Hemato-biochemical changes, molecular characterization and phylogenetic analysis of the 2022 Lumpy Skin Disease (LSD) outbreak in Cholistan, Pakistan

Abstract

The lumpy skin disease virus (LSDV) is a member of the Capripox genus of the Poxviridae family. It is the causative agent of lumpy skin, a highly contagious disease of cattle, water buffalo, sheep, and goats. In 2022, several outbreaks of LSD were reported in the Cholistan region of Pakistan, which has a large population of livestock living in arid conditions. A total of 230 blood/serum and scab samples were collected from three LSD outbreak locations. Clinically, affected cattle showed acute clinical signs characterized by skin nodules, fever, enlarged lymph nodes, emaciation, and lower leg edema. Hematological findings revealed non-significant changes in red blood cell and white blood cell counts (some animals had leukocytosis while others were leukopenic) whereas, hemoglobin level were significantly low. Platelet count, MPV, PCT, P-LRC, and P-LCC were elevated. Granulocytes were significantly low in LSD affected cattle while lymphocyte counts were significantly high. Serological findings revealed elevated protein levels, along with high creatinine and ALT concentrations. Amplification of DNA-dependent RNA polymerase 30 kDa subunit gene (RPO30) confirmed the presence of LSD virus in all suspected samples. Phylogenetic analysis showed that all Pakistani isolates clustered closely with isolates from neighboring countries. The SNPs differences were less than 20 among these isolates, indicating their close resemblance with each other. It can, therefore, be inferred that our LSD strains might be originated from neighboring Asian countries, that were affected by LSD in previous years.