The genetic diversity of viruses: consequences for blood screening and prevention of viral infection.

The evolution of viruses contributes to their diversification, whether it b e a result of their own replication, or host-pressure dependent. Certain vi ral types, groups or subtypes are therefore found in certain regions of the world or in certain populations. The development of blood screening reagen ts is nearly always based on viral antigens or viral sequences derived from 'prototype' strains or antibodies raised against these prototype strains. Therefore in situations where an individual is infected by a viral strain t hat is genetically and antigenically distantly related to the prototype str ain used in the development of the test, screening failure may occur, in th e present article, this has been illustrated via 3 models, the human immuno deficiency virus (HIV), the hepatitis B virus (HBV), and the B19 parvovirus . Viral diversity also has a negative effect on the prevention of blood-tra nsmitted viral infections. The example provided concerns vaccination failur e and/or seroprophylaxis against hepatitis B. (C) 2000 Editions scientifiqu es et medicales Elsevier SAS.