Research overview: endogenous and exogenous retroviruses across the cat family

Beyond the well-known feline immunodeficiency and leukemia viruses, felid genomes carry endogenous retroviruses and other retroelements that record ancient infections. This overview surveys the spectrum of feline retroviruses, distinguishing exogenous, currently transmitted viruses from endogenized relics fixed in host DNA. It covers how endogenous retroviruses can both protect against and complicate diagnosis of related exogenous infections, the discovery of retroviral elements across wild felid genomes, and what these sequences reveal about deep host-virus history. The synthesis connects this molecular archaeology to practical questions in disease testing and conservation genetics. It aims to give readers a broader retroviral context for the better-studied FIV and FeLV, illustrating that the cat lineage has been shaped by repeated retroviral encounters over millions of years.