My daughter is 3months old her only syptoms have been fever of 104 and being whiny with wbc of 19000 what could it be ?

Bacterial infection : The findings you have described are suggestive of a bacterial process. Prompt evaluation by your pediatrician would be wise. Best wishes!

Bacterial infection: With such a high fever and high white blood cell count, it is likely there is a bacterial infection that requires treatment, POssibilities include ear infections, pneumonia, urinary tract infections. If you require more detailed information, feel free to request virtual consult.

Infection: That is a high fever and WBC. It warrants finding a cause. It may be a UTI/pyelonephritis or a hidden pneumonia to name a couple. If she is otherwise perfectly fine watch her closely. If she is fussy and not feeding well, further workup is indicated. All the best and I hope she feels better. Also watch for any kind of a rash. See your doctor or ER if worried.