Recently, the U.S. just traded some spies with Russia. Hopefully we didn't also trade parasites. Opisthorchis felineus is a liver fluke that primarily infects cats, as its name suggests, but it is also sometimes called the "Siberian Liver Fluke" because of its prevalence in Russia. It's a typical trematode with a complicated life cycle, which in this case involves snails, then fish and then finally fish-eating mammals such as cats or, sometimes, humans. The disease in humans can cause cirrhosis and liver cancer. Over a million Russians are infected and given the amount of vodka that gets drunk in Russia, that sounds like a pretty bad combination.
Image is from this site.