Guarana (Paullinia cupana var. sorbilis) is a plant native to the central Amazon basin. Roasted seed extracts have been used as medicinal beverages since pre-Colombian times, due to their reputation as stimulants, aphrodisiacs, tonics, as well as protectors of the gastrointestinal tract. Guarana plants are commercially cultivated exclusively in Brazil to supply the national carbonated soft-drink industry and natural product stores around the world. In this report, we describe and discuss the annotation of 15,387 ESTs from guarana seeded-fruits, highlighting sequences from the flavonoid and purine alkaloid pathways, and those related to biotic stress avoidance. This is the largest set of sequences registered for the Sapindaceae family.
OBJECTIVE:To detect the presence of dengue virus in larval forms of Aedes aegypti and to associate vector presence with rainfall and incidence of disease. METHODS:Eighteen households were randomly selected for egg collection in a neighborhood of the city of Boa Vista, Roraima, in Northern Brazil. Two oviposition traps were installed per home, and removed after one week. This was repeated on a monthly basis between November 2006 and May 2007. Trap positivity rate and egg density were calculated. Following the eclosion of 1,422 eggs, 44 pools of at least 30 larvae each were formed, which were evaluated for presence of dengue virus using RT-PCR and hemi-nested PCR. Dengue incidence rates in the period were correlated with rainfall rates. The association between these two variables and the number of eggs collected was determined using Pearson correlation. RESULTS:None of the pools tested positive for presence of dengue virus, despite the high incidence of dengue in the neighborhood during the studied period. The density of Ae. aegypti increased with rainfall, but was not correlated with incidence of dengue. CONCLUSIONS:The results suggest that transovarial transmission of dengue virus in mosquitoes occurs at a very low frequency, and therefore virus persistence in urban settings may not depend on such transmission. The mosquito population increased during the rainy season due to increased formation of breeding sites; the lack of correlation with incidence of dengue may be due to underestimation of incidence data during epidemics.
OBJECTIVE:To detect the presence of dengue virus in larval forms of Aedes aegypti and to associate vector presence with rainfall and incidence of disease. METHODS:Eighteen households were randomly selected for egg collection in a neighborhood of the city of Boa Vista, Roraima, in Northern Brazil. Two oviposition traps were installed per home, and removed after one week. This was repeated on a monthly basis between November 2006 and May 2007. Trap positivity rate and egg density were calculated. Following the eclosion of 1,422 eggs, 44 pools of at least 30 larvae each were formed, which were evaluated for presence of dengue virus using RT-PCR and hemi-nested PCR. Dengue incidence rates in the period were correlated with rainfall rates. The association between these two variables and the number of eggs collected was determined using Pearson correlation. RESULTS:None of the pools tested positive for presence of dengue virus, despite the high incidence of dengue in the neighborhood during the studied period. The density of Ae. aegypti increased with rainfall, but was not correlated with incidence of dengue. CONCLUSIONS:The results suggest that transovarial transmission of dengue virus in mosquitoes occurs at a very low frequency, and therefore virus persistence in urban settings may not depend on such transmission. The mosquito population increased during the rainy season due to increased formation of breeding sites; the lack of correlation with incidence of dengue may be due to underestimation of incidence data during epidemics.
Dengue is the most important arboviral disease worldwide. We report the complete genome sequence of a dengue virus serotype 4, genotype II strain isolated in 2010 from a patient with classical dengue fever in Boa Vista, Roraima, Brazil. D engue virus (DENV) infections are the most important cause of arthropod-borne viral diseases worldwide (7). DENVs are single-stranded RNA viruses which belong to the Flavivirus genus of the Flaviviridae family; four immunologically related types, also known as serotypes, are recognized (DENV-1 to DENV-4) (5). Phylogenetic analyses have shown that each serotype may be further separated into different genotypes, and four DENV-4 genotypes have been described (13).DENV-4 and DENV-1 were first recorded in Brazil during an outbreak in 1981 and 1982 in Boa Vista, the capital of Roraima State (11). Unlike the other serotypes, DENV-4 was not detected again in Brazil until 2008, when it was reported in autochthonous cases occurring in Manaus, the capital of Amazonas State (3). In 2010, DENV-4 reemerged in Roraima (1), this time spreading to several Brazilian states. To date, no complete Brazilian DENV-4 genome sequence has been reported, although this is an important issue that can contribute to our understanding of DENV-4 epidemiology.Here we report the complete genome sequencing of a DENV-4 strain, Br246RR/10, which was isolated from a male patient presenting with classical dengue fever in Boa Vista, Roraima, Brazil, on 8 September 2010, 4 days after the onset of symptoms. His serum was NS1 enzyme-linked immunosorbent assay (Bio-Rad) positive and was therefore inoculated onto Aedes albopictus C6/36 monolayers for an indirect immunofluorescence assay for viral typing (8). Cell supernatants were used for a seminested reverse transcription-PCR protocol (9) to confirm the DENV-4 serotype. A second reverse transcription reaction was conducted using a reverse primer, D4AS1, which was designed to recognize the last 21 nucleotides (nt) in the 3= region common to all DENV-4 genotypes. DENV-4 strain Br246RR/10 was further amplified using eight primer pairs to generate overlapping amplicons spanning the entire viral genome. All sequencing was carried out using an ABI 3130 Sanger-based genetic analyzer (primer sequences are available upon request). One contig containing high-quality trace files was assembled using Geneious Pro 5.5.3 (2) and a single reference sequence (GenBank accession no. NC_002640).The complete genome sequence of Br246RR/10 is 10,649 nt long, with a 5= untranslated region (UTR) of 101 nt, followed by a polyprotein precursor coding sequence of 10,164 nt and a 3= UTR of 384 nt. A full-genome MegaBLAST search with Br246RR/10 returned Colombian (2005) and Venezuelan (2007) DENV-4 strains as the closets matches. A phylogenetic analysis based on the 1,485-nt region (positions 939 to 2423), which encodes the envelope protein, was conducted using the maximum-likelihood method with the PhyML (6) plugin for Geneious and nucleotide sequences encompassing the four known DENV-4 genotypes (...
Serum samples from 150 NS1-negative (Platelia ELISA) patients presumptively diagnosed with dengue were analyzed by the TaqMan probed real-time reverse transcription PCR (TaqMan qRT-PCR) method. The qRT-PCR positive samples were tested for serotype by semi-nested RT-PCR and a qualitative immunochromatographic assay for IgG and IgM. Molecular detection methods showed 33 (22%) positive samples out of 150 NS1-antigen negative samples. Of these, 72% were collected up to day 2 after the onset of symptoms, when diagnostic sensitivity of NS1-antigen test assays is significantly enhanced. Most of the cases were not characterized as secondary infection. Twenty-eight samples were successfully serotyped, 75% of which for DENV-4, 14% for DENV-2, 7% for DENV-3 and 4% for DENV-1. These findings reaffirm the hyperendemic situation of the state of Roraima and suggest a lower sensitivity of the NS1 test, mainly when DENV-4 is the predominant serotype. Health care providers should therefore be aware of samples tested negative by NS1 antigen assays, especially when clinical symptoms and other laboratory data results show evidence of dengue infection.
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