Abstract
A field study was undertaken to (i) measure the prevalence of feline leukaemia virus (FeLV) exposure and FeLV infection in a cross-section of healthy Australian pet cats; and (ii) investigate the outcomes following natural FeLV exposure in two Australian rescue facilities. Group 1 (n = 440) consisted of healthy client-owned cats with outdoor access, predominantly from eastern Australia. Groups 2 (n = 38) and 3 (n = 51) consisted of a mixture of healthy and sick cats, group-housed in two separate rescue facilities in Sydney, Australia, tested following identification of index cases of FeLV infection in cats sourced from these facilities. Diagnostic testing for FeLV exposure/infection included p27 antigen testing using three different point-of-care FeLV kits and a laboratory-based ELISA, real-time polymerase chain reaction (qPCR) testing to detect FeLV proviral DNA in leukocytes, real-time reverse-transcription PCR (qRT-PCR) testing to detect FeLV RNA in plasma, and neutralising antibody (NAb) testing. Cats were classified as FeLV-uninfected (FeLV-unexposed and presumptively FeLV-abortive infections) or FeLV-infected (presumptively regressive and presumptively progressive infections). In Group 1, 370 FeLV-unexposed cats (370/440, 84%), 47 abortive infections (47/440, 11%), nine regressive infections (9/440, 2%), and two progressive infections (2/440, 0.5%) were identified, and 12 FeLV-uninfected cats (12/440, 3%) were unclassifiable as FeLV-unexposed or abortive infections due to insufficient samples available for NAb testing. In Groups 2 and 3, 31 FeLV-unexposed cats (31/89, 35%), eight abortive infections (8/89, 9%), 22 regressive infections (22/89; 25%), and 19 progressive infections (19/89; 21%) were discovered, and nine FeLV-uninfected cats (9/89; 10%) were unclassifiable due to insufficient samples available for NAb testing. One of the presumptively progressively-infected cats in Group 3 was likely a focal FeLV infection. Two other presumptively progressively-infected cats in Group 3 may have been classified as regressive infections with repeated testing, highlighting the difficulties associated with FeLV diagnosis when sampling cats at a single time point, even with results from a panel of FeLV tests. These results serve as a reminder to Australian veterinarians that the threat of FeLV to the general pet cat population remains high, thus vigilant FeLV testing, separate housing for FeLV-infected cats, and FeLV vaccination of at-risk cats is important, particularly in group-housed cats in shelters and rescue facilities, where outbreaks of FeLV infection can occur.
Highlights
In many countries, the prevalence of feline leukaemia virus (FeLV) infection in domestic cats has decreased since the 1970s and 1980s [1,2]
Studies have demonstrated that progressive FeLV infections remain common in some regions, such as Southeast Asia and Brazil, where the prevalence is 12–25% [9,10,11,12,13], and recently in Australia a prevalence of 13% (72/563) was reported, with the majority of infections identified in sick cats tested as part of routine diagnostic investigations [14]
Despite the reported decrease in the prevalence of FeLV infection in pet cats living in Europe, Australia, and the USA, the threat of regressive and progressive FeLV infections persists, with regressive infections being more than four times as common as progressive infections in pet cats in Australia
Summary
The prevalence of feline leukaemia virus (FeLV) infection in domestic cats has decreased since the 1970s and 1980s [1,2]. Studies have demonstrated that progressive FeLV infections remain common in some regions, such as Southeast Asia and Brazil, where the prevalence is 12–25% [9,10,11,12,13], and recently in Australia a prevalence of 13% (72/563) was reported, with the majority of infections identified in sick cats tested as part of routine diagnostic investigations [14]. This finding highlights that the possibility of FeLV infection should still be considered by Australian veterinarians. The risk of FeLV infection remains sufficiently high in the general cat population that current guidelines recommend shelter staff test all incoming cats of unknown retroviral status for FeLV infection following a six-week quarantine period [8]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
