Feline immunodeficiency virus subtypes in domestic cats in New Zealand

Authors: Meers J, Zwijnenberg RJG, Seddon JM, Kann RKC
Publication: New Zealand Veterinary Journal, Volume 55, Issue 6, pp 358-360, Dec 2007
Publisher: Taylor and Francis

Animal type: Cat, Companion animal
Subject Terms: Clinical pathology, Diagnostic procedures, Viral, Immune system/immunology, Disease/defect, Infectious disease
Article class: Correspondence

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Abstract: Feline immunodeficiency virus (FIV), a lentivirus of the Retroviridae family, is common among domestic cats worldwide. FIV infection is characterised by a gradual depletion of CD4+ lymphocytes, which ultimately results in immunosuppression (Pedersen et al 1989; Bendinelli et al 1995). Following a prolonged asymptomatic period, some infected cats succumb to secondary or opportunistic infections, severe weight loss, and sometimes neurological signs and neoplasia (Pedersen et al 1989; Ishida and Tomoda 1990; Bendinelli et al 1995). The prevalence of FIV is variable around the world, ranging from 1–12% in healthy cats to 15–44% in sick cats, and differences in prevalence are generally thought to reflect the different ways in which cats are managed (Pedersen et al 1989; Hartmann 1998). Since biting most effectively transmits the virus, higher prevalence is found in regions where cats are allowed to roam more freely outdoors. In New Zealand, the prevalence of FIV is reported to range from 6.8% in healthy cats to 20.9–27.3% in sick cats (Swinney et al 1989; Jones et al 1995). Five FIV subtypes (A, B, C, D and E) have been described based on the genetic diversity of the variable V3–V5 region of the envelope (env) gene. Subtypes A and B are the most widely distributed subtypes worldwide and have been found in the United States of America, Canada, Europe, Australia and Japan (Bachmann et al 1997; Nishimura et al 1998; Kann et al 2006a). Subtype C is also relatively common and has been isolated in Canada, Taiwan, South Africa and Vietnam (Bachmann et al 1997; Uema et al 1999; Nakamura et al 2003; Kann et al 2006b). Subtypes D and E have a more limited distribution; Subtype D has been reported in Japan and Vietnam whilst Subtype E is present in Argentina only (Kakinuma et al 1995; Pecoraro et al 1996; Nakamura et al 2003). Hayward et al (2007) documented the presence of Subtypes A and C in the domestic and feral cat populations in New Zealand. Here, we report on a study that confirms these findings and identifies dual subtype infection, and we discuss the implications of this work for vaccine efficacy and viral pathogenicity.

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