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

Orf and Sheep and goat pox

Cattle

Bovine Papular Stomatitis, Cow Pox, Pseudocowpox, Lumpy Skin Disease and Vaccinia

Pigs

Swinepox

Cats

Cow Pox

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