Pathomorphological changes of the thymus of pigs at different stages of development of clinically expressed circovirus infection type ІІ


Keywords: PCV2-infection, optical density Ig G і Ig M, viral load, thymus, immunohistochemistry

Abstract

PCV2-infection of pigs plays an important role in the infectious pathology of pigs, having a significant impact on the economy of pig farms in different countries. Pathomorphological changes in the body of pigs with PCV2-infection occur moderately and in stages, as a result of the simultaneous launch of a set of mechanisms to counter the causative agent of the disease, resulting in the formation of a whole spectrum of reactive and pathological processes. The main “target” for PCV-2 is the immune system, and the multiplication of PCV-2 in the cells of the immune system leads to their death and development of immunodeficiency state. Thymus is the central organ of lymphocytopoiesis and imunopoiesis, in it occurs differentiation of all cellular forms of mature T-lymphocytes in the pre-T-lymphocyte stage, which migrate from the bone marrow to the bloodstream. The growth and development of the thymus, as well as the bone organs, is in direct interaction with the growth and development of the spleen, lymph nodes and is reflected in the structure of the interstitial connective tissue and lymphoid parenchyma. Purpose: determination of pathomorphological changes in the thymus of pigs at different stages of the development of clinically expressed PCV2-infection. Methods. The work was carried out in pig farms of Ukraine, with intensive technology of pig rearing, at the department of normal and pathological anatomy of agricultural animals and the Scientific and Research Center for Biosafety and Environmental Control of the Agroindustrial Complex Resources of Dnipro State Agrarian and Economic University. For pathomorphological studies, animals were selected with clinical signs of active PCV2‑infection (in 1 ml of whole blood of which contained more than 107 copies of the PCV-2 virus equivalent gene) and also piglets with positive optical density of specific antibodies (Ig G and Ig M) in serum blood. Pathomorphological changes were characterized by gradual exhaustion of the lymphoid parenchyma with a sharp decrease in the area of the cortical substance of the particles. Against the background of the degradation of the lymphoid parenchyma of the organ, there is a tendency to increase the relative area of the interstitial connective tissue, as well as the absolute size and number of thymic bodies, has been established.

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References

Baimishev, H.B., Shevchenko, B.P., & Seitov, M.S. (2009). Anatomy of the organs of internal secretion and hemocytopoiesis. Samara: Book.

Gavrilin, P.N., & Evert, V.V. (2015). Koncepcija me-hanizmov povrezhdenija organov immunoj sistemy u svinej pri cirkovirusnoj infekcii (sindrom mul'tisistemnogo istowenija) [The concept of mecha-nisms of damage to organs of the immune system in pigs with circovirus infection (syndrome of multisys-tem exhaustion)], Naukovo-tekhnichnyi biuleten NDTs biobezpeky ta ekolohichnoho kontroliu resursiv APK [Science and Technology Bulletin of SRC for Biosafety and Environmental Control of Agro-industrial Complex], 3(2), 12–20 (in Russian).

Gavrilina, O.G., & Evert, V.V. (2016). Metodychni osoblyvosti zastosuvannia imunohistokhimichnoi di-ahnostyky tsyrkovirusnoi infektsii svynei [Methodical features of application of immunohistochemical diag-nostics of circovirus infection of pigs]. Problems of animal science and veterinary medicine: Veterinary sciences. Collection of scientific works of the Kharkov State Zooveterynary Academy, Kharkov, 32, 294 301 (in Ukrainian).

Goralsky, L.P., Khomich, V.T., & Kononsky, O.I. (2011). Osnovy histolohichnoi tekhniky i morfofunktsionalni metody doslidzhennia u normi ta pry patolohii [Basis of histological technology and morphofunctional methods of dosage in normology with pathology]. Zhitomir: Polissya (in Ukrainian).

Krakowka, S., Ellis, J.A., McNeilly, F., Ringler, S., Rings, D.M., & Allan, G. (2001). Activation of the immune system is the pivotal event in the production of wasting disease in pigs infected with porcine circovirus-2 (PCV-2). Veterinary Pathology, 38, 31–42. doi: 10.1354/vp.38-1-31.

Brunborg, I.M., Moldal, T.S., & Jonassen, C.M. (2004). Quantitation of porcine circovirus type 2 isolated from serum/plasma and tissue samples of healthy pigs and pigs with postweaning multisystemic wasting syndrome using a TaqMan-based real-time PCR. Journal of Virological Methods, 122(2), 171–178. doi: 10.1016/j.jviromet.2004.08.014.

Nauwynck, H.J., Sanchez, R., Meerts, P. Lefebvre, D.J., Saha, D., Huang, L., & Misinzo, G. (2012). Cell tro-pism and entry of porcine circovirus 2. Virus Re-search, 164, 43–45. doi: 10.1016/j.virusres.2011.11.003.

McIntosh, K.A., Tumber, A., Harding, J.C., Krakowka, S., Ellis, J.A., & Hill, J.E. (2009). Development and vali-dation of a SYBR green real-time PCR for the quantification of porcine circovirus type 2 in serum, buffy coat, feces, and multiple tissues. Veterinary Microbiology, 133, 23–33. doi: 10.1016/j.vetmic.2008.06.010.

Doster, A., Subramaniam, S., Yhee, J., Kwon, B., Yu, C., Kwon, S., & Osorio, F. (2010). Distribution and char-acterization of IL-10-secreting cells in lymphoid tis-sues of PCV2-infected pigs. Journal of Veterinary Science, 11, 177–183. doi: 10.4142/jvs.2010.11.3.177.

Dvorak, C.M., Puvanendiran, S., & Murtaugh, M.P. (2013). Cellular pathogenesis of porcine circovirus type 2 infection. Virus Research, 174, 60–68. doi: 10.1016/j.virusres.2013.03.001.

Lopez-Rodriguez, A., Dewulf, J., Meyns,T. Del-Pozo-Sacristan, R., Andreoni, C., Goubier, A., Chapat, L. et al. (2016). Effect of sow vaccination against porcine circovirus type 2 (PCV2) on virological profiles in herds with or without PCV2 systemic disease. The Canadian Veterinary Journal, 57, 619–628. http://hdl.handle.net/1854/LU-8047986.

Gavrilin, P.N., Gavrilina, E.G., & Evert, V.V. (2017). Histoarchitectonics of the parenchyma of lymph nodes of mammals with different structure of intranodal lymphatic channel. Ukrainian Journal of Ecology, 7(3), 96–107. doi: 10.15421/2017_54.

Chianini, F., Majо, N., Segales, J. Dominguez, J., & Do-mingo, M. (2003). Immunohistochemical characterisation of PCV2 associate lesions in lymphoid and non-lymphoid tissues of pigs 185 with natural postweaning multisystemic wasting syndrome (PMWS). Veterinary Immunology and Immunopathology, 94, 63–75. doi: 10.1016/s0165-2427(03)00079-5.

Opriessnig, T., Meng, X.J., & Halbur, P.G. (2007). Porcine circovirus type 2-associted disease: Update on current terminology, clinical manifestations, pathogenesis, diagnosis, and intervention strategies. Journal of Veterinary Diagnostic Investigation, 19(6), 591–615. doi: 10.1177/104063870701900601.

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Published
2019-04-02
How to Cite
Evert, V. (2019). Pathomorphological changes of the thymus of pigs at different stages of development of clinically expressed circovirus infection type ІІ. Scientific Messenger of LNU of Veterinary Medicine and Biotechnologies. Series: Veterinary Sciences, 21(93), 113-120. https://doi.org/10.32718/nvlvet9320