A new look at the etiological structure of pig streptococcosis

Abstract

Streptococcosis of pigs is an urgent problem for the pig industry in Russia, manifested in various forms of pathology, causing significant economic damage to enterprises and to the country as a whole. Due to the high tropism of bacteria of the genus Streptococcus, infection can occur in various clinical forms, which is also caused by the initial localization of pathogens such as in the tonsils and nasal cavity of animals, including normal microflora, in the genitourinary system and in the digestive tract. Along with epizootic significance, pathogenic streptococci have epidemiological significance, since pathogenicity extends not only to animals, but also to humans. Within the framework of state epizootic monitoring in Russia the Streptococcus infection is not considered as controlled one, which is why it is difficult to analyze the current prevalence of streptococci, the modern etiological structure of the causative agents of the disease and the features of its epizootic process. So, for a long time, it was believed that pig streptococcosis is caused solely by the species Streptococcus suis, but this conclusion is outdated in reality and needs to be reviewed. In particular, as a result of the work carried out, at least 22 species of bacteria of the genus Streptococcus circulate in pig breeding complexes in Russia, of which Streptococcus dysgalactiae (two subspecies), Streptococcus porcinus, Streptococcus suis, Streptococcus pyogenes, Streptococcus are most often identified alactolyticus, Streptococcus entericus, etc. These isolates were isolated from animals exhibiting any clinical manifestations or pathological changes (posthumous) characteristic of streptococcal infections. When determining the pathogenic properties of the isolated streptococcal isolates, it was determined that most cultures of Streptococcus dysgalactiae, Streptococcus porcinus, Streptococcus suis, Streptococcus pyogenes cause the death of laboratory animals (white mice with the intraperitoneal method of infection), which indicates the ability of these species to provoke pathogen diseases. Thus, the results suggest that the species Streptococcus suis should not be considered the only etiologically significant causative agent of streptococcosis in pigs, and the system of treatment and preventive measures at disease-favorable enterprises should be adjusted, taking into account the actualized this work information.