Forms of bacterial hemorrhagic septicemia course in fisheries of the North Caucasus regions

Abstract

Summary. Bacterial hemorrhagic septicemia of fish is widespread in the Russian Federation, including in the regions of the North Caucasus. Clinically, the disease is manifested by the presence of separate serous-hemorrhagic sites on the skin, usually in the head and abdomen, inflammation of the fins, ulcerations (abscesses) on the skin, ascites and occasionally protrusion of the anus. The etiological structure of bacterial hemorrhagic septicemia of fish includes a wide range of pathogens belonging to both the Aeromonadaceae family and bacteria of other families: Pseudomonadaceae, Enterobacteriaceae, Streptococcaceae, Bacillaceae, Staphylococccaceae, Moraxellaceae, Flavobacteriaceae, Microavocacteriaceae, Microavocactaeceae. The main causative agents of bacterial hemorrhagic septicemia of fish are opportunistic bacteria of the genus Aeromonas. This disease can occur in three forms: acute, subacute and chronic. The form of the course of bacterial hemorrhagic septicemia of fish depends on the temperature of the water, the species of the fish, the contamination of the reservoir, the amount of oxygen, the density of fish and other factors that reduce the resistance of the fish organism. The incubation period of bacterial hemorrhagic septicemia of fish on average lasts from three to thirty days. Bacterial hemorrhagic septicemia of fish most often occurs in the form of endogenous autoinfection, which is caused by weakly virulent pathogens located in the body of fish - representatives of the normal intestinal microflora. At the acute form of the disease, the death of fish reaches 90-100%, at subacute - up to 75%. The climatic conditions of the regions of the North Caucasus - high year-round water temperature, sharp fluctuations in the temperature of water and air in the winter-spring and autumn-winter periods contribute to the spread of bacterial hemorrhagic septicemia of fish in natural waters.