Virus hiện diện trong cả bạch cầu allogeneic và là virion trong huyết tương (lây truyền qua tất cả các loại sản phẩm máu). (a) Human Immunodeficiency Virus (HIV-1, HIV-2) III. Virus hiện diện trong huyết tương như các hạt virus miễn phí (lây truyền qua tất cả các loại sản phẩm máu). | Blood Transfusion Transmitted Infections 145 Table . Viruses known to be transmitted by blood transfusion I. Viruses present in allogeneic leukocytes only transmitted by red cells and platelets but not transmitted by frozen plasma cryoprecipitate or plasma derivatives . a Cytomegalovirus CMV or HHV-5 b Epstein-Barr Virus EBV or HHV-4 c Human T-Lymphotrophic Virus HTLV-1 11 d Human Herpes Virus type 6 HHV-6 e Human Herpes Virus type 8 HHV-8 II. Viruses present in both allogeneic leukocytes and as virions in plasma transmitted by all types of blood products . a Human Immunodeficiency Virus HIV-1 HIV-2 III. Viruses present in plasma only as free virions transmitted by all types of blood products . a Hepatitis A HAV b Hepatitis B HBV c Hepatitis C HCV d Hepatitis D HDV e Hepatitis E HEV f Hepatitis G HGV g B19 parvo virus Among the viruses in this group routine tests are performed only for the HTLV viruses. The transmission of all viruses in this group by blood transfusion is likely to be either greatly reduced or eliminated by the use of leukoreduction filtration but in practice at this time this approach is only used to prevent CMV infection Chapter 38 . Group II viruses are those which are present both in allogeneic leukocytes and in plasma. They are therefore transmitted by all types of blood products. The most important virus in this group is the human immunodeficiency virus es HIV type 1 and type 2 . Since May of 1985 all blood donations have been routinely screened for the antibody to HIV-1 and since early 1996 routinely screened for p-24 antigen an early plasma marker of HIV infection. This has been success- 34 146 Clinical Transfusion Medicine ful in eliminating the vast majority of potentially infectious units. Regrettably blood donors who are exposed to HIV virus may be infectious for a period prior to development of plasma markers either of p-24 or of anti-HIV-1 . This period is sometimes described as the serosilent window period and constitutes the .
