HI
It is supposedly a 48 hour bug but it can leave you feeling very rough for a while longer and really depends upon how fit you are when you start off.
I had it when my twin sons were about 7 weeks old. It was not fun, but even with quite a heavily depressed immune system I was eating and drinking agin within about 12 hours of receiving an anti emetic from the GP although I needed the loo for quite a while longer. However I was still relatively young and fit. MY GPS concern was to ensure I could get rehyrdated as much as possible to continue breastfeeding my sons and providing antibodies to prevent such young children getting it (who do not have a lot of fluid in them). Happily they didn't!
They will keep dementia patients to their rooms if possible to try and prevent spread and some are not aware of the feeling of sickness and being sick (I have had this graphically described to me by one of the Nurses in Mum's home who has nursed when it has happened in another dementia unit)
It is very difficult to stop the spread as if someone vomits the droplets spread rapidly.
The basic care is to ensure that you do not become seriously dehyrdated as this and the imbalance in your system is what makes you feel so ill. You have to drink eventhough you do not feel like it. It is a virus so antibiotics do not help. The Gps may prescribe anti-emetics or anti diaorhea drugs but not both as the body has to have a means of fluching itself through. (Sorry if too much info)
I do hope that your Mum is feeling better soon. It is so scarey when they are ill and you are so far away.
((((hugs))))