Invasion of brown bear (Ursus arctos) trichinosis in the Amur region and morphological parameters of capsules of trichinella larvae

Trichinellosis is a parasitic disease caused by the introduction of Trichinella larvae into the body. Humans become infected by eating animal meat infected with Trichinella larvae. For the population of the Far Eastern Federal District, one of the main sources of invasion is the brown bear. The aim of the study was to determine the extensiveness and intensity of invasion (EI, II), as well as to study the morphological parameters of the capsules of brown bear Trichinella larvae (Ursus arctos) in the Amur Region. An analysis of official statistics from the Veterinary Department of the Amur Region and the State Budgetary Institution JSC Amur Regional Veterinary Laboratory for the period 2019-2023 showed that wild animals infected with trichinellosis were brown bear, wild boar and badger. The FSBSI FEzRVI conducted its own studies to study the infection of brown bears with Trichinella larvae. The EI, II, and capsule shape index of Trichinella larvae were determined. Morphological measurements of Trichinella larval capsules were performed using an ocular micrometer, measured in micrometers. Using compressor microscopy and digestion in IZHS, infection of a brown bear in the Amur Region was revealed with the EI of 12.5% and II of 84.7 lic/g, with p<0.05. The morphological indices of the capsules and larvae are as follows: capsule length 425.7±7.49 μm, width 388.4±3.81 μm, lateral capsule thickness 39.2±1.69 μm, poles 44.8±2.68 μm, Trichinella larval thickness 40.5±1.45 μm, with each index being reliable at p<0.05. The capsule shape index of Trichinella larvae was 0.91 µm (round shape). The EI and II indices of the brown bear indicate a focus of natural trichinellosis in the Amur Region. The morphological values of the capsule shape of Trichinella larvae in the brown bear of the Amur Region can be used to study the period of infection of animals.

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