Special Issue "Feline Retroviruses"

Guest Editor
Prof. Brian J. Willett
MRC-University of Glasgow Centre for Virus Research, Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, Henry Wellcome Building, Garscube Estate, Bearsden Road, Glasgow G61 1QH, UK
Website: http://www.gla.ac.uk/researchinstitutes/iii/cvr/rrl/
E-Mail: brian.willett@glasgow.ac.uk
Phone: +44 141 330 3274
Fax: +44 141 330 2271
Interests: FIV; FeLV; retroviruses; AIDS; viral immunology

Dear Colleagues,

In 1964, Bill Jarrett and colleagues at the University of Glasgow Veterinary Hospital reported in Nature that kittens injected with material from the mediastinal mass of an 8.5-year-old female cat developed lymphosarcoma. Examination of tissue sections under electron microscopy revealed the presence of virus-like particles that bore a striking resemblance to "the virus of murine leukaemias". These seminal studies launched the field of feline retrovirology; the virus that had been identified was subsequently named feline leukaemia virus (FeLV) and millions of cats are now vaccinated successfully against FeLV every year. Since then, cats have been shown to harbour spumaviruses (FFV, feline foamy virus), replication-competent endogenous retroviruses (RD114)  and lentiviruses (feline immunodeficiency virus, FIV).

This special edition of "Viruses" aims to examine the areas of current interest in feline retrovirology. The issue will expand on our understanding of innate resistance/intrinsic immunity to retroviral infection and the host pathogen interactions that determine the outcome of retroviral diseases in felids. It will consider the prospects for the development of safe and efficacious FIV vaccines and the use of feline retrovirus-derived vectors for gene therapy and the likely benefits to both human and veterinary medicine.

Prof. Brian J. Willett
Guest Editor

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Type of Paper: Article
Title: Renal Alterations in Feline Immunodeficiency Virus (FIV)-Infected Cats: A Natural Model of Lentivirus-Induced Renal Disease Changes
Authors: Alessandro Poli ¹, Natasa Tozon ²,  Grazia Guidi ³,  Mauro Pistello ^4,*
Affiliations: ¹ Department of Animal Pathology, Prophylaxis and Food Hygiene, Veterinary Faculty, University of Pisa,  Viale delle Piagge 2, 56124 Pisa, Italy; E-Mail: apoli@vet.unipi.it (A.P.); ² Clinic for Small Animal Medicine and Surgery, Veterinary Faculty, University of Ljubljana, Gerbičeva 60, SI-1000 Ljubljana, Slovenia; E-Mail: Natasa.Tozon@vf.uni-lj.si (N.T.); ³ Department of Veterinary Clinic, Veterinary Faculty, University of Pisa,  Via Livornes, San Piero a Grado,  Pisa, Italy; E-Mail: guidi@vet.unipi.it (G.G.); ⁴ Department of Experimental Pathology, University of Pisa, Via S. Zeno, 35/39, 56127 Pisa, Italy; E-Mail: mauro.pistello@med.unipi.it (M.P.); * Author to whom correspondence should be addressed; mauro.pistello@med.unipi.it (M.P.);
Tel.: +39- 050 - 2213781; Fax: +39-050 -2213524.
Abstract: Human Immunodeficiency Virus (HIV) is associated with several renal syndrome including acute and chronic renal failures but the underlying pathogenic mechanisms are unclear.   HIV and feline immunodeficiency virus (FIV) share numerous biological and pathological features, including renal alterations. We investigated and compared the renal damages in 51 experimentally infected and 21 naturally infected cats. Compared to the latter, the experimental infected cats exhibited same mesangial widening and glomerulonephritis, milder proteinuria, a common occurrence in FIV infection, and lower tubular and interstitial alterations. Also lower were the numbers of giant protein tubular cats and tubular microcysts. In contrast, diffuse interstitial infiltrates and glomerular and interstitial amyloidosis were detected only in naturally infected cats.   Similar alterations are found in HIV infected patients thus supporting the idea of a causative role of FIV infection in renal disease and underlining the relevance of the FIV and its natural host as an animal model to investigate lentivirus-associated nephropathy.
Keywords: Cat; feline immunodeficiency virus; FIV; kidney diseases; renal pathology

Type of Paper: Article
Title: Clinical Aspects of Feline Immunodefiency and Feline Leukemia Virus Infection
Author: Katrin Hartmann
Affiliation: Prof., Dr. med. vet., Dr. habil., Dipl. ECVIM-CA, Clinic of Small Animal Medicine, (Medizinische Kleintierklinik) Ludwig Maximilian University Munich, Veterinaerstrasse 13, 80539 Munich, Germany, E-mail hartmann@uni-muenchen.de, Phone +49-89-2180-2653, Personal Assistant +49-89-2180-2651, Fax       +49-89-2180-16501
Abstract: Feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV) are retroviruses with global impact on the health of domestic cats. The two viruses differ in their potential to cause disease. FIV can cause an acquired immunodeficiency syndrome that increases the risk of developing opportunistic infections, neurological diseases, and tumors. In most naturally infected cats, however, FIV itself does not cause severe clinical signs, and FIV-infected cats may live many years without any health problems. FeLV is more pathogenic, and was long considered to be responsible for more clinical syndromes than any other agent in cats. FeLV can cause tumors (mainly lymphoma), bone marrow suppression syndromes (mainly anemia) and lead to secondary infectious diseases caused by suppressive effects of the virus on bone marrow and the immune system. Today, FeLV is less commonly diagnosed as in the last 20 years prevalence has been decreasing in most countries. However, FeLV importance my be underestimated as it has been shown that regressively infected cats (that are negative in routinely used FeLV tests) also may develop clinicals signs. This article provides an overview about clinical syndromes in FIV-infected cats as well as in progressively and regressively FeLV-infected cats.

Type of Paper: Article
Title: Administration of Fozivudine Tidoxil as a Single-Agent Therapeutic during Acute Feline Immunodeficiency Virus Infection Does Not Alter Chronic Infection
Authors: Michelle M. Miller, Jonathan E. Fogle *
Affiliation: Immunology Program, Department of Population Health and Pathobiology, North Carolina State University College of Veterinary Medicine, Raleigh, NC 27607, USA; E-Mail: mmdollar@ncsu.edu
* Author to whom correspondence should be addressed; E-Mail: jefogle@ncsu.edu; Tel.: +011-1-919-513-6248; Fax: +011-1-919-513-6464.
Abstract: Initiating combination antiretroviral therapy (ART) during acute HIV infection has been correlated with decreased viral set point and improved lymphocyte function.  However, the long term effects of single-agent therapy administered only during the acute stage of infection (interrupted treatment) remain largely uncharacterized.  In this study we provide longitudinal data using the feline immunodeficiency virus (FIV) model for HIV infection.   Infected cats were treated with a prophylactic single-agent therapy, Fozivudine tidoxil (FZD), for six weeks, starting one day before infection.  The initial acute infection study, reported elsewhere, demonstrated a decrease in plasma and cell associated viremia at two weeks post-infection (PI) in FZD-treated cats as compared to placebo-treated cats.  We hypothesized that this early alteration in plasma and cell associated viremia would alter the virus set point and ultimately affect the outcome of chronic infection.  Here we provide data at one, two and three years PI for plasma and/or cell associated viremia, total lymphocyte counts and CD4:CD8 ratios.  There was no difference in viremia or cell counts between treated and nontreated groups at all time points tested.  Contrary to our hypothesis, these results suggest that treatment with a single agent anti-retroviral drug during acute lentivirus infection does not significantly alter viral load and immune function during the chronic, asymptomatic stage of infection.
Keywords: Acquired immunodeficiency syndrome; lentivirus; FIV; antiretroviral therapy (ART); Zidovudine; Fozivudine