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Objective: This study aims to determine the prevalence of Occult Hepatitis B and C Infections among Egyptian injection drug users (IDUs) and identify key risk factors contributing to their occurrence within this high-risk group. Methods: In this cross-sectional study, 200 Egyptian IDUs were assessed. Participants were negative for Hepatitis B surface antigen and hepatitis C virus (HCV) RNA, with anti-HCV positive patients who achieved sustained virologic response after treatment included. Quantitative polymerase chain reaction (PCR) was used to detect HCV RNA in plasma and peripheral blood mononuclear cells, while HBV DNA was identified via nested PCR. Comparisons were made between Occult Hepatitis B infection (OBI) positive and OBI negative subgroups, as well as between other comprehensive income (OCI) positive and OCI negative subgroups. A significance level of 0.05 was set, with P-values below this indicating statistical significance. Statistical comparisons between OBI and OCI-positive and negative groups were performed using the Mann–Whitney U test and Chi-square test. Results: OBI was found in 32% of IDUs, while OCI was detected in 42% of IDUs, and was present in 53.6% of seropositive individuals. All OBI patients showed a significant increase in all liver function tests, while OCI patients had significant elevations in alanine transaminase and aspartate transaminase values. HIV coinfection was identified in 39.1% and 26.1% of OBI and OCI cases respectively. OBI and OCI coinfection were detected in 31 patients. Conclusion: Hidden infections such as OBI and OCI remain an overlooked public health issue in Egypt’s IDU population. These findings highlight the need for targeted strategies to address these reservoirs of infection and could inform similar approaches in countries with comparable HBV/HCV epidemiology. [ABSTRACT FROM AUTHOR]

Objective To investigate the status of occult hepatitis B virus infection(OBI) among blood donors in Quzhou, Zhejiang, and to analyze the mutation of S region in blood donors with anti-HBc+ alone and non anti-HBc+ alone. Methods The OBI samples were screened by ELISA and NAT; the HBV DNA was amplified and sequenced; 20 anti-HBc+ alone and 25 not anti-HBc+ alone samples were obtained. Results The detection rate of OBI in Quzhou was 0.10%(155/161 045), and the positive rate of anti-HBc was 74.19%(115/155). The detection rate of OBI increased with the age of blood donors(P

Liver damage can progress through different stages, resulting in cirrhosis or hepatocellular carcinoma (HCC), conditions that are often associated with viral infections. Globally, 42% and 21% of cirrhosis cases correlate with HBV and HCV, respectively. In the Americas, the prevalence ranges from 1% to 44%. The WHO has the goal to eliminate viral hepatitis, but it is important to consider occult HBV infection (OBI), a clinical condition characterized by the presence of HBV genomes despite negative surface antigen tests. This review aims to provide an overview of recent data on OBI, focusing on its role in the development of hepatic diseases and its significance in the WHO Viral Hepatitis Elimination Plan. Specific HBV gene mutations have been linked to HCC and other liver diseases. Factors related to the interactions between OBI and mutated viral proteins, which induce endoplasmic reticulum stress and oxidative DNA damage, and the potential role of HBV integration sites (such as the TERT promoter) have been identified in HCC/OBI patients. Health initiatives for OBI research in Latin American countries are crucial to achieving the WHO's goal of eradicating viral hepatitis by 2030, given the difficulty in diagnosing OBI and its unclear association with hepatic diseases. [ABSTRACT FROM AUTHOR]

Liver damage can progress through different stages, resulting in cirrhosis or hepatocellular carcinoma (HCC), conditions that are often associated with viral infections. Globally, 42% and 21% of cirrhosis cases correlate with HBV and HCV, respectively. In the Americas, the prevalence ranges from 1% to 44%. The WHO has the goal to eliminate viral hepatitis, but it is important to consider occult HBV infection (OBI), a clinical condition characterized by the presence of HBV genomes despite negative surface antigen tests. This review aims to provide an overview of recent data on OBI, focusing on its role in the development of hepatic diseases and its significance in the WHO Viral Hepatitis Elimination Plan. Specific HBV gene mutations have been linked to HCC and other liver diseases. Factors related to the interactions between OBI and mutated viral proteins, which induce endoplasmic reticulum stress and oxidative DNA damage, and the potential role of HBV integration sites (such as the TERT promoter) have been identified in HCC/OBI patients. Health initiatives for OBI research in Latin American countries are crucial to achieving the WHO’s goal of eradicating viral hepatitis by 2030, given the difficulty in diagnosing OBI and its unclear association with hepatic diseases.

Objective: This study aims to determine the prevalence of Occult Hepatitis B and C Infections among Egyptian injection drug users (IDUs) and identify key risk factors contributing to their occurrence within this high-risk group., Methods: In this cross-sectional study, 200 Egyptian IDUs were assessed. Participants were negative for Hepatitis B surface antigen and hepatitis C virus (HCV) RNA, with anti-HCV positive patients who achieved sustained virologic response after treatment included. Quantitative polymerase chain reaction (PCR) was used to detect HCV RNA in plasma and peripheral blood mononuclear cells, while HBV DNA was identified via nested PCR. Comparisons were made between Occult Hepatitis B infection (OBI) positive and OBI negative subgroups, as well as between other comprehensive income (OCI) positive and OCI negative subgroups. A significance level of 0.05 was set, with P-values below this indicating statistical significance. Statistical comparisons between OBI and OCI-positive and negative groups were performed using the Mann-Whitney U test and Chi-square test., Results: OBI was found in 32% of IDUs, while OCI was detected in 42% of IDUs, and was present in 53.6% of seropositive individuals. All OBI patients showed a significant increase in all liver function tests, while OCI patients had significant elevations in alanine transaminase and aspartate transaminase values. HIV coinfection was identified in 39.1% and 26.1% of OBI and OCI cases respectively. OBI and OCI coinfection were detected in 31 patients., Conclusion: Hidden infections such as OBI and OCI remain an overlooked public health issue in Egypt's IDU population. These findings highlight the need for targeted strategies to address these reservoirs of infection and could inform similar approaches in countries with comparable HBV/HCV epidemiology., Competing Interests: The authors declare that they have no competing interests., (Copyright: © International Journal of Health Sciences.)

Purpose: The aim of this study was to report the results of the use of real-time polymerase chain reaction (PCR) for the diagnosis of hepatitis B virus (HBV) infection in cornea donors at the Central Eye Bank of Iran. Methods: Between 2014 and 2016, all cornea donors that had negative screening serologic results for hepatitis B (HB) surface antigen, HB surface antibody (Ab), hepatitis C virus Ab, human immune deficiency virus Ab, human T-cell leukemia virus Ab, and syphilis, and positive serology for HB core Ab were subjected to real-time PCR with a detection limit of 400 IU/mL to identify HBV DNA. Positive results for HBV DNA were considered occult HBV infections in these donors. Results: Over the 3-year period, 122 out of 10448 cornea donors had negative screening serologic tests outside of HB core Ab. Of which, 90 cases were subjected to real-time PCR. Occult HBV was detected in 11 cases (12.2%), resulting in the rejection of the corresponding corneas. The remaining 79 cases (87.8%) had negative results for HBV DNA and the corresponding corneas were used for transplantation. Conclusion: Implementation of PCR for the detection of occult HBV in cornea donors is necessary to not only increase the security level of cornea donation but also minimize the rejection rate of donors that have isolated HB core Ab reactivity.

Occult hepatitis B virus (HBV) infection (OBI) is defined as the presence of HBV DNA in the liver with or without detectable HBV DNA in the serum of individuals testing HBV surface antigen (HBsAg) negative using currently available assays. The prevalence of OBI among patients receiving hemodialysis (HD) treatment remains poorly characterized in South Africa despite the high prevalence of HBV. We sought to determine the prevalence of OBI in HD units in tertiary hospitals of KwaZulu‐Natal and to characterize the HBV S gene mutations potentially responsible for OBI. A cross‐sectional descriptive study of residual diagnostic plasma samples from 85 HBsAg‐negative patients receiving HD treatment was included. The PreS/S gene was amplified with a nested HBV polymerase chain reaction for downstream next‐generation sequencing, to determine the viral genotype and identify S gene mutations associated with OBI. Nine of the 85 samples had OBI, based on detectable HBV DNA. The point prevalence of OBI was 10.6% (95% control interval: 5.5%‐19.1%). Phylogenetic analysis of the samples with OBI showed that all belonged to genotype A. Three (~33%) samples had mutations in the major hydrophilic region (MHR) within the S gene, three (~33%) had mutations within the S gene but outside the MHR, whilst the remaining three had no mutations observed. The prevalence of OBI in HBsAg‐negative patients undergoing HD was 10.6%, suggesting that OBI is a clinically significant problem in patients with HD in this region. The screening methods for HBV infection need to be revised to include nucleic acid testing. [ABSTRACT FROM AUTHOR]

Background: Concurrent infections with hepatitis B virus (HBV) and hepatitis C virus (HCV) are increasingly recognized in patients with chronic hepatitis. In Egypt, the last decade showed a remarkable decline in HBV infection associated with remarkable rise in HCV infection. The probable impact of occult HBV in patients with chronic HCV infection has been previously investigated and the evidence suggests a possible correlation with lower response to anti-viral treatment, higher grades of liver histological changes, and development of hepatocellular carcinoma. The aim of this study was to analyze the possible influence of occult HBV infection on the clinical outcomes in chronic HCV patients and to compare conventional and real-time PCR in detecting HBV DNA among Hepatitis B surface antigen (HBsAg) negative chronic HCV. Methods: Sera collected from 100 chronic HCV patients (negative for HBsAg and positive for anti-HCV and HCV RNA) were tested for anti-HBc, anti-HBe and anti-HBs by ELISA, HCV-RNA viral load was determined by real-time PCR (TaqMan probe technique) and HBV DNA was detected with primers encoding the surface (S), core (C), polymerase (pol) and X genes. In addition, determination of liver enzymes including aspartate and alanine aminotransferases (AST, ALT) activities was performed. Results: Fifty-eight percent of the study group were positive for anti-HBc. Meanwhile, only 18 cases (18%) were positive for the polymerase gene by nested PCR and were considered as occult HBV. Among these 18 polymerase gene positive patients (occult HBV) anti-HBc was detected among 9 (50%) of cases. Different gene profiles were noticed among the 18 polymerase gene positive patients.

Hepatitis B virus is a major public health impasse all over the world. Recently a new form of hepatitis B infection named Occult hepatitis B Infection (OBI) has appeared globally. The OBI is defined as the presence of HBV DNA in the liver and/or blood in the absence of detectable serum HBsAg with/without anti-HBc or anti-HBs. The prevalence of OBI has been reported in hemodialysis (HD) patients in different regions of the world. Thus, this study investigated the prevalence of OBI among HD patients. The cross-sectional study was carried out on 84 HD patients. These sera were checked for HBsAg, HBc-IgG assessment using Enzyme linked immunosorbent assay. The DNA was extracted from the sera samples and tested for HBVDNA detection using Nested Polymerase Chain Reaction (Nested PCR). The liver function tests including serum alanine aminotransferase and aspartate aminotransferase levels were carried out for all the HD individuals. 52/84(61.9%) of HD were males and 32/84 (38.1%) were females. The patient’s age ranged from 25 to 64 with a mean age of 52.4±15.2 years. HBsAg and HBc-IgG were detected in 1(1.1%) female. 2 (2.4%; a female and a male) patients were positive for HBsAg. 14/84 (16.7%; 6 female and 8 male) HD patients were positive for anti-HBc but negative for HBsAg, among them 4(28.6%; 2 female and 2 male) cases were positive for HBV DNA, indicating the presence of OBI in HD patients. Even distribution of OBI among the HD was found in 2(2.36%) male and 2(2.36%) female (P>.0.05). In the present study the moderate rate of 4.76% OBI has been observed in HD patients. The prevalence of seropositive OBI among the gender was 2(2.36%) male and 2(2.36%) female. The seronegative OBI have not been detected in the present study but requires further investigation. In this study the affliction of OBI in HD patients is not clear.

Hepatocellular carcinoma (HCC), a tumor associated with high mortality, has rising worldwide incidence. Occult hepatitis B (OBI) could influence the development of HCC with a strong association with HCV infection. The risk of tumor recurrence or poor response to treatment may be due to the presence of underlying cirrhosis with viral hepatitis. The aim of this study is to assess the prevalence of OBI among patients who are hepatitis B core antibody positive with chronic hepatitis C (CHC) having HCC and assess its impact on treatment response. A total of 240 patients with CHC who were negative for hepatitis B surface antigen (HBsAg) were enrolled. One hundred twenty patients were diagnosed to have HCC for which they underwent interventional treatment whereas 120 patients had no evidence of HCC. Hematological and biochemical tests, Anti-HBc IgG, and HBV-DNA were done. Prevalence of isolated Anti-HBc IgG and HBV DNA in their sera were 70 and 23.8% respectively in HCC patients, but only 43.3% and 15.4% respectively in CHC patients. Patients who tested positive for anti-HBc IgG had one and half times higher risk of having HCC when compared patients who tested negative. Majority (84.6%) of patients with HCC who were non-responders to interventional treatment tested positive for anti-HBc IgG, and 36% of them had detectable HBV DNA in their sera. HBV DNA(+) patient had two times higher risk of having poor response to HCC intervention treatment more than patients with serum HBV DNA(−). Previous exposure to HBV had a strong association with HCC in CHC patients, and OBI is an independent risk factor for poor response to intervention treatment of HCC. [ABSTRACT FROM AUTHOR]

Hepatitis B virus is a major public health impasse all over the world. Recently a new form of hepatitis B infection named Occult hepatitis B Infection (OBI) has appeared globally. The OBI is defined as the presence of HBV DNA in the liver and/or blood in the absence of detectable serum HBsAg with/without anti-HBc or anti-HBs. The prevalence of OBI has been reported in hemodialysis (HD) patients in different regions of the world. Thus, this study investigated the prevalence of OBI among HD patients. The crosssectional study was carried out on 84 HD patients. These sera were checked for HBsAg, HBc-IgG assessment using Enzyme linked immunosorbent assay. The DNA was extracted from the sera samples and tested for HBVDNA detection using Nested Polymerase Chain Reaction (Nested PCR). The liver function tests including serum alanine aminotransferase and aspartate aminotransferase levels were carried out for all the HD individuals. 52/84(61.9%) of HD were males and 32/84 (38.1%) were females. The patient's age ranged from 25 to 64 with a mean age of 52.4±15.2 years. HBsAg and HBc-IgG were detected in 1(1.1%) female. 2 (2.4%; a female and a male) patients were positive for HBsAg. 14/84 (16.7%; 6 female and 8 male) HD patients were positive for anti-HBc but negative for HBsAg, among them 4(28.6%; 2 female and 2 male) cases were positive for HBV DNA, indicating the presence of OBI in HD patients. Even distribution of OBI among the HD was found in 2(2.36%) male and 2(2.36%) female (P>.0.05). In the present study the moderate rate of 4.76% OBI has been observed in HD patients. The prevalence of seropositive OBI among the gender was 2(2.36%) male and 2 (2.36%) female. The seronegative OBI have not been detected in the present study but requires further investigation. In this study the affliction of OBI in HD patients is not clear. [ABSTRACT FROM AUTHOR]

Occult HBV infection of hemodialysis (HD) patients is informative in terms of virus transmission. It may be of clinical importance in HD patients. The aim of this study was to investigate the prevalence of anti-HBc in the HD Patients. Number of 126 patients undergoing hemodialysis were included in this study from main hemodialysis units in Yazd. Hepatitis B surface antigens (HBsAg), hepatitis B core antibody (anti-HBc) were examined in all subjects. Finally, stored serum samples from anti-HBcAb positive, HBsAg negative patients were anonymised and tested for HBV DNA by real time quantitative PCR assay. The age range of the patients was 17-88 years. Of the 126 patients, 123 patients (97.6%) were HBC-Ab negative and 3 (2.4%) were positive. Of 3 patients with Anti-HBC positive, HBV DNA was detected in 1 patient. This study showed a low rate of isolated anti-HBc (2.4%). HBV DNA was also detected in 1 patient.

Occult HBV infection of hemodialysis (HD) patients is informative in terms of virus transmission. It may be of clinical importance in HD patients. The aim of this study was to investigate the prevalence of anti-HBc in the HD Patients. Number of 126 patients undergoing hemodialysis were included in this study from main hemodialysis units in Yazd. Hepatitis B surface antigens (HBsAg), hepatitis B core antibody (anti-HBc) were examined in all subjects. Finally, stored serum samples from anti-HBcAb positive, HBsAg negative patients were anonymised and tested for HBV DNA by real time quantitative PCR assay. The age range of the patients was 17-88 years. Of the 126 patients, 123 patients (97.6%) were HBC-Ab negative and 3 (2.4%) were positive. Of 3 patients with Anti-HBC positive, HBV DNA was detected in 1 patient. This study showed a low rate of isolated anti-HBc (2.4%). HBV DNA was also detected in 1 patient. [ABSTRACT FROM AUTHOR]

Background Concurrent infections with hepatitis B virus (HBV) and hepatitis C virus (HCV) are increasingly recognized in patients with chronic hepatitis. In Egypt, the last decade showed a remarkable decline in HBV infection associated with remarkable rise in HCV infection. The probable impact of occult HBV in patients with chronic HCV infection has been previously investigated and the evidence suggests a possible correlation with lower response to anti-viral treatment, higher grades of liver histological changes, and development of hepatocellular carcinoma. The aim of this study was to analyze the possible influence of occult HBV infection on the clinical outcomes in chronic HCV patients and to compare conventional and real-time PCR in detecting HBV DNA among Hepatitis B surface antigen (HBsAg) negative chronic HCV. Methods Sera collected from 100 chronic HCV patients (negative for HBsAg and positive for anti-HCV and HCV RNA) were tested for anti-HBc, anti-HBe and anti-HBs by ELISA, HCV-RNA viral load was determined by real-time PCR (TaqMan probe technique) and HBV DNA was detected with primers encoding the surface ( S ), core ( C ), polymerase (pol ) and X genes. In addition, determination of liver enzymes including aspartate and alanine aminotransferases (AST, ALT) activities was performed. Results Fifty-eight percent of the study group were positive for anti-HBc. Meanwhile, only 18 cases (18%) were positive for the polymerase gene by nested PCR and were considered as occult HBV. Among these 18 polymerase gene positive patients (occult HBV) anti-HBc was detected among 9 (50%) of cases. Different gene profiles were noticed among the 18 polymerase gene positive patients. [ABSTRACT FROM AUTHOR]

Background: Hepatitis B virus (HBV) transmission through blood transfusion is reduced by screening for hepatitis B surface antigen (HBsAg). However this method cannot detect the presence of occult hepatitis B virus infection. This study sought to determine the prevalence of occult hepatitis B virus infection among blood donors in Ile-Ife, Nigeria. For the first time in Nigeria we employed an automated real-time PCR- method to investigate the prevalence of occult HBV in blood donors. Methods: Blood donors screened with HBsAg immunochromatographic rapid test kits at the blood transfusion units of two hospitals and found to be negative were recruited into the study. Questionnaires to elicit risk factors for HBV infection were administered and then 10 ml of blood was collected from each donor. Plasma samples obtained from these HBsAg negative blood donors were screened again for HBsAg using an enzyme-linked immunosorbent assay (ELISA) method, and those found negative were screened for the presence of total antibody to the HBV core antigen (anti-HBc) using ELISA method. Those positive to anti-HBc were then tested for HBV DNA, using an automated realtime PCR method. Results: Five hundred and seven blood donors found HBsAg negative by immunochromatographic rapid test kits at both blood transfusion units, were tested for HBsAg using ELISA and 5 (1 %) were HBsAg positive. The 502 found negative were tested for anti-HBc and 354 (70.5 %) were found positive implying previous exposure to HBV and 19 (5.4 %) of the 354 anti-HBc positive had HBV DNA signifying occult HBV infection. No risk factors were found to be associated with the presence of HBV DNA among those who tested positive. Conclusion: Occult HBV infection exists in blood donors in Ile-Ife, Nigeria and the use of HBsAg alone for screening prospective donors will not eliminate the risk of HBV transmission in blood transfusion or stem cell transplantation. [ABSTRACT FROM AUTHOR]

Background: Hepatitis B virus is one of the most important blood born viruses. Although the sensitivity of screening tests has been considerably increased, transmission may still occur due to window period or occult hepatitis B infections (OBIs). This study was aimed at evaluating the prevalence of the anti-HBc and identifying the HBV DNA in HBsAg negative blood donors. Methods: The Blood samples from 2031 HBsAg-negative blood donors were divided into three aliquots and tested for anti-HBc, anti-HBs and HBV DNA. Serologic screening including anti-HBc and anti-HBs was performed. As a confirmatory test, all positive results for anti-HBc were retested with another kit. Two positive results were considered for anti-HBc positivity. All HBsAg negative selected donations were tested by PCR assay on pooled specimens (five samples per pool), plasma samples found to be HBsAg negative but anti-HBc positive were selected for a single-unit specimen Real-Time assay. Results: The study population had a mean age of 33.25 ± 10.09 years were mainly composed of males (94.8 %). The seroprevalance rate was 4.9 % for Anti-HBc and 31.9 % for HBsAb. The majority (58.6 %) of Anti-HBc positive cases were regular blood donors with 42-49 years being the largest age group (41.4 %). Neither individual NAT nor pooled NAT test detected any HBV DNA. Conclusion: However, Screening of anti-HBc Ab is proposed as a method to identify previous contact with HBV, but there is controversy in literature data regarding the cost-benefit of exclusion of positive anti-HBc Ab in blood donors. Our data does not suggest HBc-Ab test as a screening tool in the study setting. [ABSTRACT FROM AUTHOR]

Aim: A survey of hepatitis B virus (HBV) infection in hemodialysis (HD) patients was conducted to determine the burden and risk of infection and to suggest preventive measures against HBV infection among HD patients at nine hospitals in Hiroshima, Japan, from 1999 to 2003. Methods: HBV markers were investigated for 1860 HD patients. The prevalence, incidence of HBV and prevalence of occult HBV were calculated. Results: The prevalence of hepatitis B surface antigen (HBsAg) was 2.6%, the positive rate of anti-hepatitis B core (HBc) was 20.6% and that of anti-hepatitis B surface (HBs) was 11.7%. Among 1372 patients who started HD after the approval of erythropoietin in Japan in 1991, the prevalence of HBsAg was 2.1%. The incidence rate of HBsAg positivity was 0/1000 personyears and the incidence of anti-HBc was 0.3/1000 person-years. Among 1812 HBsAg negative patients HBV DNA was detected in two: one case was negative for anti-HBc and anti-HBs, and the other was only positive for anti-HBc. Prevalence of occult HBV was 0.11%. Conclusion: The incidence rate of HBV was much lower than that of hepatitis C virus (HCV) in the same cohort. We supposed that the discrepancy between incidence rate of HBV and that of HCV was caused by the difference of their carrier rates and of their characteristics for persistent infection. So, we concluded that it is prerequisite to grasp the burden of HBV carriers in the group to prevent new HBV infections in HD patients. [ABSTRACT FROM AUTHOR]

Summary The prevalence of end-stage renal disease has increased dramatically in developing countries. Hepatitis B virus (HBV) infection is a global health problem that represents a significant co-morbidity event that has led to outbreaks of hepatitis B. There are inadequate data concerning occult HBV infection among Egyptian chronic hemodialysis patients. This study aimed to detect occult HBV infection among chronic hemodialysis patients in Alexandria, Egypt. A cross-sectional study was performed on 100 patients with end-stage renal disease that received maintenance hemodialysis and had tested negative for HBV surface antigen. Blood samples were collected before the initiation of hemodialysis. Sera were tested for hepatitis C virus (HCV) and hepatitis B core (HBc) antibodies using ELISA, and HBV DNA was detected by SYBR Green real-time PCR using specific primers for the s and c genes and by nested PCR using pol gene-specific primers. The serum activity of alanine and aspartate aminotransferase (ALT and AST) were also measured. Anti-HCV and anti-HBc antibodies were detected in 34% and 48% of patients, respectively, and 70.6% of anti-HCV positive patients were also positive for anti-HBc antibodies. This association was statistically significant ( p = 0.001). HBV DNA was detected in 32% of the hemodialysis patients. A significant association was determined between the presence of HBV DNA and anti-HCV positivity ( p = 0.021). Aminotransferases were elevated in 21% of the studied patients, more often in patients with positive anti-HCV profiles than in patients negative for anti-HCV ( p < 0.05). In conclusion, the serological markers of HBV infection should be verified with molecular tests to investigate possible occult infections, especially among anti-HBc-positive hemodialysis patients, to improve our understanding of their clinical, laboratory, and epidemiological characteristics. [ABSTRACT FROM AUTHOR]

Monoinfection with either hepatitis B (HBV) or C virus (HCV) represents one of the major causes of chronic liver disease globally. However, in endemic areas a substantial number of patients are infected with both viruses mainly as a result of the common routes of transmission. Numerous studies have demonstrated that dually infected patients carry a greater risk of advanced liver disease, cirrhosis and hepatocellular carcinoma compared with monoinfected patients. The choice of treatment is based on the virological profile of each patient taking into account the dominant virus pattern. In predominant HCV, standard combination treatment with pegylated interferon and ribavirin has proven equally effective in HBV/HCV-coinfected patients as well as in HCV-monoinfected patients. Strikingly, approximately 60% of patients with inactive HBV infection before HCV treatment may present HBV reactivation while others experience hepatitis B surface antigen seroconversion after clearing HCV, demonstrating the complexity of the interaction between the two viruses during the follow up. The therapeutic strategies for the predominant HBV dually infected patients are more vague, although high genetic barrier nucleos(t)ide analogues play an indisputable role. Finally, the recently approved combination treatments for chronic hepatitis C containing direct-acting antivirals may definitely change the treatment protocols in the future although there is no experience with these drugs in dually infected patients until today. [ABSTRACT FROM AUTHOR]

Occult hepatitis B is characterized by the absence of hepatitis B surface antigen (HBsAg) but the presence of HBV DNA. Because diagnosis of hepatitis B virus (HBV) typically includes HBsAg detection, occult HBV remains largely undiagnosed. Occult HBV is associated with increased risk of hepatocellular carcinoma, reactivation to chronic HBV during immune suppression, and transmission during blood transfusion and liver transplant. The mechanisms leading to occult HBV infection are unclear, although viral mutations are likely a significant factor. In this study, sera from 394 HIV-positive South Africans were tested for HBV DNA and HBsAg. For patients with detectable HBV DNA, the overlapping surface and polymerase open reading frames (ORFs) were sequenced. Occult-associated mutations-those mutations found exclusively in individuals with occult HBV infection but not in individuals with chronic HBV infection from the same cohort or GenBank references-were identified. Ninety patients (22.8%) had detectable HBV DNA. Of these, 37 had detectable HBsAg, while 53 lacked detectable surface antigen. The surface and polymerase ORFs were cloned successfully for 19 patients with chronic HBV and 30 patients with occult HBV. In total, 235 occult-associated mutations were identified. Ten occult-associated mutations were identified in more than one patient. Additionally, 15 amino acid positions had two distinct occult-associated mutations at the same residue. Occult-associated mutations were common and present in all regions of the surface and polymerase ORFs. Further study is underway to determine the effects of these mutations on viral replication and surface antigen expression in vitro. J. Med. Virol. 87:388-400, 2015. © 2014 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

We investigated the prevalence of occult hepatitis B virus ( HBV) infection in Japanese chronic hemodialysis patients. Hemodialysis patients ( n = 1041) were screened for occult HBV. The presence of hepatitis B surface antigen ( HBsAg), hepatitis B surface antibody, and hepatitis B core antibody (anti- HBc) was determined by various chemiluminescent immunoassays. HBV-DNA was quantified in patients positive for anti- HBc using quantitative real-time polymerase chain reaction. Among the 1041 patients, six (0.6%) were HBsAg-positive and 218 (20.9%) were anti- HBc-positive. All HBsAg-positive patients also tested positive for the presence of HBV DNA. Of 212 HBsAg-negative and anti- HBc-positive patients, three were positive for HBV DNA. Our study showed that the prevalence of occult HBV infection in chronic hemodialysis patients from eastern Japan was 0.3%. [ABSTRACT FROM AUTHOR]

Aim: Occult HBV infection (O-HBV) is defined as low level HBV replication in the absence of detectable circulating HBV surface antigen. O-HBV has been implicated in HBV reactivation, advanced liver fibrosis and cirrhosis, reduced interferon response rates, elevated liver enzyme levels, and the development of hepatocellular carcinoma. However, the prevalence of O-HBV has not been clearly established in certain at-risk populations, such as injection drug users. Methods: Therefore, the current pilot study examined the prevalence of O-HBV in a prospective cohort designed to assess the role of injection and non-injection drug use (IDU) on HIV-associated comorbidities. Results: Utilizing two distinct real-time polymerase chain reaction assays, HBV DNA was not detected in 99 participants examined. Conclusion: This finding is in contrast to other data from US IDU cohorts and suggests that the prevalence of O-HBV infection is very specific to the cohort studied, is sensitive to other confounding variables such as hepatitis C virus and/or HIV serostatus, and should not be generalized across risk groups or distinct cohorts. [ABSTRACT FROM AUTHOR]

The article presents a study which determines the frequency of occult hepatitis B virus infection (OBI) among blood donors in Sudan. A cross-sectional study was carried between 2011 and 2012 involving 100 samples of negative hepatitis B surface antigen (HBsAg) collected from blood donors who attended the Central Blood Bank. The result shows the presence of the S, C, and X genes. It concludes that HBV could be transmitted using the HBsAg as detection marker, through blood transfusion.

Purpose: HBV DNA quantification is used for individuals with uninterpretable serological tests, occult HBV infections, decreasing the window period of the disease, and treatment follow-up. Although there are commercial qPCR assays, they are expensive. In this study, we developed a highly sensitive quantitative TaqMan Real-Time PCR with an exogenous internal control to quantify HBV DNA in serum/plasma., Methods: A specific primer/probe set was designed for the S conserved region of various HBV genotypes. The primer/probe set was evaluated experimentally and in-silico. An exogenous internal control was included to monitor the effects of inhibitors. The standard plasmid was titrated using three different methods to prepare the seven standards for the assay. The functional characteristics of the in-house assay were evaluated using the standards. Two hundred clinical specimens were also tested., Results: The LOD of the in-house assay was 40 IU/mL, and the assay was linear from 3.26Log10 to 9.26Log10 IU/mL. The analytical and clinical sensitivity of the assay was 100% and 92.15%, respectively. The analytical and clinical specificity of the assay was 100% and 98.97%, respectively. The positive and negative predictive values of the assay were determined to be 98.94% and 92.38%, respectively. The highest coefficient of variation of the inter/intra-assay was 5.1%. The accuracy was close to 100% for all standards, and the correlation between the in-house assay and commercial kit AltoStar® PCR Kits 1.5 was remarkable. The results of the clinical samples using the standards titrated using AcroMetrix™ HBV Panel, Artus® HBV RG PCR Kit, and AltoStar® PCR Kits 1.5 were comparable (r ​= ​0.942, 0.951, 0.951)., Conclusions: The results indicate that the in-house assay is highly sensitive and specific, reproducible, and cost-benefit. Thus, it can be used to detect and quantify HBV DNA in research and clinical settings., Competing Interests: Declaration of competing interest The authors declare that they have no conflict of interest., (Copyright © 2022 Indian Association of Medical Microbiologists. Published by Elsevier B.V. All rights reserved.)

Abstract: Background: The role of occult hepatitis B virus infection as a cause of liver disease is still debated although many studies found a higher prevalence of this condition in subjects than those without liver disease compared. A recent meta-analysis showed an increased risk of hepatocellular carcinoma for occult hepatitis B virus infection. Aims: We carried out a meta-analysis of observational studies to summarize the existing evidence and assess quantitatively the association between occult hepatitis B virus infection and chronic liver disease. Methods: We searched the available literature on this issue published up to May 2012 using PubMed and EMBASE. All articles that provided enough information to estimate the chronic liver disease risk associated with occult hepatitis B virus infection were selected. Fourteen studies were retrieved. Results: A total of 1503 subjects with (cases) and 2052 without chronic liver disease (controls) were included. The summary odds ratio for chronic liver disease from all studies was 8.9 (95% confidence interval: 4.1–19.5). The meta-analysis restricted to 7 studies with more precise effect estimate (wt%>8%) provided a lower odds ratio estimate (odds ratio=3.9; 95% confidence interval: 1.7–9.0). Conclusions: These findings suggest a relevant association between occult hepatitis B virus infection and chronic liver disease, confirming the hypothesis that hepatitis B virus may play a pathogenic role even in the “occult” status. [Copyright &y& Elsevier]

. Occult hepatitis B virus (HBV) infection is characterized by the absence of detectable hepatitis B surface antigen (HBsAg) in the serum, despite detectable HBV DNA. Investigations of the mechanisms underlying the development of occult HBV infection are lacking in the current literature, although viral mutations in the surface region, resulting in decreased HBsAg expression or secretion, represent one potential mechanism. Wild-type HBsAg expression vectors were constructed from genotype-matched chronic HBV sequences. Site-directed mutagenesis was then utilized to introduce three genotype A mutations - M103I, K122R and G145A - associated with occult HBV infection in vivo, alone and in combination, into the wild-type HBsAg vectors. Transfection of Huh7 and HepG2 cell lines was performed, and cell culture supernatants and cell lysates were collected over 7 days to assess the effects of these mutations on extracellular and intracellular HBsAg levels. The G145A mutation resulted in significantly decreased extracellular and intracellular HBsAg expression in vitro. The most pronounced reduction in HBsAg expression was observed when all three mutations were present. The mutations evaluated in vitro in the current study resulted in decreased HBsAg expression and potentially increased hepatic retention and/or decreased hepatic secretion of synthesized HBsAg, which could explain the lack of HBsAg detection that is characteristic of occult HBV infection in vivo. [ABSTRACT FROM AUTHOR]

Hemodialysis patients potentially have an increased risk of infection with parenterally transmitted viral agents due to an impaired host immune response and multiple transfusion requirements. Viral hepatitis is considered as a problem for hemodialysis patients because 1.9% of all deaths among this population are related to the consequence of viral hepatitis. Hepatitis B virus (HBV) is one of the most important causes of transmitted infections by the parenteral route in hemodialysis patients. Occult HBV infection is characterized by presence of HBV infection without detectable hepatitis B surface antigen (HBsAg), which harbors potential risk of HBV transmission through hemodialysis. There are conflicting reports on the prevalence of occult HBV infection (OBI) in hemodialysis patients. Considering the importance of occult HBV infection in hemodialysis patients and the growing evidence on this subject, the purpose of this review is to provide comprehensive information on OBI prevalence in hemodialysis patients and highlight the most important points in this issue. [ABSTRACT FROM AUTHOR]

Occult hepatitis B virus (O-HBV) infection is characterized by the presence of HBV DNA without detectable hepatitis B surface antigen (HBV DNA+/HBsAg−) in the serum. Although O-HBV is more prevalent during HBV/HIV co-infection, analysis of HBV mutations in co-infected patients is limited. In this preliminary study, HBV PreSurface (PreS) and surface (S) regions were amplified from 33 HIV-positive patient serum samples – 27 chronic HBV (C-HBV) and six O-HBV infections. HBV genotype was determined by phylogenetic analysis, while quasispecies diversity was quantified for the PreS, S and overlapping polymerase regions. C-HBV infections harboured genotypes A, D and G, compared to A, E, G and one mixed A/G infection for O-HBV. Interestingly, nonsynonymous–synonymous mutation values indicated positive immune selection in three regions for O-HBV vs one for C-HBV. Sequence analysis further identified new O-HBV mutations, in addition to several previously reported mutations within the HBsAg antigenic determinant. Several of these O-HBV mutations likely contribute to the lack of detectable HBsAg in O-HBV infection by interfering with detection in serologic assays, altering antigen secretion and/or decreasing replicative fitness. [ABSTRACT FROM AUTHOR]

Background and Aim: Occult hepatitis B virus (HBV) infection is defined by the detectable serum HBV–DNA in HBV surface antigen-negative patients. This retrospective study aims to evaluate the therapeutic effects of combined pegylated interferon (PEG–IFN) plus ribavirin (RBV) in patients with concurrent occult HBV/hepatitis C virus (HCV) dual infection. Methods: In total, 126 consecutive chronic hepatitis C (CHC) patients who received combined PEG–IFN and RBV therapy were included. Patients were divided into the occult HBV/HCV dual infection group or the HCV-monoinfected group according to whether or not they had the detectable serum HBV–DNA. The biochemical and virological responses to combined therapy were compared between these two groups. Serum HCV-RNA and HBV–DNA were checked before treatment, at the end of treatment as well as at 6- and 12-months' follow up in the occult HBV/HCV group. Result: Six patients were seropositive for HBV–DNA and were included in the occult HBV/HCV dual infection group. There were no statistical differences in the biochemical and virological responses to combined therapy between these two groups. Undetectable serum HBV–DNA was noted at the end of the treatment and the 6- and 12-months' follow up in patients with occult HBV/HCV dual infection. Conclusion: Occult HBV infection in CHC patients is rare. The biochemical and virological responses to combined PEG–IFN and RBV therapy might be similar in CHC patients with or without occult HBV infection. The serum HBV–DNA level was low in patients with occult HBV/HCV dual infection who responded to combined therapy. [ABSTRACT FROM AUTHOR]

Hepatitis B virus (HBV) and hepatitis C virus (HCV) infections are frequent in patients with end-stage renal disease who are on maintenance hemodialysis. There are limited data about the prevalence of occult HBV infection in patients on long-term hemodialysis. Occult HBV is defined as positive HBV DNA in the blood in the absence of hepatitis B surface antigen in the serum. In this study, we determined the prevalence of occult HBV in hemodialysis patients with or without HCV infection. The study included 116 patients with end-stage renal disease on chronic hemodialysis, of whom 64 patients were HCV RNA positive (Group 1), and 52 were HCV RNA negative (Group 2). We found that four of 64 (6.3%) hemodialysis patients with HCV infection (Group 1) had occult HBV, while only two of 52 (3.8%) hemodialysis patients without HCV (Group 2) had occult HBV. We then examined whether gender-matched hemodialysis patients with positive HBV DNA in the two hemodialysis groups differed in specific parameters, ie, age, degree of liver dysfunction, and presence of coinfection with schistosomiasis, a common parasitic infection of the liver. We found no significant difference between the groups having positive HBV DNA with regard to serum levels of liver enzymes, aspartate transaminase, albumin, and hepatitis B core antigen (P > 0.05). However, we detected significantly higher levels of alanine transaminase, a prolonged duration of hemodialysis, and higher levels of schistosomal antibodies in Group 1 than in Group 2. Interestingly, we found that the presence of schistosomal antibodies, history of past blood transfusion, and longer hemodialysis duration could distinguish patients with occult HBV infection from those with HBV DNA negative infection in hemodialysis patients. In conclusion, the prevalence of occult HBV in chronic hemodialysis patients is low, and does not significantly differ between hemodialysis patients with or without HCV coinfection. [ABSTRACT FROM AUTHOR]

Abstract: Chronic hepatitis B virus infection is characterized by persistent detectable levels of hepatitis B surface antigen (HBsAg) and HBV DNA in the serum. In contrast, HBsAg is not detectable during occult HBV infection, despite the presence of HBV DNA. An altered host immune response could play a role in the development of occult HBV infection; however, potential differences in immune responses among chronic and occult HBV-infected patients have not been evaluated in vivo. In the current study, we evaluated serum levels of regulatory, apoptotic, and fibrotic/anti-fibrotic cytokines/markers as indicators of immune responses in 25 chronic and 12 occult HBV-infected patients. More than half of the patients in both chronic and occult HBV infection groups had IL-2, IL-4, IL-13, and IFN-γ levels below detectable limits. In contrast, most patients had detectable levels of IL-8, IL-10, IP-10, sFas, sFasL, and TGF-β1. Of these, only sFas was significantly different between the two groups, with lower levels observed during occult compared to chronic HBV infection (p =0.01). As a surrogate marker of apoptotic inhibition, decreased sFas during occult HBV infection suggests that apoptosis occurs at different rates in occult compared to chronic HBV infection and therefore, may contribute to persistence of occult HBV infection. [Copyright &y& Elsevier]

Abstract: Background: The clinical significance of occult hepatitis B virus (HBV) infection, defined as the presence of HBV DNA in individuals with HBV core antibodies (anti-HBc) in the absence of HBV surface antigen (HBsAg), is unclear in HIV-infected patients. This information is needed to determine the importance of detecting and treating occult HBV in this population. Objective: To determine if HIV-infected patients with occult HBV infection have an increased incidence of transaminitis. Study design: We performed a cohort study among randomly selected HBsAg−/anti-HBc+ HIV-infected patients in the Penn CFAR Database and Specimen Repository. HBV DNA was qualitatively detected using a transcription-mediated amplification assay. Hepatic transaminase levels, the main study outcome, were collected at 6-month intervals from the time of occult HBV determination. Results: Among 97 randomly selected subjects without baseline transaminitis, 13 (13%) had occult HBV. These subjects more frequently had detectable HIV RNA. The 2-year incidence of transaminitis among HIV-infected subjects with occult HBV (50 events/100 person-years) was not significantly different from those without occult HBV (38 events/100 person-years; adjusted incidence rate ratio=1.36 [95% CI, 0.72–2.59]). Conclusions: Occult HBV did not increase the incidence of hepatic transaminitis over 2 years. Future studies should determine whether occult HBV is associated with other clinically important outcomes, particularly hepatocellular carcinoma. [Copyright &y& Elsevier]

Occult hepatitis B virus (HBV) in blood donors is considered as a potential risk for transmission of HBV infection. The aim of this study was to determine the prevalence of anti-hepatitis B core antibody (anti-HBC) positivity in Egyptian blood donations as well as to estimate the frequency of HBV-DNA in anti-HBc-positive donations. The study included 760 Egyptian healthy blood donors, representing 26 different Egyptian governorates screened according to routine practice for the presence of hepatitis B surface antigen (HBsAg), hepatitis C virus (HCV) antibodies (Abs), HIV-1/2 Abs and Treponema Abs. The accepted blood units for donation were tested for the presence of total anti-HBc Abs by two tests. Positive units for anti-HBc were further tested for HBV-DNA by polymerase chain reaction. According to routine screening, a total of 48/760 units (6·3%) were rejected [38 (5%) HCV-Ab-positive units, 9 (1·18%) HbsAg-positive units and 1 (0·13%) Treponema-Ab-positive unit]. Among the accepted blood units for donation, prevalence of anti-HBc was 78/712 units (10·96%). HBV-DNA was detected in 9/78 (11·54%) of the anti-HBc-positive units, and thus, occult HBV infection was detected in 9/712 (1·26%) of the accepted blood donations. Implementing anti-HBc test to the routine assay for the forthcoming two decades would certainly eliminate possible HBV-infected units. Rejection of these units will be beneficial to decrease the risk of HBV transmission with its potential consequences particularly in immunocompromised recipients. [ABSTRACT FROM AUTHOR]

The article examines the prevalence, risk factors and outcomes for occult Hepatitis B virus (HBV) infection among HIV-infected patients. The results indicate that occult HBV occurred in a sizable proportion of HIV-infected patients and was associated with detectable HIV and the absence of chronic THC. It did not increase the risk of transaminitis and future studies should examine the long-term clinical implications of occult HBV in HIV-infected patients.

The article explores the prevalence and significance of occult Hepatitis B virus (HBV) in a prospective cohort of HIV-infected patients. The result indicate that forty-three percent of those with HBV were not previously identified as HBV, which highlight the need for ongoing screening in high-risk populations. Occult HBV may occur in persons with all negative serologic markers, representing a challenge for identification.

Abstract: Background/Aim:: Occult hepatitis B virus (HBV) infection is characterized by the presence of HBV DNA in the absence of hepatitis B surface antigen (HBsAg) in the patient serum. Although such infections have been identified in patients with chronic hepatitis C, the clinical significance of those co-infections is still not understood. Our aim was, therefore, to assess the prevalence and clinical consequences of occult HBV infection in chronic hepatitis C patients undergoing antiviral therapy. Methods:: The study population consisted of 53 HBsAg-negative patients with chronic hepatitis C treated with IFN/ribavirin or IFN/ribavirin/amantadine. Nine patients experienced a viral breakthrough (BT), 30 were non-responders (NR) and 14 were responders (R). HBV-DNA detection by PCR was performed using primers specific for the S region of the HBV genome and HCV-RNA detection by PCR with primers localised in both the 5′NC and core region of HCV genome, before, during and after treatment. Viral genome sequences were also studied. Results:: Occult HBV genomes were found in the serum of four of 53 (7.5%) patients, unrelated to anti-HBc status. No significant differences in biochemical, virological, or histological markers, age, duration of infection, were observed in patients with or without HBV DNA. There was an inverse correlation in the evolution of HBV DNA and HCV RNA levels. Direct sequencing showed that S gene of occult HBV presented mutations in the “a” determinant while no specific mutation in the core region of HCV was observed. None of the four patients co-infected with HBV and HCV were responders to anti-HCV therapy. Conclusion:: In our clinical setting, the prevalence of occult HBV co-infection among patients with chronic hepatitis C was low and independent of the presence of markers of previous HBV infection. Further studies in larger cohort of patients are warranted to determine if occult HBV co-infection may be involved in HCV resistance to combination therapy. [Copyright &y& Elsevier]

Background: Occult hepatitis B virus infection (OBI) is a challenging entity. Due to the increase in invasive procedures, blood transfusions, and difficulties in diagnosing OBI, patients are more likely to acquire OBI. This cross-sectional study was conducted to assess the prevalence of OBI by hepatitis B virus (HBV)-DNA detection, the prevalence of HBV infection by total hepatitis B core antibody (HBcAb) detection, and the potential risk factors for HBV infection in patients receiving haemodialysis regularly., Methods: This study included 80 patients receiving haemodialysis regularly, without acute or chronic HBV infection. They were selected from the dialysis units in Sana'a city, Yemen from June 2016 to June 2017. Patients who were positive for hepatitis B surface antigen and hepatitis B surface antibody were excluded from this study. Blood samples were taken prior to each haemodialysis session, and serological markers of HBV were included. HBcAb was measured by enzyme-linked immunosorbent assay, and HBV-DNA was measured by polymerase chain reaction., Results: HBV-DNA was detected in four patients (5%) and HBcAb was detected in 38 patients (47.5%). There was a significant association between HBV-DNA and HBcAb in patients receiving haemodialysis regularly., Conclusions: Patients who test positive for HBcAb should undergo additional HBV-DNA testing to allow accurate HBV screening and prevent infection of other patients., Competing Interests: None declared., (© 2022 The Authors.)

Occult hepatitis B virus (HBV) and occult hepatitis C virus (HCV) infections are characterized by lack of virological serum markers of infection with intrahepatic presence of the viral genome. These occult infections have been detected in chronic hepatitis or cirrhosis of unknown etiology. Moreover, occult HBV infection is recognized as a risk factor for the development of hepatocellular carcinoma, but the possible pathogenic role of occult HCV infection in this malignancy has not been studied. Comar and colleagues have retrospectively analyzed the presence of HBV and HCV genomes in eight hepatocellular carcinoma tissues, finding occult HBV and occult HCV infections in one and two cancerous liver tissues, respectively. This study provides evidence for the existence of occult HCV infection in the development of certain cases of hepatocellular carcinoma of unexplained origin. [ABSTRACT FROM AUTHOR]

Background: The recent rise in the incidence of hepatitis B virus (HBV) infections in a densely populated city of eastern India ("mixing vessel" of people of varied socio-economic and immune status) prompted this study. Applying saliva on fingers for enumerating bank notes is a common practice in the Indian subcontinent. Paper notes may be a potential source of "horizontal" transmission of this virus, especially if there are cuts/bruises on the oral mucous membrane or skin., Aim: To investigate whether paper currencies could be a plausible mode of horizontal transmission of HBV infection., Methods: Polymerase chain reactions (PCR) followed by nucleotide sequencing was done for the detection of HBV. Hepatitis B virus surface antigen enzyme-linked immunosorbent assay(HBsAg ELISA) was performed on all HBV deoxyribonucleic acid-positive samples to check the detectability of the virus. Atomic force microscopy (AFM) was carried out for visual confirmation of HBV particles in ultracentrifuged/immunoprecipitated samples from currency paper washings., Results: HBV-specific PCRs on pellets obtained after ultracentrifugation/ immunoprecipitation of the currency paper washings detected potentially intact/viable HBV (genotype D2) in 7.14% of samples ( n = 70). AFM gave the visual confirmation of HBV particles in ultracentrifuged/immunoprecipitated samples from currency paper washings. However, HBV isolates from the currency notes could not be detected by HBsAg ELISA., Conclusion: It is a common practice in the Indian subcontinent to count paper currencies by applying saliva on fingertips. Paper notes may be a potential source of "horizontal" transmission of this virus, especially if there are cuts/bruises on the oral mucous membrane or skin, but it was practically not possible to demonstrate experimentally such transmission. Detection of potentially intact/viable and "occult" HBV from currency poses potential risk of silent transmission of this virus among the general population., Competing Interests: Conflict-of-interest statement: The authors declare that they have no conflict of interest., (©The Author(s) 2020. Published by Baishideng Publishing Group Inc. All rights reserved.)

Occult hepatitis B infections (OBI) represent a reservoir of undiagnosed and untreated hepatitis B virus (HBV), hence the need to identify mutations that lead to this phenotype. Functionally characterizing these mutations by in vitro studies is time-consuming and expensive. To bridge this gap, in silico approaches, which predict the effect of amino acid (aa) variants on HBV protein function, are necessary. We developed an algorithm for determining the relevance of OBI-associated mutations using in silico approaches. A 3 kb fragment of subgenotypes A1 and D3 from 24 chronic HBV-infected (CHB) and 24 OBI participants was analyzed. To develop and validate the algorithm, the effects of 68 previously characterized occult-associated mutations were determined using three computational tools: PolyPhen2, SNAP2, and PROVEAN. The percentage of deleterious mutations (with impact on protein function) predicted were 52 (76.5%) by PolyPhen2, 55 (80.9%) by SNAP2, and 65 (95.6%) by PROVEAN. At least two tools correctly predicted 59 (86.8%) mutations as deleterious. To identify OBI-associated mutations exclusive to Botswana, study sequences were compared to CHB sequences from GenBank. Of the 43 OBI-associated mutations identified, 26 (60.5%) were predicted by at least two tools to have an impact on protein function. To our knowledge, this is the first study to use in silico approaches to determine the impact of OBI-associated mutations, thereby identifying potential candidates for functional analysis to facilitate mechanistic studies of the OBI phenotype. [ABSTRACT FROM AUTHOR]

Occult hepatitis B virus infection (OBI) is manifested by presence of HBV-DNA in the absence of detectable Hepatitis B surface antigen (HBsAg) with or without anti-HBV antibodies. Hence it is a potential threat in blood transfusion medicine. This study was carried out to determine the prevalence of OBI as well as evaluate the effectiveness of using Hepatitis B surface antigen (HBsAg) marker alone in the diagnosis of HBV infection among HBsAg negative blood donors in Ilorin, Nigeria. A purposive sampling, including samples from 206 already donated and prescreened blood units from HBsAg negative from apparently healthy volunteer blood donors at the General Hospital Blood Transfusion Centre, Ilorin, Nigeria, were collected for further laboratory analysis for this study. Five millilitres of blood was collected and plasma sample tested for the presence of HBsAg using a commercially available ELISA kit. In addition, Polymerase Chain Reaction (PCR) was used for molecular detection of HBV DNA in each of the samples. Data was analyzed using descriptive statistics, Chi square at p = 0.05. Of the 206 HBsAg Micropoint® rapid kits pre-screened seronegative samples collected from the blood transfusion centre, 8 (3.9%) samples were positive for the presence of HBsAg when retested using ELISA in the laboratory. Eighteen of the 206 samples (8.7%) were HBV-DNA positive by a semi-nested PCR technique giving an OBI rate of 8.7%. Out of the 18 HBV-DNA positive samples, 17 (4.4%) were from males and only one (5.6%) was from a female donor. Analysis of the 18 HBV DNA positive samples using genotype specific primers into genotype A and Non-A showed that 15 (83.3%) were HBV genotype A, while 2 (11.1%) were genotypes other than A (Non-A), one (5.6%) sample had mixed genotypes (A & non-A). A prevalence of 8.7% OBI found in this study indicates substantial risk of post transfusion HBV infection in the study area in Nigeria. Hence, the need to include HBV DNA detection in the routine blood screening that is, using Nucleic Acid Testing (NAT) technique for transfusion safety in the country.