Rotavirus gastroenteritis is an infection of the stomach and intestines and common symptoms include vomiting and diarhoea which can be quite severe.
Our son had it at 9 months old and was hospitalised with dehydration - he suffered for many weeks with it. It's really important to check your child doesn't become dehydrated. If you are concerned you must contact your GP.
I found a link that offers some advice for parents and I hope it helps:
http://www.nhs.uk/Conditions/Rotavirus-gastroenteritis/Pages/Introductio...