Hepatitis B virus. Computer model showing the structure of the protein coat (capsid) surrounding a hepatitis B virus (HBV) particle (virion). HBV particles consist of an outer lipid envelope and an icosahedral protein coat encasing DNA (deoxyribonucleic acid), the genetic material of the virus. HBV is transmitted through shared bodily fluids, either sexually or by sharing hypodermic needles. It can also be transmitted from a mother to her baby at birth. The virus targets the liver and infection causes loss of appetite, nausea, vomiting, fever and jaundice (yellowing of the eyes and skin).