Molecular characterisation of porcine reproductive and respiratory syndrome virus from pigs in Kerala

Abstract

Porcine reproductive and respiratory syndrome (PRRS) caused by an arterivirus is characterised by reproductive disorders in sows, and post-weaning pneumonia and growth reduction in piglets. Though the virus has been detected in Kerala, no systematic study has been carried out to ascertain its genotype and molecular epidemiology. In the present study, 7 PRRS virus (PRRSV) positive samples collected from incidences of PRRS in Kerala during 2017-2019 were subjected to ORF5, ORF7 and Nsp2 gene based reverse transcription polymerase chain reaction and the specific amplicons generated were sequenced. On BLAST analysis it was revealed that all the sequences were of genotype 2 (North American genotype). Phylogenetic analysis of ORF5 sequences, grouped them under subgenotype 4 with close clustering with other isolates from Kerala, Mizoram and Assam. Nsp2 gene sequence based phylogenetic analysis grouped the isolates under subgenotype 3 with similarities to isolates from Mizoram. Phylogenetic analysis based on ORF7, clustered the isolates under study with PRRSV isolates from Mizoram and Meghalaya. In Nsp2 sequences, a 30 amino acid discontinuous deletion was observed. On analysis of amino acid sequences of ORF5 of Kerala isolates and those from India, it was seen that the Kerala isolates showed closer similarity to PRRSV isolates from Assam than to the other Indian isolates. The study reveals that PRRSV strains prevalent in Kerala share close relationship with other PRRSV isolates in India. This may be due to spread of the virus from these regions to Kerala due to animal movement. Concerted efforts should be undertaken to check unauthorized animal movement to control spread of this economically important disease.

Isolation and molecular characterization of GP5 glycoprotein gene of Betaarterivirus suid 2 from Mizoram, India

“…Since ORF5 is the most variable region containing both neutralizing and non-neutralizing epitopes, N-linked glycosylation sites, apoptotic cell death induced region; so phylogenetic differences are more prominent in this region [ 12 , 14 , 26 ]. The close similarity of Indian strains and their relation with other highly pathogenic strains were also reported by Rajkhowa et al [ 28 ]; Zohlimpuia et al [ 42 ]; Chaithra et al [ 4 ]. If we observe the timeline of the highly pathogenic strain of Betaarterivirus suid 2 outbreaks in the south-east Asian region then it can be assumed that the virus has entered Mizoram from neighboring Myanmar.…”

“…Zohlimpuia et al [42]; Chaithra et al [4]. If we observe the timeline of the highly pathogenic strain of Betaarterivirus suid 2 outbreaks in the south-east Asian region then it can be assumed that the virus has entered Mizoram from neighboring Myanmar.…”

Molecular characterization of porcine reproductive and respiratory syndrome virus identified in 2021 from Nepal

“…The sequences used in this study are listed in Tables 2 – 4 . Phylogenetic and molecular analysis were carried out using MegaX software ( 23 ) and the phylogenetic trees were generated (see Figures 2 – 4 ) (neighbor joining method with 1,000 bootstrap replicates).…”