Investigations of influence of colostral antibodies on development of pathomorphological changes following experimental infection of piglets with classical swine plague virus

Abstract

The pathomorphological changes established following infection with the virus of classical swine plague in non-immune individuals are well known. However, piglets present a problem from the clinical-pathological aspect, in which this virus can be multiplied in spite of established colostral antibodies, but without the exhibiting of the clinical symptoms characteristic for the disease. The question of the characteristics of the pathomorphological finding is raised in the event of the breakdown of the colostral immunity of the piglets. With the objective of determining the influence of colostral antibodies on the development of pathomorphological changes in classical swine plague, piglets aged 28, 35, 44, and 54 days, originating from sows that had received a vaccine of the K-strain of the classical swine plague virus, were experimentally infected with a virulent variety of this virus (Becker strain). The control group comprised non-vaccinated animals originating from non-vaccinated sows. Following the death and/or sacrificing of the piglets in the experiment, a pathomorphological examination was performed of all organic systems and the presence of classical swine plague virus antigens was established in organs and tissues of piglets using the immunoenzyme (ELISA) test. Even though clinical signs characteristic for this disease were not found in all animals following artificial infection, the pathomorphological findings following death and/or sacrificing indicated a successful experimental infection and was typical for the acute course of classical swine plague. Bleeding was established in most organs and serous membranes (haemorrhagic diathesis). However, certain variations were also established regarding the expression and distribution of the pathomorphological changes in certain animals.

Patomorfološke promene koje se ustanovljavaju posle infekcije izazvane virusom klasične kuge svinja (KKS) kod neimunih jedinki su dobro poznate. Međutim, sa kliničko-patološkog aspekta problem predstavljaju prasad, kod kojih se i pored ustanovljenih kolostralnih antitela virus klasične kuge svinja može da umnožava, ali bez ispoljavanja kliničkih simptoma karakterističnih za KKS. Postavlja se pitanje karakteristika patomorfološkog nalaza u slučaju probijanja kolostralnog imuniteta prasadi. Radi ustanovljavanja uticaja kolostralnih antitela na razvoj patomorfoloških promena kod KKS, izvedena je eksperimentalna infekcija virulentnim virusom KKS (soj Beker) prasadi u uzrastu 28, 35, 44. i 54. dana koja potiču od krmača vakcinisanih K-sojem virusa KKS. Kontrolna grupa je obuhvatala nevakcinisane jedinke, koje potiču od nevakcinisanih krmača. Posle uginuća i/ili žrtvovanja prasadi u ogledu, obavljen je patomorfološki pregled svih organskih sistema i prisustvo antigena virusa KKS je utvrđivano u organima i tkivima prasadi imunoenzimskim (ELISA) testom. Iako nakon veštačke infekcije kod svih jedinki nisu ustanovljeni klinički znaci karakteristični za klasičnu kugu svinja, patomorfološki nalaz posle uginuća i/ili žrtvovanja je ukazao na uspešnu eksperimentalnu infekciju i bio je tipičan za akutni tok KKS. Ustanovljena su krvarenja u većini organa i seroznih membrana (he- moragična dijateza). Međutim, utvrđene su i izvesne varijacije u pogledu izraženosti i distribucije patomorfoloških promena kod pojednih jedinki.