Hepatitis B viruses. Coloured transmission elect- ron micrograph (TEM) of hepatitis B viruses (large green circles), a cause of liver inflammation. The smaller circles and the rod-shaped objects are surplus viral coat (capsid) protein from infected liver cells. These non-infectious antigens (foreign proteins) are used to make vaccines against hepatitis B. The complete viruses are called Dane particles. Hepatitis B is transmitted by infected blood passed mainly through sexual intercourse or the sharing of needles by intraven- ous drug users. Symptoms include headache, fever, weakness and jaundice. Magnification unknown.