The porcine circovirus type 2 (PCV2) genome encodes three major open reading frames (ORFs) encoding the replicase proteins (ORF1), the viral capsid protein (ORF2), and a protein with suggested apoptotic activity (ORF3). Previous phylogenetic analyses of complete genome sequences of PCV2 from GenBank have demonstrated 95-100% intra-group nucleotide sequence identity. However, although these isolates were readily grouped into clusters and clades, there was no correlation between the occurrence of specific PCV2 genotypes and the geographic origin or health status of the pig. In the present study, a unique dataset from a field study spanning the years pre and post the recognition of postweaning multisystemic wasting syndrome (PMWS) in Sweden was utilized. Using this dataset it was possible to discriminate three Swedish genogroups (SG1-3) of PCV2, of which SG1 was recovered from a pig on a healthy farm ten years before the first diagnosis of PMWS in Sweden. The SG1 PCV2/ORF2 gene sequence has been demonstrated to exhibit a high genetic stability over time and has subsequently only been demonstrated in samples from pigs on nondiseased farms. In contrast, SG2 was almost exclusively found on farms that had only recently broken down with PMWS whereas the SG3 genogroup predominated in pigs from PMWS-affected farms. These results further support the results obtained from earlier in vitro and in vivo experimental models and suggest the association of specific PCV2 genogroups with diseased and nondiseased pigs in the field.

The present study describes the reasons of post-weaning distress in Estonian pig herds. Here we examined the natural cases of Lawsonia intracellularis and porcine circovirus 2 (PCV2) infection and co-infections.The presence of L. intracellularis in swine herds were tested by PCR and by histopathological methods, whereas PCV2 was detected by real-time-PCR and immunohistochemical stainings. Seven of the 11 investigated herds with signs of post-weaning wasting were infected with L. intracellularis and all 11 herds with PCV2.From the analysed samples 22.2% were infected with L. intracellularis and 25% with PCV2. The results of microbiological studies suggested that the piglets suffered from enteritis and pneumonia. Escherichia coli and Pasteurella multocida often aggravated the process of illness. The frequency of L. intracellularis was high in pigs 7-12 weeks old (18.5-42.7%) and PCV2 infection was too high in pigs 7-12 weeks old (24.8-32.7%). E. coli was often a co-factor with L. intracellularis and PCV2.The primary reasons of post weaning wasting were PCV2 and E. coli, later aggravated by L. intracellularis and other pathogens. Our results indicated that different pathogens have an important role in developing post-weaning wasting.Proliferative intestinal inflammation caused by L. intracellularis is mainly characterised by its localization and morphological findings. The main gross lesions were the enlargement of mesenteric lymph nodes and thickening of the wall of ileum. In post-weaning multi-systemic wasting syndrome there are characteristic histological lesions in lymphoid tissues. They consist of a variable degree of lymphocyte depletion, together with histiocytic and/or multinucleate giant cell infiltration. This basic lymphoid lesions is observable in almost all tissues of a single severely affected animal, including lymph nodes, Peyer's patches and spleen. Sporadically, multifocal coagulative necrosis may be observed.

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The H1N1 influenza strain Mexico 2009 (H1N1pandemic09) led to mild symptoms (with no or low fever) in Estonia during the 2009-2010 outbreak. Due to the lack of clinical signs, it was difficult to estimate the real spreading of this influenza virus in Estonia and no cases of H1N1 influenza were officially registered in animals either. We used an ELISA method to screen blood sample collections for the presence of anti-H1N1 and anti-H3N2 antibodies. All sera were also tested with the hemagglutination inhibition (HI) assay. Out of the 123 samples from human patients, 23 (i.e. 18.7%) were seropositive for the H1N1pandemic09 virus. In addition, blood samples from six persons were positive for both H1N1 and H3N2 viruses, while according to the data from the Estonian Health Board, people aged 15-65 had a general disease rate of around 3.9%. Almost all of the tested animals from two herds (out of four studied) were seropositive for H1N1pandemic09. The seven HA protein sequences isolated from Estonia were aligned with a consensus sequence of the pandemic H1N1 HA sequences from Mexico using ClustalW, and 12 amino acids substitutions were found.

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