Hepatitis E virus particles, coloured transmission electron micrograph (TEM). The virus particles are the spherical objects (purple). This virus is a non-enveloped, single-stranded RNA virus (based on ribonucleic acid). Like other hepatitis viruses, it causes inflammation of the liver. The acute inflammation from hepatitis E is not usually fatal, but causes incapacitating fever, pain and vomiting. Hepatitis E is more common in developing countries, and it is thought to be spread from infected animals to humans. There is currently (as of 2007) no vaccine, and prevention involves the improvement of sanitation. Magnification: x85,000 when printed at 10cm wide.