FEATURES OF THE COURSE OF THE INFECTIOUS PROCESS AND MANIFESTATIONS OF THE PIG REPRODUCTIVE AND RESPIRATORY SYNDROME

Abstract

Porcine reproductive and respiratory syndrome (RRSS) is an extremely dangerous viral disease of pigs. The economic damage consists of losses associated with impaired reproductive function of sows, abortions, stillbirths, and the death of piglets shortly after birth (up to 80... 100%). The article uses author's photographs of pathological material obtained during extensive epizootological investigations of cases of RRCC, as well as photographs of research results obtained by other authors. The aim of the study was to analyze the results of leading scientists dealing with the problem of RRCC, the features of the course of the infectious process and the manifestation of manifestation in this pathology, and to emphasize them. It has been established that the PRRCC virus, having entered the body of pigs through the mucous membranes of the respiratory, digestive or genital tract, multiplies in macrophages. The multiplication of the virus in the components of cellular protection causes immunosuppression and temporarily reduces local resistance, thereby creating conditions for infection of animals with other pathogens. Further, viremia occurs, which lasts from 4 to 8 weeks, with damage to the endothelial cells of blood vessels and the development of vasculitis, which causes tissue edema. In addition, the causative agent of RRCC in internal organs multiplies in reticulocytes, as well as in circulating monocytes. The placenta, like alveolar macrophages, is a target organ for the RRCC virus. At the junction with the uterus, it peels off due to necrotic cell decay, as a result of which infected macrophages migrate through the placenta and the virus multiplies in fetal tissues. In respiratory syndrome, the virus first develops in alveolar macrophages, destroys some of them, disrupts the immune system of the lungs, and thereby opens the gates to the secondary microbiota. As a result of infection, the activity of the cilia of the ciliated epithelium of the respiratory tract is suppressed, which contributes to the development and accumulation of pathogens in them with tropism to the epithelium of the respiratory tract. Interstitial pneumonia is a typical sign of RRCC caused by secondary microflora.