A Multiplex Nanopore Sequencing Approach for the Detection of Multiple Arboviral Species.

The emergence and continued geographic expansion of arboviruses and the growing number of infected people have highlighted the need to develop and improve multiplex methods for rapid and specific detection of pathogens. Sequencing technologies are promising tools that can help in the laboratory diagnosis of conditions that share common symptoms, such as pathologies caused by emerging arboviruses. In this study, we integrated nanopore sequencing and the advantages of reverse transcription polymerase chain reaction (RT-PCR) to develop a multiplex RT-PCR protocol for the detection of Chikungunya virus (CHIKV) and several orthoflaviviruses (such as dengue (Orthoflavivirus dengue), Zika (Orthoflavivirus zikaense), yellow fever (Orthoflavivirus flavi), and West Nile (Orthoflavivirus nilense) viruses) in a single reaction, which provides data for sequence-based differentiation of arbovirus lineages.

Cross-Sectional Study to Determine the Prevalence of Hepatitis B and C Virus Infection in High Risk Groups in the Northeast Region of Brazil.

Background: HBV (Hepatitis B Virus) and HCV (Hepatitis C Virus) infections are more prevalent in vulnerable populations than the general population. The objective of this study was to investigate the prevalence of HBV and HCV infection in HIV-positive patients (GI), chronic renal failure (CRF) patients (GII) and coagulation disorder individuals (GIII). Methods: A cross-sectional study was conducted from June 2014 to March 2015. Serum samples were tested for markers of hepatitis B and C by enzyme-linked immunosorbent assay (ELISA). Sociodemographic, epidemiological, clinical and laboratory data and accompanying statistical analyses were performed using Epi Info™ 7. Results: A total of 348 individuals were recruited, i.e., 154 HIV-positive, 143 CRF and 51 coagulopathy patients. Among them, more than 66% were men, and the predominant age group was 26-35 years in GI and 56-65 years in GIII. Most patients had more than 8 years of education (66.2% in GI, 60.6% in GIII and 46.1% in GII), with a family income between 100-400 dollars in more than 48% of patients. The prevalence of the HBsAg marker was 3.9%, 7% and 3.9%, total anti-HBc was 28.6%, 55.9% and 31.4%, and anti-HCV was 1.3%, 12.6% and 47% for GI, GII and GIII, respectively. However, the prevalence of anti-HBs was greater than 70% in all groups. Conclusions: This study shows a high prevalence of HBV and HCV among specific groups compared to the general population. Factors such as age, income, number of sexual partners, sexually transmitted disease burden, blood transfusion history or blood products and blood transfusions before 1994 were associated with a higher prevalence for these infections.

Improved detection of dengue-1 virus from IgM-positive serum samples using C6/36 cell cultures in association with RT-PCR.

Dengue is the most important arboviral disease in the world, and its diagnosis is primarily made by serology. Virus isolation has been successful mainly in clinical samples obtained during the acute phase of illness, and is carried out through inoculation of clinical samples into C6/36 cell monolayers followed by the detection of infection by indirect immunofluorescence assay (IFA). We compared the efficiency of RT-PCR and IFA in the detection of dengue-1 virus after inoculation of C6/36 cells with samples obtained in the convalescent period of dengue infection. Out of 75 IgM-positive samples inoculated into C6/36 cells, 2 were positive by IFA while 17 were positive by RT-PCR. The 2 IFA-positive samples were collected during the acute phase of the illness; 17 positive samples were found by RT-PCR, including the 2 detected by IFA. For both methods, we also investigated the time necessary for viral detection using a fixed dose of 1 x 10(4) viruses/ml. RT-PCR and IFA detected the dengue virus 1 and 4 days after virus inoculation, respectively. The results obtained here indicate that RT-PCR is the most sensitive method in the detection of dengue viruses using C6/36 cells for viral isolation.