Canine Infectious Hepatitis is spread only among domestic dogs and
other wild canids which include wolves, coyotes, and foxes.
In fact, one of the first parts of prey that wolves and
other wild canids often eat before peripheral muscle are portions of the intestinal tract, which (since their prey are usually herbivores) tend to be full of partially digested carbohydrates.
Wolves, just like
any other wild canid — other than domestic dogs — are never dewormed, after all.
Dogs are descended from wolves, and we can look at wolves and
other wild canids to see the kind of conformation required for healthy living.