It is impossible to diagnose typhoid fever
in one day whether clinically or by investigaions. The investigations for typhoid fever are as follows:
1. Blood culture
in the first week.
2. Widal test
in the second week. We usually advise widal test after 5 days of fever.
3. Another rapid test is available in the first week but it is not very reliable.
In your daughter's case typhoid fever can be suspected and treatment started accordingly by the treating doctor.
Your daughter can have a normal but light diet.
I hope I have answered your query to your satisfaction. Please feel free in case your require any clarification.
Wishing your daughter an early recovery.