Computer virus. Conceptual computer artwork of a mosquito transmitting a computer virus program to a computer. The computer virus can contain many types of instructions, usually harmful, and carry them out in an extremely destructive manner, often wiping out large amounts of information and then transmitting itself onwards to another computer. The mosquito is an insect that is a vector (agent of transmission) for many human diseases. TCP/IP stands for Transmission Control Protocol/Internet Protocol. Many viruses are spread on the internet, the global communications network.