In March 2020, WHO declared a pandemic state due to SARS-CoV-2 having spread. TaqMan-based real-time RT-qPCR is currently the gold standard for COVID-19 diagnosis. However, it is a high-cost assay, inaccessible for the majority of laboratories around the world, making it difficult to diagnose on a large scale. The objective of this study was to standardize lower cost molecular methods for SARS-CoV-2 identification. E gene primers previously determined for TaqMan assays by Colman et al. (2020) were adapted in SYBR Green assay and RT-PCR conventional. The cross-reactivity test was performed with 17 positive samples for other respiratory viruses, and the sensibility test was performed with 8 dilutions (10 based) of SARS-CoV-2 isolated and 63 SARS-CoV-2-positive samples. The SYBR Green assays and conventional RT-PCR have not shown amplification of the 17 respiratory samples positives for other viruses. The SYBR Green-based assay was able to detect all 8 dilutions of the isolate.

South America is considered to have a low prevalence of hepatitis B virus (HBV) infection, although areas with a relatively high prevalence have been identified in northern Brazil. Few epidemiological studies of populations at risk of HBV infection are available for this region. Given this, in the present study, we investigated the prevalence of HBV and the factors associated with infection among illicit drug users (DUs) in the Marajó Archipelago, northern Brazil. In this cross-sectional study, we collected samples and epidemiological information from DUs in 11 municipalities of the Marajó Archipelago. The diagnosis was established by ELISA and real-time PCR; and genotyping was done by multiplex real-time PCR. Statistical modeling was based on simple and multiple logistical regressions with the Hosmer-Lemeshow test. The mean age of the 466 DUs was 28.4 years, and most were male. The most-consumed illicit drugs were crack cocaine and marijuana. In all, 171 DUs were exposed to HBV, with genotypes A, D and F being identified. The factors associated with higher frequencies of HBV infection were (i) male gender, (ii) age above 35 years, (iii) anti-HIV positivity, (iv) tattoos, (v) the use of injected drugs, (vi) the use of illicit drugs for more than 3 years, (vii) sexual relations without protection, (viii) sexual relations with another DU, and (ix) more than 10 sexual partners in the past 24 months. In summary, this study provides important insights into the dynamics of HBV infection among DUs in the Marajó Archipelago. We hope that these findings will contribute to the development of strategies, actions and public health policies aimed at preventing and controlling this viral infection more effectively.

Hepatitis C virus (HCV) infection causes acute and chronic liver disease and may lead to cirrhosis, liver failure or hepatocellular carcinoma. The behavior of illicit drug users (DUs) typically exposes them to risks of viral infection. In the Brazilian Amazon region, a number of studies have identified high rates of drug use among adolescents, and a high prevalence of HBV infection in DUs, disseminated by sexual and parenteral activities. However, the epidemiological scenario of HCV infection in the region is still poorly understood. This study determined the prevalence, genotypes, and risk factors for HCV infection among DUs of the Marajó Archipelago. This cross-sectional study collected samples and epidemiological information from DUs in 11 municipalities. The diagnosis was established by EIA and real-time PCR, and the samples were genotyped by multiplex real time PCR. The data were analyzed by simple and multiple logistical regression. In 466 DUs, 28.3% had anti-HCV antibodies, and 25.5% had HCV-RNA. In 92 injecting drug users, 88.0% had anti-HCV antibodies, and 80.4% had HCV-RNA. Genotypes 1 and 3 were detected, with three cases of mixed infections. The multivariate analysis indicated associations of HCV infection with age (≥ 35 years), tattoos, intravenous drug use, shared use of injection equipment, and the daily and long-term (> 3 years) use of illicit drugs. These findings will contribute to the development of effective measures for the prevention of HCV infection among Brazilian DUs, as well as its general population.

Hereditary hemochromatosis is a disorder of iron metabolism characterized by increased iron intake and progressive storage and is related to mutations in the HFE gene. Interactions between thalassemia and hemochromatosis may further increase iron overload. The ethnic background of the Brazilian population is heterogeneous and studies analyzing the simultaneous presence of HFE and thalassemia-related mutations have not been carried out. The aim of this study was to evaluate the prevalence of the H63D, S65C and C282Y mutations in the HFE gene among 102 individuals with alpha-thalassemia and 168 beta-thalassemia heterozygotes and to compare them with 173 control individuals without hemoglobinopathies. The allelic frequencies found in these three groups were 0.98, 2.38, and 0.29% for the C282Y mutation, 13.72, 13.70, and 9.54% for the H63D mutation, and 0, 0.60, and 0.87% for the S65C mutation, respectively. The chi-square test for multiple independent individuals indicated a significant difference among groups for the C282Y mutation, which was shown to be significant between the beta-thalassemia heterozygote and the control group by the Fisher exact test (P value = 0.009). The higher frequency of inheritance of the C282Y mutation in the HFE gene among betathalassemic patients may contribute to worsen the clinical picture of these individuals. In view of the characteristics of the Brazilian population, the present results emphasize the need to screen for HFE mutations in beta-thalassemia carriers.

Background: Previous studies found a high prevalence of pathogens among female sex workers (FSWs) in the Amazon region, and established their parenteral and sexual transmission. This study estimated the prevalence of hepatitis C virus (HCV) infection and associated risk factors, and the frequency of HCV genotypes and resistance-associated substitutions (RASs) in this vulnerable group. Methods: Distinct sampling methods were used to access 412 FSWs in cities and riverside communities in the Amazon region from 2015 to 2018. Three methods for HCV diagnosis were used to determine infection status. HCV genotypes and RASs were identified by sequencing and nucleotide fragment analysis. An association between HCV infection and exposure factors was determined by bivariate and multivariate analysis. Results: In total, 44 (10.7%) FSWs were exposed to HCV, and 32 (7.8%) of them had active infection. Nine socioeconomic characteristics and risky sexual behaviors were associated with HCV exposure, particularly unprotected sex and condom exemption for the clients who paid extra money. Genotype 1 (81.3%) and 3 (18.7%) were detected. The frequency of FSWs with RASs was 23.1% (6/26) for grazoprevir related to the occurrence of substitutions Y56F and S122G. Conclusions: HCV infection among FSWs is highly prevalent and dominated by genotype I. Urgent preventive and treatment measures are required to reduce HCV infection in FSWs and the general population.

Background Elevated rates of Hepatitis C Virus (HCV) infection have been reported in epidemiological studies with people who used illicit drugs (PWUIDs) in different Brazilian regions. In Brazil’s Amazon region, studies have already identified the common use of illicit drugs among adolescents and the high prevalence of HCV infections among PWUIDs. However, all studies done with PWUIDs were conducted with small samples and within limited geographic coverage. This study determined the prevalence and risk factors for HCV infection in PWUIDs in the Amazon region, northern Brazil, as well as estimating the prevalence and factors associated with the HCV spontaneous clearance (HSC). Methods This cross-sectional study accessed 1666 PWUIDs from multiple municipalities of the Amazon region. Socio-demographic, economic, drug use and health-related information were collected through interviews. Blood samples collected were tested for the presence of anti-HCV antibodies and RNA-HCV. HCV genotypes were identified by real-time polymerase chain reaction (PCR). Logistic regressions were run to identify factors independently associated with HCV infection status and HSC. Results In total, 577 (34.6%) featured HCV antibodies, of which 384 (23.1%) had active HCV infection and 193 (11.6%) indicated HSC. Genotypes 1 (80.2%) and 3 (18.8%) were detected. HCV infection status was associated with the length of illicit drug use history, factors related to parenteral and sexual transmission, and factors of socio-economic marginalization leading to potential risk activities for HCV. HSC was associated with the ethnic (including indigenous) background of participants. Conclusions High levels of HCV infection were detected in PWUIDs. Genotype 1 was predominant. Intense use of illicit drugs, unprotected sexual intercourse, high number of sexual partners and social marginalization were associated with all HCV infection. HSC was associated with origin (Amazonian-born) and non-white (e.g., Black or Indigenous) of PWUIDs. These findings emphasize the need for improve HCV prevention and control services and care for PWUIDs in the Brazilian Amazon region. Electronic supplementary material The online version of this article (10.1186/s12879-019-4270-2) contains supplementary material, which is available to authorized users.

Occult hepatitis B virus (HBV) infection has been reported among patients with hepatitis C virus (HCV) infection and hepatocellular carcinoma (HCC). Our aim was to evaluate the presence of occult HBV infection in patients with HCV-related liver cirrhosis (LC) with or without HCC in São Paulo, Brazil. Serum and liver tissue samples from 50 hepatitis B surface antigennegative patients with HCV-related LC who underwent liver transplantation at the University of São Paulo School of Medicine Hospital from 1993 to 2004 were divided into groups with LC only (N = 33) and with LC plus HCC (N = 17). HBV DNA was assayed for serum and paraffin-embedded liver tissue (tumoral and non-tumoral) using real time PCR and only 1 case with HCC had HBV DNA-positive serum. All liver samples were negative. HCV genotype 3 was detected in 17/39 (43.7%) cases. In conclusion, using a sensitive real time PCR directed to detect HBV variants circulating in Brazil, occult hepatitis B infection was not found among HCV-positive cirrhotic patients and was rarely found among HCV-positive HCC patients. These results are probably related to the low prevalence of HBV infection in our population. Furthermore, we have also shown that HCV genotype 3 is frequently found in Brazilian cirrhotic patients, particularly when they also have HCC. More studies involving a large number of cases should be carried out to confirm these data and to further characterize Brazilian HCV genotype isolates to elucidate genetic features that might be related to its carcinogenic potential.

This study analyzed the genotype distribution and frequency of lamivudine (LAM) and tenofovir (TDF) resistance mutations in a group of patients co-infected with HIV and hepatitis B virus (HBV). A cross-sectional study of 847 patients with HIV was conducted. Patients provided blood samples for HBsAg detection. The load of HBV was determined using an "in-house" real-time polymerase chain reaction. HBV genotypes/subgenotypes, antiviral resistance, basal core promoter (BCP), and precore mutations were detected by DNA sequencing. Twenty-eight patients with co-infection were identified. The distribution of HBV genotypes among these patients was A (n = 9; 50%), D (n = 4; 22.2%), G (n = 3; 16.7%), and F (n = 2; 11.1%). Eighteen patients were treated with LAM and six patients were treated with LAM plus TDF. The length of exposure to LAM and TDF varied from 4 to 216 months. LAM resistance substitutions (rtL180M + rtM204V) were detected in 10 (50%) of the 20 patients with viremia. This pattern and an accompanying rtV173L mutation was found in four patients. Three patients with the triple polymerase substitution pattern (rtV173L + rtL180M + rtM204V) had associated changes in the envelope gene (sE164D + sI195M). Mutations in the BCP region (A1762T, G1764A) and in the precore region (G1896A, G1899A) were also found. No putative TDF resistance substitution was detected. The data suggest that prolonged LAM use is associated with the emergence of particular changes in the HBV genome, including substitutions that may elicit a vaccine escape phenotype. No putative TDF resistance change was detected after prolonged use of TDF.