Your dog can get infected with a type of parasite that could kill not only the pooch itself, but potentially you too.
The tapeworm in question is known as Echinococcus multilocularis, and requires two mammalian hosts to complete its lifestyle. The adults will latch onto the intestinal wall of their primary host, which tends to be wild canines such as coyotes and foxes, although domestic dogs and cats can also fill this role, until they are ready to release their eggs. These then pass through the canine and are excreted in their feces.
This is where the secondary host comes in, which is usually a rodent like a rat. Rodents ingest the eggs, which then typically develop into larvae in the liver, but also lungs and other organs, in multiocular cysts or tumors. It is only when a canine then consumes an infected rodent that the larvae then get back into the primary host, where they mature into adults in the intestine and start the cycle all over again.
Humans, however, can take the place of the rats and mice if they happen to ingest the eggs found in the feces of foxes or coyotes. Typically those most at risk include people working closely with these animals such as trappers, hunters, and vets, but the infection can also occur if someone eats herbs or berries gathered from the wild. Pet owners, however, need to be careful too, particularly if your dog or cat is frequently eating rodents in regions where the parasite is found.