Sick dogs are extremely frustrating. BTW, some viruses and diseases can be zoonotic and can infect different species animals and humans. I had no idea if Norovirus did or didn't, but it appears that Norovirus isn't a singe virus but a group, some types can affect animals and humans. Apparently there have been reports of animals being infected with Human Norovirus. I check all the info on Nexgard Without Vet Prescription