Most of the time even doctor could not correctly identify the root problem, whether it's virus or bacteria or H1N1 or other flu. I have experienced before that I took my kid to 2 different doctors, they had different diagnosis, one suggested antibiotics, the other one not suggested it. My children had fever for 6 consecutive days, then recovered suddenly without any runny nose and cough, so strange.
Most important thing is if the child still behaves relatively normal, e.g. if he/she can eat well, sleep well, play well, react normally. Be sure to react quickly if the child suddenly become worse off.
How old is your daughter? My daughter is 5 years old and also has fever starting from 27/3, today is day 6 already. On day 4, her fever has drop down gradually, but resume rising up today, back to 39 C. So worry.