Whereas blood and body fluids are the primary vehicles of transmission, virus may also be spread by contact with body secretions such as semen, saliva, sweat, tears, breast milk, and pathologic effusions
vertical transmission from mother to child during birth
transfusion, blood products, dialysis, needle-stick accidents among health care workers, intravenous drug abuse, and sexual transmission
vertical transmission produces a high rate of chronic infection.
strong response by virus-specific CD4+ and CD8+ interferon γ-producing cells are associated with the resolution of acute infection.
damage to the virus-infected cells by CD8+ cytotoxic T cells.