Hepatitis B virus (HBV) causes significant morbidity and mortality globally primarily due to its ability to cause hepatitis, liver cirrhosis and hepatocellular carcinoma. The Kenya National Blood Transfusion Services screens for Hepatitis B antibodies using the chemiluminescent microparticle immunoassay method. This test does not inform on the genotypic characteristics of the virus or the actual presence of the virus in blood. This study therefore sought to determine the serologic and genotypic profiles of HBV circulating among the voluntary blood donors in Nairobi. Blood samples were collected in plain and EDTA vacutainers and tested for the Hepatitis B surface antigen (HBsAg). HBV DNA was then extracted from plasma, its overlapping P/S gene amplified and sequenced. The resulting sequences were used to analyze for the circulating genotypes and mutations within the P and S genes. Bivariate statistical analysis was used to determine the association between demographic factors and HBV infection. A seroprevalence of 2.3% (n = 7) was reported. The age group 19–28 years was significantly associated with HBV infection. Nine samples were positive for HBV DNA; these included 2 HBsAg positive samples and 7 HBsAg negative samples. Genotype A, sub genotype A1 was found to be exclusively prevalent while a number of mutations were reported in the “a” determinant segment of the major hydrophilic region of the S gene associated with antibody escape. RT mutations including mutation rt181T in the P gene conferring resistance against Lamivudine and other ʟ-nucleoside drugs were detected. There is a high prevalence of occult HBV infections among these blood donors and therefore the testing platform currently in use requires revision.

中文翻译：

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肯尼亚内罗毕低风险自愿献血者 HBV 的血清阳性率和基因型特征

乙型肝炎病毒 (HBV) 在全球范围内导致显着的发病率和死亡率，主要是由于其能够引起肝炎、肝硬化和肝细胞癌。肯尼亚国家输血服务中心使用化学发光微粒免疫分析法筛查乙型肝炎抗体。该测试不会告知病毒的基因型特征或病毒在血液中的实际存在。因此，本研究试图确定在内罗毕自愿献血者中传播的 HBV 的血清学和基因型特征。在普通和 EDTA 真空采血管中收集血液样本并检测乙型肝炎表面抗原 (HBsAg)。然后从血浆中提取 HBV DNA，对其重叠的 P/S 基因进行扩增和测序。所得序列用于分析 P 和 S 基因内的循环基因型和突变。双变量统计分析用于确定人口因素与HBV感染之间的关联。据报道，血清阳性率为 2.3% (n = 7)。19-28 岁年龄组与 HBV 感染显着相关。9 个样本 HBV DNA 呈阳性；其中包括 2 个 HBsAg 阳性样本和 7 个 HBsAg 阴性样本。发现基因型 A，亚基因型 A1 是唯一普遍存在的，而在与抗体逃逸相关的 S 基因主要亲水区的“a”决定簇中报告了许多突变。检测到 RT 突变，包括 P 基因中的突变 rt181T，导致对拉米夫定和其他ʟ-核苷药物产生抗性。