BACKGROUND Occult hepatitis B virus (HBV) - characterized by the absence of detectable HBsAg in the presence of HBV DNA - represents a potential threat for blood safety. OBJECTIVES This study was conducted with the aim to investigate the serological and molecular characterization of occult HBV infection (OBI) among blood donors in Mozambique. METHODS 1,502 blood donors were tested for HBsAg. All HBsAg-negative individuals were tested for HBV DNA. Antibodies against HBV core, surface and HBe antigen (anti-HBc, anti-HBs, HBeAg) were measured in HBV DNA positive individuals. FINDINGS 1435 serum samples were HBsAg negative and 16 positive for HBV DNA, 14 confirmed to have OBI, corresponding to a frequency of 0.98%. Of the 14 OBI infections identified, 13/14 (92.8%) were positive for anti-HBc, 4/14 (28.5%) for anti-HBs, and no samples were reactive for HBeAg. Of the 14 OBI cases, nine samples (64.2%) were sequenced for the S/P region. Eight samples (88.9%) belonged to genotype A1 and one (11.1%) to genotype E. One escape mutation (T123A) associated with OBI and various amino acid substitutions for genotype A1 and E were observed. MAIN CONCLUSIONS Our results show the importance of using nucleic acid amplification test to detect occult hepatitis B infection in blood donors in Mozambique.

中文翻译：

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莫桑比克马普托献血者中隐匿性乙型肝炎的分子和血清学特征

背景技术隐匿性乙型肝炎病毒（HBV）的特征是在存在HBV DNA的情况下不存在可检测的HBsAg，对血液安全性构成潜在威胁。目的进行这项研究的目的是调查莫桑比克献血者中隐匿性HBV感染（OBI）的血清学和分子特征。方法对1,502名献血者进行了HBsAg检测。所有HBsAg阴性个体均进行了HBV DNA检测。在HBV DNA阳性个体中测量了针对HBV核心，表面和HBe抗原的抗体（抗HBc，抗HBs，HBeAg）。发现1435份血清样本的HBsAg阴性和HBV DNA阳性的16份，其中14份被确认具有OBI，对应的频率为0.98％。在确定的14种OBI感染中，抗HBc阳性的占13/14（92.8％），抗HBs阳性的占4/14（28.5％），而且没有样品对HBeAg具有反应性。在14例OBI病例中，对S / P区测序了9个样品（64.2％）。八个样本（88.9％）属于基因型A1，一个样本（11.1％）属于基因型E。观察到一个与OBI相关的逃逸突变（T123A）以及基因型A1和E的各种氨基酸替代。主要结论我们的结果表明，使用核酸扩增试验检测莫桑比克献血者中隐匿性乙型肝炎感染的重要性。