PLEROCERCOIDS OF CESTODES OF THE DIPHYLLOBOTHRIUM GENUS OF SALMONIDS FROM THE LOWER AND MIDDLE OB

Abstract

Since 2009, the Tyumen branch of the FGBNU “VNIRO” (“Gosrybtsentr”) has been carrying out the program “Monitoring of infection of commercial fish of the Ob-Irtysh basin with helminths dangerous to human health and carnivorous animals”. As part of the implementation of this program, in 2016–2018, a study of salmon-shaped (whitefish and pike) was conducted for the presence of plerocercoids of the genus Diphyllobothrium, which are characteristic of fish in the Ob-Irtysh basin. Freshly caught fish was taken for the study, which ensured the presence of live larvae and the differentiation of the desired plerocercoids. In this case, the method of parallel cuts of the muscles, a visual examination of the body cavity, organs located in it, and microscopy of compressed fat from the intestine was used. Two types of plerocercoids difillobotriid were found in whitefish (D. dendriticum and D. ditremum). The main carrier of these larvae is peled, other species of whitefish, although they become infected, but are secondary intermediate hosts. Comparing the infection of peled with plerocercoids, diphyllobothriide, firstly, it is necessary to point out the simultaneous parasitization of capsulated D. dendriticum and D. ditremum on the intestine (esophagus and stomach). Secondly, the prevalence of D. ditremum over D. dendriticum in terms of the extensiveness of infection. The third type difillobotriid D. latum (wide tapeworm) parasitizes only predatory fish, including pike.