Feline immunodeficiency virus (FIV) is a member of the Retroviridae family. This virus is not very stable in the environment, so close contact between cats is necessary for transmission. The virus is transmitted by biting (saliva), sexual contact, intrauterine or via breast milk. FIV attacks the lymphoid tissues, leading to immunodeficiency and the development of chronic, difficult-to-treat secondary infections, neoplasia (lymphoma) and eventually complete immune system failure.
