FIV Ab/ FeLV Ag
With the commercial launch in Australia in 2004 of a feline immunodeficiency virus (FIV) vaccine; Fel-O-Vax FIV®, the landscape for FIV diagnosis changed substantially. Point-of-care (POC) antibody detection kits, which had been the mainstay for diagnosis of FIV Ab/ FeLV Ag infection since the early 1990s, were no longer considered accurate for use in FIV-vaccinated cats, to the production of vaccine-induced antibodies that were considered indistinguishable from those produced in natural FIV infections.
Consequently, attention turned to alternative diagnostic methods, such as nucleic acid detection. However, in the last 5 years, we have published a number of studies emphasizing that FIV PoC test kits vary in their methodology, resulting in different accuracy in FIV-vaccinated cats. Importantly, we demonstrated that two commercially available FIV antibody test kits (Witness™ and Anigen Rapid™) were able to accurately distinguish between FIV-vaccinated and FIV-infected cats, and concluded that testing with either the kits offer an alternative to PCR testing.
This review summarizes relevant findings from our work published in a variety of peer-reviewed research journals to inform veterinarians (particularly veterinarians in Australia, New Zealand, and Japan, where the FIV vaccine is currently commercially available) about how the approach to the diagnosis of IVF infection has changed. Included in this review are our work investigating the performance of three commercially available FIV PoC test kits in FIV-vaccinated cats and our recommendations for the diagnosis of FIV infection; the effect of primary FIV vaccination (three FIV vaccinations, 4 weeks apart) on PoC test kit performance; our recommendations regarding annual testing of FIV-vaccinated cats for “vaccine breakthroughs”; and the possible off-label use of saliva for the diagnosis of FIV infection using some FIV PoC test kits.
We also investigated the accuracy of the same three brands of feline leukaemia virus (FeLV) diagnostic test kits, using blood and saliva as diagnostic samples. Based on these results, we reviewed our recommendations for confirmatory testing when veterinarians are presented with a positive result on the FeLV PoC Test Kit. Finally, we conclude with our results from the largest and most recent FIV and FeLV seroprevalence study conducted in Australia to date.
Keywords: feline immunodeficiency virus; feline leukaemia
virus; diagnosis at the point of care; vaccination.