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Journal of Wildlife Diseases, 35(1), 1999, pp. 121124 Wildlife Disease Association 1999

Feline Viruses in Wildcats from Scotland

M. J. Daniels,1,3 M. C. Golder,2 O. Jarrett,2 D. W. MacDonald1 1 Wildlife Conservation Research Unit, Depart-ment of Zoology, University of Oxford, South Parks Road, OXFORD OX1 3PS, UK; 2 Department of VeterinaryPathology, University of Glasgow, Bearsden, GLASGOW G61 1QH, UK; 3 Corresponding author.

ABSTRACT: Few data are available on theprevalence of feline viruses in European wild-cats (Felis silvestris). Previous surveys have in-dicated that wildcats may be infected with thecommon viruses of domestic cats, apart fromfeline immunodeficiency virus (FIV). In thepresent study, 50 wildcats trapped throughoutScotland (UK) between August 1992 and Jan-uary 1997 were tested for evidence of viral in-fection. All were negative for FIV by severalserological or virological methods. By contrast,10% of the cats were positive for feline leuke-mia virus (FeLV) antigen and infectious virus

was isolated from 13% of a smaller subset. Ofthe wildcats tested for respiratory viruses, 25%

yielded feline calicivirus (FCV) and althoughno feline herpesvirus was isolated, 16% of thesamples had neutralizing antibodies to this vi-rus. Antibodies to feline coronavirus (FCoV)

were found in 6% of samples. Feline foamy vi-rus (FFV) was an incidental finding in 33% ofsamples tested. This study confirms that wild-cats in Scotland are commonly infected withthe major viruses of the domestic cat, exceptfor FIV.

Key words: Feline calicivirus, feline coronavirus, feline foamy virus, feline herpesvirus, fe-line immunodeficiency virus, feline leukemia

virus, Felis silvestris, survey, wildcats.

Domestic cats (Felis silvestris catus) andEuropean wildcats (Felis silvestris silves-tris) are considered subspecies and thereare currently no exclusive morphologicalor genetic criteria for distinguishing be-tween the two (reviewed in Daniels et al.,1998). However, there is evidence for clin-al variation in morphology, genetics andecology, such that cats living wild in north-ern Scotland (UK) may be consideredwildcats (Daniels, 1997). A small number

of wildcats was sampled in Scotland forcommon feline viruses (McOrist et al.,1991). Although there was evidence of in-fection with some viruses, none tested pos-itive for feline immunodeficiency virus(FIV), in contrast to prevalence of up to57% reported in feral domestic cats inEngland (Yamaguchi et al., 1996).

More recently an opportunity arose toextend these findings. A sample of 50 wild-cats (27 females and 23 males) wastrapped throughout northern Scotland be-tween August 1992 and January 1997 andtested for FIV and five other feline virusesincluding feline leukemia virus (FeLV), fe-line coronavirus (FCoV), feline calicivirus(FCV), feline herpesvirus (FHV) and fe-line foamy virus (FFV). After samplingwildcats were released. Details of trappingtechniques, anesthesia, sampling tech-niques, and the locations of wildcatstrapped are described in Daniels (1997)and Daniels et al. (1998).

Blood was obtained from anesthetizedcats into lithium heparin and oropharyngealswabs were collected into transport medi-um (Leibovitz-15 medium (Life Technolo-gies Ltd, Paisley, UK) with 10% fetal bo-vine serum and antibiotics). The sampleswere posted and arrived in the laboratorywithin 48 hr of collection. Plasma was sep-

arated from the blood and tested for FeLVp27 antigen (Indochem C Lutz, Ruedlin-gen, Switzerland) by enzyme immunoassayand virus isolation at (Feline Virus Unit,University of Glascow, Glascow, UK; Jarrettand Ganiere, 1996). Antibodies to FCoVwere assayed by indirect immunofluores-cence (IF; Addie and Jarrett, 1992) at Fe-line Virus Unit (M. C. Golder, unpubl.data). A similar IF test was used to detectanti-FIV antibodies, using CrFK cells (fromR. A. Crandell) infected with FIVGL-8 astarget cells. Antibodies to FIV were alsodetected by western blotting (M. C. Gold-er, unpubl. data); (supplied by Feline VirusUnit) (Hosie and Jarrett, 1990). Isolation ofFIV was attempted by the growth of virusfrom concanavalin A activated peripheralblood mononuclear cells (PBMC) (Hosieand Jarrett, 1990). Growth of FIV was de-

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SHORT COMMUNICATION 123

or Florida panthers (Roelke et al., 1993).Given that it has been suggested that theseriousness of FIV infection in domesticcats is a result of a relatively recent infec-

tion rather than the proposed historical ge-netic host-parasite symbiosis found in pu-mas (Carpenter et al., 1996; Vande Woudeet al., 1997), then potentially lack of ex-posure could pose a threat.

The prevalence of FeLV is similar tothat reported for domestic cats (Yamagu-chi et al., 1996). One possibility for thesurvival of this virus in wildcats is that thevir us may be transmitted conge nitallywithin a few families since transmission ofFeLV is mainly by the oronasal route oracross the placenta (Jarrett, 1994). Alter-

natively, transmission could be a result ofcontact with domestic or feral domesticcats.

The isolation rate of FCV was relativelyhigh and may indicate that this virus wasacquired by direct contact with other car-riers. It is also possible that the virus wastransmitted from carrier dams to theiryoung kittens. The failure to isolate FHVis not surprising since in domestic cats thisvirus is carried as a latent infection and isshed only intermittently from the orophar-ynx (Gaskell and Dawson, 1994). However,the population had been exposed to FHVsince 16% of the wildcats tested had highlevels of FHV neutralizing antibodies.

Comparable prevalence of FCV andFCoV has been reported in populations ofwild felids with no evidence of associatedmortality (e.g., Roelke et al., 1993; Paul-Murphy et al., 1994). The low prevalenceof antibodies to FCoV (3/49) was consis-tent with the fact that this virus is muchmore common in domestic cats in multicathouseholds than in free-ranging pet cats

kept singly or in feral or stray cats. Directcontact is not necessary for the transmis-sion of FCoV which may be spread indi-rectly through the contamination of theenvironment with infected feces (Stoddartand Bennett, 1994).

The incidental finding of FFV in cul-tures from PBMC is the first demonstra-

tion of this virus in free-living wildcats inScotland. The rates for the isolation ofFFV were similar to those for domesticcats in the UK (Jarrett et al., 1974). While

FFV is common in domestic cats, it is asyet not associated with any disease condi-tion (Gaskell and Bennett, 1994) and un-likely to be a significant pathogen in thewild population.

Trapping was carried out under licencefrom Scottish Natural Heritage (SRA:02:96/(R)SRA:02:96) and anesthesia andblood sampling under Home Office Li-cence (PIL 60/4400). The study was fund-ed by Scottish Natural Heritage, TuskForce, J&B Care For The Rare and vehi-cles kindly supplied by Asia and Kia Mo-

tors. We gratefully acknowledge the land-owners throughout Scotland who gave per-mission to work on their land. We thankM. McDonald and J. Simpson of the Fe-line Virus Unit for their valuable assistancein analyses of samples.

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Received for publication 5 December 1997.