Transmission of Major Arboviruses in Brazil: The Role of Aedes aegypti and Aedes albopictus Vectors

Arthropod‐borne viruses (arboviruses) are transmitted to a mammalian host by an infected arthropod vector. More than 130 types of arboviruses are known to cause disease in susceptible vertebrate hosts and are responsible for some of the most explosive epidemics of emerging infectious diseases in recent decades. The transmission cycle requires three essential components: virus, vector and vertebrate. Understanding the role of the vector in the arboviruses transmission is critical to improve emerging arbovirus disease control strategies. Since 2015, Brazil is faced with the challenge of three co-circulating arboviruses of major public health importance. Dengue virus (DENV) infection has been a public health for 30 years, which has suffered several epidemics caused by all four serotypes. The emergence of Chikungunya virus (CHIKV) and Zika virus (ZIKV) in Brazil poses new challenges to clinicians and public health authorities. In urban and suburban areas, those arboviruses are transmitted between people by Aedes mosquitoes in the subgenus Stegomyia, especially Ae. aegypti (the main vector) and potentially Ae. albopictus. Factors relating to the environment and the vector‐virus interactions can influence the dynamics of arboviruses transmission. This chapter describes the main biology aspects of the Ae. aegypti and Ae. albopictus that can influence the success of the transmission of main arboviruses in Brazil and provide information to understand the role of those factors in this dynamic relation

Interação vírus-vetorcaracterização da região 3\2019 não-codificante (NC) de vírus dengue tipo 3 (DENV-3), isolados de mosquitos e humanos, após a infecção experimental sucessiva e simultânea em mosquitos

Made available in DSpace on 2015-11-04T13:29:14Z (GMT). No. of bitstreams: 2 thais_carneiro_ioc_mest_2014.pdf: 1876010 bytes, checksum: 1e2c6b5de2029c4c9787f8070f8c3d9e (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2015-04-14Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Rio de Janeiro, RJ, BrasilA dengue é considerada a mais importante das doenças virais transmitida por artrópodes que acomete o homem. O vírus dengue (DENV) é mantido na natureza através de replicação cíclica em hospedeiros vertebrados e mosquitos Aedes, sendo o Aedes aegypti o principal vetor. O seqüenciamento completo de DENV-3 isolado de Ae. aegypti naturalmente infectado do Rio de Janeiro em 2001 e de um caso humano em 2002, demonstrou uma similaridade de 99% com DENV-3 isolado de um caso fatal humano ocorrido no mesmo período. A análise da região 3´NC do genoma viral demonstrou uma mutação nesta região, sugerindo uma deleção de 8 nucleotídeos (nts) na inserção de 11nts, característica de DENV-3 isolados no Brasil. Neste estudo, avaliamos se as diferentes variantes de DENV-3 na interação vírus-vetor através da determinação da competência vetorial em Ae. aegypti. As cepas de DENV-3 BR74886 #5 (cepa representativa do vírus com inserção de 11nts na região 3\2019NC) e BR73356 #5 (cepa representativa do vírus com a deleção de 8 nts), apresentando títulos de 8 x 107 PFU/mL e 7,3 x 107 PFU/mL, respectivamente, mantiveram suas características na região 3\2019NC do genoma viral após cinco passagens em cultura celular e foram selecionadas para a infecção experimental. A estratégia de infecção consistiu na utilização de 2.925 fêmeas de Ae. aegypti, sendo que 2.340 da geração F1 da população de Tubiacanga (RJ) e 585 da cepa controle Paea A população experimental se mostrou competente para transmitir as duas cepas virais de DENV-3, no entanto a disseminação viral no corpo do mosquito apresentou-se de forma heterogênea, sugerindo haver vantagens para a cepa com inserção de 11 nts, uma vez que disseminou-se mais rapidamente. Quando as fêmeas de Ae. aegypti foram alimentadas com ambas as cepas, a disseminação no vetor comportou-se de maneira semelhante à observada quando alimentadas com a cepa representativa da inserção de 11 nts. A análise das cepas de DENV-3 detectadas nas cabeças das fêmeas após replicação in-vivo por 14 dias, não identificou alterações nas características de cada cepa. No entanto, a análise desta região demonstrou uma prevalência do vírus com a inserção de 11 nts quando as fêmeas foram alimentadas com as duas cepas simultaneamente. Variações entre os títulos virais foram observados nas salivas de fêmeas infectadas com as diferentes cepas virais, sugerindo que embora ambas as cepas de DENV-3 possam ser transmitidas na natureza, a cepa com a inserção de 11 nts possui maior eficácia. Os resultados indicam que diferentes cepas virais, variantes genéticas ou mutações que ocorram em um mesmo genótipo podem impactar na competência vetorial dos mosquitos, podendo afetar diretamente o potencial epidêmico de uma cepa de vírus em particularDengue is considered the most important arthropod - borne viral disease that affects humans. Dengue virus (DENV) is maintained in nature by a cyclic replication in vertebrate hosts and Aedes mosquitoes, with the Aedes aegypti as the main vector. The complete sequencing of a DENV - 3 strain isolated from Ae. aegypti naturally infected in Rio de Janeiro in 2001 and from a h uman case occurred in 2002 demonstrated a similarity of 99% with a DENV - 3 isolated from a human fatal case occurred in the same period. However, the analysis of the 3 Untranslated Region (UTR) of the viral genome showed a mutation in this region, suggestin g a deletion of 8 nucleotides (nts) within the 11 nucleotides insertion, characteristic of DENV - 3 isolated in Brazil. In this study, we evaluated whether the distinct DENV - 3 variants presenting those characteristics showed differences on the virus - vector i nteraction by determining the vector competence of two populations of Ae. aegypti . The DENV - 3 strain BR74886#5 (with the 11nts insert in the region 3' UTR ) and the strain BR73356#5 (with an 8 nts deletion), presented titers of 8 x 10 7 PFU/mL and 7.3 x 10 7 PF U/mL, respectively, maintained its characteristics in the 3' UTR region of the viral genome after five passages in cell culture and were selected for experimental infection. The infection strategy consisted in the use of 2,925 female Ae. a egypti : 2,340 of a F1 generation from the Tubiacanga (RJ) population and 585 Paea control mosquitoes. The experimental population proved to be competent to transmit the two DENV - 3 strains. However, the viral dissemination in the body of the mosquito presented heterogeneousl y, suggesting that there are advantages for the strain with 11 nts insertion in the 3' UTR , once disseminated more rapidly . When Ae. aegypti were fed with the both strains, the viral dissemination in the vector was similar to that observed when fed with 11 nts insertion in the 3' UTR . The analysis of the 3' UTR from the DENV - 3 strains detected in the heads of females after in - vivo replication for 14 days, did not identify changes in the 3’ UTR of each strain. However, the analysis of the females infected with two strains simultaneously detected only the presence of the strain carrying the 11 nts insertion in the 3' UTR . Viral titer differences were observed in the saliva of the experimentally infected Ae. a egypti females suggesting that even tough both variants are transmissible, the variant presenting the 11nts is more efficiently transmitted. The results indicate that different viral strains, genetic variants or mutations that occur in the same genotype may impact on the vector competence of mosquitoes, which c an directly affect the epidemic potential of a particular virus strai

NS1 Antigenemia and Viraemia Load: Potential Markers of Progression to Dengue Fatal Outcome?

Submitted by Sandra Infurna ([email protected]) on 2018-09-18T15:40:27Z No. of bitstreams: 1 flaviaB_santos_etal_IOC_2018.pdf: 2392586 bytes, checksum: fb1781d3cf9eca6c46eaf0bf0538c74b (MD5)Approved for entry into archive by Sandra Infurna ([email protected]) on 2018-09-18T15:53:05Z (GMT) No. of bitstreams: 1 flaviaB_santos_etal_IOC_2018.pdf: 2392586 bytes, checksum: fb1781d3cf9eca6c46eaf0bf0538c74b (MD5)Made available in DSpace on 2018-09-18T15:53:05Z (GMT). No. of bitstreams: 1 flaviaB_santos_etal_IOC_2018.pdf: 2392586 bytes, checksum: fb1781d3cf9eca6c46eaf0bf0538c74b (MD5) Previous issue date: 2018Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Imunologia Viral. Rio de Janeiro, RJ, Brasil / Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Flavivírus. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Flavivírus. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Imunologia Viral. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Imunologia Viral. Rio de Janeiro, RJ, Brasil / Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Transmissores de Hematozoários. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Flavivírus. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Flavivírus. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Imunologia Viral. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Imunologia Viral. Rio de Janeiro, RJ, Brasil.Dengue is a worldwide problem characterized by a multifactorial pathogenesis. Considering the viral components, it is known that high viremia or high levels of the secreted nonstructural protein 1 (NS1) may be associated with a more severe disease. We aimed to characterize the NS1 antigenemia and viremia in dengue fatal and non-fatal cases, as potential markers of progression to a fatal outcome. NS1 antigenemia and viremia were determined in Brazilian dengue fatal cases (n = 40) and non-fatal cases (n = 40), representative of the four dengue virus (DENV) serotypes. Overall, the fatal cases presented higher NS1 levels and viremia. Moreover, the fatal cases from secondary infections showed significantly higher NS1 levels than the non-fatal ones. Here, irrespective of the disease outcome, DENV-1 cases presented higher NS1 levels than the other serotypes. However, DENV-2 and DENV-4 fatal cases had higher NS1 antigenemia than the non-fatal cases with the same serotype. The viremia in the fatal cases was higher than in the non-fatal ones, with DENV-3 and DENV-4 presenting higher viral loads. Viral components, such as NS1 and viral RNA, may be factors influencing the disease outcome. However, the host immune status, comorbidities, and access to adequate medical support cannot be ruled out as interfering in the disease outcome

Rapid, noninvasive detection of Zika virus in Aedes aegypti mosquitoes by near-infrared spectroscopy

Submitted by Sandra Infurna ([email protected]) on 2018-08-02T11:05:58Z No. of bitstreams: 1 Lilha_santos_etal_IOC_2018.pdf: 554151 bytes, checksum: 91c0c589349f5e2126364e72724881df (MD5)Approved for entry into archive by Sandra Infurna ([email protected]) on 2018-08-02T11:18:06Z (GMT) No. of bitstreams: 1 Lilha_santos_etal_IOC_2018.pdf: 554151 bytes, checksum: 91c0c589349f5e2126364e72724881df (MD5)Made available in DSpace on 2018-08-02T11:18:06Z (GMT). No. of bitstreams: 1 Lilha_santos_etal_IOC_2018.pdf: 554151 bytes, checksum: 91c0c589349f5e2126364e72724881df (MD5) Previous issue date: 2018University of Queensland. Queensland Alliance for Agriculture and Food Innovation. St. Lucia, Queensland, Australia.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Mosquitos Transmissores de Hematozoários. Rio de Janeiro, RJ. Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Mosquitos Transmissores de Hematozoários. Rio de Janeiro, RJ. Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Mosquitos Transmissores de Hematozoários. Rio de Janeiro, RJ. Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Mosquitos Transmissores de Hematozoários. Rio de Janeiro, RJ. Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Mosquitos Transmissores de Hematozoários. Rio de Janeiro, RJ. Brasil.University of Miami Miller School of Medicine. Department of Public Health Services. Miami, FL, USA.U.S. Department of Agriculture. Agricultural Research Service. Center for Grain and Animal Health Research. Manhatta, USA / University of Miami Miller School of Medicine. Department of Publica Health. Miami, FL, USA.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Mosquitos Transmissores de Hematozoários. Rio de Janeiro, RJ. Brasil / Universidade Federal do Rio de Janeiro. Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular. Rio de Janeiro, RJ, Brasil.University of Queensland. Queensland Alliance for Agriculture and Food Innovation. St. Lucia, Queensland, Australia.The accelerating global spread of arboviruses, such as Zika virus (ZIKV), highlights the need for more proactive mosquito surveillance. However, amajor challenge during arbovirus outbreaks has been the lack of rapid and affordable tests for pathogen detection inmosquitoes. We show for the first time that near-infrared spectroscopy (NIRS) is a rapid, reagent-free, and cost-effective tool that can be used to noninvasively detect ZIKV in heads and thoraces of intact Aedes aegypti mosquitoes with prediction accuracies of 94.2 to 99.3% relative to quantitative reverse transcription polymerase chain reaction (RT-qPCR). NIRS involves simply shining a beam of light on a mosquito to collect a diagnostic spectrum. We estimated in this study that NIRS is 18 times faster and 110 times cheaper than RT-qPCR. We anticipate that NIRS will be expanded upon for identifying potential arbovirus hotspots to guide the spatial prioritization of vector control

Dengue type 4 in Rio de Janeiro, Brazil: case characterization following its introduction in an endemic region

Abstract Background Due to the populations’ susceptibility, DENV-4 introduction in 2010 led to the occurrence of explosive epidemics in the following years in Brazil. In 2011, DENV-4 was identified in Rio de Janeiro (RJ) and it was prevalent in 2012 and 2013. Here, we aimed to characterize clinical, epidemiological and laboratorial aspects of DENV-4 cases after this serotype introduction in an endemic scenario. Methods Dengue suspected cases (n = 3727) were received and analyzed from January 2011 to December 2013, during outbreaks occurred in RJ, Brazil. Samples were submitted to virological, serological and molecular methods for case confirmation. DENV-4 cases (n = 705) were characterized according to the type of infection, disease severity and, viremia levels and NS1 antigenemia were accessed. Representative strains were partial sequenced for genotyping. Results DENV-4 was identified in 44.2% (705/1593) of dengue positive cases, virus isolated in 48.7% of the cases. Anti-DENV IgM was detected in 39.4% of the cases, however an increased detection was observed in cases with ≥4 days of symptoms (57.0%). NS1 antigen was identified in 41.5% of DENV-4 cases however, after immune complexes dissociation, the detection significantly increased (87.6%). Females were more affected than males, so did children aged 11–15 years old. Primary cases were more frequently observed than secondary ones and most of them were classified as dengue. No differences on NS1 antigenemia and viraemia within the groups were observed. Despite the higher frequency of severe disease on individuals >65 years old, no differences were observed among the groups and type of infection. However, DENV-4 fatal cases were more frequent on secondary infections (57.1%). DENV-4 Genotype II was identified with a probable origin from Venezuela and Colombia. Conclusions It has been shown that laboratorial diagnosis is still a reliable tool for the disease surveillance, detecting and confirming emerging epidemics. Despite the occurrence of secondary infections, most DENV-4 cases presented a mild disease. As RJ is endemic for dengue, high rates of secondary infections would be expected. Despite the existence of two genotypes, only Genotype II was identified in our study

Rapid, noninvasive detection of Zika virus in mosquitoes by near-infrared spectroscopy

The accelerating global spread of arboviruses, such as Zika virus (ZIKV), highlights the need for more proactive mosquito surveillance. However, a major challenge during arbovirus outbreaks has been the lack of rapid and affordable tests for pathogen detection in mosquitoes. We show for the first time that near-infrared spectroscopy (NIRS) is a rapid, reagent-free, and cost-effective tool that can be used to noninvasively detect ZIKV in heads and thoraces of intact mosquitoes with prediction accuracies of 94.2 to 99.3% relative to quantitative reverse transcription polymerase chain reaction (RT-qPCR). NIRS involves simply shining a beam of light on a mosquito to collect a diagnostic spectrum. We estimated in this study that NIRS is 18 times faster and 110 times cheaper than RT-qPCR. We anticipate that NIRS will be expanded upon for identifying potential arbovirus hotspots to guide the spatial prioritization of vector control

DENV-1 Genotype V in Brazil: Spatiotemporal dispersion pattern reveals continuous co-circulation of distinct lineages until 2016

Submitted by Sandra Infurna ([email protected]) on 2019-02-08T15:38:54Z No. of bitstreams: 1 fernandaB_nogueira_etal_IOC_2018.pdf: 2567629 bytes, checksum: 2b64c7ba0484dc18ff101c9638713946 (MD5)Approved for entry into archive by Sandra Infurna ([email protected]) on 2019-02-08T15:54:49Z (GMT) No. of bitstreams: 1 fernandaB_nogueira_etal_IOC_2018.pdf: 2567629 bytes, checksum: 2b64c7ba0484dc18ff101c9638713946 (MD5)Made available in DSpace on 2019-02-08T15:54:49Z (GMT). No. of bitstreams: 1 fernandaB_nogueira_etal_IOC_2018.pdf: 2567629 bytes, checksum: 2b64c7ba0484dc18ff101c9638713946 (MD5) Previous issue date: 2018Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Imunologia Viral. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Imunologia Viral. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Imunologia Viral. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Flavivírus. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Flavivírus. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Flavivírus. Rio de Janeiro, RJ, Brasil.Laboratório Central de Saúde Pública do Ceará. Fortaleza, CE, Brasil.Laboratório Central de Saúde Pública do Rio de Janeiro. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Flavivírus. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Flavivírus. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Imunologia Viral. Rio de Janeiro, RJ, Brasil.In Brazil, DENV-1 introduced in the 80's, remained the prevalent serotype from 2012 to 2016. After its re-emergence in the country in 2009, the co-circulation of different viral lineages was identified, however, its transmission dynamics afterwards, was not fully characterized. In this study, we performed the continuous molecular surveillance after the reemergence period (2012 to 2016), covering the 30 years of circulation of DENV-1 in Brazil. Phylogenetic analysis allowed confirmation of the continued presence of genotype V, as well as three distinct co-circulating lineages. The molecular characterization of the E gene presented two new amino acid substitutions previously unidentified in the country. Phylogeographic analysis has shown that a large flow of migrations has occurred between Brazil and Argentina in the last 10 years

First report of the East-Central South African 1 Genotype of Chikungunya Virus in Rio de Janeiro, Brazil

bioRxiv preprint first posted online Oct. 20, 2016. The copyright holder for this preprint (which was not peer-reviewed) is the author/funder. It is made available under a CC-BY-NC-ND 4.0 International license.Submitted by Sandra Infurna ([email protected]) on 2018-02-15T14:04:36Z No. of bitstreams: 1 jessica_silva_etal_IOC_2017.pdf: 295978 bytes, checksum: 84ccd315cea4b5258dc6045f540fa0d8 (MD5)Approved for entry into archive by Sandra Infurna ([email protected]) on 2018-02-15T14:04:48Z (GMT) No. of bitstreams: 1 jessica_silva_etal_IOC_2017.pdf: 295978 bytes, checksum: 84ccd315cea4b5258dc6045f540fa0d8 (MD5)Made available in DSpace on 2018-02-15T14:04:48Z (GMT). No. of bitstreams: 1 jessica_silva_etal_IOC_2017.pdf: 295978 bytes, checksum: 84ccd315cea4b5258dc6045f540fa0d8 (MD5) Previous issue date: 2017Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Imunologia Viral. Rio de Janeiro, RJ. Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Imunologia Viral. Rio de Janeiro, RJ. Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Imunologia Viral. Rio de Janeiro, RJ. Brasil.Universidade Federal do Estado do Rio de Janeiro. Escola de Medicina e Cirurgia. Rio de Janeiro, RJ, Brasil / Universidade do Estado do Rio de Janeiro. Faculdade de Ciências Médicas. Rio de Janeiro, RJ, Brasil / Rio Laranjeiras Hospital. Rio de Janeiro, RJ, Brasil.Universidade Federal do Estado do Rio de Janeiro. Escola de Medicina e Cirurgia. Rio de Janeiro, RJ, Brasil / Universidade do Estado do Rio de Janeiro. Faculdade de Ciências Médicas. Rio de Janeiro, RJ, Brasil / Rio Laranjeiras Hospital. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Imunologia Viral. Rio de Janeiro, RJ. Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Imunologia Viral. Rio de Janeiro, RJ. Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Imunologia Viral. Rio de Janeiro, RJ. Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Imunologia Viral. Rio de Janeiro, RJ. Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Imunologia Viral. Rio de Janeiro, RJ. Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Imunologia Viral. Rio de Janeiro, RJ. Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Flavivirus. Rio de Janeiro, RJ. Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Imunologia Viral. Rio de Janeiro, RJ. Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Imunologia Viral. Rio de Janeiro, RJ. Brasil.Chikungunya virus (CHIKV) is an arbovirus that causes an acute febrile illness characterized by severe and debilitating arthralgia. In Brazil, the Asian and East-Central South African (ECSA) genotypes are circulating in the north and northeast of the country, respectively. In 2015, the first autochthonous cases in Rio de Janeiro, Brazil were reported but until now the circulating strains have not been characterized. Therefore, we aimed here to perform the molecular characterization and phylogenetic analysis of CHIKV strains circulating in the 2016 outbreak occurred in the municipality of Rio de Janeiro

30 years of dengue fatal cases in Brazil: a laboratorial-based investigation of 1047 cases

Abstract Background Dengue viruses (DENV) have emerged and reemerged in Brazil in the past 30 years causing explosive epidemics. The disease may range from clinically asymptomatic infections to severe and fatal outcomes. We aimed to describe the epidemiological, clinical and laboratorial aspects of the dengue fatal cases received by a Regional Reference Laboratory, Brazil in 30 years. Methods A total of 1047 suspected fatal dengue cases were received from 1986 to 2015 and analyzed in the Laboratory of Flavivirus, FIOCRUZ. Suspected cases were submitted to viral detection, serological and molecular methods for cases confirmation. Influence of gender, age, serotype and type of infection (primary/secondary) on death outcome, as well the interactions between serotype and age or infection and age and type of infection were also studied. Results A total of 359 cases (34.2%) were confirmed and DENV-1 (11.1%), DENV-2 (43.9%), DENV-3 (32.8%) and DENV-4 (13.7%) were detected. Overall, fatal cases occurred more often in primary infections (59.3%, p = 0.001). However, in 2008, fatal cases were mainly associated to secondary infections (p = 0.003). In 2008 and 2011, deaths were more frequent on children and those infected by DENV-2 presented a higher risk for fatal outcome. Moreover, children with secondary infections had a 4-fold higher risk for death. Conclusions Dengue is a multifactorial disease and, factors such as viral strain/serotype, occurrence of secondary infections and co-morbidities may lead to a severe outcome. However, the high dengue incidence and transmission during epidemics, such as those observed in Brazil may overwhelm and collapse the public health services, potentially impacting on increased disease severity and mortality

Following in the Footsteps of the Chikungunya Virus in Brazil: The First Autochthonous Cases in Amapá in 2014 and Its Emergence in Rio de Janeiro during 2016

Currently, Brazil lives a triple arboviruses epidemic (DENV, ZIKV and CHIKV) making the differential diagnosis difficult for health professionals. Here, we aimed to investigate chikungunya cases and the possible occurrence of co-infections during the epidemic in Amapá (AP) that started in 2014 when the first autochthonous cases were reported and in Rio de Janeiro (RJ) in 2016. We further performed molecular characterization and genotyping of representative strains. In AP, 51.4% of the suspected cases were confirmed for CHIKV, 71.0% (76/107). Of those, 24 co-infections by CHIKV/DENV, two by CHIKV/DENV-1, and two by CHIKV/DENV-4 were observed. In RJ, 76.9% of the suspected cases were confirmed for CHIKV and co-infections by CHIKV/DENV (n = 8) and by CHIKV/ZIKV (n = 17) were observed. Overall, fever, arthralgia, myalgia, prostration, edema, exanthema, conjunctival hyperemia, lower back pain, dizziness, nausea, retroorbital pain, and anorexia were the predominating chikungunya clinical symptoms described. All strains analyzed from AP belonged to the Asian genotype and no amino acid changes were observed. In RJ, the East-Central-South-African genotype (ECSA) circulation was demonstrated and no E1-A226V mutation was observed. Despite this, an E1-V156A substitution was characterized in two samples and for the first time, the E1-K211T mutation was reported in all samples analyzed