The biology of parasitic protists, the characteristic features of the invasions they cause, methods for their diagnosis, prevention and treatment are described.The systematization of helminths, general and particular characteristics of trematodosis, cestodosis, and nematodosis are given.< p>Information is presented on the most important taxa of arthropods, diseases associated with them, methods of preparing for laboratory research, counting and review.Graphs of logical structures and tables summarizing the basic information for each nosological unit are provided. p>For students of educational institutions implementing educational programs of secondary specialized education in the specialty "Medical and diagnostic business".