Opisthorchiasis in Western Siberia: Epidemiology and distribution in human, fish, snail, and animal populations.

Opisthorchiasis is a widespread helminth infection in Russia. The largest opisthorchiasis endemic focus in the world is the Ob river watershed in Western Siberia. The main causative agent of this condition is the liver fluke, Opisthorchis felineus.

Isotopic evidence for the spatial heterogeneity of the planktonic food webs in the transition zone between river and lake ecosystems.

Resources and organisms in food webs are distributed patchily. The spatial structure of food webs is important and critical to understanding their overall structure. However, there is little available information about the small-scale spatial structure of food webs.

Parasite-induced changes in nitrogen isotope signatures of host tissues.

To estimate isotopic changes caused by trematode parasites within a host, we investigated changes in the carbon and nitrogen isotope ratios of the freshwater snail Lymnaea stagnalis infected by trematode larvae. We measured carbon and nitrogen stable isotopes within the foot, gonad, and hepatopancreas of both infected and uninfected snails. There was no significant difference in the delta13C and delta15N values of foot and gonad between infected and uninfected snails; thus, trematode parasite infections may not cause changes in snail diets.