College of Veterinary Medicine, China Agricultural University, Beijing, China.
Virol J. 2010 Mar 17;7:60. doi: 10.1186/1743-422X-7-60.
The objective of this study is to established evidence of the existence of a novel member of the hepadnavirus family endemic in swine. Temporarily this virus was designated as swine hepatitis B virus (SHBV). This SHBV can be detected by using human hepatitis B virus diagnostic kits including ELISA, immunohistochemical staining, and transmission electron microscopy (TEM). Also seroprevalence of pig farms in Beijing, China, and pathological features of SHBV infection was determined.
Screened result shows that overall prevalence of HBsAg was 24.8%, closed to that of anti-HBsAg, whereas HBeAg and anti-HBe were barely detectable. The distribution of HBsAg and HBcAg was examined by immunohistochemistry of liver samples. Typical hepatitis pathological change, such as spotty parenchymal cell degeneration, necrosis of hepatocytes and proliferation of fibrous connective tissue were observed during histopathological analysis. Analysis of HBsAg-positive serum with TEM revealed two morphologic forms, 20 nm and 40 nm sized particles, similar to small spherical and Danes particles of HBV. Observation of the ultrastructure of the liver also found HBV-like particles in the nucleus of hepatocytes.
Our research result implies that SHBV could be a causative agent of swine. The discovery of SHBV will unveil novel evolutionary aspects of hepatitis and provides new information for further hepadnavirus research.
本研究旨在证实一种新型猪乙型肝炎病毒（SHBV）的存在，该病毒属于肝炎病毒科。该病毒可以使用人类乙型肝炎病毒诊断试剂盒（包括 ELISA、免疫组织化学染色和透射电子显微镜（TEM））进行检测。还检测了中国北京养猪场的血清阳性率和 SHBV 感染的病理特征。
筛查结果显示，HBsAg 的总阳性率为 24.8%，接近抗 HBsAg，而 HBeAg 和抗 HBe 则几乎检测不到。通过对肝组织样本进行免疫组织化学分析，检测了 HBsAg 和 HBcAg 的分布。在组织病理学分析中观察到典型的肝炎病理变化，如点状实质细胞变性、肝细胞坏死和纤维结缔组织增生。用 TEM 分析 HBsAg 阳性血清发现了两种形态，即 20nm 和 40nm 大小的颗粒，类似于乙型肝炎病毒的小球形和 Dane 颗粒。对肝的超微结构观察还发现，HBV 样颗粒存在于肝细胞的核内。
我们的研究结果表明，SHBV 可能是猪的致病因子。SHBV 的发现将揭示肝炎的新进化方面，并为进一步的肝炎病毒研究提供新信息。
