Serological characterization of occult hepatitis B virus infection among blood donors in India

IntroductionDiscovery of hepatitis B infections characterized by the presence of viral genome without detectable HBsAg (Occult Hepatitis; OBI) has initiated a considerable amount of research in this regard. Our study is a serological and molecular characterization of OBI among the donors who donated at our blood bank during the study period.Material and MethodDuring the study period HBsAg ELISA non reactive ID-NAT reactive donors samples were screened for presence of antibody against HBc, HBs and HBe. Molecular analysis of these NAT yield samples was undertaken for detection of the viral load and genotyping.ResultWe studied 28,134 HBsAg ELISA non reactive donor samples. On testing them with ID-NAT, HBV DNA was detected in 25 samples. Eighteen samples out of these 25 NAT yield were further worked up. The 66.6% of the NAT yield samples (12 out of 18) were reactive for antibody against HBc. The 25% (3 out of 12) of these NAT yield samples having antibody against core antigen also had antibody against HBs. The 27.7% (5 out of 18) of NAT yield detected by ID-NAT did not have any detectable serological marker in blood. Four out of 12 core antibody positive NAT yield samples had genotype A HBV infection.ConclusionAs per our study molecular detection of HBV DNA by ID-NAT, we were able to analyze 18 HBV NAT yield cases among 28,134 HBsAg ELISA non reactive donors. Out of 18, 12 donors were OBI whereas the rest (6) were in window period (WP yield) of HBV infection. One out of every 3.6 NAT yield detected by ID-NAT was non reactive for all serological markers.     

深圳献血人群隐匿性乙型肝炎病毒全基因序列系统进化树分析

目的了解深圳献血人群隐匿性乙型肝炎B和C基因型及亚型的分布规律,研究不同毒株全基因序列进化关系。方法对30例HBsAg(-)/HBV DNA(+)标本进行基本核心启动子/前C区(BCP/PC,295 bp)、HBV全基因(3 162 bp)巢式PCR扩增,PCR产物克隆后测序。2者均为阳性的5份标本合成3 215 bp长的全基因序列,与GenBank中已发表的HBV A～H基因型23株的全序列进行系统进化树分析确定基因型,将所属基因型B和C亚型再作系统进化树分析,以确定基因亚型。结果获得5例全基因序列,4例为C型,1例为B型。分属于C2,C2,C2,C1和B2亚型。3例C2亚型与日本、马来西亚基因亚型的进化距离最近,C1株与马来西亚和泰国2例携带者的病毒株进化距离最近。B2株与印度尼西亚华裔基因亚型的病毒株进化距离最近。结论深圳献血人群隐匿性乙型肝炎感染病毒基因亚型有C2,C1,B2,以C2亚型为主。     

不同核酸检测方法对献血者隐匿性乙肝病毒感染的研究

目的了解无偿献血者中隐匿性乙肝病毒感染情况,并比较不同核酸检测方法对隐匿性乙肝病毒感染检测能力的差异。方法分别采用nested-PCR和Procleix Ultrio全自动核酸检测系统对无偿献血者血浆标本进行HBV核酸检测,对核酸阳性标本进行HBV DNA序列分析。结果在总计9 209例次标本的检测中,共有9 159例为HBsAg(-);HBsAg(-)标本中nested-PCR方法检出18例HBV DNA阳性(0.19%,18/9 159),而Procleix Ultrio检出7例(0.076%,7/9 159),两者间差异有统计学意义(P<0.05);测序结果显示隐匿性HBV感染者中C基因型所占的比例(64.7%,11/17)明显高于HBsAg阳性的HBV感染者(23.1%,6/23,P<0.01)。结论闽南地区无偿献血者中存在较高比例的隐匿性乙肝病毒感染;不同核酸检测方法对献血者隐匿性乙肝病毒感染的检测能力存在差异。     

Risk factors for chronic hepatitis B virus infection among blood donors in Bangalore,India

Objectives and Aim: We performed a study of hepatitis B virus (HBV) risk factors among blood donors in Bangalore, India. Background: HBV infection is prevalent in India and poses a potential risk of transmission by blood transfusion, but studies of risk factors for hepatitis B surface antigen (HBsAg) carriage among Indian blood donors are lacking. Methods/Materials: Using a case‐cohort design, we enrolled 71 cases with repeatedly reactive HBsAg results and a cohort of 212 contemporaneous blood donors with unknown HBsAg status. Questionnaire data were analysed using multivariable logistic regression. Results: In our multivariate analysis controlling for age, HBsAg positivity was associated with repeat donor status (OR = 0·34, 95% CI 0·17–0·71 vs first‐time donor status), residence outside Bangalore and Hosur (rural areas) (OR = 15·66, 95% CI 3·60–68·07vs Bangalore residence), having been a customer at a local barber shop (OR = 4·07, 95% CI 2·06–8·03), close contact with a person who had jaundice (OR = 13·64, 95% CI 3·71–50·24) and cigarette smoking (OR = 3·25, 95% CI 1·39–7·60). Conclusion: In addition to recognised demographic risk factors, associations with patronage of local barbers and contact with jaundiced individuals suggest behavioural risk factors that could be adopted as exclusionary criteria for blood donation in India.     

献血者感染HBV相关危险行为因素的调查研究

目的研究献血者感染乙肝病毒(HBV)的相关危险因素。方法对203名单纯HBsAg阳性的献血者及406名所有血液检测项目均阴性的献血者进行对照研究,应用多因素条件Logistic回归模型分析与HBV感染有关的因素,并对危险因素的人群归因危险度(PAR)进行估计。结果筛选出5项与感染HBV有关的因素,研究发现使用共用剃刀、乙肝家族史、内窥镜检查史、牙科治疗史、未注射乙肝疫苗可以增加乙肝感染的危险性,其危险度(OR)分别是:4.010 2、2.808 2、5.815 7、1.758 3、4.044 4,人群归因危险度分别是:43.39%,5.50%,1.75%,13.46%,29.91%。5项危险因素总的人群归因危险度为66.78%。结论使用共用剃刀、乙肝家族史、内窥镜检查史、牙科治疗史、未注射乙肝疫苗是HBV感染的危险因素。     

闽南地区无偿献血者隐匿性乙型肝炎病毒感染研究

目的研究闽南地区无偿献血者中隐匿性乙型肝炎病毒感染(OBI)情况,探讨现有输血传播乙肝病毒(HBV)的检测方法的有效性。方法依据多种与HBV相关血清学指标的检测情况对献血者标本进行HBV携带风险评价分级,对较高携带风险的标本做单份多区段巢式-PCR检测其HBV DNA,对低携带风险的标本做10份混合的巢式-PCR检测。采用这一方案,对闽南地区19 360例HBsAg阴性的无偿献血者标本做检测分析。结果闽南地区HBsAg阴性献血者中的HBV DNA阳性检出率为0.21%(40/19 360,95%CI:0.15%—0.28%),属于OBI;其中抗-HBc阳性检出率85%(34/40),但阳性预测值仅为3.4%(34/995,95%CI:2.4%—4.7%);HBV NRAg阳性预测值30%(6/20),但灵敏度为15%(6/40)。结论现有筛查体系下无偿献血者中仍存在一定比例的OBI,需要寻求更为有效的检测方法。     

Trends in prevalence of hepatitis B virus infection among Iranian blood donors, 1998–2007

Assessment of the quality of donor selection and safety of the blood supply can be estimated by monitoring the prevalence of the serologic markers of infectious disease in screening tests. In the present study, changes in rates of hepatitis B virus (HBV) infection are studied in the period 1998–2007 in Iranian Blood Transfusion Organization (IBTO). Prevalence of serological marker of HBV infection [hepatitis B surface antigen (HBsAg)] was evaluated in blood donations in Iran as well as for Fars province representing a low prevalence, and Sistan-Baluchestan (S&B) province as a high prevalence region throughout 1998–2007. For assessing frequency of infection, the prevalence of HBsAg per 100 000 donations and 95% confidential intervals (95% CIs) is calculated. P value is estimated by χ² test. A total of 14 599 783 donations were collected during 10 years. The overall HBsAg prevalence rates declined from a 1.79% (1789/100 000 donations) in 1998 to 0.41% (409/100 000 donations) in 2007 in Iran. In Fars province, HBsAg prevalence decreased from 0.89% in 92 999 donations in 1998 to 0.34% in 148 014 donations in 2007 and in S&B province, the rate of HBsAg has gone down from 3.74% in 44 036 donations in 1998 to 1.15% in 56 057 donations in 2007. The frequency of HBV infection entering the blood supply has decreased over this period as a result of improvement in donor recruitment and selection, usage of software in transfusion services and possibly decreasing HBV infection prevalence in general population.     

Hepatitis B virus DNA in blood donors with anti-HBc as a possible indicator of active hepatitis B virus infection in Yucatan, Mexico

Hepatitis B virus (HBV) may be present in serum even when negative for HBV surface antigen (HBsAg). If routine screening of sera for anti-HBV core antigen (anti-HBc) is not done, low-level HBV viraemia may not be identified. A study was done on the presence of HBV DNA in serum samples from Mexican blood donors negative for HBsAg. Sera from 158 volunteer blood donors, negative for HBsAg and anti-HBs, but positive for anti-HBc, were analysed using nested polymerase chain reaction (PCR). HBV DNA was detected in sera from 13 (8.23%) of the 158. Specificity of the PCR-amplified products was corroborated using Southern blot. Single strand conformation polymorphism (SSCP) analysis showed identical SSCP-banding patterns for all 13 PCR products, suggesting similar cDNA sequences. Occult HBV infection was observed in approximately 8% of anti-HBc only donors. The absence of HBsAg in the blood of apparently healthy individuals may not be sufficient to ensure lack of circulating HBV, and blood containing anti-HBc only may be infectious until proven otherwise.     

Risk factors for hepatitis C virus infection among blood donors in northern Thailand

BACKGROUND: The epidemiology, virology, and risk factors for hepatitis C virus (HCV) infection among blood donors in northern Thailand have not been extensively evaluated. STUDY DESIGN AND METHODS: We did a prospective matched case-control study of blood donors who tested positive for HCV and were confirmed by recombinant immunoblot assay or nucleic acid testing. Infected donors were matched with one to four HCV-uninfected donors for sex, age +/- 5 years, and donation at the same site within 15 days of the HCV-positive donor. Married donors were invited to bring their spouse for HCV testing. RESULTS: Among 166 matched sets, a history of intravenous drug use (IDU), reported by 58 HCV infected donors (35.5%) and 2 HCV-negative donors, was strongly associated with HCV infection (odds ratio [OR], 107.6; 95% confidence interval, 14.8-780.7). In multivariate analysis among donors without a history of IDU, significant risk factors included a history of a blood transfusion (OR, 28.8), immediate family with a history of hepatitis/jaundice (OR, 4.4), six or more lifetime sexual partners (OR, 2.7), and increased frequency of blood donation (OR, 0.9). Six of 45 spouses of HCV-infected donors, and none of 44 spouses of uninfected donors, were HCV positive (p = 0.005). CONCLUSION: Our data indicate that illicit IDU and a history of transfusion are important risk factors for HCV infection in Thailand. Also, our data suggest there may be some risk of transmission by sex or other close contact between spouses.     

Prevalence of antibodies to hepatitis B core antigen and occult hepatitis B virus infections in Korean blood donors

BACKGROUND: This study was performed to determine the prevalence of antibodies to hepatitis B core antigen (anti‐HBc) among Korean blood donors and frequencies of hepatitis B virus (HBV) DNA and antibodies to hepatitis B surface antigen (anti‐HBs) in anti‐HBc–positive donors. STUDY DESIGN AND METHODS: A total of 12,461 consenting blood donors were consecutively enrolled from Korean Red Cross Blood Services from April to October 2008. All of the donors were screened for anti‐HBc with an electrochemiluminescence immunoassay. Repeat‐reactive anti‐HBc–positive donors were assayed for anti‐HBs and for HBV DNA using a multiplex test (Cobas TaqScreen, Roche Molecular Systems) on individual donation. RESULTS: Of the 12,461 donors, 1682 (13.5%) were reactive for anti‐HBc. Among different age groups, there was a steady increase in the anti‐HBc–positive rate, ranging from 2.0% in the age group of less than 20 years to 80.0% in the age group of 60 years and older (p < 0.0001). Of the anti‐HBc–positive donors, 1523 (90.5%) were anti‐HBs positive. HBV DNA was detected in two donors who were anti‐HBc positive and hepatitis B surface antigen negative. The prevalence of occult HBV infection was 0.016%, and the HBV nucleic acid test (NAT) yield was 1 in 838 (0.12%). CONCLUSION: This study helps to determine the current status of hepatitis B infection and the prevalence of occult HBV infection in the blood donor population in Korea. We estimate that in Korea, up to 161 units per million donated units from blood donors may contain HBV DNA. Although the potential infectivity of these units has been debated upon, the HBV NAT assay could prevent certain transfusion‐transmitted HBV infections.