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.