Abstract
In this article, the authors conducted a study of the state of knowledge and prevalence of methorchosis in the territory of Northern Kazakhstan. The domestic and foreign literature was analyzed, where the presence of the pathogen of methorchosis in Kazakhstan was noted, but studies were not conducted at the proper level. The authors of the article conducted studies of the intermediate and final hosts of the pathogens of the family Opisthorchiidae. Molecular genetic studies have shown in one of the intermediate hosts, fish of the cyprinid family, the presence of a mixed infection with the main species Opisthorchis felineus and Metorchis bilis. The obtained nucleotide sequences were registered in the international NCBI GenBank database. In addition, the presence of a mixed infection in one of the final hosts of representatives of wild carnivores (foxes) was proved. Marita were isolated from the liver, their morphological and molecular identification was carried out, as a result of which they belong to the species O. felineus and M. bilis. In the final study, the authors conducted biochemical and molecular-genetic studies of the blood serum of patients with a diagnosis of opisthorchiasis. The study showed that the incidence rate was 6.2% and these indicators are consistent with official statistics from open sources. The study of biological material selected from patients with a confirmed ELISA diagnosis of "opisthorchiasis", also allowed to prove mixed invasion in people in the study region. Key words: PCR, methorchosis, opisthorchiasis, mixed invasion