Phylogenetic analysis of Dengue virus 1 isolated from South Minas Gerais, Brazil

Abstract Dengue is a major worldwide public health problem, especially in the tropical and subtropical regions of the world. Primary infection with a single Dengue virus serotype causes a mild, self-limiting febrile illness called dengue fever. However, a subset of patients who experience secondary infection with a different serotype can progress to a more severe form of the disease, called dengue hemorrhagic fever. The four Dengue virus serotypes (1–4) are antigenically and genetically distinct and each serotype is composed of multiple genotypes. In this study we isolated one Dengue virus 1 serotype, named BR/Alfenas/2012, from a patient with dengue hemorrhagic fever in Alfenas, South Minas Gerais, Brazil and molecular identification was performed based on the analysis of NS5 gene. Swiss mice were infected with this isolate to verify its potential to induce histopathological alterations characteristic of dengue. Liver histopathological analysis of infected animals showed the presence of inflammatory infiltrates, hepatic steatosis, as well as edema, hemorrhage and necrosis focal points. Phylogenetic and evolutionary analyses based on the envelope gene provided evidence that the isolate BR/Alfenas/2012 belongs to genotype V, lineage I and it is probably derived from isolates of Rio de Janeiro, Brazil. The isolate BR/Alfenas/2012 showed two unique amino acids substitutions (SER222THRE and PHE306SER) when compared to other Brazilian isolates from the same genotype/lineage. Molecular models were generated for the envelope protein indicating that the amino acid alteration PHE 306 SER could contribute to a different folding in this region located within the domain III. Further genetic and animal model studies using BR/Alfenas/2012 and other isolates belonging to the same lineage/genotype could help determine the relation of these genetic alterations and dengue hemorrhagic fever in a susceptible population

Dengue-4 false negative results by Panbio (R) Dengue Early ELISA assay in Brazil

Background: Dengue is a serious public health problem in numerous countries. the ability to rapidly diagnosis dengue is important for patient triage and management. Detection of dengue viral protein, NS1, represents a new approach to dengue diagnosis.Objective: the present study aims to evaluate if there are false negative results using the NS1 Ag rapid assay (Panbio (R) Dengue Early ELISA) in two different epidemiological situations (epidemic and non-epidemic).Study design: 220 serum samples from patients with clinical symptoms of classical dengue fever were tested by NS1 antigen capture ELISA and Multiplex-Nested-PCR.Results: in samples collected in a non-epidemic period we found a 100% agreement of ELISA and RTPCR in dengue negative samples and 85% agreement of ELISA and RT-PCR in dengue positive samples. But when we tested samples during an epidemic period (large DENV-4 outbreak) we found 15% false negative results (p<0.05) in dengue negative samples.Conclusions: Due to false negative results for DENV-4, the sole use of the Panbio Dengue Early ELISA assay as a screening method for monitoring circulating dengue serotypes must be reevaluated. (C) 2013 Elsevier B.V. All rights reserved.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fac Med Sao Jose do Rio Preto FAMERP, BR-15090000 Sao Jose Do Rio Preto, SP, BrazilUniv Estadual Paulista Julio de Mesquitta & Filho, Sao Jose Do Rio Preto, SP, BrazilUniversidade Federal de São Paulo UNIFESP, São Paulo, BrazilPrefeitura Sao Jose do Rio Preto, Dept Vigilancia Saude, Sao Jose Do Rio Preto, SP, BrazilUniv Fed Mato Grosso, Sinop, Mato Grosso, BrazilTufts Univ, Cummings Sch Vet Med, Dept Infect Dis & Global Hlth, North Grafton, MA USAUniversidade Federal de São Paulo UNIFESP, São Paulo, BrazilFAPESP: 2012/11733-6FAPESP: 2011/10458-9Web of Scienc