Prevalence of feline immunodeficiency virus infection in domesticated and feral cats in eastern Australia

Abstract

Serum samples from 340 pet cats presented to three inner city clinics in Sydney Australia, 68 feral cats from two separate colonies in Sydney, and 329 cattery-confined pedigree and domestic cats in eastern Australia, were collected over a 2-year period and tested for antibodies directed against feline immunodeficiency virus (FIV) using immunomigration (Agen FIV Rapid Immunomigration test) and enzyme-linked immunosorbent assay methods (Snap Combo feline leukaemia virus antigen/FIV antibody test kit, IDEXX Laboratories). Western blot analysis was performed on samples in which there was discrepancy between the results. Information regarding breed, age, gender, housing arrangement and health status were recorded for all pet and cattery-confined cats, while the estimated age and current physical condition were recorded for feral cats. The FIV prevalence in the two feral cat populations was 21% and 25%. The majority of FIV-positive cats were male (60-80%). The FIV prevalence in cattery-confined cats was nil. The prevalence of FIV in the pet cat sample population was 8% (27/340) with almost equal prevalence in 'healthy' (13/170) and 'systemically unwell' (14/170) cats. The age of FIV-positive pet cats ranged from 3 to 19 years; all FIV-positive cats were domestic shorthairs with outside access. The median age of FIV-positive pet cats (11 years) was significantly greater than the median age of FIV-negative pet cats (7.5 years: P<0.05). The prevalence of FIV infection in male pet cats (21/172; 12%) was three times that in female pet cats (6/168; 4%; P<0.05). With over 80% of this pet cat population given outside access and continued FIV infection present in the feral population, this study highlights the need to develop rapid, accurate and cost-effective diagnostic methods that are not subject to false positives created by concurrent vaccination against FIV. This is especially important in re-homing stray cats within animal shelters and monitoring the efficacy of the new vaccine, which has not been challenged against Australian strains. The absence of FIV within cattery-confined cats highlights the value in routine screening and indoor lifestyles. This study provides cogent baseline FIV prevalences in three cat subpopulations which can be used for appraising potential disease associations with FIV in Australia.

Demographics and husbandry of pet cats living in Sydney, Australia: Results of cross-sectional survey of pet ownership

“…As has been emphasised recently in a study of renal disease in Australian cats (White et al 2005), the male: female ratio in 'normal cats' must be considered when looking for gender associations in specific diseases. Conditions previously documented to have a male preponderance, such as FIV infection (Norris et al 2007, Gabor et al 2001, lymphosarcoma (Gabor et al 1998), nocardiosis , feline infectious peritonitis (Norris et al 2005) and cryptococcosis (O'Brien et al 2003) would be even more likely to be strongly linked with male gender considering the data for normal cats presented here.…”

“…Many published surveys of disease concerning Australian cats quote reference hospital populations that comprise 30%, or even 46% pedigree cats (Norris et al 2007), rather than the 23.4% recorded in this survey. This is potentially because owners of purebred cats are more likely to seek veterinary attention and especially referral to specialist centres compared to "moggies".…”

“…This intent was specifically to complement previous and ongoing investigations into renal disease ; infectious diseases caused by feline coronavirus (Norris et al 2005, Bell et al 2006 a and, feline leukaemia virus (Malik et al 1997), feline immunodeficiency virus (FIV) (Norris et al 1999, Gabor et al 2001, Norris et al 2007, Cryptococcus (O'Brien et al 2003), Nocardia and Mycobacterium (Malik et al 2002); as well as lymphosarcoma (Gabor et al 1998) and other cancers. In all of these studies, inferences concerning potential associations between disease, and age and/or gender, were based on reference populations of hospital patients, which were likely not representative of healthy normal cats.…”

Cryptococcosis in domestic animals in Western Australia: a retrospective study from 1995–2006

“…Some previous studies have found an increased incidence of FeLV and FIV infection in cats with cryptococcosis compared with the prevalence in the hospital population [43], with seropositivity for FeLV and FIV being associated with less favourable outcomes [68]. Australian studies [36,44], in contrast, have found that the prevalence of FIV infection in cats with cryptococcosis was not significantly different from a population of ''sick'' cats from the same area, and further studies of FIV seroprevalence have supported this contention [70]. Furthermore, it was found that many cats with concurrent FIV had comparable CD4 counts to cats with cryptococcosis [71], could be successfully treated and did not relapse when therapy was discontinued [37].…”

Occurrence of Feline Immunodeficiency Virus (FIV) and Feline Leukemia (FeLV) in S&atilde;o Lu&iacute;s-MA

“…However, using molecular methods, this prevalence decreases to 4 to 2% of the worldwide cat population (Hayward et al, 2007). This variation is due to population density, reproductive status, age, gender and living conditions, in particular the frequency of street visitation and reproductive disputes (Norris et al, 2007). In Brazil, FIV has been detected through serological research and PCR, in domiciled and straydomestic cats, in São Paulo, Rio de Janeiro, Rio Grande do Sul and Minas Geraisstates, with a prevalence that varied between 2 and 37.5% for FIV and 8 to 63% for FeLV (Caldas et al, 2000;Souza et al, 2002;Caxito et al, 2006;Almeida et al, 2004).…”