While hepatitis E is a growing health concern in Europe, epidemiological data on hepatitis E virus (HEV) in Estonia are scarce. Along with imported HEV infections, autochthonous cases are reported from European countries. Both domestic and wild animals can be a source of human cases of this zoonosis. Here, we investigated the presence of anti-HEV antibodies and HEV RNA in domestic pigs and wild boars, as well as in pig farm workers and hunters in Estonia. Anti-HEV antibodies were detected in 234/380 (61.6 %) of sera from domestic pigs and in all investigated herds, and in 81/471 (17.2 %) of meat juice samples from wild boars. HEV RNA was detected by real-time PCR in 103/449 (22.9 %) of fecal samples from younger domestic pigs and 13/81 (16.0 %) of anti-HEV-positive wild boar samples. Analysis of sera from 67 pig farm workers and 144 hunters revealed the presence of HEV-specific IgG in 13.4 and 4.2 % of the samples, respectively. No HEV RNA was detected in the human serum samples. Phylogenetic analyses of HEV sequences from domestic pigs and wild boars, based on a 245 bp fragment from the open reading frame 2 showed that all of them belonged to genotype 3. The present study demonstrates the presence of HEV in Estonian domestic pig and wild boar populations, as well as in humans who have direct regular contact with these animals. Our results suggest that HEV infections are present in Estonia and require attention.

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.

Trichinella spp. are relevant zoonotic pathogens in Estonia. The aim of this nationwide cross-sectional study was to estimate the seroprevalence of Trichinella spp. in domestic pigs (Sus scrofa domestica) and hunted wild boars (Sus scrofa). Serum samples from 374 pigs, originating from 14 farms, and meat juice samples from 470 wild boars were tested for immunoglobulin G antibodies against Trichinella excretory/secretory antigens using a commercial enzyme-linked immunosorbent assay (ELISA). Antibodies against Trichinella were not detected in the domestic pigs, indicating effective parasite control strategies in the farms. By contrast, 42.1% of the wild boars tested positive, indicating substantial infection pressure in the sylvatic cycle. Further analysis of a subset of the wild boar samples, using another ELISA and Western blot, yielded a confirmed seroprevalence estimate of 17.4%. A substantial proportion of wild boars in Estonia had evidence of exposure to Trichinella spp. and may have carried infective larvae. Undercooked Estonian wild boar meat is a potential source of Trichinella spp. infections to humans and other hosts.

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.

No abstract