FELINE IMMUNODEFICIENCY VIRUS IS SHED IN SEMEN FROM EXPERIMENTALLY AND NATURALLY INFECTED CATS

Although a laboratory isolate of feline immunodeficiency virus (FIV), FIV-NCSU1, has been transmitted by artificial insemination in domestic cats, transmission by naturally infected males during mating has not been reported. In order to determine whether virus shedding in semen i s unique to the NCSU1 isolate, we analyzed electroejaculates from four specific-pathogen-free males infected with another laboratory strain, FIV-Petaluma, and eight random source males with naturally acquired i nfections. Seminal cell lysates from the cats infected with the Petalu ma isolate were screened by nested polymerase chain reaction amplifica tion for FIV gag DNA, Seminal cells and seminal plasma from these FIV- Petaluma cats were further analyzed for the presence of virus by cocul tivation with a feline CD4+ T cell line and Crandell feline kidney cel ls. Electroejaculates from the naturally infected cats were cocultivat ed with the T cell line. Our results demonstrated that cell-free FIV w as present in seminal plasma from two FIV-Petaluma cats and two natura lly infected cats. Cell-associated seminal virus was detected in all o f the FIV-Petaluma infected cats and one naturally infected cat. Secre tion of viral gag p26 antigen, an indication of active viral replicati on, was evident in cocultures containing motile sperm purified by a sw im-up procedure from a FIV-Petaluma cat. These results confirm that FI V shedding in semen is not restricted to a specific virus isolate, Fur thermore, swim-up sperm from FIV-infected cats may be infectious in vi tro.