Genetic diversity of porcine circovirus

This article is dedicated to the species diversity of porcine Circovirus that has been the causative agent of a disease caused by Porcine Circovirus widespread in pig farms of the Russian Federation and worldwide. The disease caused by porcine circovirus type II (PCV2) has various clinical signs accompanied by a number of syndromes as Postweaning multisystem wasting syndrome (SPMD), piglet dermatitis and nephropathy (SDNP), lymphoid, respiratory and reproductive dysfunctions and lesions in the central nervous system and gastrointestinal tract. The historical information in the review reflects the stages of porcine circovirus study, its first discovery, isolation in porcine kidney cell culture and identification of new nucleotide sequences of the virus. The presented data demonstrate the genetic differences of the viral genome, as well as the divergence in the clinics depending on the level of pathogenicity of the strains. Data of the previously unknown genotypes of Circovirus the study of their genetic sequences and the features of their distribution are presented in the article. The data on the genetic organization of porcine circovirus, its structure, virion size and nucleotide sequence length are illuminated in the article. Information was collected on the number of reading frames in the genomes of different types of circovirus, the sizes of capsid and replicative proteins, as well as their functions and influence on immune responses in the host organism, are given. It has been noted that an increase in the number of genotypes directly depends on the mutation of the capsid proteins of the circovirus. The data of phylogenetic analysis of porcine circovirus type 2 has been analyzed and in accordance with six genotypes of the virus has been identified (PCV-2a, PCV-2b, PCV-2c, PCV-2d, PCV-2e and PCV-2f). The prevalence of genotypes in the territory of the Russian Federation is provided. According to the retrospective analysis shifts in the genotypes of the virus with an increase in the virulence of the strains has been detected. It became possible to trace the distribution of genotypes across the territories of different countries, as well as to determine the prevailing types of porcine circovirus characteristic of these geographic areas as a result of the study.