@stoneMason-- I'm not sure. I believe both viral and bacterial infections can affect the gastrointestinal system. Unless you get a test to find out the pathogen causing the infection, it could be difficult to know. The symptoms for both are fairly similar. If the doctors say that it's a viral infection, then yes, the fever is a viral fever.
But even when there is a viral fever, the treatment is basically rest and lots of fluids. If there is vomiting or diarrhea, then they may give medication to stop those, a serum for dehydration and something to reduce the fever if it continues. So in terms of treatment, it doesn't really matter if the fever is viral or bacterial. The only concern is if you ate a restaurant chain or something, then there might be a significant food contamination in that area.