The new vet in Host, MO, Eli Rudkus (Vincent Venstresca) gets a call from a local cattle rancher Jacob Long (William Forsythe) about one dead cow and one that is sick. Eli takes a stool sample from the sick cow for testing. When setting up a microscope slide view one ot the parasites in the sample he breaks a beaker and cuts his finger. When he walks away to clean the wound the parasite jumps off the slide and drinks the blood., so when he returns its 5 times as big as it was.
The local economy is run by Host Tender Meats which buys cattle from the locals but requires them to use only feed provided by the company. Genetically engineered feed which has mutated common intestinal parasites into something different. Of course mayhem insues and the CEO protrayed by David Selby tries to cover it up
