Lumpy skin disease (LSD): 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. In India, the first outbreak of LSD is reported during August 2019 in Odisha state, which then followed by outbreaks in crossbred and indigenous cattle population of other states. Present investigation designed to study the prevalence, pathomorphological changes and molecular detection of LSD virus in naturally infected cattle. 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 sequencing. The envelope protein gene (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 (0.5 - 6.5cm) on the skin particularly at neck, face, nose, tail, perineum and udder. Microscopic examination of the skin nodule biopsy tissue revealed presence of diffuse granulomatous inflammation, hyperkeratosis, focal to diffuse vasculitis and lymphangitis, vacuolar degeneration, spongiosis and acanthosis. The inflammatory cells typically comprised of macrophages, lymphocytes, neutrophils and eosinophils along with diffuse necrosis in dermis in chronic cases. The eosinophilic intracytoplasmic viral inclusions in keratinocytes and epithelial cells were detected in few cases. Gel-PCR assay detected P32 gene in 83%, F gene in 72% and RPO30 gene in 77% 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.

Isolation and molecular characterization of lumpy skin disease virus from recent outbreaks in Andhra Pradesh, India 2023

“…Preliminary detection was done by amplification of capripoxvirus specific p32 gene 192bp which was suggested by OIE (OIE, 2021) [18] . In accordance with earlier findings (Sudhakar et [23,15,21] , amplification of F gene 472 bp was used for the LSDV specific detection. Skin scabs, nasal samples, and faecal samples were the greatest sources for virus detection when compared to other sources like blood and milk because of the tissue tropism of LSDV, which was detected by the PCR assay in these samples (Tuppurainen et al, 2005; Babiuk et al, 2008) [26,3] .…”