Читать книгу Basic Virology - Martinez J. Hewlett - Страница 67

Some persistent infections are characterized by chronic, low‐level replication of virus in tissues that are constantly being regenerated so that damaged cells are eliminated as a matter of course. An excellent example described in more detail in Chapter 16, Part IV, is the persistent growth and differentiation of keratinized tissue in a wart caused by a papillomavirus. In such infections, virus replication closely correlates with the cell's differentiation state, and the virus can express genes that delay the normal programmed death (apoptosis) of such cells in order to lengthen the time available for replication.

The distantly related polyoma viruses, the BK and JC viruses, induce chronic infections of kidney tissue. Such infections are usually asymptomatic and are only characterized by virus shedding in the urine; however, in immunosuppressed individuals, infections of the brain and other organs can be seen. Thus, these persistent viruses have a role in the morbidity of late‐stage AIDS and in persons undergoing immunosuppression for organ transplants.