Hepatitis B virus (HBV) is a species of the genus Orthohepadnavirus, which is likewise a part of the Hepadnaviridae family of viruses, causes the disease hepatitis B that can establish a persistent and chronic infection in humans through immune anergy. Compared to other human viruses, HBV is unusual in that it contained a vast excess of noninfectious subviral particles composed only of viral surface proteins and lipids, appear predominantly as 22 nm spheres and filaments with a diameter of 22 nm.
