Lawsonia intracellularis and Porcine Circovirus type-2 infection in Estonia

Abstract

AbstractThe present study describes the reasons of post-weaning distress in Estonian pig herds. Here we examined the natural cases ofLawsonia intracellularisand porcine circovirus 2 (PCV2) infection and co-infections.The presence ofL. intracellularisin 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 withL. intracellularisand all 11 herds with PCV2.From the analysed samples 22.2% were infected withL. intracellularisand 25% with PCV2. The results of microbiological studies suggested that the piglets suffered from enteritis and pneumonia.Escherichia coliandPasteurella multocidaoften aggravated the process of illness. The frequency ofL. intracellulariswas 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. coliwas often a co-factor withL. intracellularisand PCV2.The primary reasons of post weaning wasting were PCV2 andE. coli,later aggravated byL. intracellularisand other pathogens. Our results indicated that different pathogens have an important role in developing post-weaning wasting.Proliferative intestinal inflammation caused byL. intracellularisis 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.