Expansion of Cytogenetically Modified Form of Opisthorchis Felineus in the Tom River Basin

In 1993, karyotyping of Opisthorchis felineus sporocysts, isolated from aquatic mollusks Bithynia inflatа in the industrial wastewater of the Siberian Chemical Combine discovered cytogenetically modified 12-chromosome specimens. In 2012–2013, a repeated study of the spread of these mutant trematodes in the lower course of the river Tom was carried out. It was established that specimens with sporocysts of O. felineus having 2n=12 were found in 8 of 10 places of catching. The caught goldfish were used to isolate metacercariae to infest golden hamsters in the experimental conditions. After 5 months, the hamster livers were processed to extract marita specimens and the number of chromosomes in their ovaries and testes was cytogenetically determined. The results of analysis of the spread of O. felineus carried out by this method showed the presence of 12-chromosome form of the Opisthorchis marita in all places of fishing out in the lower course of the river Tom. Analysis of the 12-chromosome karyotype allows to conclude that this mutation was a result of Robertsonian fusion of chromosomes 3 and 6 of 14-chromosome form of karyotype.