Molecular detection and characterisation of classical swine fever virus in Andhra Pradesh, India

Abstract

An outbreak of Classical Swine Fever (CSF) was recorded in a back yard piggery farm in Bhimavaram mandal, West Godavari district of Andhra Pradesh, where mortality was observed in more than 20 pigs. The animals initially exhibited symptoms such as pyrexia, lethargy, and conjunctivitis. As the disease progressed, erythematic patches appeared on the abdomen, ears, and inside thigh regions, accompanied by tremors and circling movements just before death. Post-mortem examination revealed congestion and haemorrhages in vital organs and pneumonia in lungs. Reverse Transcriptase Polymerase Chain Reaction (RT-PCR) targeting 5' UTR, specific to Pestivirus was performed on three post-mortem samples, all of which tested positive. The PCR product was sequenced and compared using NCBI Nucleotide BLAST, which indicated 96% identity with Classical Swine Fever isolates. Phylogenetic analysis placed the PCR product close to CSF isolates under Subgroup 2.2 from Kerala, Uttar Pradesh and Mizoram states of India.