Detection of feline herpes virus 1 via polymerase chain reaction and immunohistochemistry in cats with ulcerative facial dermatitis, eosinophilic granuloma complex reaction patterns and mosquito bite hypersensitivity
Ulcerative dermatitis caused by feline herpes virus 1 (FHV‐1) is an uncommon disease characterized by cutaneous ulcers secondary to epidermal, adnexal and dermal necrosis. Differential diagnoses for FHV‐1 lesions include, but are not limited to, mosquito bite hypersensitivity and eosinophilic granuloma complex. Histopathological diagnosis of FHV‐1 dermatitis is based on the detection of the intranuclear inclusion bodies. In cases where intranuclear inclusions are missing but clinical and histological findings are compatible with FHV‐1 dermatitis, immunohistochemistry (IHC) and PCRs have been used. In this retrospective study, we evaluated the presence of FHV‐1 by IHC and PCR in skin biopsies and compared the results of the two tests. Sixty‐four skin biopsy specimens from cats with compatible lesions were reviewed and tested via PCR and IHC for evidence of FHV‐1. Polymerase chain reaction was positive in 12 of 64 biopsies; PCR and IHC were positive only in two of 64 biopsies, and these cases were considered true positive cases. The higher number of PCR‐positive cases was possibly attributed to amplification of viral DNA from a live attenuated vaccination, but a previous FHV‐1 infection with subsequent amplification of latently inserted FHV‐1 could not be excluded. If clinical signs and histopathology suggest FHV‐1 infection in the absence of typical inclusion bodies, IHC is the preferred diagnostic test; PCR may be useful for initial screening, but due to false positives is not sufficient for a definitive diagnosis.
Document Type: Research Article
Affiliations: 1: Ambulatorio Veterinario Dott.ssa Jommi Elena, Via Fabio Filzi, 14 20124 Milano, Italy 2: Animal Pathology, Hygiene and Veterinary Public Health Department, Faculty of Veterinary Medicine, Via Celoria 10, 21100 Milano, Italy 3: Ambulatorio Veterinario Associato, C.so Traiano 99/D, 10135 Torino, Italy
Publication date: December 1, 2011