Groundhogs don't usually get sick. They will not get rabies that often and only disease they are prone to contract once in a while is roundworm, because they might eat something with roundworm larvae (which will then develop in their body). However, there is not much reason to concern that groundhog with roundworm will infect your pet, other animal in your household or even member of your family, because roundworm transfers through infected meat (and your pets will most likely not eat groundhog, right?!).
Although groundhogs are diurnal animals, i.e. animals active during the day, they try to stay away from people and their pets and will try to avoid any contact unless they feel threatened-which is the only reason why groundhog might attack your pet or you.
If you have a dog and your dog barks at groundhog, groundhog will most likely try to run away-especially if your dog is a big one. In a case when you have a cat, conflict is probably non-existent, because these two species don't have any interest one for other.
Groundhog might try to respond to attack only if being attacked by a small dog (but hopefully, your small dog will know better then to attack larger animal).
Groundhogs are usually no threat to your pets, but more often they are pray to larger wild animals, such as coyote or a bobcat, who often pray on young groundhogs for food. This is the reason why you can most likely be sure that there are no larger predators around, if you happen to see a groundhog in your yard or a garden-this means that groundhog feels safe enough to be there in a search for food.
Groundhogs don't get sick that often, as we have already mentioned, but mortality rate is quite high, particularly during first 12 months of life. Cold winters and natural predators kill young groundhogs, so not that many of them live to see their second year of life. During these first months, they might catch pneumonia during cold winter months, or they will starve simply because they didn't create fat layer thick enough to keep them alive till spring.
We are the Pest Education Network, a non-profit organization that focuses on wildlife and pest removal education. Our approach utilizes Integrated Pest Management, a strategy advocating prevention and humane methods.