Feline leukemia virus (FeLV) and Feline immunodeficiency virus (FIV) are two retroviruses that are deadly to the domestic cat (Felis catus) and important to the conservation of the threatened wild felids worldwide. Differences in the frequencies of occurrence and the existence of varying related viruses among felid species have incited the search for understanding the relationships among hosts and viruses into individual and population levels. Felids infected can die of related diseases or cope with the infection but not show pathognomonic or overt clinical signs. As the home range for eight species of neotropic felids and the home to hundreds of felids in captivity, Brazil has the challenge of improving its diagnostic capacity for feline retroviruses and initiating long term studies as part of a monitoring program