Molecular detection, Isolation and characterization of lumpy skin disease virus in Andhra Pradesh, India

Lumpy Skin Disease (LSD) is an emerging transboundary disease in India caused by LSD virus that shares genetic relatedness with sheep pox and goat pox viruses in the genus capripox virus. In the recent past, India has experienced LSD outbreaks in several states. The current study deals with the recent LSD outbreaks (2022) from cattle in Andhra Pradesh (AP). A total of 89 outbreaks were recorded in AP from various districts. Capripox genus specific (P32 gene) PCR was used for identification of the disease. Out of a total number of 868 clinical samples tested, 178 samples were positive for LSDV genomic DNA with 20.51 percentage positivity. From the positive samples, 21 samples representing different geographical regions of the state were processed for isolation of virus in MDBK cell line and LSDV was isolated from 12 samples. Specific CPE was observed at 3rd blind passage in MDBK cell line. The virus was also adapted to vero cells wherein CPE was observed within the first adaptation passage. The isolates were confirmed as LSDV by ORF036 and ORF011 LSDV specific PCRs yielding 606 bp and 1134 bp PCR products respectively. The PCR product of the partial ORF036 gene from Vizianagaram district isolate was sequenced and phylogenetic analysis was performed. The isolate clustered closely with Indian isolates from Tamil Nadu, Karnataka, Haryana and Rajasthan states and also with field isolates from Bangladesh, Myanmar, and Nigeria. It clustered away from the LSDV Neethling vaccine strains, strains from Kenya (1958), heterologous vaccine strains and some Indian strains of 2019 outbreak.