Biology of Avian Retroviruses

Abstract

Avian retroviruses have, in the past, been placed taxonomically in a subgenus termed vernacularly “avian type C oncoviruses” of the genus type C oncovirus group, within the subfamily Oncovirinae, family Retroviridae (Matthews, 1982). The recent new classification of retroviruses place them into a separate genus (see Coffin, Chapter 2). Four distinct “species” of avian retrovirus have been described (Matthews, 1982; Porterfield, 1989): 1. Leukosis-sarcoma group viruses (also termed avian sarcoma and leukemia viruses). These are exogenous and endogenous viruses recognized mainly in the domestic fowl and which cause a variety of leukotic disorders, sarcomas, and other tumors. 2. Reticuloendotheliosis viruses. These are exogenous viruses in several species of domesticated poultry and appear to be related to mammalian retroviruses. They cause lymphomas and acute reticulum cell and other tumors. 3. Lymphoproliferative disease virus of turkeys. This is an exogenous virus of turkeys which causes a lymphoproliferative disease. 4. Pheasant type C oncoviruses. These are endogenous viruses of golden and Lady Amhurst pheasants and are apparently non-pathogenic. They are unrelated to the endogenous leukosissarcoma group viruses which also occur in certain species of pheasants.