202 JOURNAL OF SMALL ANIMAL PRACTICE • VOL 45 • APRIL 2004 INTRODUCTION Cowpox virus is an Orthopoxvirus found only in Western Europe and Asia. The dis- ease it causes in cats has been called ‘feline cowpox’ and ‘catpox’. Wild rodents seem to be a reservoir for cowpox virus (Maren- nikova and others 1978, Kaplan and oth- ers 1980, Bennett and others 1999, Chantrey and others 1999, Hazel and oth- ers 2000, Wolfs and others 2002). Cases in domestic cats are typically seen in the autumn, and are associated with the peak population of the rodent hosts (Chantrey and others 1999, Pfeffer and others 2002). Human infections in Great Britain are reported to be in single figures per year and are often associated with disease in pet cats (Baxby and others 1994, Baxby and Bennett 1997). In cats, the typical initial skin lesion is an ulcerated nodule with crust, usually on the head or forelimbs. This is the site where the cat will have had direct contact with the rodent and local virus replication has occurred. After one or two weeks, sec- ondary skin lesions appear. They start as macules or small erythematous nodules that often ulcerate, scab and later heal, producing scarring (Bennett and others 1999). Concurrent oral lesions have been reported to occur in about 20 per cent of feline cases (Bennett and others 1990). The appearance of systemic signs is unusual, other than mild pyrexia, depres- sion and occasionally diarrhoea, which are associated with transient viraemia (Bennett and others 1999). Pneumonia is a severe complication which is occasion- ally associated with cowpox infection but there are only two detailed case reports documenting this in cats (Hinrichs and others 1999, Hübner 2002). To date, cases with signs confined to oral lesions have not been reported. Likewise, cases that have exhibited large areas of skin necrosis, intractable oedema or loss of digits are not recorded in the existing veterinary literature. CASE HISTORIES Case 1 A four-year-old, neutered male, domestic shorthair cat presented with an acute- onset, non-pruritic dermatosis in August 1999. The animal was a rodent hunter and showed no evidence of systemic disease. There was no history of previous der- matoses and no evidence of contagion to humans or in-contact pets. The skin lesions were confined to the lips and were bilateral and roughly symmetrical. They consisted of ulceration with small areas of dark brown crust (Fig 1). Under general anaesthesia, three ulcers (<5 mm diameter) were found on the caudal tongue and soft palate. There was moderate bilateral enlargement of the submandibular lymph nodes. No other lesions were found on thorough examination. Punch biopsies were taken from the lip lesions. Histopathology of the muco- cutaneous junction showed hydropic de- generation of keratinocytes; eosinophilic, intracytoplasmic inclusion bodies; and deep dermatitis with perifolliculitis, folli- culitis and furunculosis (Fig 2). This was considered consistent with cowpox infec- tion. Embedded tissue was deparaffinised with xylene (Merck), rehydrated and washed in phosphate-buffered saline. DNA was extracted using the QIA Mini Kit (Qiagen; Hilden). A PCR with primers targeting the Orthopoxvirus gene of the 14 kDa protein (A27L) was performed, as described by Essbauer and others (2002). D. R. GODFREY, C. J. BLUNDELL, S. ESSBAUER*, M. PFEFFER*, D. H. SHEARER†, J. R. REST‡ AND J. F. M. BAKER† Journal of Small Animal Practice (2004) 45, 202–205 Cowpox virus infections are reported typically to cause focal ulcerated, crusted skin lesions, sometimes with mild systemic illness and concurrent oral lesions. Severe systemic illness usually only occurs in young or immunosuppressed individuals. This report describes four cases of cowpox infection in cats which illustrate variations to the usual presentation of the virus. The poxvirus infections were confirmed histopathologically, serologically and by PCR analysis. Unusual presentations of cowpox infection in cats Nine Lives Veterinary Practice for Cats, 2068 Stratford Road, Hockley Heath, West Midlands B94 6NT *World Health Organization Centre for Collection and Evaluation of Data on Comparative Virology, Consulting Laboratory for Poxviruses, Institute of Medical Microbiology, Infectious and Epidemic Diseases, Veterinärstrasse 13, D-80539 Munich, Germany †Finn Pathologists, Weybread, Diss, Norfolk IP21 5TT ‡24 Lower End, Swaffham Prior, Cambridge CB5 0HT C. J. Blundell’s present address is The Oxfordshire Cat Clinic, Larkmead Veterinary Group, Cholsey, Oxfordshire OX14 9PA M. Pfeffer’s present address is Institute of Microbiology, German Armed Forces, Neuherbergstrasse 11, D-80937 Munich, Germany D. H. Shearer’s present address is Vetcutis, Holly House, Pulham St Mary, Diss, Norfolk IP21 4QQ J. F. M. Baker’s present address is Patolovet- Patologia Veterinaria Unipessoal, Lda. Av. Duarte Pacheco, 232. 8135-104 Almancil, Portugal