MSD Manual

Please confirm that you are a health care professional

honeypot link

Pseudocowpox in Cattle

(Milker’s Nodules)


Paul Gibbs

, BVSc, PhD, FRCVS, College of Veterinary Medicine, University of Florida

Last full review/revision Feb 2021 | Content last modified Feb 2021
Topic Resources

Pseudocowpox, a common, mild infection of the udder and teats of cows, is caused by a parapoxvirus and occurs worldwide. The virus of pseudocowpox is related to those of contagious ecthyma Contagious Ecthyma read more and bovine papular stomatitis Papillar Stomatitis in Large Animals Viral papillomas are found around the lips and mouths of young animals, particularly in cattle from 1 mo to 2 yr old. In some herds, the rate of occurrence may be 100%. The lesions are characteristically... read more Papillar Stomatitis in Large Animals . These parapoxviruses differ morphologically from vaccinia virus and other poxviruses. They have a limited host range and cannot be propagated in fertile eggs; they will grow in some cell cultures, although relatively poorly.

Lesions of pseudocowpox begin as small, red papules on the teats or udder. These may be followed rapidly by scabbing, but small vesicles or pustules may develop before scabs form. Scabs may be abundant and can be removed without causing pain. Granulation occurs beneath the scabs, resulting in a raised lesion that heals from the center and leaves a characteristic horseshoe or circular ring of small scabs. This stage is reached in ~7–12 days. Some lesions persist for several months, giving the affected teats a rough feel and appearance, and more scabs may form (see associated photos, parts 2C and 2D) . The infection spreads slowly throughout milking herds, and a variable percentage of cows shows lesions at any time. Cattle may become reinfected in subsequent lactations.

The scabbed lesions may be confused with mild traumatic injuries to the teats and udder. Scabs examined with an electron microscope frequently show characteristic virus particles.

Control of infection within a herd is difficult and depends essentially on hygienic measures, such as teat dipping, to destroy the virus and prevent transmission. Little immunity appears to develop.

People may become infected with painless, but itchy, purplish red nodules that are generally present on the fingers or hands. These lesions cause little disturbance and disappear after several weeks.

Others also read
Download the Manuals App iOS ANDROID
Download the Manuals App iOS ANDROID
Download the Manuals App iOS ANDROID
Test your knowledge
Tumors of the Skin and Soft Tissues
Which of the following diagnostic techniques is LEAST likely to distinguish a benign skin neoplasm from a malignant one? 
Become a Pro at using our website 

Also of Interest

Become a Pro at using our website