Origin of porcine circovirus type 2 (PCV2) from swine affected by PCV2-associated diseases in Croatia.

Porcine circovirus type 2 (PCV2) causes some of the most significant economic losses in pig production. Several multisystemic syndromes have been attributed to PCV2 infection, which are known as PCV2-associated diseases (PCVDs). This study investigated the origin and evolution of PCV2 sequences in domestic pigs and wild boars affected by PCVDs in Croatia. Viral sequences were recovered from three wild boars diagnosed with PCV2-systemic disease (PCV2-SD), 63 fetuses positive for PCV2 DNA as determined by PCR, 14 domestic pigs affected with PCV2-SD (displaying severe interstitial nephritis) and five domestic pigs with proliferative and necrotising pneumonia. Seventeen complete PCV2 genomes were recovered. Phylogenetic and evolutionary analyses based on median-joining phylogenetic networks, amino acid alignments and principal coordinate analysis were performed using complete genomes, as well as complete and partial ORF sequences for ORF1 and ORF2. Two of the 17 PCV2 sequences belonged to PCV2a, 14 to PCV2b and one was unclustered. PCV2b was the predominant genotype in Croatia and has been linked to international trade as a route of introduction. Correlation between particular viral strains with PCVDs is lacking.

Presence of Torque teno sus virus in porcine circovirus type 2-associated disease in Croatia.

Torque teno virus (TTV) is ubiquitous and species-specific, and two different TTV species, Torque teno sus virus 1 (TTSuV1) and Torque teno sus virus 2 (TTSuV2), have been described in domestic pigs and wild boars. Whether these two species are involved in clinical cases of porcine circovirus type 2-associated disease (PCVDs) remains unknown. This study investigates the presence of TTSuV in 85 fetuses, pigs and wild boars infected by PCV2 and affected by PCVDs other than postweaning multisystemic wasting syndrome (PMWS) and porcine dermatitis and nephropathy syndrome. It also explores the genetic diversity of identified strains using phylogenetic analysis. The presence or absence of TTSuV was determined in 85 samples of PCV2-containing organs from 85 infected animals using a specific, one-step PCR method. A nucleotide distance matrix between sequences was computed to infer phylogeny based on a median-joining (MJ) network. TTSuV2 showed high prevalence in animals affected by nephropathy and proliferative and necrotising pneumonia (PNP), and both TTSuV1 and TTSuV2 showed high prevalence in wild boars affected by PMWS. TTSuV1 showed low prevalence in animals affected by nephropathy and PNP, and both TTSuV1 and TTSuV2 showed low prevalence in animals with reproductive disorders. MJ network analysis revealed significant genetic diversity among Croatian isolates.