The aim of study was to investigate porcine circovirus-2 (PCV2) impact on the morphological sight of pig lymph nodes. The research was carried out in 2010. Three Latvian farms were investigated (from Latgale and Kurzeme) and thirty 5-15 weeks old pigs with clinical signs of Postweanig Multisystemic Wasting Syndrome were selected and observed. Four lymph nodes from each animal for histological and immunohistochemical investigations were taken. Thirty structural parameters of a lymph node were detected on histological slides: visualization of follicle structure, lymphocyte depletion and amount of histiocytic cell infiltration. As a result, changes in lymph nodes with PCV2 antigen were detected in all these structural parameters: increasing amount of PCV2 antigen in pig lymph nodes, but the greatest changes were in the follicles structure in lymph node. The increased amount of PCV2 antigen in lymph node; significantly decreases the amount of lymphocytes and increases the amount of histiocytes in them. Porcine circoviruss-2 in lymph node basically distributes from the lymph node cortex into the medulla, as well the amount of PCV2 antigen in lymph node also increased.

Parafasciolopsosis is a parasitological disease which is caused by the liver fluke Parafasciolopsis fasciolaemorpha. This parasite which belongs to herbivores often causes invasion in elks (Alces alces). The aim of our study was to diagnose the parasite and investigate what kind of histopathological changes it caused in the liver tissue. The study took place in Latvia University of Life Sciences and Technologies, Faculty of Veterinary Medicine, Laboratory of Comparative Pathology and Laboratory of Parasitology. During the study from 2017 to 2018 we collected liver samples and faeces from 46 felled elks of different age and gender, from all over Latvia. Ten grams of faeces were examined for trematode eggs by sedimentation method and a section of liver was examined for the presence of flukes and the histological structure of the liver. In this study Parafasciolopsis fasciolaemorpha were found in 11 samples of liver from 46 elks, with invasion extensity of 24%. The histopathological examination of the liver samples revealed fibrosis, proliferation of bile ducts, pericholangitis, calcerous deposits in bile ducts and other notable histological changes in the liver tissue that can cause hepatic trematodes.