Lumpy Skin Disease and Pseudo-Lumpy Skin Disease

Abstract

Lumpy skin disease (LSD) is a poxvirus infection of cattle in which cutaneous nodules and lymphadenitis develop. The disease occurs sporadically in cattle in African countries. Generally the prevalence is low but serious epidemics may develop at intervals. Much of the epidemiological information suggests that transmission is indirect and that insects play a part in the spread of LSD.

The main clinical signs are those of fever, the development of multiple, painful skin nodules and lymphadenitis. As lesions progress the center of the cutaneous lesions becomes hard, necrotic and difficult to remove (so-called “sitfasts”). On pathological examination lesions may be present in internal organs. Histology of the lesions shows the presence of intracytoplasmic inclusion bodies in epithelial and mononuclear cells.

A clinically similar disease caused by bovid herpesvirus 2 (BHV2) is known as pseudo-lumpy skin disease (pseudo LSD). Bovid herpesvirus 2 is also associated with another clinical syndrome, that of marnmillitis. Pseudo-LSD disease has been reported mainly from Africa and mammillitis from more temperate regions.

In both syndromes skin nodules develop. Those on the teat break down readily into ulcers. On the hairy skin, nodules of the superficial layers become necrotic and, with the exudate, form a dry scab which eventually separates, leaving a hairless pigmented area.

Histopathology of early lesions shows syncytial formation and eosinophilic intranuclear inclusion bodies.

Confirmation of LSD and pseudo-LSD is most accurately obtained by virus isolation.