Genetic variability of hepatitis B virus in Uruguay: D/F, A/F genotype recombinants

Hepatitis B virus (HBV) infection is a serious global health problem. Approximately 2 billion people worldwide have been infected, and approximately 350 million individuals currently suffer from HBV-induced chronic liver infection, which causes 600,000 deaths annually from chronic hepatitis, cirrhosis and hepatocellular carcinoma. HBV is classified in eight genotypes (A-H), and two more have been proposed (I-J). In this paper, complete genome sequences of nine Uruguayan HBV are reported. Five samples belong to genotype F1b and one to genotype A2. Three HBV recombinants were detected: A1/F1b, A2/F1b and D3/F1b. The following mutations were detected: a G1896A substitution, a 33-nucleotide deletion from position 2896 to 2928 in the Pre-S1 region involving Pre-S1 residues 3-13, a 33-nt deletion in the Pre-S1 region involving nt 2913-2945 and Pre-S1 residues 9-19. More F genotypes strains than expected were detected in this study, supporting the hypothesis that there are more people of indigenous origin than declared in our population. Also, one third of the samples analyzed were recombinants. This cannot be explained by the low HBV prevalence in Uruguay, but a high HBV infection rate in drug addicts and dialysis patients could act in favor of multiple-genotype HBV infections that could lead to recombination.

Phylogenetic analysis of the NS5 gene of dengue viruses isolated in Ecuador

Dengue virus (DENV) is a member of the genus Flavivirus of the family Flaviviridae. DENV causes a wide range of diseases in humans, from the acute febrile illness dengue fever (DF) to life-threatening dengue hemorrhagic fever/dengue shock syndrome (DHF/DSS). There is not knowledge of the genetic relations among DENV circulating in Ecuador. Given the emerging behaviour of DENV, a single tube RT-PCR assay using a pair of consensus primers to target the NS5 coding region has been recently validated for rapid detection of flaviviruses. In order to gain insight into the degree of genetic variation of DENV strains isolated in Ecuador, DENV NS5 sequences from 23 patients were obtained by direct sequencing of PCR fragments using the mentioned one step RT-PCR assay. Phylogenetic analysis carried out using the 23 Ecuadorian DENV NS5 sequences, as well as 56 comparable sequences from DENV strains isolated elsewhere, revealed a close genetic relation among Ecuadorian strains and DENV isolates of Caribbean origin. The use of partial NS5 gene sequences may represent a useful alternative for a rapid phylogenetic analysis of DENV outbreaks.