Reovirus particles. Coloured transmission electron micrograph (TEM) of hundreds of particles (blue) of a reovirus infecting a host cell. The nucleus of the cell (green) is at centre. Viruses consist of a core of genetic material enveloped in protein coats. They rely on cellular genetic replication processes to make copies of themselves. A virus particle will infect a cell and then use the cell to make hundreds of copies of itself. This will kill the cell, and the next generation of virus particles is released to infect more cells. The reoviruses can cause febrile convulsions due to high temperatures when they infect humans.