Pathological and Virological Studies on an Outbreak of Lumpy Skin Disease among Cattle in Kalubia Governorate-Egypt

Abstract

This work was proposed to study pathologic characteristics of lumpy skin disease (LSD) among naturally infected cattle and to demonstrate LSDV antigen within different tissues including the skin nodules, regional lymph nodes, lung and liver using PCR and immunohistochemistry. Among the infected cattle, one dairy cattle and 5 calves were dead (mortality rate is 6.97%). The major gross alterations in all investigated cases included numerous 1-5 cm well circumscribed, round cutaneous nodules covered the whole body in most cases with severe enlargement of superficial lymph nodes. The main microscopical changes were severe ballooning degeneration of the epidermis, dermatitis, with severe vasculitis affecting the dermal blood vessels. Multiple intracytoplasmic eosinophilic inclusions were present in degenerated epidermal cells. Several pathological changes were also detected in the liver, lung, kidney, intestine and lymph nodes. Strong positive PCR signals were appeared in skin nodules, lung and lymph node. Additionally, positive immunoperixodiase reaction was demonstrated in the skin, lung, kidney and lymph nodes. Furthermore, LSDV was isolated on chorio-allantoic membrane (CAM) of spf embryonated chicken eggs from skin nodules and regional lymph nodes collected from dead animals. Virion particles were observed on CAM by electron microscope. Finally, it could be concluded that skin lesions is a constant lesion in both young and adult animals together with systemic infection in severely infected animals.