Human figure with viruses. Computer graphic showing a silhouette of a human figure, on a background of viruses. This abstract image may depict the many viral agents which can infect humans. Such viruses include HIV which causes AIDS, the measles virus and influenza virus, and viruses responsible for herpes and hepatitis. As seen here, viruses are made up of a protein coat of many shapes and symmetrical forms. Spikes on the coat facilitate viral attachment and infection of their host cells. Inside the viral coat is genetic material in the form of RNA or DNA.