Although the damage in most infections is believed to result from direct invasion by the virus and not from a host-mediated antigen-antibody or antigen-lymphocyte reaction, the pathogenesis of bunyaviruses in the vertebrate host has not been extensively studied
The damage to the kidneys in hemorrhagic fever with renal syndrome and to the brain and retina in Rift Valley fever occurs after humoral antibody is formed. These complications have been postulated to result from a host reaction.