THE SURVIVAL OF MUSCULAIRE TRICHINELLA NATIVA IN SEA WATER

Seacoasts, especially the tidewide zone, are the place of concentration for many species of animals and birds that migrate here in order to find food, which is presented in the form of sea ejections of the marine mammals’ corpses or fallen terrestrial animals here. Taking into account the environmental significance of the transmission mechanisms of Trichinella through necrophagy, it is important to know how long Trichinella larvae are able to be viable in the corpses of dead animals in the tidewide zones, i.e. in zones that are exposed to sea water. The purpose of this study was to determine the time period of preserving the viability of musculaire Trichinella when they were in sea water. The experiment was performed on a model – a guinea pig carcass, which was kept in different environment at different temperature conditions. It was found out that Trichinella larvae in the muscles of guinea pigs remained viable in sea water (experimental group) during 73 days at room temperature. In fresh water (control group) they remained viable during 23 days. Under the conditions of a domestic refrigerator, Trichinella larvae remained viable during 113 days in the experimental group, while in the control group they lived no more than 33 days from the moment of setting the experiment. The results of the bioassay tests performed on Syrian hamsters turned out to be positive in all the cases; all the animals were infected with different infection intensity

HELMINTHS OF WOLF IN THE VORONEZH RESERVE AND ADJACENT TERRITORIES

The wolf is the largest predatory mammal in the Central Black Soil region of Russia. The close trophic relationships of the wolf with wild ungulates and other animals play an important role in the formation of the modern predator helminth fauna. Helminthological materials from the wolf have been collected in the Voronezh Reserve and in adjacent natural areas for a long-term period (1981–2018). The modern fauna of the helminths of the wolf of the Voronezh Reserve contains 16 species. The main taxonomic groups of helminths (trematodes, cestodes, and nematodes) in the wolf are represented unevenly. The maximum number of helminth species is registered among nematodes – 12 species (Aonchothe caputorii, Eucoleus aerophilus, E. boehmi, Pearsonema plica, Calodium hepaticum, Trichinella nativa, Toxocara canis, Toxaskaris leonina, Uncinaria stenocephala, Crenosoma vulpis, Molineus patens, Dirofilaria repens). We have identified three species of cestodes (Dypilidium caninum, Taenia hydatigena, T. krabbei) and one species of trematodes (Alaria alata). The highest infection rates were registered for A. alata: the extensiveness of invasion (EI) is 92.3%, the intensity of invasion is 149.7 specimens, an abundance index is 138.2 specimens. High rates of wolf invasion by certain nematode species were revealed: E. boehmi (69.2%); P. plica (46.2%); E. aerophilus (38.5%); C. hepaticum (15.4%) and nematode T. nativa (27.9%). More than ten species of helminths of the wolf are of significant epidemiological and epizootological importance for this area.

PECULIARITIES OF THE NATURAL ORIGIN OF TRICHINELLOSIS IN THE CHUKOT PENINSULA TERRITORY

Trichinellosis is a natural focal nontransmissive zoonotic disease, the causative agent of which is the nematode Trichinella nativa (T2). The collection of biological material was carried out on the territory of the coastal settlements of the Chukot Peninsula. The objects of the presented work were the representatives of the order carnivore (Carnivora) of the following families: canids (Canidae), feline (Felidae), bears (Ursidae), walrus (Odobenidae), seal (Phocidae) and the whale (Сetacea). Larvae detection from the muscle tissue of animals was carried out by standard methods. Infection rates were determined by the extensiveness (EI) and intensity of invasion (II).During the evolution Trichinella have acquired a wide range of hosts with similar trophic relations, and therefore they ensure the long-term functioning of the natural focus. The organism of the animals, which are host species, plays the role of reservoir (the reservation phase). There were the following components of the guest component among the studied host species: 5 species of terrestrials, and 4 species of marine mammals. The animals’ contamination ranged from 60.0% to 100% in terrestrials, and it ranged from 0.9% to 4.3% in marine animals. Successful circulation of Trichinella nativa (dispersion phase, distribution) under the extreme conditions of Arctic region became possible due to several reasons. They are: getting tolerated to low temperatures in the process of evolution, the process of decay and a number of other adaptive properties that allow them to maintain viability and invasive properties in the corpses of terrestrial carnivores and marine mammals during the long winter. The natural focus of trichinellosis on the territory of the Chukot Peninsula is unique and multifaceted in nature, and it is of interest for researchers to learn environmental and general biological laws, taking into account the traditional economic activities of the indigenous population.

EFFECT OF POSITIVE TEMPERATURES ON THE GLYCOGEN CONTENT IN TRICHINELLA LARVAE

In the present study, the effect of positive temperatures on the content of glycogen, the main reserve polysaccharide of trichinella, which plays an important role in their metabolism, was studied. The concentration of glycogen, determined by the modi-fied method of E.O. Danchenko and A.A. Chirkina (2010), was 0.007 μg per 1 T. nativa larva on the third day of the experiment, which corresponded to the time period for their viability to zero.Trichinosis is a helminthic disease of humans and animals that belongs to the group of dangerous helminth toxic diseases. Due to the fact that trichinella mainly exhibit anoxybiotic metabolism, their main storage substance is glycogen, which they ac-cumulate in significant quantities at the muscular stage of development [3]. Consid-ering the fact that under the influence of positive temperatures, the newly isolated Trichinella larvae exhibit mobility, the mobilization of energy resources, primarily glycogen, to ensure the basal metabolism and motor activity continues until the en-ergy sources are reduced to a critical level. In this study, we established the concen-tration of glycogen in Trichinella nativa larvae in conjunction with the viability index under the influence of elevated temperatures, affecting the intensity of metabolism.

The epidemiology of trichinellosis in the Arctic territories of a Far Eastern District of the Russian Federation

Trichinellosis, a zoonotic disease caused by nematodes of the genus Trichinella, is still a public health concern in the Arctic. The aims of this study were to investigate the seroprevalence of anti-Trichinella IgG in aboriginal peoples of two settlements in the Chukotka Autonomous Okrug (Russian Federation) on the Arctic coast of the Bering Sea, and to evaluate the survival of Trichinella nativa larvae in local fermented and frozen meat products. A seroprevalence of 24.3% was detected in 259 people tested by an enzyme-linked immunosorbent assay (ELISA). The highest prevalence was detected among people who consumed traditional local foods made from the meat of marine mammals. Trichinella nativa larvae were found to survive for up to 24 months in a fermented and frozen marine mammal meat product called kopalkhen. Since the T. nativa life cycle can be completed in the absence of humans, it can be expected to persist in the environment and therefore remain a cause of morbidity in the human populations living in Arctic regions.

A survey of helminths of polar bears in the Russian Arctic

The polar bear Ursus maritimus is a circumpolar species classified as vulnerable and included in the IUCN Red List. It is considered to be practically free of helminth parasites with the only species reported being Trichinella spiralis s. l. Samples of feces were collected on Chukotka coast, Wrangel Island and on ice floes in the Kara, Laptev and Chukchi seas in 2013-2015 in different seasons of the year. Coprological diagnostics was carried out using the standard flotation and sedimentation methods. In the samples collected in the snow-free period, a single sample (3.7%) was found to contain eggs of the nematode Toxascaris sp. In three out of 9 samples collected in the winter, eggs of a cestode Diphyllobothrium sp., of unidentified trematodes (presumably Heterophyidae) and of the strongylid nematode Uncinaria stenocephala were found as well as the first stage nematode larvae tentatively identified as Crenosoma sp. Viable Trichinella nativa larvae were recovered from the muscles of a female animal from north of Yakutia.