interrupted after five generations, when the threshold of 20% mortality was reached. For each population, three experimental and two control groups, not exposed to insecticides, were kept independently. For both populations, quantitative bioassays revealed, in the selected groups, acquisition of resistance to malathion and negative impact of malathion selection on deltamethrin and temephos resistance levels. In the control groups resistance to all evaluated insecticides decreased except, unexpectedly, to deltamethrin. Analysis of the main resistance mechanisms employed routine methodologies: biochemical and molecular assays for, respectively, metabolic resistance and quantification of the NaV pyrethroid target main kdr mutations at positions 1016 and 1534. No diagnostic alteration could be specifically correlated with malathion selection, neither with the unusual deltamethrin increase in resistance levels observed in the control groups. Conclusions/Significance Our results confirm the multifactorial character of insecticide resistance and point to the need of high throughput methodologies and to the study of additional field vector populations in order to unravel resistance mechanisms.

by Jo-Chi Kao, Wei-Chun HuangFu, Tsung-Ting Tsai, Min-Ru Ho, Ming-Kai Jhan, Ting-Jing Shen, Po-Chun Tseng, Yung-Ting Wang, Chiou-Feng Lin
Background The antiparasitic agent niclosamide has been demonstrated to inhibit the arthropod-borne Zika virus. Here, we investigated the antiviral capacity of niclosamide against dengue virus (DENV) serotype 2 infection in vitro and in vivo. Principle finding Niclosamide effectively retarded DENV-induced infection in vitro in human adenocarcinoma cells (A549), mouse neuroblastoma cells (Neuro-2a), and baby hamster kidney fibroblasts (BHK-21). Treatment with niclosamide did not retard the endocytosis of DENV while niclosamide was unable to enhance the antiviral type I interferon response. Furthermore, niclosamide did not cause a direct effect on viral replicon-based expression. Niclosamide has been reported to competitively inhibit the mTOR (mammalian target of rapamycin), STAT3 (signal transducer and activator of transcription 3), and NF-κB (nuclear factor kappa-light-chain-enhancer of activated B cells) signaling pathways; however, selective inhibitors of those pathways did not reduce DENV infection. Similar to the vacuolar-type H+-ATPase inhibitor bafilomycin A1, both niclosamide and other protonophores, such as CCCP (carbonyl cyanide m-chlorophenyl hydrazone), and FCCP (carbonyl cyanide-p-trifluoromethoxyphenylhydrazone), effectively reduced endosomal acidification and viral dsRNA replication. Co-administration of a single dose of niclosamide partially decreased viral replication, viral encephalitis, and mortality in DENV-infected ICR suckling mice. Significance These results demonstrate that niclosamide diminishes viral infection by hindering endosomal acidification.

by Li-Teh Liu, Tenneth Dalipanda, Rooney Jagilly, Ying-Hui Wang, Ping-Chang Lin, Ching-Yi Tsai, Wen-Ter Lai, Jih-Jin Tsai

Dengue virus (DENV) infection causes various clinical presentations, including asymptomatic infection, dengue with or without warning signs and severe dengue. An early and accurate diagnosis of DENV infection during the first few days of illness supports clinical management and significantly reduces dengue-associated mortality and morbidity. However, it is very difficult to confirm DENV infection in endemic regions without qualified dengue diagnostic laboratories. In this study, we evaluated the performance of two commercially available rapid diagnostic tests (RDTs) using serum samples collected in the Solomon Islands during the 2013 DENV-3 outbreak. The sensitivity and specificity of the tests were calculated by comparing the results of DENV nonstructural protein 1 (NS1), IgM and IgG RDTs with those obtained by qRT-PCR. We also compared the results of the DENV IgM/IgG RDT with those obtained using an IgM/IgG capture enzyme-linked immune-sorbent assay (ELISA). The sensitivities of the SD and CTK NS1 RDTs were similar (90.9% and 92.6%), and the specificity of the SD NS1 RDT was significantly higher than that of the CTK NS1 RDT (100% versus 78.8%). The inclusion of IgM and IgG in the RDT did not significantly increase the sensitivity for DENV diagnosis. Compared with the SD IgM RDT, IgM capture ELISA had the same specificity but higher sensitivity. User-friendly RDTs remain the first choice and the most convenient tool in dengue endemic regions, where laboratory facilities and the corresponding infrastructure are lacking. Our study provided important and practical information for comparing the performance and validity of the different RDTs for rapid dengue detection.

by Ana C. Carro, Luana E. Piccini, Elsa B. Damonte
Background Dengue is the most prevalent arthropod-borne viral human disease in tropical and subtropical regions, caused by four dengue virus (DENV) serotypes. In spite of the increasing global incidence, no specific antiviral therapy is available. Cells of the mononuclear phagocyte lineage are the main targets either for direct antibody (Ab)-independent or Ab-mediated human DENV infection, usually associated to the severe forms of disease. Since the virus entry may be a convenient therapeutic alternative, this study aimed to investigate the mode of DENV internalization into myeloid cells in the absence and presence of DENV Ab and evaluate the inhibitory activity of diverse biochemical inhibitors of endocytosis. Methodology/principal findings By infectivity assays and quantitative RT-PCR determinations, it was demonstrated that DENV-2 entry into U937 and K562 cells in the absence of Ab was highly inhibited by the early treatment with ammonium chloride, chlorpromazine and dynasore, but it was not affected by methyl-β-cyclodextrin, indicating that DENV-2 utilizes a low pH-dependent, clathrin- and dynamin-mediated endocytic infectious pathway for the direct entry into both human myeloid cells. To study the Ab-mediated entry of DENV, the experimental conditions for enhancement of infection were established by inoculating immune complexes formed with DENV-2 and the Ab 2H2 or 3H5. The internalization of DENV-2-2H2 or DENV-2-3H5 complexes in both myeloid cells was also dependent on acid pH and dynamin but a differential requirement of the clathrin-mediated endocytic route was observed depending on the FcγR involved in the complex uptake: the infection through FcγRII was dependent on clathrin-coated vesicles whereas the internalization pathway mediated by FcγRI was independent of clathrin. This property was not serotype-specific. Conclusions/significance DENV entry into myeloid cells in the absence or presence of Ab can be blocked by diverse biochemical inhibitors affecting the cellular factors involved in endocytosis. The identification of the virus-host interactions involved in virus penetration may allow the finding of host-targeted antivirals widely active against diverse pathogenic flaviviruses with similar requirements for virus entry.

by Akhilesh C. Mishra, Vidya A. Arankalle, Swapnil A. Gadhave, Pritam H. Mahadik, Shubham Shrivastava, Mandar Bhutkar, Varsha M. Vaidya
Background In India, dengue disease is emerging as the most important vector borne public health problem due to rapid and unplanned urbanization, high human density and week management of the disease. Clinical cases are grossly underreported and not much information is available on prevalence and incidence of the disease. Methodology A cross sectional, stratified, facility based, multistage cluster sampling was conducted between May 4 and June 27, 2017 in Pune city. A total of 1,434 participants were enrolled. The serum samples were tested for detection of historical dengue IgG antibodies by ELISA using the commercial Panbio Dengue IgG Indirect ELISA kit. Anti-dengue IgG-capture Panbio ELISA was used for detection of high titered antibodies to detect recent secondary infection. We used this data to estimate key transmission parameters like force of infection and basic reproductive number. A subset of 120 indirect ELISA positive samples was also tested for Plaque Reduction Neutralizing Antibodies for determining serotype-specific prevalence. Findings Overall, 81% participants were infected with dengue virus (DENV) at least once if not more. The positivity was significantly different in different age groups. All the adults above 70 years were positive for DENV antibodies. Over 69% participants were positive for neutralizing antibodies against all 4 serotypes suggesting intense transmission of all DENV serotypes in Pune. Age-specific seroprevalence was consistent with long-term, endemic circulation of DENV. There was an increasing trend with age, from 21.6% among

by Manjunath B. Shankar, Rosa L. Rodríguez-Acosta, Tyler M. Sharp, Kay M. Tomashek, Harold S. Margolis, Martin I. Meltzer

Dengue is a mosquito-borne viral illness that causes a variety of health outcomes, from a mild acute febrile illness to potentially fatal severe dengue. Between 2005 and 2010, the annual number of suspected dengue cases reported to the Passive Dengue Surveillance System (PDSS) in Puerto Rico ranged from 2,346 in 2006 to 22,496 in 2010. Like other passive surveillance systems, PDSS is subject to under-reporting. To estimate the degree of under-reporting in Puerto Rico, we built separate inpatient and outpatient probability-based multiplier models, using data from two different surveillance systems—PDSS and the enhanced dengue surveillance system (EDSS). We adjusted reported cases to account for sensitivity of diagnostic tests, specimens with indeterminate results, and differences between PDSS and EDSS in numbers of reported dengue cases. In addition, for outpatients, we adjusted for the fact that less than 100% of medical providers submit diagnostic specimens from suspected cases. We estimated that a multiplication factor of between 5 (for 2010 data) to 9 (for 2006 data) must be used to correct for the under-reporting of the number of laboratory-positive dengue inpatients. Multiplication factors of between 21 (for 2010 data) to 115 (for 2008 data) must be used to correct for the under-reporting of laboratory-positive dengue outpatients. We also estimated that, after correcting for underreporting, the mean annual rate, for 2005–2010, of medically attended dengue in Puerto Rico to be between 2.1 (for dengue inpatients) to 7.8 (for dengue outpatients) per 1,000 population. These estimated rates compare to the reported rates of 0.4 (dengue outpatients) to 0.1 (dengue inpatients) per 1,000 population. The multipliers, while subject to limitations, will help public health officials correct for underreporting of dengue cases, and thus better evaluate the cost-and-benefits of possible interventions.