Poxvirus Skin Infections
Introduction
Poxviridae infect many species and disease often affects the skin, although systemic infections may also occur in which clinical signs of the disease may or may not be apparent.
Poxvirus infections often cause proliferative epithelial lesions in birds whereas papular and/or pustular epithelial lesions are characteristic of poxvirus-infected mammals and only in some cases do they become proliferative.
The poxviruses are the largest animal viruses which contain single, linear molecules of double-stranded DNA.
Skin lesion development
Lesions develop due to viral invasion of the epithelium leading to vascular injury and ischaemic necrosis.
There is stimulation of the host DNA and the formation of hyperplastic nodules.
Skin lesions usually progress from papule to vesicle, to umbilicated pustule, to crust and finally to a scar.
Poxviruses with skin signs
Sheep and goats
Cattle
Bovine Papular Stomatitis, Cow Pox, Pseudocowpox, Lumpy Skin Disease and Vaccinia
Pigs
Cats
Avian species
Fowl Pox, Pigeon Pox and Canary Pox
Rabbits
Myxomatosis, Shope fibroma virus and Malignant rabbit fibroma virus
Diagnosis
A definitive diagnosis is made histologically by observing the characteristic intracytoplasmic inclusion bodies in epithelial cells.
References
Quinn, P.J. (1994) Clinical veterinary microbiology Elsevier Health Sciences
Hirsh, D. (2004) Veterinary microbiology Wiley-Blackwell