Lassa fever virus. Coloured transmission electron micrograph (TEM) of a single Lassa virus, cause of Lassa fever. It belongs to the Arenaviridae group of viruses. Here, the virus is stained negatively to show surface spikes (yellow) which assist the virus to infect its host cells. Lassa fever occurs in West Africa. Rats harbour the virus which is spread by inhaling rat urine, or coughed droplets of infected patients. High fever, headache and severe muscular pain result, and death may occur due to heart or kidney failure. Antiviral drugs may be of assistance. Magnification: x55,000 at 6x7cm size. x150,000 at 8x10"~PORTRAIT"