INSERT HOST IN THE LIFE CYCLE OF ALARIA ALATA (TREMATODA, STRIGEIDIDA) IN THE NATURAL ENVIRONMENT OF THE CENTRAL BLACK-EARTH ZONE

Currently, an increase in cases of infection of wild and domestic carnivores with the trematode Alaria alata (Trematoda, Strigeidida) is currently recorded in the CentralBlack-Earth Zone. The trematode A. alata has a complex life cycle involving intermediate, insert and reservoir hosts. We obtained new data on the realization of thelife cycle of A. alata in the natural environment of the Central Black-Earth Zone. The moor frog (Rana arvalis), green toad (Bufotes viridis) and spade-footed toad (Pelobates fuscus) are recorded as insert hosts. Infection with mesocercarias A. alata of the moor frog is 20% (the prevalence) and 23 specimens (infection intensity). The moor frog is the most numerous species among amphibians and is characterized by high in-touch capabilities with carnivorous mammals. The moor frog is the main insert host in the circulation of A. alata in natural biocenoses. We have identified the localization of the Alaria mesocercarias in the moor frog, namely, the pericardium and subcutaneous tissue of the intermaxillary space. We determined the distribution of mesocercarias in moor frogs of this year's brood: 71% in the head; 25.8% in the hind legs; 22.6% in the trunk; and 3.2% in the front legs. The green toad and spade-footed toad were also classified as insert hosts of A. alata (prevalence of infection was less than 10%; and infection intensity was 4.0 specimens). Mesocercarias were found in frog larvae (24.6%; 2.6 sp.).