Sanja Aleksić-Kovačević

The role of hepatic myofibroblasts in liver cirrhosis in fallow deer (Dama dama) naturally infected with giant liver fluke (Fascioloides magna).

BackgroundThis paper describes liver cirrhosis in 35 fallow deer infected with the giant liver fluke, as well as the distribution, origin, and role of myofibroblasts in its development.ResultsIn liver of infected deer, stripes of connective tissue are wound around groups of degenerated and regenerated liver lobuli. In the connective tissue, lymphocytes and macrophages which often contain parasite hematin are also present. The walls of the bile ducts are thickened, the epithelium multiplied with mucous metaplasia, and desquamated cells, parasite eggs and brown pigment are present in their lumen.In the livers with cirrhosis, immunopositivity to α-SMA and desmin was observed in cells in portal and septal spaces, at the edge between fibrotic septa and the surrounding parenchyma and in perisinusoidal spaces. These cells vary in size, they are round, oval, spindle-shaped or irregular in shape, similar to vascular smooth muscle cells. The derangement of epithelial-mesenchymal interactions detected in chronic cholangiopathies is most probably the pro-fibrogenic mechanism in liver cirrhosis of fallow deer (Dama dama) infected with the giant liver fluke (Fascioloides magna).ConclusionMyofibroblasts, especially hepatic stellate cells (HSCs), play an important role in the synthesis of extracellular matrix components in the development of parasitic fibrosis and cirrhosis in the liver of fallow deer.

Investigation of an outbreak of mycobacteriosis in pigs

BackgroundA high proportion of pigs imported to Serbia from a Lithuanian breeding herd reacted positively against avian and/or bovine tuberculin. The pigs were euthanized and lesions characteristic for mycobacterial infection were detected. An investigation of potential mycobacteriosis in the pigs imported to Serbia and the possible source of infection in the Lithuanian herd were therefore initialised.ResultsFormalin fixed, paraffin embedded lymph nodes from tuberculin positive animals were examined by real-time PCR for IS1245 and IS6110. IS1245 was detected in 55% and IS6110 in 11% of the samples. Seven of the ten IS6110 positive samples were positive for IS1245. Eleven lymph nodes from 10 pigs and 15 environmental samples were collected from the Lithuanian breeding herd and cultured for mycobacteria. M. avium subsp. hominissuis was detected in all lymph nodes and from eight samples of peat and sawdust. Isolates with identical and related IS1245- and IS1311 RFLP profiles were detected from swine and peat.ConclusionsThis study demonstrated cross reactions between avian and bovine tuberculin in pigs. Real-time PCR indicated infection with M. avium in the Serbian pigs. However, as a small proportion of the lymph nodes were positive for IS6110, infection with bacteria in the M. tuberculosis complex could not be ruled out. Analyses confirmed the presence of M. avium subsp. hominissuis in porcine and environmental samples from the Lithuanian breeding herd. The results indicate peat as a source of M. avium subsp. hominissuis infection in these pigs, and that the pigs imported to Serbia were infected with M. avium subsp. hominissuis.

Cellular basis of chronic obstructive pulmonary disease in horses.

Chronic obstructive pulmonary disease (COPD) is an inflammatory obstructive disease of the airways characterized with hypersensitivity of the airway tissues to various allergens, most commonly the fungi contained in the poor-quality hay and straw bedding-Saccharopolyspora rectivirgula, Aspergillus fumigatus, and Thermoactinomyces vulgaris. It is manifested clinically in middle-aged horses with recurrent episodes of dyspnea, chronic cough, and their reduced athletic and working capacity. Pulmonary emphysema and lack of pulmonary collapse are the most common gross lesion. Pathohistological findings in horses with COPD are chronic bronchitis/bronchiolitis, with characteristic changes in lumen, mucosa, submucosa, and smooth muscle layer and alveolar emphysema, both distensive and destructive form. Increased immunoreactivity in lungs and tracheobronchial lymph nodes is also noted. Most common lesions seen on cytology imprint smears from tracheal bifurcation is thick, viscous, PAS-positive mucus that forms Curschmanns spirals. Dominant cell population consists of desquamated airway epithelial cells, as well as eosinophils, neutrophils, mast cells, erythrocytes, and alveolar macrophages. Primary pulmonary pathogens as well as potential contaminants and secondary infection agents were isolated bacteriologically from lung samples. All of the aforementioned findings correlate pointing to the fact that chronic bronchitis/bronchiolitis represents a basic substrate of COPD, which have combined inflammatory and immunological etiology, and emphysema is secondary to airway obstruction.

Role of hepatic stellate cells (HSCs) in the development of hepatic fibrosis in cats with polycystic kidney disease (PKD).

Hepatic stellate cells (HSCs) play a significant role in hepatic fibrogenesis. In the following study we described the distribution of cells that express alpha-smooth muscle actin (α-SMA) and desmin in the cat liver with various degrees of fibrosis, as well as the significance of hepatic stellate cells and portal myofibroblasts in the genesis of fibrosis in cats with polycistic kidney disease. Liver samples from 15 necropsied Persian cats were examined microscopically, using H&E and Masson-trichrom methods and immunohistology for α-SMA and desmin. Liver fibrosis was confirmed in cats with terminal stage of chronic cholangiohepatitis and it was characterized by connective tissue septa which divide the liver parenchyma into irregular lobuli. Inflammation in the cat liver is connected with the activation of periductal myofibroblasts. The intensity of immunopositivity of perisinusoidal HSCs to α-SMA and desmin varied depending on the degree of fibrosis and was the strongest in livers of cats with cirrhosis.

Skin and skeletal system lesions of european pond turtles (Emys orbicularis) from natural habitats

Water pollution is known to play an important role in the pathogenesis of plastron, carapace and skin diseases of turtles. In this study, a total of 150 European pond turtles (Emys orbicularis) of different age and both sexes, originating from natural habitats in Serbia, were examined for morphological changes of the skin, plastron, carapace and skeletal system. The turtles were taken out from their natural habitats in Lake Ludas, Lake Palic and Lake Tresetiste. After artificial hibernation, they were subjected to detailed examination, sampled and treated, and finally returned into their natural habitat. Biopsies from the skin and shell were subjected to histopathological examination and microbiological analysis. X-ray scanning was also performed to detect changes in the skeletal system. Macroscopic changes of the skin, most frequently degenerative, inflammatory or neoplastic diseases, were diagnosed in 49.33% of the turtles examined. Dermatitis of different origin and form was the most prominent histopathological finding (28.00%). In the plastron, inflammatory and degenerative processes were frequently found. Osteopathy and mechanical injuries were the dominant findings. Macroscopic changes of the plastron, carapace and skeletal system were diagnosed in 67.33% of the turtles examined. Using X-ray scanning, generalised osteopathy, anomalies and malformations of different aetiology were also diagnosed on the tail and legs. Microbiological examinations showed the presence of a variety of bacterial and fungal agents, either primary pathogens or potential polluters, which invaded the skin and shell, or were present in cloacal swab samples. Bacterial infection was diagnosed in 76.66% of the turtles, first of all in those with skin and shell necrosis. Mycoses were diagnosed in 33.33% of the animals.

DISTRIBUTION OF PORCINE CIRCOVIRUS 2 CAP ANTIGEN IN THE LYMPHOID TISSUE OF PIGS AFFECTED BY POSTWEANING MULTISYSTEMIC WASTING SYNDROME

The lymphatic organs of 50 pigs from a total of eight farms located at different sites in the epizootiological region of North Bačka County were studied to obtain data on the prevalence of circoviral infections in Serbia. All of the pigs examined had clinical signs suggestive of postweaning multisystemic wasting syndrome (PMWS). All pigs underwent necropsy and tissue samples were taken for histopathological, immunohistochemical (IHC) and PCR analysis. The presence of porcine circovirus 2 (PCV2) was established by PCR analysis in the organs of the pigs tested. The most frequent histopathological lesions of lymphoid tissue linked with the presence of positive immunostaining for PCV2 Cap antigen confirmed the existence of PMWS in all farms tested in North Bačka County. Using PCR, histopathological and IHC techniques, the presence of PMWS was proved in the Republic of Serbia. During necropsy, generalised enlargement of the lymph nodes was evident. The most common histopathological finding was lymphocyte depletion in the follicular and perifollicular areas of lymph nodes. Infiltration by macrophages was also recorded. By IHC analysis, the cytoplasm of macrophages was shown to contain a large amount of the ORF2-coded Cap antigen of PCV2. Lymphocyte depletion and large numbers of macrophages were recorded in the tonsils, spleen, intestinal lymphatic tissue, Peyers patches and ileocaecal valve. The presence of typical granulomatous lesions with multinuclear giant cells (MGCs) was also recorded in the lymphatic tissue. Cap antigen was shown to be present in macrophages and less often in lymphocytes.

Expression of α-SMA, desmin and vimentin in canine liver with fibrosis

In this work, 36 canine livers with fibrosis were examined. Based on the degree of fibrosis, the livers were classified into three groups: 1- mild portal fibrosis; 2- moderate portal fibrosis with mild periportal and septal fibrosis; 3- severe portal fibrosis with marked periportal and septal fibrosis or cirrhosis. Normal liver sections obtained from five dogs with no evidence of infectious, neoplastic, or cardiovascular diseases were used as controls. The degree of fibrosis was evaluated on liver sections stained according to Massons trichrome method. It was proved using an immunohistochemical method that HSC and periductal myofibroblasts are immunoreactive to desmin, vimentin and α-SMA. Desmin, vimentin and α-SMA positive cells in the portal triad were significantly more numerous in dogs with fibrosis of the third degree than in the controls or all other examined livers. The density of α- SMA, vimentin and desmin-positive cells in the portal triad was in correlation with the degree of fibrosis, which cannot be said for HSC. These results suggest that portal myofibroblasts have a significant role in the process of liver fibrosis in dogs.

Retrospective study of canine epithelial and melanocytic tumors

Out of the total number of canine tumors examined at the Department of pathology based on biopsy and section materials over the last five years skin tumors and mammary gland tumors were proved to be the two largest groups diagnosed in 33.4% and 36% of cases, respectively. Cutaneous tumors were diagnosed in 211 cases, i.e., in 123 (58.3%) male dogs and 88 (41.7%) bitches, of different breeds, on average 7 years old. Among the total number of 211 skin tumors, 32 types of cutaneous neoplasms were diagnosed, with epithelial and melanocytic tumors being the most predominant, followed by hematopoietic tumors and mesenchymal tumors of the skin and soft tissues. In our bioptic and section materials, epithelial and melanocytic skin tumors were the most frequent -123 cases (58.75%) with four subgroups within the group tumors with adnexal differentiation - 66 cases (53.23% of all epithelial and melanocytic skin tumors), epidermal tumors - 25 cases (20.16% of all epithelial and melanocytic skin tumors), tumors without squamous or adnexal differentiation -16 cases (12.90% of all epithelial and melanocytic skin tumors) and finally melanocytic tumors -14 cases (11.29% of all epithelial and melanocytic skin tumors). The age of dogs with epithelial and melanocytic cutaneous tumors ranged between 5 months to 15 years. The fact that the number of skin tumors diagnosed in 1999 was doubled in 2002 is of particular importance, which may be, the result of increasingly high interest of clinicians for biopsy-based diagnosis.

MORPHOLOGICAL AND IMMUNOHISTOCHEMICAL EXAMINATION OF TUMOR CELLS IN MAREK'S DISEASE

In this paper are described the macroscopic, microscopic and immunophenotypic characteristics of tumors in Marek’s disease (MD). Liver, kidneys, lungs, heart, proventriclus, ovary and nerves of sciatic plexus collected from 20 chickens aged 8 to 24 weeks were examined. Lymphoproliferative enlargement in various organs of focal and diffuse character was found. The affected organs were enlarged, compact and very brittle, irregular in shape, grayish-red or grayish-white and of fatty consistency. Most often characteristic changes were in the spleen, liver, proventriculus and ovary that usually had a compact or ribbed, fatty cauliflower like formation, different in size. On histological examination proliferation of small and medium size lymphocytes, lymphoblast cells, Marek’s disease cells and activated reticulum cells were found. Tumor proliferates predominantly consisted of lymphoblasts and had all the characteristics of a lymphoma. Immunohistochemical analysis revealed that lymphoma cells in MD are of CD3 + phenotype. In liver proliferates numerous CD79+ cells were found perivasculary, which is an interesting finding demanding further research. .

Mycobacteriosis in Pigs – An Underrated Threat

Abstract Although Mycobacterium avium subspecies are generally not considered food pathogens, the infections caused by these particular nontuberculous mycobacteria (NTM) can represent a serious threat to immunocompromised population. Additionally, infections with a member of Mycobacterium Avium Compex (MAC) can affect the efficiency of BCG vaccines used for the humans. In infected animals, M. avium may be present in different tissues without apparent clinical symptoms and macroscopic lesions. Veterinary meat inspection would then fail to recognize infected animals and such meat and meat products thereof could enter the human diet. The aim of this paper is also to analyze the current control policy in Europe according to infections of pigs with the members of MAC, and point out the risks for public health. By analyzing a large number of meat samples and other dietary nutrients, different groups of authors have provided evidence to support the hypothesis that M. avium is present in the everyday environment. Therefore, food as a source of infection with mycobacteria should not be ignored. The control of mycobacteria requires a better diagnostic approach, having in mind recent positive cases of M. avium subspecies hominissuis (MAH) in an increasing number of exported pigs from EU countries to Serbia. The introduction of reliable diagnostic methods for MAH could result in decreasing the occurrence of infection in pigs, as well as in humans, having in mind that WHO reported 10 million new cases of tuberculosis-mycobacteriosis in the human population in 2015 with 21% of these cases occurring in immunocompromised individuals and children.