[An estimate of the potentials for eliminating aqueous biocenoses relative to free-living life forms of Opisthorchis felineus]. / Otsenka éliminatsionnykh potentsialov vodnykh biotsenozov po otnosheniiu k svobodnozhivushchim zhiznennym formam Opisthorchis felineus.

Different methods of estimating the elimination potential of invertebrate hydrobionts, members of water biocenoses, in relation to freeliving instars such as egg (miracidium) and cercarium of O. felineus are considered. Calculatons and conclusions are based on field and laboratory investigation carried out in the period 1985-1992. The elimination process in biocenoses does not practically influence on the intensivity of infection, but influences significantly on the extensivity of the infection of the molluscs Codiella with O. felineus larvae. This process is also the cause of low extensivity of infection of Codiella in natural water reservoirs (usually less than 1-2.5%) in all infection centres of exUSSR area including Western Siberia. The eggs (miracidia) of O. felineus are eliminated with different effectivity by invertebrate of nectobentos (oligichaeta, molluscs, and with less rate by arthropods). Coracidia are eliminated generally by nectoplancton crustaceans and water insect larvae. Invertebrate hydrobionts eliminate about 70% cercaria of the number of cercaria of the number coming out the infected molluscs being intermedial hosts.

[Biological shedders of Opisthorchis cercariae (experimental research)]. / Bioéliminatory tserkarii opistorkhisa (éksperimental'nye issledovaniia).

To elaborate biological controlling measures and enhance the biological shedding [correction of bioeliminating] potential of biocenosis, 12 species of hydrobionts from 7 orders were tested for eliminating activity. The larvae of dragonflies and scale insects revealed the highest activity (eliminated from 67 to 77% cercaria). It has been established that, with the test exposition time of 3 hours, maximum elimination of cercaria takes place in the first hour of the experiment.