Genotype Shift of Malaysian Porcine Circovirus 2 (PCV2) from PCV2b to PCV2d within a Decade

Abstract

This paper aims to update the molecular status of porcine circovirus 2 (PCV2) in Malaysia. Firstly, the molecular detection rate of PCV2 in farm and sampled pig population were reported to be 83.78% (31/37 farms) and 83.54% (66/79 pigs) positive for PCV2, respectively. PCV2 was detected across all age groups, from fetuses, porkers to sows. Co-detection of PCV2 and PCV3 antigens was also reported at a rate of 28.77% (21/73). Secondly, PCV2 antigen was also detected in Malaysian abattoir lung samples: 18 out of 19 (94.74%) samples originating from clinically healthy finishers were tested positive. Further, this is the first study to confirm the circulation of PCV2 in the wild boar population roaming Peninsular Malaysia, where 28 out of 28 (100%) wild boar lung samples were found positive. One decade earlier, only genotype PCV2b was reported in Malaysia. This most recent update revealed that genotypes PCV2a, PCV2b and PCV2d were present, with PCV2d being the predominant circulating genotype. PCV2 cap gene nucleotide sequences in this study were found to be under negative selection pressure, with an estimated substitution rate of 1.102 × 10−3 substitutions/site/year (ssy).

Phylogenetic and Structural Analysis of Porcine Circovirus Type 2 from 2016 to 2021 in Jilin Province, China

“…Furthermore, PCV2 is a DNA virus with a high genetic evolution rate. The evolutionary rate of the PCV2 Cap gene has been estimated to be 1.102-1.2 × 10 −3 substitutions/site/year [38,39]. The higher evolution rate of PCV2 makes it easier to recombine and generate new genotypes.…”

Emergence of novel porcine circovirus 2d strains in Thailand, 2019–2020

“…In recent years, a genotype shift toward PCV2d can be observed in various countries, particularly in Asia. These countries include China ( 19 ), South Korea ( 20 ), Vietnam ( 21 ), Malaysia ( 22 ), and Thailand ( 18 ). In Thailand, the prevalence of PCV2d has been increasing since 2010, with only PCV2d detected by 2015 ( 18 ).…”

Chromogenic in situ hybridization technique for detecting porcine circovirus 3 in lung and lymphoid tissues

“…Porcine circovirus 2, PCV3, and PCV4 antigens were detected using PCR, as described previously by Tan et al . [ 8 , 11 , 15 ]. The PCR was done to detect the PRRS viral antigen using the RealPCR PRRSV Type 1 and Type 2 Multiplex RNA Mix (IDEXX, US) according to the manufacturer’s instructions.…”