Child With Chill, Fever And Headache. Loss Of Appetite. Is It Summer Disease?

my nine yr old daughter has the chills headache low fever and soar throat , my grandaughter which lives in the same house was diagnosed with summers disease, but only had a fever over night and the following night she broke out with the rash . my nine yr old has no rash but has been running a fever, soar throat and headache for a day in a half. i have been giving her plenty to drink because she lost her apetite, i was told by my granddaughters Dr that the summers disease starts off with a fever and soar throat, what shall i do besides fluid and tylenol .