Detection of feline immunodeficiency virus (FIV) nucleic acids in FIV-seronegative cats

Abstract

A study was undertaken to determine the rate of viral transmission among naive specific-pathogen-free (SPF) cats living in close contact with feline immunodeficiency virus (FIV)-infected cats. Twenty SPF cats were housed in the same rooms with experimentally FIV-infected seropositive and virus culture-positive cats for 2 to 4 years and were monitored for the presence of FIV nucleic acids and antibodies. Only 1 of the 20 cats became seropositive and virus culture positive and developed signs of disease. Genomic DNA from bone marrow and peripheral blood mononuclear cells (PBMC) of 10 of 19 healthy-appearing seronegative cats became positive for FIV DNA by the polymerase chain reaction. Twenty-eight SPF cats housed as groups in separate quarters and never exposed to FIV-infected cats were uniformly negative for FIV DNA. FIV RNA transcripts were detected in concanavalin A-stimulated PBMC cultures from 4 of 10 FIV DNA-positive, seronegative cats by in situ hybridization. PBMC from three of four naive SPF cats acquired FIV nucleic acids after the cats were transfused with blood and bone marrow from FIV genome-positive, seronegative donors. Three of five FIV-seronegative cats housed for years with naturally FIV-infected cats in a private household were also found to harbor FIV DNA, indicating that the same phenomenon occurred in the field. These findings demonstrate that cats living in close contact with FIV-infected seropositive cats can acquire FIV nucleic acids without developing detectable levels of serum antibodies or disease.

Occult Systemic Infection and Persistent Simian Immunodeficiency Virus (SIV)-Specific CD4+-T-Cell Proliferative Responses in Rhesus Macaques That Were Transiently Viremic after Intravaginal Inoculation of SIV

“…Thus, the phenomenon of seronegative transient viremia in rhesus macaques following intravaginal inoculation of pathogenic SIVmac is more likely due to latent or very low level productive infection rather than to an abortive infection or immune viral clearance. Similar observations were reported for cats infected with feline immunodeficiency virus (9,34) and for chimpanzees infected with HIV-1 (44). Whether latent infection of nonpermissive cells is a strategy for lentivirus persistence is not known (1), and there is currently no operational definition of latent infection in vivo for HIV or SIV.…”

Feline Immunodeficiency: ABCD Guidelines on Prevention and Management

“…✜ Seronegative/PCR positive results may also be found when cats living in close contact with FIVinfected seropositive cats become provirus positive without developing antibodies or disease. 44 Such cats are infected and will usually seroconvert weeks to months later.…”

Vaccine protection against feline immunodeficiency virus: setting the challenge

“…Serological methods correlate well with virus isolation, since it has always been possible to isolate infectious virus from seropositive cats. Discordant cats, (seronegative but from which virus may be isolated), are very rare 86 …”