Most of the over 300 members of the Bunyaviridae family are arthropod-borne.  The specific vectors and life cycles differ but typically involve mammalian and avian reservoir hosts with arthropod vectors. Transovarial transmission among these arthropods is an important process for overwintering.  For example, the virus in an infected female arthropod infects the eggs so that the larvae, nymphs, and adults of the following generations are infected and capable of transmitting the virus to vertebrate hosts.  Humans become infected when bitten by the arthropod--typically a mosquito or tick.  In the genus Hantavirus, the viruses are transmitted by urine, saliva, and fecal material.  Humans become infected when they come into contact with these rodents or inhale the aerosolized particulate matter. Most of the viruses are not transmissible from human to human. The Crimean-Congo Hemorrhagic Fever virus (CCHF) is, however, transmitted between humans.