Insights on Zika virus envelope gene conservation in American outbreaks.

Phylogenetic studies with Zika virus (ZIKV) have been conducted in Brazil. In this study, we sequenced 8 new sequences of the ZIKV envelope (E) gene from strains of cases from the Paraná and Mato Grosso do Sul states in 2016. A low phylogenetic signal was observed, with more than 40% of unresolved quartets, and the Maximum Likelihood Tree grouped all sequences in the Brazilian branches within the Asian genotype. In addition, a Shannon entropy analysis was conducted, showing a high stability in the E protein through the ZIKV polyprotein. Taken together, these results suggest a high degree of conservation in the ZIKV E gene from the recent American outbreaks.

Evolutions and upcoming on Zika virus diagnosis through an outbreak: A systematic review.

Zika virus (ZIKV) is an enveloped, positive single-stranded sense RNA virus transmitted by Aedes species. Many efforts have been conducted to find a good, reliable and cost-effective test for ZIKV diagnosis. Diagnosis is still imprecise, expensive and there is not a standard model. We investigated the publications on ZIKV diagnostics and analyzed varieties of diagnostic methods, sensibility, specificity, and the evolution of new methodologies. Conducted in accordance with the PRISMA-P statement, three blocks of MeSH terms were assembled: group I: virus infection; group II: diagnostic methodologies; group III: characteristics and varieties on diagnostic methods. Search was performed on PubMed, Web of Science and SCOPUS databases. Eighteen articles were retrieved, reporting serological and molecular diagnostic techniques. Serum was used as the main biological material in the serological diagnosis, but urine and sperm were presented as an alternative. Molecular methods used structural and nonstructural regions of ZIKV genome. Experimental methodologies were more efficient, faster, and cheaper. Serological tests are faster and less expensive than molecular assays, but molecular assays are more specific. The use of both methodologies would be the most appropriate and reliable way to obtain correct diagnostic results.

Nationwide overview of the distribution of hepatitis B virus genotypes in Brazil: a 1000-sample multicentre study.

The influence of hepatitis B virus (HBV) genotypes in the natural history of the disease and its response to antiviral treatment have been addressed in many studies. In Brazil, studies on HBV genotype circulation have been restricted to specific population groups and states. Here, we have conducted a nationwide multicentre study with an unprecedented sample size representing all Brazilian regions in an effort to better understand the viral variants of HBV circulating among chronic carriers. Seven HBV genotypes were found circulating in Brazil. Overall, HBV/A was the most prevalent, identified in 589 (58.7 %) samples, followed by HBV/D (23.4 %) and HBV/F (11.3 %). Genotypes E, G, C and B were found in a minor proportion. The distribution of the genotypes differed markedly from the north to the south of the country. While HBV/A was the most prevalent in the North (71.6 %) and Northeast (65.0 %) regions, HBV/D was found in 78.9 % of the specimens analysed in the South region. HBV/F was the second most prevalent genotype in the Northeast region (23.5 %). It was detected in low proportions (7 to 10 %) in the North, Central-West and Southeast regions, and in only one sample in the South region. HBV/E was detected in all regions except in the South, while monoinfection with HBV/G was found countrywide, with the exception of Central-West states. Our sampling covered 24 of the 26 Brazilian states and the Federal District and is the first report of genotype distribution in seven states. This nationwide study provides the most complete overview of HBV genotype distribution in Brazil to date and reflects the origin and plurality of the Brazilian population.

HBV carrying drug-resistance mutations in chronically infected treatment-naive patients.

BACKGROUND: Nucleoside/nucleotide analogue (NA) treatment causes selection pressure for HBV strains carrying mutations conferring NA resistance. Drug-resistance mutations occur in the reverse transcriptase (RT) region of the HBV polymerase gene and spontaneously arise during viral replication. These mutations can also alter the hepatitis B surface (HBs) protein and in some cases reduce binding to HBs antibodies. The spread of NA-resistant HBV may impact the efficacy of antiviral treatment and hepatitis B immunization programmes. In this study, we used direct sequencing to assess the occurrence of HBV carrying known mutations that confer NA resistance in the largest cohort of treatment-naive patients with chronic hepatitis B (CHB) to date. METHODS: HBV DNA samples isolated from 702 patients were sequenced and the RT region subjected to mutational analysis. RESULTS: There was high genetic variability among the HBV samples analysed: A1 (63.7%), D3 (14.5%), A2 (3.3%), A3 (0.1%), B1 (0.1%), B2 (0.1%), C2 (0.9%), D1 (0.9%), D2 (4.6%), D4 (5.1%), D unclassified subgenotype (0.7%), E (0.6%), F2a (4.6%), F4 (0.4%) and G (0.4%). HBV strains harbouring mutations conferring NA resistance alone or combined with compensatory mutations were identified in 1.6% (11/702) of the patients. CONCLUSIONS: HBV strains harbouring resistance mutations can comprise the major population of HBV quasispecies in treatment-naive patients. In Brazil, there is a very low frequency of untreated patients who are infected with these strains. These findings suggest that the spread and natural selection of drug-resistant HBV is an uncommon event and/or most of these strains remain unstable in the absence of NA selective pressure.

Genetic diversity of HCV in Brazil.

BACKGROUND: Many studies have documented the molecular epidemiological scenario of HCV within individual Brazilian states, but we still have an incomplete understanding of the dispersion dynamics of the virus in different regions throughout the country. METHODS: A total of 676 HCV NS5B gene sequences of subtypes 1a (n=321), 1b (n=170) and 3a (n=185), isolated from seven different Brazilian states covering four out of five regions were analysed in the present study. We also analysed 22 HCV NS5B gene sequences of minor genetic variants including genotype 2 (n=13), genotype 4 (n=6) and subtype 5a (n=3). Brazilian HCV sequences were aligned with sequences of non-Brazilian origin and subjected to maximum likelihood phylogenetic analyses. RESULTS: These analyses revealed that the Brazilian HCV epidemic resulted from multiple introductions and autochthonous transmission of subtypes 1a, 1b, 3a and genotypes 2, 4 and 5. Brazilian HCV subtype 1a epidemic is dominated by the dissemination of one major clade; while Brazilian HCV subtypes 1b and 3a epidemics are characterized by concurrent dissemination of several independent HCV lineages. Some HCV Brazilian lineages of subtypes 1a, 1b, 2b and 3a were successful in becoming established and disseminated through several regions in the country. Despite significant phylogenetic intermixing of Brazilian sequences, the distribution of HCV strains from different states across lineages was not completely homogeneous. CONCLUSIONS: These results demonstrate the existence of multiple introductions and local propagation of both prevalent and uncommon HCV genetic variants in Brazil and identify some major Brazilian HCV clades with nationwide dissemination. This study also suggests that the observed HCV diversity in Brazil has been shaped by both frequent viral migration among regions and in situ viral dissemination.

The precore mutation is associated with severity of liver damage in Brazilian patients with chronic hepatitis B.

BACKGROUND: The clinical relevance of the G1896A precore mutation in chronic hepatitis B is still poorly understood. OBJECTIVES: To assess the frequency of G1896A precore mutation in Brazilian patients with chronic hepatitis B, as well as its relation to the viral genotype, serum HBV-DNA levels and liver damage. STUDY DESIGN: Fifty chronic hepatitis B patients (29 HBeAg-negative and 21 HBeAg-positive) were studied. HBV-DNA was quantified by the Amplicor HBV Monitor test and precore region and S gene were amplified and submitted to automatic sequencing. The histological activity index (HAI), degrees of hepatic fibrosis and distribution of core antigen (HBcAg) in hepatocytes were determined. RESULTS: Precore mutation occurred in 1/21 (4.8%) HBeAg-positive patients and in 17/29 (58.6%) HBeAg-negative (p < 0.0001). Genotype D was identified in 56.5%, genotype A in 41.3%, and genotype F in 2.2%. The frequency of genotypes D and A, as well as serum levels of ALT and HBV-DNA were similar in patients infected with wild type and with precore mutant. Patients infected with precore mutant presented a higher frequency of moderate/severe HAI (p: 0.03) and moderate/severe fibrosis and cirrhosis (p: 0.03) than those infected with wild type. There was no association between G1896A mutation and cytoplasmic expression of HBcAg. CONCLUSIONS: Precore mutation was frequent among Brazilian subjects with chronic hepatitis B and its presence was associated with greater severity of liver disease.

Hepatitis B virus infection in Haemodialysis Centres from Santa Catarina State, Southern Brazil. Predictive risk factors for infection and molecular epidemiology.

BACKGROUND: Patients under haemodialysis are considered at high risk to acquire hepatitis B virus (HBV) infection. Since few data are reported from Brazil, our aim was to assess the frequency and risk factors for HBV infection in haemodialysis patients from 22 Dialysis Centres from Santa Catarina State, south of Brazil. METHODS: This study includes 813 patients, 149 haemodialysis workers and 772 healthy controls matched by sex and age. Serum samples were assayed for HBV markers and viraemia was detected by nested PCR. HBV was genotyped by partial S gene sequencing. Univariate and multivariate statistical analyses with stepwise logistic regression analysis were carried out to analyse the relationship between HBV infection and the characteristics of patients and their Dialysis Units. RESULTS: Frequency of HBV infection was 10.0%, 2.7% and 2.7% among patients, haemodialysis workers and controls, respectively. Amidst patients, the most frequent HBV genotypes were A (30.6%), D (57.1%) and F (12.2%). Univariate analysis showed association between HBV infection and total time in haemodialysis, type of dialysis equipment, hygiene and sterilization of equipment, number of times reusing the dialysis lines and filters, number of patients per care-worker and current HCV infection. The logistic regression model showed that total time in haemodialysis, number of times of reusing the dialysis lines and filters, and number of patients per worker were significantly related to HBV infection. CONCLUSIONS: Frequency of HBV infection among haemodialysis patients at Santa Catarina state is very high. The most frequent HBV genotypes were A, D and F. The risk for a patient to become HBV positive increase 1.47 times each month of haemodialysis; 1.96 times if the dialysis unit reuses the lines and filters > or = 10 times compared with haemodialysis units which reuse < 10 times; 3.42 times if the number of patients per worker is more than five. Sequence similarity among the HBV S gene from isolates of different patients pointed out to nosocomial transmission.

Freqüência de anticorpos anti-Cysticercus cellulosae em indivíduos de cinco municípios da regiäo norte do Estado do Paraná - Brasil / Frequency of anti-cysticercus cellulosae antibodies in individuals from five counties in the southern region of Brazil

Realizou-se inquérito sorológico e epidemiológico para cisticercose em indivíduos de cinco municípios da regiäo Norte do Estado do Paraná, Brasil. De 2.180 indivíduos investigados através da reaçäo de imunofluorescência indireta, 69 (3,2 por cento) apresentaram títulos significativos de anticorpos anti-Cysticercus cellulosae. Os percentuais de indivíduos com títulos significativos encontrados em Sarandi (6,6 por cento) e Marialva (4,7 por cento) näo diferem estatisticamente (Z=1.319, P=0,0936), mas diferem dos percentuais encontrados em Mandaguaçu, Paiçandu e Maringá (P<0,01). Destes indivíduos, 47,9 por cento estavam na faixa etária de 21 a 49 anos e 79,4 por cento eram do sexo feminino. Foi comum o relato de queixas como "dores de cabeça" (70,6 por cento), "tonturas" (57,4 por cento) e "convulsöes" (7,4 por cento), além de história de teníase (22,1 por cento) e hábitos de ingestäo de carne crua bovina (41,2 por cento) ou suína 27,9 por cento) e carne com "canjiquinha' (25,0 por cento)