Lumpy Skin Disease: Pathomorphological Features and Molecular Detection in Dairy Cattle of West Coastal India

Abstract

Lumpy skin disease (LSD) is an emerging pox viral disease affecting cattle population worldwide. Present investigation designed to study the prevalence, pathomorphological changes and molecular detection of LSD virus in naturally infected cat-tle. The overall morbidity of LSD was 4.48% among 30 dairy farms. Skin nodular biopsy, whole blood and serum samples (n= 66) were collected for the diagnosis of LSD by histopathology, PCR and gene sequencing. The envelope protein (P32), Fusion protein (F) and DNA dependent RNA polymerase 30 kDa subunit (RPO30) genes were targeted for PCR testing. Out of 66, 46 cattle showed generalized skin nodules and papules of various sizes on the skin particularly at neck, face, nose, tail, perineum and udder. Microscopically, skin nodule biopsy revealed presence of diffuse granulomatous inflammation, hyperkeratosis, focal to diffuse vasculitis and lymphangitis, vacuolar degeneration, spongiosis and acanthosis. The inflammatory cells along with diffuse necrosis seen in the dermis. Gel-PCR assay detected P32 gene in 80%, F gene in 70% and RPO30 gene in 75% of skin biopsy samples. Three blood samples were also found positive for P32 gene by PCR. Whereas, TaqMan™probe Real Time PCR targeting EEV glycoprotein gene (LSDV126) detected LSDV in 94% of biopsy samples and three blood samples which indicated its higher sensitive for the diagnosis of LSDV. Phylogenetic analysis of RPO30 gene sequence showed that the isolates from this study were grouped in same cluster with LSDV isolates of Bangladesh, Kenya and other Indian isolates detected during 2019-20.