Since you've already taken her to the vet and know she has a virus, you must have some medication for her. How are you getting her to take it?

A dog can go for a few days without eating, but they need water. How is she doing with drinking?

How does she act? Tired? Depressed? Playful? Friendly? Scared? Stressed?

If she is OK otherwise, put her food down at the same time every day and pick it up after about a half hour. No treats in between. Dogs won't starve themselves to death in a few days. Maybe sprinkle a very little garlic powder on the food to encourage her. Canned food can cause diarhera. If that doesn't work, call your vet.