Thank you for your question. I appreciate your concern, especially as your granddaughter is an infant. From the history you have provided, it seems to be a viral, most probably a rota viral infection which is common among infants. It usually settles in 5 to 7 days, although a few loose stools a day can persist till 14 days. The main advice I give my patients is to not worry about the number of loose stools, but to look at the oral intake of fluids and feeds, how much urine she is passing per day and her activity. If any of the above three is decreased dramatically, or she is passing blood in her motions, only then it should be a cause for concern.
I would suggest the following:
1. zinc supplements for 14 days as it decreases the duration of diarrhoea
2. continue
breastfeeding if baby is on breast feeds
3. if baby has been started on complementary feeds, to give fluids like tender coconut and buttermilk as they are very rich in electrolytes
4. the care takers of the baby to wash their hands well with soap and water after cleaning the baby, before feeding etc to avoid spread of infection.
Hope this answers your question. I would be happy to answer any more questions you might have. Wish her a speedy recovery.