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.