Introduction. The problem of transfusion safety in relation to parenteral viral hepatitis still remains relevant. Viral hepatitis B (HB) remains the most common viral infection transmitted through transfusion procedures. One of the natural phases of chronic hepatitis B (CHB) is occult hepatitis B infection (OBI), characterized by an undetectable HBsAg (regardless of the other serological markers content) in the presence of hepatitis B virus (HBV) DNA in the liver tissue and an extremely low, up to undetectable, level of viral load in the blood. In the Republic of Guinea, as in most countries on the continent, the prevention of HBV transmission through transfusion is still based on HBsAg serological testing of donors only. In this connection, OBI remains as a potential threat to blood transfusion safety. Detection of HBV DNA is a reliable preventive measure against transmission of the virus from donors with HBsAg-negative HBV infection, especially in highly endemic regions. In this regard, the study was conducted to substantiate recommendations for improving blood safety against the background of significant HBV prevalence in the Republic of Guinea.The aim of the work was the evaluation of serological and molecular markers of HBV infection in blood donors in the Republic of Guinea.Material and methods. We examined 250 blood samples obtained from donors living in Conakry, Republic of Guinea. Samples were tested for the presence of serological (surface antigen, HBsAg; antibodies (ABs) to surface (anti-HBs IgG) and core (anti-HBc IgG) antigens) and molecular (DNA) markers of HBV infection.Results and discussion. The overall detection rate of hepatitis B markers was 83.2%; HBsAg was detected in 16.4% of all individuals. The high incidence of HBsAg in men (19.55%) compared to women (8.45%) was shown, the relative risk of HBV infection with the formation of HBsAg-positive chronic hepatitis B in males was also significantly higher. The prevalence of the HBV DNA in the study group was 30.4%, the OBI cases accounted for 15.6%. The prevalence of this form of the disease was shown in donors aged 30–49 years (24.78%), in the group of people younger than 30 years, the incidence was lower (8.73%), and at the age of over 50 years, OBI was not detected. Based on the phylogenetic analysis of 76 virus isolates, it was shown that genotype E prevails in the examined group (85.53%).Cases of pathogen DNA detection occurred in HBsAg-negative blood donors in the presence of anti-HBs IgG (n = 4), as well as in the simultaneous presence of ABs anti-HBs IgG and anti-HBc IgG (n = 7). The viral load exceeded 200 IU/ml in OBI samples. Escape mutations were detected by sequencing in each OBI sample, contributing to the virus escaping from diagnostic based on screening for HBsAg.Conclusion. Assessment of the prevalence viral hepatitis B markers in blood donors, determination of genotypes and clinically significant mutations of virus variants are necessary to ensure safe medical manipulations, control and prevention of the spread of this infectious agent.

Aim: To study the hepatitis A (HAV) and hepatitis Е (HEV) prevalence in the Southern region of Vietnam based on the frequency analysis of the antibodies to hepatitis A and E viruses detection in the local population and groups at increased risk of infection.Materials and methods. Serological markers of enteral viral hepatitis were determined in blood serum samples from adults aged 18 to 65 years of three groups: conditionally healthy individuals (n = 397), HIV-infected (n = 316), and patients with chronic viral hepatitis (n = 268). The ELISA method was used for the qualitative detection of anti-HAV IgG, anti-HAV IgM, anti-HEV IgG, anti-HEV IgM.Results. When analyzing the prevalence of anti-HAV IgG in samples obtained from conditionally healthy, HIV-infected, and patients with chronic viral hepatitis, no differences were found between the groups. The incidence of anti-HAV IgG in the general group (n = 981) was 80.1%, in the absence of anti-HAV IgM. There were no gender-age differences in the frequency of anti-HAV IgG in the examined groups. Antibodies anti-HEV IgG in the groups of conditionally healthy, patients with chronic viral hepatitis, and HIV-infected were present in the samples in 36,2%, 33,2%, and 39,8% of cases, respectively. The prevalence of anti-HEV IgM in these groups was 3,27%, 4,1%, and 3,79%, respectively. In the general group (n = 981), anti-HEV IgG was detected in 36,6% of cases, anti-HEV IgM in 3,66%, which corresponds to the prevalence of antibodies to HEV in endemic regions.Conclusion. A high incidence of enteral viral hepatitis markers was shown in residents of South Vietnam, including the groups of conditionally healthy, patients with chronic viral hepatitis, and HIV-infected. There is an obvious need for further studies of the spread extent of hepatitis A and hepatitis E in the Socialist Republic of Vietnam using currently available highly sensitive diagnostic methods, including sequencing of the virus›s nucleotide sequences.

The aim of this study was to assess the prevalence and study of the molecular genetic characteristics of the human immunodeficiency virus in pregnant women of the Republic of Guinea.Materials and methods. The material for the study was blood plasma samples of 972 pregnant women from the Republic of Guinea. The patients were examined for the presence of HIV infection serological (Ag+Ab) and molecular markers (RNA). For patients with a positive PCR result and a sufficient viral load (>500 c/ml), the genetic sequences of the pol gene fragment responsible for the synthesis of pro and rev proteins were obtained by Sanger sequencing. These sequences were used for phylogenetic analysis and examined for drug resistance mutations.Results and discussion. 12.96% of patients was positive in ELISA. Among women who were positive in ELISA, RNA was detected in 76.98% of cases, however, in 11 cases, RNA was detected in patients without serological markers of HIV infection, so the incidence of HIV RNA in the entire surveyed population was 11.11%. In the vast majority of cases, the circulating recombinant form 02_AG is found. Based on the analysis, we assume a significant contribution of recombinant forms of HIV to the genetic diversity of the virus in the region under study.The incidence of DR mutations was quite high (26.80%). The most frequent substitutions were in position 20 of the protease (70.10%, 95% CI 59.96–78.98%), of which the K20I mutation was dominant. In addition, the L10I/V mutation was relatively common, increasing the replication of viruses with other PI resistance mutations. Among the mutations associated with HIV resistance to NNRTIs, a non-polymorphic mutation V179T was found.Conclusion. An important factor influencing the effectiveness of Prevention of Mother to Child Transmission identified in this study was the high prevalence of PDR among pregnant women in Guinea. The high prevalence of drug resistance mutations found in this study in pregnant women, as well as in ART-naive women, indicates that current regimens in Guinea are insufficient to prevent vertical HIV infection.

A method for detecting HBV DNA in peripheral blood at low viral load using real-time PCR was developed and its significance in identifying HBsAg-negative viral hepatitis B was evaluated. When developing the method, blood plasma samples and liver tissue biopsy material were used from 128 patients living in St. Petersburg, in various regions of the Russian Federation, as well as in the Central Asia countries. We also used blood plasma samples from 96 pregnant women and 37 hemodialysis center patients living in Northwestern Federal District, 199 foreign citizens undergoing medical examination to obtain work permits at the Directorate for Migration in the Northwestern Federal District, 397 conditionally healthy people living in the Socialist Republic of Vietnam. HBV was detected by nested PCR. Analytical sensitivity was tested using the stepwise dilution method. According to the method developed by us, at the first stage, the HBV DNA is amplified using at the first stage oligonucleotides flanking the genome region 2932-3182 ... 1-1846 nt., and at the second stage two oligonucleotides pairs to the genome virus regions (gene S and gene X) and corresponding oligonucleotide fluorescently labeled probes complementary to the amplified fragments regions carrying fluorophores at the 5’-end, and non-fluorescent quenchers at the 3’-end. The channel corresponding to the FAM fluorophore detects the HBV DNA S-region amplification product, and the channel corresponding to the ROX fluorophore detects the HBV DNA X-region amplification product. The method sensitivity for DNA extraction from plasma with a 100 μl volume was 10 IU/ml. Obtaining a threshold cycle Ct for only one FAM or ROX fluorophore may indicate the HBV DNA presence in a sample at a load of less than 10 IU / ml, HBV detection in this case is possible with a repeated PCR study of the corresponding sample with HBV DNA extraction from an increased plasma volume (200-1000 μl). The developed method makes it possible to identify various HBV genovariants, both characteristic and rare in the Russian Federation, circulating in other world regions. The method can be used to detect HBV in risk groups, in the population, as well as in screening blood donors in order to ensure the blood transfusions safety.

Objective of our work was to assess prevalence of the primary HCV drug resistance mutations in the NS5b gene in patients with newly diagnosed HIV infection.Materials and methods. The study material was 196 blood plasma samples from patients living in the North-Western Federal District with newly diagnosed HIV. Samples were examined for the anti-HCV antibodies and HCV RNA presence. If HCV RNA was detected, amplification was performed using three primers pairs that co-flanked the NS5b gene. After sequencing the indicated gene nucleotide sequence, the virus subtype was determined and drug resistance mutations were detected.Results and discussion. Antibodies to HCV were detected in 18.87 % of HIV-infected individuals. HCV RNA was detected in 18.36 % of the patients, including 89.18 % anti-HCV-positive and 1.88 % anti-HCV-negative. It was shown that co-infection is more common in men (77.8 %) compared to women (22.2 %) – χ2 = 3.996 at p = 0.0456, df = 2. The difference in the HIV viral load between the groups with HIV monoinfection and with HIV + HCV coinfection was demonstrated (χ2 = 6.284 at p = 0.0432, df = 2). A significant difference between the groups by the CD4 + lyphocytes number was shown. In the phylogenetic analysis, the HCV subtypes are distributed as follows: HCV 1b – 47.2 %, HCV 3a – 30.6 %, HCV 1a – 13.9 %, HCV 2a – 5.5 % and only one sample was defined as HCV 2k – 2.8 %, respectively. Nine samples (25 %) presented NS5b mutations in  the positions related to the development of drug resistance of HCV, including two samples among HCV genotypes 1a and 3a (i.e., 5.6 % of the total HIV + HCV group), as well as five samples among HCV 1b (13.9 % of the total group). Mutations among HCV 1a were C316Y and N444D substitutions. Among HCV 1b, C316N, C451S, S556N/G substitutions were identified. Among patients with HCV 3a, 2 samples (5.6 %) with a D310N mutation associated with an unfavorable disease prognosis were found. The introduction of direct sequencing of HCV nucleotide sequences into the routine laboratory diagnostics will allow us to estimate the primary drug resistance mutations prevalence in risk groups to predict the HCV life-threatening complications development – fibrosis, cirrhosis, hepatocellular carcinoma, as well as the outcome of antiviral therapy prognosis. The data obtained can be rationally used to assess the dynamics of the HCV primary pharmacoresistance prevalence among HIV-infected individuals.