Cryptokotyle lühe, 1899 (trematoda: heterophyidae): special characteristics of developmental biology and epizootiology

Abstract

This review presents the scientific studies data on the special characteristics of developmental biology and epizo- otiology of Cryptocotyle trematodes, which belong to Heterophyidae family and pose a threat to the health of the endotherms, including humans, i.e., it is a typical zoonosis. These trematodes are predominantly widespread in the Mediterranean region, namely, in the western Mediterranean region and the Aegean province. The trematodes of Cryptocotyle genus are found in Europe, Asia, North and South America, and Antarctica. They are typical bio- helminths, i.e., they have a complicated life cycle, where the initial intermediate hosts are mollusks, the second ones – fish of different species, the definitive and final hosts are piscivorous birds, carnivorous animals (foxes, wolves, dogs, cats, etc.), and humans. Cryptocotylosis is remarkable for its seasonal prevalence, which depends on the climatic zoning of territories. For instance, in the territorial waters of Ukraine, the highest indices of crypto- cotylosis invasion among Agonidae fish are mainly observed in summer and autumn, but the peak of the invasion comes in autumn. The parasitizing of Cryptocotyle trematodes in the organism of mollusks impacts the reproduc- tion ability and behavioral specificities (motility) of the latter. The invaded fish have black pigment spots on the surface of their bodies – these are metacercariae. In the organism of definitive hosts, the agent is localized in the gastrointestinal tract and may cause inflammatory processes in the mucous membrane of the intestines and changes in parenchymatous organs, which demonstrates the toxic effect of the parasite on the host organism. The diagnos- tics of cryptocotylosis is based on detecting the agent in the host organism and its further taxonomic identification by its anatomic and morphological specificities. The pollution of the aqueous medium with organic and inorganic residues impacts the organisms of both hosts and parasites.